Metal Casting Made Easy

Đồ án môn công nghệ chế tạo máy

Metal casting made easy

A complete guide for the hobby

metal caster

Learn the techniques for green sand casting

How to select scrap aluminium & bronze, How to melt metal in your hobby foundry

Section two of this hobby foundry ebook will show you all the details

and complete specifications to build a “Gas Fired Crucible Furnace”

The last section will show how to build the best

labour saving device any, hobby foundry

worker could wish for…

“The Motorised Gyratory Riddle” will deliver

silky smooth freshly conditioned sand every

time

Eliminate “manual sieving” of your sand

forever!

This hobby foundry ebook has been written and compiled by

Col Croucher Australia

Copyright: Aug 2002

You are licensed to print one edition of this ebook

Please respect my intellectual rights

You are licensed to print one edition of this ebook 1

Introduction to the backyard foundry 4

The subjects covered in this ebook: 4

Castings from metal 5

About the author 6

DISCLAIMER 7

Operating and reading this ebook 8

Moulding and foundry work 9

Sand Mould Schematic Diagram 9

Foundry equipment & tools 10

Foundry tools 1a 11

Foundry tools 1b 12

Foundry tools 1c 13

Foundry tools 1d 14

Making foundry patterns 15

Pattern making materials 16

Pattern draft 17

Core prints 18

Pattern basics 19

Silicon R.T.V & Reproduction patterns 20

Casting shake out time 21

Gates & Runners 22

Reconditioning foundry sand 23

WARNING ABOUT WET SAND 23

Eleven steps for sand moulding 24

Step two: Setting the pattern on the mould board 25

Green sand & baked sand cores 29

Using sand & steel cores 30

Building your gas-fired furnace 32

Furnace lid lift arrangement 33

Scrap metal: what to melt 34

Melting scrap bronze metal 35

Furnace ignition: Lighting up for the first time 36

Follow These Steps: 36

Common Sand Casting Faults 37

Glossary: Common foundry terms. 38

Judging temperatures by eye 39

The Home Metal Foundry 40

Home foundry projects 41

Project 01:Door hinges 41

Project 02: Clutch slave cylinder 43

Project 03: Timing chest back-plate 44

Project 04: M.G T Type Aero Screen Base 45

Green sand recipes 46

Temperature Control Methods 47

The Pine Stick Temperature Method 47

Simplicity! 48

Part 02 49

Building a propane gas fired furnace 50

Introduction 50

The furnace building materials 51

Notes Cont’d 52

Sheet metal former 52

Authors disclaimer 53

Constructing the furnace 54

Construction notes 55

The outer rolled steel reinforcing bands 55

Determining the furnace dimensions 56

Furnace illustrations 57

Furnace illustrations contd 58

Furnace Floor Levelling Adjuster 59

Construction details of furnace frame 59

The Upper Support Column 61

Furnace Lid Clamp Band 62

Furnace lid lifting & swivel mechanism 63

Furnace building specification sheet 65

Building spec sheet cont’d 66

Designing and building the furnace burner 67

The furnace burner illustration 68

The burner pipe venturi section 69

Burner nozzle 70

Machining the gas Jet 70

Assembled gas jet 72

The outer burner pipe 72

Air blast control 72

Controlling the air blast 73

How to cure flame blowouts 73

Controlling the total gas flow 74

The refractory material 75

Filling the furnace walls 76

Old time refractory mix for crucible or cupola furnace 77

The following steps are by volume & not weight! 77

Running in your new furnace 78

Follow These Steps: 78

Different views of furnace 79

Furnace Views Cont’d 79

Crucible specifications 80

Part 03 82

The Motorised Gyratory Riddle. 83

Introduction 83

Disclaimer 84

Safety Hints 84

Riddle construction outline 85

Flexible Drive coupling 87

Rotating Disc Shaker Assembly. 88

Images for construction reference 89

Self-Aligning Bearing Layout 90

Sieve Cradle Clamp Assembly Details 91

Building methods: Gyratory Sand Riddle 93

Building sequence 93

Building the riddle: 94

Fabrication tips 95

Machining parts 96

Welding 96

Operating the gyratory riddle safely 97

Introduction to the backyard foundry

A worldwide hobby metal casting renaissance is occurring, hobbiest’s around the globe are re-discovering the metal casting skills and techniques of the “Old Masters,

who achieved spectacular results using basic tools, equipment &“Know How”, learnt

through many years of trial and error, as well as well proven methods & techniques Don’t ever be afraid of making a mistake, for, without mistakes, you will never truly learn! The author has been metal casting for about thirteen years All of the

equipment needed for backyard foundry work was built in the home workshop I call it

my boutique foundry because it is so small

This 3-part volume hobby casting guide ebook will give you information on how to

build all of your own foundry gear You will need some basic metal workshop tools, e.g Welder, angle grinder, power drill and other small hand tools that most people entering into foundry work seem to have already Hopefully this will be the case with

you If you don’t, then why not do a joint project with a friend Share the COST, and share the FUN

The subjects covered in this ebook:

1 How to melt & cast metals

2 Building a Gas Fired Furnace

3 Building a Motorized Gyratory Riddle

Section One: Metal casting Made Easy

The topics covered in this ebook will range from making simple wood patterns & cores, preparing foundry sand & ramming up your mould boxes

How to select bronze and aluminium scrap metal to break up & melt into ingots to use later for your casting work

The various tools & equipment you will need for moulding work will be explained

We’ll discuss the different furnaces that can be built to melt your metal, (covered in the next section) plus a host of other material you will need to know about, to get started in this age old craft of “METAL CASTING”

In this ebook you’ll find high quality photographs that accompany the text all the way through The step-by-step sand moulding photographs and description will help you

to fully understand the methods & techniques involved with moulding and casting metal

Hobby metal casting is highly contagious, and after a couple of sessions of melting and pouring, you will be hooked on the process Your imagination and the skills that you develop will be the only limiting factor in your progress & success

When I started out fourteen years ago, there was very little info around for the home

metal caster that made any sense, I searched high and low for the right books,

(especially for info on die cast Al pistons) but found that most of them were for the foundry industry specialists While these books were excellent for the purpose, they were not much help to the home foundry worker!

Whether you intend to just make things for your own enjoyment, or you aim to get

serious & gain enough skills to start making things for payment, is entirely up to you Whatever you do, “DON’T RUSH" into trying to make money out of your venture,

take it slowly, learn your craft, and practice all you can, which will help you to make

the best product possible

Castings from metal

Bronze & Aluminium items are the result of

Sand casting techniques

Have been used for thousands of years to Cast Iron, Bronze, Gold & Silver artworks

as well as simple tools and implements used by various civilizations, such as the Egyptians, the ancient craftsmen produced amazing bronze castings with their simple equipment Teams of people blowing air down long tubes provided the heat to the primative furnaces

Society has now become more reliant on new technology, the old techniques of hands on small-scale metal casting have started to rapidly disappear into the annals

of history Except for the small band of interested people like you, who’ll help to keep the craft alive

Today there is a great resurgence in backyard metal casting; people wanting to melt

& pour metal, can do so right in their own backyards, with basic tools & equipment There is no rocket science involved!

Whether you want to cast Vintage Car or Motorcycle parts, or you want to cast your very own Artworks in Bronze or Aluminium Or, you just want to have a go at metal casting; this book has been written for you, the novice & semi advanced metal caster

There is nothing more satisfying than creating something, and showing you’re new found skills to your friends and family This ebook will show & describe how to

achieve metal casting results that maybe you never thought possible

As you learn basic foundry skills, you will be amazed at what you can achieve by learning and applying the simple skills of this intriguingcraft

There are plenty of foundry sites around on the net that will simply show you some photos of home built items, but they do not cover the full details required to enable you to build the same item Feel free to print one copy of this manual, but please respect my intellectual property & copyright It is illegal to provide pirate copies of copyright work If you want to use text from this ebook for some reason, then please email us for permission I want you to treasure this ebook

You may print your own hard copy instruction manual to have by your side, to refer to when required You can quickly look up and read about certain subjects or articles, or look at well illustrated pictures and plans, which help you to learn how to do all the different processes required during the moulding & casting processes Or to build the equipment you want for your home foundry workshop

About the author

My interest in metal work stems from my boyhood days, I was fascinated as I watched my father work the farm “Blacksmith Charcoal Forge” to heat metal to do repair's to farm

Building a go-kart project started me on the road to ”HOME FOUNDRY WORK” The go-kart

needed wheels, so the quest for ”casting know how” started (In this e book you will see the turned patterns for the wheel project) By following simple pattern making methods I made useable wheel rim patterns and then cast the wheels (Success at last)

The First Furnace Built

This was the crudest contraption one could find, but it worked, I was able to melt enough aluminium to cast the Kart wheels after a couple of initial failures?

(Remember… you learn from your mistakes)

The furnace was built from a few old house bricks stacked up on the ground, to form a round container to hold a pile of fuel charcoal A short length of 2” pipe fed into the bottom of the charcoal bed provided the air blast (From a borrowed household vacuum cleaner)?

Don’t underestimate the melting capability of charcoal It is an amazing fuel With the correct air blast, it will melt most metals (especially when used in a cupola furnace), it is quite

effective when used to melt aluminium, and many hobby casters start out with a charcoal furnace The only problem is the charcoal supply; if you cant make your own, then you may find it difficult to find a reliable supply (We have a free charcoal-making guide available from our web site)

Every furnace needs “Air blast”; you won't have to look for anything too fancy to supply a good quantity of air for your furnace A good second-hand domestic vacuum cleaner will

deliver plenty of air to melt Aluminium or Bronze in a Gas Fired Furnace

The domestic vacuum cleaner is an excellent choice to provide the blast for a charcoal furnace Just check before you buy a vacuum cleaner to make sure the hose can be attached

on an outlet socket to make it blow instead of suck, most important!

There is nothing more satisfying, than creating something unique in your own workshop

Especially when you conceive an idea, make a pattern, ram the sand mould, pour the casting, and then finish it on your own lathe, etc

There are home metal casters all over the world creating their own unique products; you will

be joining these ranks of backyard founders, creating your own special items

You don’t need sophisticated equipment to achieve good results with your home foundry operation It certainly makes life a lot easier to use good equipment But if you can’t afford to have the best right from the outset, understand that you don’t need it

Several years passed before I was able to build really good equipment, but, it was only after operating simple equipment, which enabled me to custom design and build an excellent Gas

Fired Furnace, and the associated gear that went with it I am still making equipment as

required The equipment is really just a miniature version of the big commercial gear Always keep your eye out for good ideas that you can adopt to your foundry operation

DISCLAIMER

Foundry work is lots of fun

You will get much enjoyment from your metal casting creations, but please take

CARE when handling molten metal Temperatures from 740DegC to 1300Deg C can

inflict a very serious injury due to unsafe practices Don't ever put wet scrap metal

or ingots into molten metal, it will explode, showering you with molten metal You are dealing with old technology here; the associated risk of injury should

be fully understood by all who attempt this craft!

Please go and buy protective clothing, eye & face shields, Leather apron & good quality leatherwork boots Nothing will spoil your fun more than a serious burn on your body I have experienced the pain of small splashes of hot metal I can tell you it

is “NO FUN”

Please read this e book, not as an entire lesson on the art of metal casting, but more

as an introduction to setting up your own backyard foundry One section read by itself will “NOT FULLFILL” your needs, Although there is enough ground covered for most people to grasp the methods required to build your own equipment, and to do some good sand castings

This hobby foundry ebook has had worldwide acclaim for the info, and teaching it contains, but your learning should not stop with this ebook alone Hobby foundry work is a journey of discovery & fulfilment as you learn the techniques of this

intriguing craft Seek out others with an interest in metal casting & learn from them also

Building your own foundry equipment

The tools and methods explained in this e book have worked extremely well for the author However there are lots of tools & equipment that you will be able to construct your self Arc welding will be involved in the construction If you feel that you are a competent welder, then by all means go ahead and make your own tools

Please be careful if you are constructing a pair of CRUCIBLE TONGS Think what would happen if the lifting tongs “Failed” while removing a full crucible of “molten metal” out of the furnace, it would not be nice, would it?

If you are not a competent welder, go find someone who is! Perhaps you have a

friend who is interested in what you are doing Combine your talents to create the things you need for your foundry With a combined effort, you will soon build the basics to get started Then you can move onto the more advanced facets of sand casting

You are accepting responsibility for your own actions

The Author “WILL NOT” be held responsible for carelessness on your behalf I have

no control over the way you conduct the practices in your home workshop All I can

do is warn you to be very careful in the way that you carry out your craft Abide by the rules and everything will be fine Be CARELESS and you will PAY for it through INJURY

Your foundry equipment can be fabricated with normal tools, machines & equipment found in well-equipped home workshops At times you will need to have access to a lathe The machined parts will not be complicated or difficult to make Basic lathe turning methods will suffice, & I’m sure that most people who are attracted to metal casting would already have reasonable machines in the backyard workshop

If not I would suggest that you talk with friends who may know of someone who can help you out

Another way to get access to good workshop machines, is to enrol in a night class at the local Tech College… and work on your own projects…simple The course will be worth every penny you pay for it

Operating and reading this ebook

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Quote

Use what talents you posses

The forests would be very quiet indeed

If the birds that sang there

Were only those that sang best

Author unknown

****

"A man only learns in two ways, one by reading,

and the other by association with smarter

people"

==Will Rogers==

*****

Tuition is high in the school of experience and

there are no free scholarships

Benefit by the experience of others

Moulding and foundry work

Moulding is the process where a pattern is pressed or imbedded into special sand to the desired shape or form Or the pattern can be placed on a moulding board, and the sand is rammed or compressed around the pattern

After the pattern has been carefully moulded, rapped & extracted from the sand mould, the mould is lightly blown out (to rid the cavity of loose sand particles) closed,

& molten metal is then poured into the cavity When the metal has cooled, the casting

is extracted from the sand complete with gates, runners & risers attached to the raw casting

The Home Foundry worker will principally be involved with Green Sand Moulding and casting Other forms of sand casting can be used, but for now, we’ll concentrate on the green sand method

Your green sand must posses the following properties:

Porosity: To allow air and steam to escape from the mould during casting

Cohesion: Ability of sand particles to cling or adhere together while the mould is

being rammed up (Bentonite is the binder used for this purpose)

Refractoriness: Ability of the sand to withstand the severe heat of the molten metal

For Aluminium castings, the green sand needs to be a fine grade (ASF 80 to 130) If you have sourced your sand from a commercial foundry, it would most likely be about right for you to start using in your home foundry set up

Sand Mould Schematic Diagram

Section view of Green Sand Mould box

Study the above diagram carefully; this is the type of mould box that would be used

in a commercial foundry operation Spend some time studying this sketch; there is a lot to be learnt from it Use this sketch as a reference at any stage of your casting

work, you may learn more from it as you improve your skill levels NOTE: The set up

above would normally include an internal core!

Foundry equipment & tools

Quick Tip: For a Cheap Starter Crucible

Weld a plate on the bottom of some heavy pipe (4”w x 6” tall) lined with

a mixture made of fireclay & graphite, will make a good cheap crucible Dry it carefully before fireing to cure the lining

A plain steel pot can be used for small melts, but pieces of oxidized metal will flake off and end up mixed with the melt

Crucible

The crucible is the vessel used to hold the molten metal, they are available in many different sizes, and a good size start out with is a number 6 or 8 You need a crucible

that holds about 6 to 8KG of Aluminium Capacity is quoted by weight in Bronze Ask

your supplier to help you with your choice You will find suppliers under foundry supplies in the yellow pages, or on the net, silicon carbide crucibles are the best quality crucibles Cheaper clay graphite crucibles are also available at a lower price and may suit your purpose

Mould Boxes

You will need one or two to start with A handy size to have is 10 X 12“ X 3”

constructed from steel or wood They are made in two halves, the bottom is called

The Drag; the top one is called The Cope I chose steel for mine, which is a lot

stronger, and will last a lot longer than wooden boxes Steel boxes won't burn when

hot metal is spilt on them, which does happen The boxes need to have a pin

register at each end to provide an accurate register for the mould boxes during the moulding operations Identify matching corners with coloured paint or marks of some

sort There is nothing more frustrating than putting your mould boxes back together the wrong way around, and only realizing this after you have poured & retrieved your ugly casting from the sand mould

Plastic Rubbish Bins

You need at least two bins, use them to store your green sand; the sand is not really green in colour The colour is really quite black You use water to temper or condition the sand, so that you can ram it around your patterns and mould with it Your sand will keep nice and moist in the bins for several weeks You will find that there are periods where you might not do any casting for a month or so If you could not keep it moist during that time, the sand would need complete reconditioning all over again

Hand Ramming Tool

A simple device, turn this item on your lathe out of hardwood, one end is round and flat like a large hammer and the other end is wedge shaped for getting into corners

etc Just make the part that you hold in you hand a comfortable fit Make your ramming tool to the size you require Two or three ramming tools could be made up

hand-in different sizes to suit the different size mould boxes & patterns you might have

Foundry tools 1a

Crucible Tongs

These are tools that you can construct your self, as long as you have confidence in your own welding, The flat steel material to use is 1"X 1/4" or 5/16" thick (Depending

on the weight of the crucible) Take a look at the image above, which should give you

an idea on how to construct them This design is used to lift the crucible straight up and out of the furnace The crucible is then placed in to the pouring shank The tongs need to be a neat fit around the crucible, without putting any undue pressure on any one part of the crucible

Vent Wire Rod

This is used to put vent holes in the sand moulds A normal bicycle wheel spoke is

just ideal for this purpose Sometimes you may have to use a rod that is 1/8” thick

Make it long enough to go down through the sand to just touch the pattern You put several holes all over the mould The holes allow the steam to escape, which is

generated by the molten metal as it flows into the sand mould This helps prevent

porosity and steam blows in the casting To make the tool easier to use, put a small wooden knob on the top, which will rest in palm of the hand while venting the mould

Gate Cutting Tool

A gate cutting tool is used to hand cut a flow channel for the metal to flow from the

down sprue across to where the metal enters the mould cavity, it is simply made from

a piece of thin sheet metal Cut from an old jam tin, make it about 2 1/2"long Bend it

into a “U” shape, and you have your gate cutter There is an easier way to do this

and I will show you later on in the book in the moulding section

Sprue Tool & Riser’s

Another small tool to make on the lathe, you might like to make a few of these, as

they come in handy For now, turn up a couple in the following size 7” long X 1.1/2”

at the top, tapering down to 1/2” at the bottom This tool creates the vertical-pouring hole, which directs the hot metal to the in-gate, or flow channel that you created and into the mould cavity The sprue will also act as a choke to control the flow of metal

into the mould cavity

Quick Tip

The length of the handles needs to be about three to four feet in length This length will keep your hands a good distance from the hot crucible (wear your arm length glovThe clamping leverage to hold the pot full of metal will also

be less with long ha

es.) ndles

Quick Tip

Any type of timber will suffice for sprue sticks, turn up as many as you may need, sand them smooth and finish with some shellac so that they are easy to pull from the sand

Drill a small hole and place a small locating pin in one end, the pin locates in another hole drilled in the pattern or ingate, which prevents the sprue from shifting during ramming

Foundry tools 1b

Quick Tip

Build and use one of these motorized riddles and you will wonder how you ever lived without one! Reconditioning foundry sand would have to

be the most labour intensive chore in the home foundry

“The Motorized Gyratory Riddle” The complete plans are included in this three part ebook

Hand Sieve or Riddle

A hand sieve is used to place finely sieved sand over the patterns as you start to

mould You will also use the sieve to recondition your sand after you have done some moulding/casting operations Using your hand sieve to recondition your sand can become quite labour intensive Complete construction details are available in the

next section “How To Build The Motorized Gyratory Riddle.” This will make the job

much easier, quicker and a lot more efficient After using the motorized riddle you would not use a hand sieve again

Quick Tip

Your moulding bench can be of any size; unless you are limitedwith the size of your work area Make sure you mount the bench on casters; shopping trolley caster wheels are ideal

The top of the bench needs to be of timber or a zinc coated sheet metal, a good base for the sheet metal is ¾” thick craft- wood

Moulding Bench

Build your self a sturdy moulding bench, you will be doing a lot of moulding on it, so

make it good & solid I built mine out of second-hand RHS (Rectangular Hollow

Section) Steel tube; it measures about 6-foot long, and about 3 1/2 foot wide, it seems to be about right for the work that I do Don’t spend money on new materials; try to obtain recycled timber or steel You will find it an advantage to put some caster wheels on the bench so that you are able to move it about your shed (Look for caster wheels at the junkyard) Add some lower shelves for extra storage space Build the bench at a height to suit you and no one else; you will be the one doing all the

work on it You don’t want it to be too high or to low

Foundry tools 1c

Mould blower tube

A simple tool used to blow small grains of sand out of the mould This is a short length of plastic tube (1/4”Dia), place one end in your mouth, the other in your hand and guide it around the cavity while blowing gently to get rid of loose sand particles etc out of the cavity A small air compressor can also be used to do the job, but you have to be careful you don’t blow bits of your sand mould away in the process Best

to stick with the mouth blower first

Furnace air blower

No need to spend big dollars here Look around the house; have you got an old

Vacuum Cleaner lying around that is not being used anymore? If not, buy an old Electrolux model, which has a sliding electronic speed control on it You will find it just right for adjusting the airspeed/volume to the furnace Most second hand shops would have one This type of vacuum cleaner will deliver as much air as you need for

a home size gas fired furnace (Remember to reverse to BLOW & NOT SUCK) If it

delivers too much air, you may have to put an adjustable waste or blast gate on the

delivery line to adjust the pressure

Corer makers trowel

Take a trip to your hardware store; just buy a cheap long narrow trowel, something like a plasterer would use, a straight narrow rectangular blade You don’t have to buy the proper tool; you can use other things as well You may possibly be able to even make your own trowel

Foundry tools 1d

Pattern draw spikes

Make these from old wood screws, braze a piece of 1/4” rod and add a ”T” piece on

top so that you can turn it into your wood pattern to remove it from the sand Simple tools like this that will make your work much easier Make some draw spikes in different sizes as your patterns will be large & small

Rapping bar & rapper

These two items are used to “Loosen” the pattern before removal from the sand,

when you rap a pattern; it has the effect of slightly enlarging the size of the

impression made by the pattern in the sand The rapping bar is held down firmly on

the pattern and then you take the Rapper, which is a “U” shaped device, with a handle, and rap side to side on the bar very quickly to loosen the pattern Rap north -

south then east - west on your pattern A large open - end spanner can be used in an emergency as a rapper

Bottom & top mould boards

Cut two boards from 3/4” thick form ply, a little larger than the size of your mould boxes that you made On one of them put some 1 1/4” X 1 3/4” runners on the

bottom as supports, so that it sits evenly on your bench or the floor, the runners also stiffen the board

Quick Tip:

Use a length of 1x1x 3/16” angle iron

to make your screed bar, weld somhandles on each end for comfort e

Mould strike of screed bar

Use this tool to scrape or screed of excess sand that is left on the mould after the ramming process is complete (Especially the bottom of the Drag), this will leave a nice flat surface, to continue moulding operations after you have inverted (rolled) the mould box onto the mould board Made cheaply from a piece of timber or some metal, put some handles on it and it’s ready to use

Making foundry patterns

Before you can create any “casting” a pattern of the object to be cast must be made

in order to form the necessary “impression” in the “sand mould” One would normally

use timber to produce patterns, i.e White pine, cedar, maple , mahogany etc Other

materials such as casting plaster can be used to make simple shape one off

patterns, or to create impressions of something that you may have already made, and wish to replicate the item to create more patterns To enable a multiple pattern set up on the mould board

The timber used for pattern making should be easy to work with, should not splinter and kiln dried, otherwise shrinkage and warpage will ruin your good work!

The home craft person will use standard carpenters tools, with the addition of a few special ones such as a wood or metal turning lathe, routers and special cutters used

in a pedestal drill You may own a band saw and other luxury power equipment in your workshop These tools will enable you to produce some good patterns to work with in your foundry But excellent patterns can be made with simple wood work hand tools, so there is no need to buy expensive new tools

Pattern shrinkage

Owing to the shrinkage of molten metal on solidification, your pattern must be made

slightly over size to allow for this All metals have a different “shrinkage ratio” this

“Ratio” is determined from a “pattern makers” rule (Available at foundry suppliers) This is like a standard rule except it has four shrinkage ratios on it When you draw

up your pattern, you scale it from the correct shrinkage ratio, to allow for shrinkage, machining & boring etc, (E.g Aluminium has a ratio of 3/16” per foot shrinkage) Pattern draft

Remember to allow plenty of draft or taper on vertical walls, and to create a generous radius where the vertical walls meet horizontal planes on your patterns The quickest way to make radius fillets is with a ball bearing of the right size, brazed onto a thin steel rod Heat the ball bearing tool gently in a soft flame; lay the small bits of bees wax in the area you wish to fill

Run the warm ball tool back and forth along the fillet line, the melted wax will form a nice clean fillet radius Clean excess wax of with a small scraper, and then rub

smooth with steel wool (You can even shellac over the wax when finishing) Sand the patterns smooth all over; finally finish the pattern of with two or three coats of shellac, sanding smooth between each coat

Pattern identification

Some pattern makers use colour codes on the patterns, to denote various operations

to be carried out on the casting If you feel like doing this, then by all means do it, although not required in the home foundry This will also help to remind you as to which way you should mould and cast the object

BLACK: Indicates the surface to be left rough

RED: indicates the surface to be machined

YELLOW: Indicates where the core prints are to be located You can also devise your own colour scheme to denote certain other things

Generally speaking, a casting face to be machined should be cast “FACE DOWN” giving you a good clean flat surface to work with

Pattern making materials

Go - Kart wheel patterns

Tip

MDF is cheap if you can get hold of off cuts from the local joinery shop However, there is one small drawback, the patterns do tend to crack and they need

be handled with care But if you look after MDF patterns you will get a good moulding life from them Solid timberpatterns are expensiv

to

e to make

The Front & Rear wheel rim pattern halves are shown here, four castings for the front (small rim half) & the same for larger rear rim was required The patterns were not difficult to make 3/4” thick square blocks of craft wood were glued together to make a large block The thick block was then machined in the lathe to make the patterns Careful sanding and shellacking soon had some nice patterns to mould with

Easy to work soft white pine timber has been the main material used down through the ages for pattern production Its ease of use in machining or carving makes it ideal for patterns At times a foundry pattern shop may require production patterns to be made

These are generally made from aluminium or cast iron for really heavy use, where tens of thousands of casting impressions are required

Craft wood (MDF)

For your home foundry pattern making, wood is going to be just fine Another

material you will find very use full is craft-wood This is a medium density fiberboard; (not unlike common chipboard, but much finer) several layers can be joined (glued)

on top of the other to form a thick block This can then be secured in a four-jaw metal working lathe chuck, or fixed to a wood turning lathe chuck, and turned into the required shape This was the method used to make the Go - Kart wheel patterns shown above

Craft wood is very dusty to work with, it is recommended that you use a facemask to

keep the dust out of your lungs Once the craft wood is sanded, and has had one or

two coats of shellac it is not so dusty then

Timber Types

Other timber’s used for patterns include jelutong, cherry wood, white pine &

mahogany, plus other close grained easy to work timbers

Some timbers are not suitable, because of the grain structure and poor machining and finishing properties You may have to experiment, before you find a good pattern timber in your area Search out a local pattern maker, he will advise you what’s available at a reasonable cost

Ask him for some tips on pattern making while you’re there, he may even be willing to let you hang around and watch while crafting some patterns Making friends with someone like that would be invaluable to you, and help your pattern making skills The biggest factor with your own pattern making is the practice that you put into it Your skill levels will only be as good as the effort that you apply to your pattern

making

A person with good basic wood working skills will have no trouble with the "how To"

of pattern making, they will only build on their experience to become very good at it

Pattern draft

In order to be able to extract the pattern from the sand, the vertical sides of the

pattern have to be tapered slightly This is called “Pattern Draft” next time you are

looking at a sand casting, study it carefully; you will see where the “draft” has been built into the pattern Examine also where the vertical planes meet the horizontal planes Note the Fillet radius that has been made using bees wax or some other filler This creates a smooth transition between the vertical & horizontal planes

Wax pattern fillets

A very simple way to finish pattern corner fillets is with a ball bearing brazed onto a slender steel rod The technique is to place the bits of bee’s wax in the fillet, heat the ball bearing slightly with a soft flame, and slide the ball up & down the fillet The bee’s wax will flow along the joint and the ball will create a nice radius Make different size tools, as you will need them eventually

It is essential for the pattern to be dead smooth all over, with no rough spots

anywhere The taper or draft is necessary to allow the sand moulder to be able to extract the pattern, with out breaking or damaging any part of the sand mould

You will be able to make single piece, or split patterns in your own workshop A single piece pattern is one with the parting line on the top or bottom edge, simple to make and simple to mould & cast

The split pattern is made in two parts, and aligned with two small steel pins imbedded

in one pattern half, these engage in the other half pattern, which has matching

When casting a nameplate, you need to make a runner that feeds the casting in

equal points all around the casting to avoid this problem

Feeders & risers

The strategic placement of risers or feeders will also promote sound castings and even solidification It is not unusual to find almost as much metal used for gates and risers, as that which is used for the casting That is just a part of foundry work; you have to accept that, Re-melting of the scrap is common anyway, so it is not really wasted

Patterns, Gates & Runners can be mounted permanently on the pattern board for rapid mould making operations When both drag & cope have been rammed up, all the channels are already formed ready to pour

I found this method to be the quickest way to do moulding and casting in the home foundry set up When your not using the pattern boards, just hang them up so they wont get damaged

Pattern making is a complex craft and there are some very good books available covering all aspects of pattern making The best way of course, is to get to know a pattern maker, do some time with him & learn the finer points of the craft

Failing that you will just have to teach your-self You will learn more by doing than watching, so get to it, have a go; it won't matter if you have few failures Start with simple one-piece patterns first off, this will help to build your confidence and skills

Core prints

What if you want to cast something that is hollow inside like a bearing bushing? To

achieve this, turn up your pattern slightly under size, allowing for shrinkage and the machining allowance When you turn the pattern, you will need to turn what is known

as core prints on the ends of the pattern (Small round pegs or dowels) A split pattern would need to be made

Do some careful measurements of the original part that you wish to reproduce, and then you will be able to turn the pattern up in the lathe (Allowing for shrinkage Etc) The core prints have to be almost the same diameter as the round sand cores you will use with the pattern This will ensure that the cores will be held securely when the two mould halves are joined together, and during the pour, you don’t want a core shift

If you study the photo below, you will see what we mean This example is a very

simple split pattern, made up to cast a small double “V” pulley for a project Yes, I

could have bought one ready made for $$$ But this pattern and pulley were made for next to nothing It was made during weekend fun time The pattern was whizzed

up on the lathe, sanded smooth, shellacked, dried, and coated again with shellac Finished again with steel wool, and it was ready to use

Do not be confused about this picture, there are two different patterns shown here The one in the foreground

is the split pattern with core prints turned on each end

Note the steel locating alignment pins; (Centre Line of pattern) these locate the patterns during mould ramming The other pattern is a one-piece pattern used to cast a

blank double “V” pulley (Both castings were to be used

in the same project)

Split pattern & core prints

Solid, one piece Pattern and split pattern Both were used to make double “V” Belt

pulleys for a casting project The type of pattern that you use will depend on how you want to do your casting You may need sand cores So turn core prints on the end’s

of the pattern If not, just make up a solid pattern Finish it well, and it should mould and pull from the sand without any trouble

Wood-turner's trick to make split patterns

Before turning up a split pattern, prepare the timber to provide two halves, of

sufficient size to make your item Sand them smooth all over Now cut some strips of

medium brown (craft) wrapping paper Lightly Smear PVA wood glue over both pieces of wood, place a strip of brown craft paper between the two pieces of wood,

clamp together lightly overnight

Next day place your pattern in the lathe & turn to the correct size, working from any drawings that you have at hand When you are finished, look carefully for the glue line, which appears as a faint cream colour against the wood

Insert a fine sharp knife blade or chisel and ease the blade into the brown paper, the paper should start to give, and the two halves will begin to Part Company You

should end up with two pattern halves, which has split along the brown paper glue

line The trick is to not put too much glue on the paper and the wood pattern It is the paper that tears and splits as you force the pattern halves apart Using this

mounted, on both sides of a mount board, complete with in-gates and runners This method enables moulds to be rammed up very quickly

Pattern basics

To give you a total in depth study into pattern making in this ebook would be folly The field is very specialized, and you would need to study for years to become expert

at it But fear not, as I said previously, if you have basic wood working skills and

equipment, and understand the basic principles of pattern making, you will no doubt

be able to make some useful patterns to give you success with your own casting work The main thing to watch for when making patterns is to allow a generous amount of draft or taper on any vertical part of the pattern To be careful where you place parting lines, and make sure that there are no undercuts which will snag or pull sand away with the pattern when you pull the pattern from the sand

And to also allow for metal shrinkage, i.e make the pattern oversize

Pattern making in the home foundry is mostly pure common sense, don’t get overly ambitious with your projects and you wont end up discouraged by too many failures Foundry work can throw plenty of challenges at you, when venturing into difficult, or overly ambitious casting projects

Start with simple projects and build your skills on the success that you achieve You should not be afraid to give something a go, approach your pattern making with some

thought at what you have to do to succeed Failures will happen, but don’t be

discouraged by that, you will learn plenty from your mistakes

Pattern finishing

Timber is the most likely material you will use for your patterns, using the right timber will make the job easier, and it will be simple to apply a good smooth finish If you don’t finish the pattern properly there is a good chance that some moulding sand will come away with the pattern, forcing you to dump the mould and start again This is frustrating and time wasting; it is much better to put the effort into a well-made

pattern in the first place

Multiple patterns

Sometimes multiple patterns are required to make several castings of the same item

in a single pour This mean’s making duplicate patterns, and mounting them on a

board with the gates and runners This is a quick & easy way to make small

quantities from just a few sand moulds in the home foundry

To make duplicate patterns from an original, a special silicon RTV compound is

used It is especially designed for this process After the silicon mould impression has

been made and cured, you simply pour diluted Car Body Filler into the RTV mould,

let it set overnight The body filler wont stick to the RTV, so you can flick the body filler casting out of the mould next morning, and repeat the process again to create more accurate duplicate patterns

It is possible to increase the amount of hardener to hasten the curing time of the car filler material; but it is probably best to let the filler cure slowly

When you have completed your new repro patterns, it’s time to make your runners and gates (MDF is available in different thickness and works fine for this purpose) Mount these with your patterns where you need them Give everything a final smooth over with steel wool, and you should be ready to mould and cast It pays to do a test sand mould first, to see how the mounted patterns “Pull” from the sand You will save

always a small rough edge on the pattern somewhere that needs removing because

it pulls some sand with the pattern when parting the moulds

Silicon R.T.V & Reproduction patterns

Mounted patterns made from poured car body filler

The images below show how an original M.G part was used as a pattern to produce

RTV 585 silicon moulds Ordinary car body filler was thinned with Styrene

monomer, and used as a casting medium to produce the working patterns

Mix the body filler with S/Monomer until it is like light cream Add the required amount

of hardener, then pour it into the silicon mould, and leave this to set over night The patterns can be removed next morning and the process repeated to create more

patterns You could make endless quantities of working patterns using this method The silicon is good for hundreds of epoxy castings

Quick Tip

Silicon RTV moulding compound is a great material to use when reproducing items such as emblems, badges etc, or other intricate objects Remember that you can’t have undercuts with sand castings; otherwise you won’t be able to pull the mould from the pattern without damaging the sand mould

RTV Silicon Mould Car Body Filler patterns

The RTV 585-silicon mould used to reproduce the original MG oil cap Make a simple captive mould to pour the silicon into with part to be reproduced face up on the

bottom board The mould cures overnight Complete instructions are enclosed with the product if you decide to venture into this pattern making technique

RTV Half Mould Car Body Filler patterns

These Aero Screen End cap patterns were made in a half mould, unfortunately the mould stuck together during the making process (Hence the rough finish after

separation) The car body filler was poured into the mould, which set over night The process was repeated until there were enough patterns to do the job The finished patterns can be seen above right These are now ready for pattern board mounting

Polyester resin patterns

The original M.G parts were used as the pattern to produce RTV 585 silicon repro moulds Ordinary car body filler was thinned with Styrene monomer until it has the consistency of light dairy cream Add the required amount of hardener, (Follow the

Instructions in the kit) and then pour into the silicon mould, leave to set over night The patterns can be removed next morning, and the process repeated again to

create more patterns You could make endless quantities of patterns using this

method The silicon is good for hundreds of impressions

Note: The silicon RTV 585 is mixed with a catalyst 60R Mix gently to avoid air

entrapment in the silicon Complete instructions are included with the RTV kits

Casting shake out time

to heavy parts of the casting

Sometimes it may take two or three goes at getting a perfect casting from a new pattern

Opening the mould box

This is what you will find when you open the sand mould box (Cope & Drag) A sound sand-casting, & hopefully without any faults Notice how the sand has lost most of its moisture; you can see the dry line the hot metal has created The bulk of the sand mould still has large amounts of moisture; it is only the sand right near the hot casting which has had the moisture driven out of it This moulding sand will be far

to dry to do further moulding with, after the casting has been removed it is time to put

the sand back through the Motorized Riddle or hand sieve to recondition and

temper (Add water, no more than 6%) to get it ready for another moulding session

Reproducing small parts

Often, an original part can be used for the pattern, if you can accept some

shrinkage and it is fairly flat all over and has not got any undercuts, then you may be

in luck Find the edges or line that would make the parting line Ram up a drag mould box and screed of excess sand; Sprinkle some graphite over the sand to act as a parting powder

1 Your small part can be imbedded face down into the sand, (tap the pattern with a light hammer and piece of dowel) to the parting line

Follow this with the top half of the mould (Cope) and ram it up also, you will find that you have a very well defined impression of your object in both parts of the mould All you would need to do now is to

Cut the gates and runners, as well as make the down sprue hole and you are ready for pouring The down sprue can be made with a short piece of ½” dowel pressed into the sand near the pattern, simply cut an in-gate from the sprue to the pattern This is one of the easiest ways to reproduce small castings You do need to practice making your impressions Don’t forget to use your parting powder in between your moulds, other wise, the sand will stick together, and parts of the mould will pull away When you first start to mould you will have to think what you have to do, but after some practice it all becomes automatic You won't even think about what the next step will be

The step-by-step sand moulding instructions will be shown soon, and this will make the process a whole lot clearer for you to understand There are several steps &

procedures to follow when ramming your sand moulds To a beginner it may look a little daunting to try and remember all the steps, but once you have done it a few times you wont even think about what comes next

Gates & Runners

Mounted patterns & runners

The picture above shows an example of runners and patterns mounted on a board These small patterns are body bobbins, which are used to create mounting points in fibreglass car bodies The bobbin patterns are split and mounted both sides of the board The brown strips are the gates, (made from craft-wood) on the other side of the board, is a wide runner at 90 Deg to these, it is placed in the middle of the board

& distributes metal to every in-gate channel, and about twenty bobbins are cast with just one pour

The gates are tapered down at the entry point into the cavity; so that the bobbins can

be broken of by hand after they have cooled and removed from the sand mould

You will only ever do this once, and then you will learn

to check that everything is right before closing your mould box

This shot clearly shows the in-gates and runners When doing small production casting runs, consider setting up your patterns, gates & runners like this Note also

the fairly large risers, which provided generous amount of feed metal to the castings

It is fiddly work to set all this up on the board; but you only have to do it once If you need to do another casting run at some stage The moulding step is done pretty quickly, with out any fuss

Production time goes up, and the moulding time is a lot less That is important when you start to do small production runs with your foundry set up

Most of your casting work could be carried out with a layout similar to the one above Occasionally the need will arise for a casting to be fed from below, a very handy type

of gate for this application is a horn gate It is shaped just like a cow horn Moulders

of yesteryear used this type of feed gate almost all of the time It provides a constant stream of clean bright metal with almost no turbulence in the casting cavity

Reconditioning foundry sand

Due to the intense heat of the metal castings, the moisture that you so carefully put into the sand will be driven out This used moulding sand will now have to be put back through the sieve to have the correct amount of water added to it

Reconditioning of the sand (By adding a small percentage of water, about 4 to 6%) is essential after every moulding & casting operation You can use the hand sieve, or if

you want to make life easy, a “Motorized Gyratory Riddle” will reduce the effort for

you

Full construction details are shown in the last section of this ebook “Build the

Gyratory Riddle” This machine is simple to construct, which is powered by a small

1/3rd HP washing machine motor

Foundry sand has to be able to breathe within it self This is known as permeability When hot metal is poured into the mould cavity, quite a bit of steam and gas is

generated while this is going on There will be steam shooting out of the vent holes in the moulds, as well as working its way through the sand within the mould

Sometimes your sand will have an excessive build up of burnt clay fines and other waste, the clay fines can have the effect of reducing the breathing ability of the sand

If it gets really bad, the sand may have to be discarded, and a new batch made up A batch of sand can be rescued by mixing fresh olivine sand and more Bentonite After a couple of mould/pouring cycles it seems to be OK again

WARNING ABOUT WET SAND

DO NOT pour hot metal into a WET sand mould, you will create an instant STEAM BOMB, hot metal will BLOW BACK out of the sprue hole with much force NEVER PUT your face directly over the pouring hole for this reason, and always wear your safety gear

Sand Types

There are many different types of moulding sand, some founders say you need special sands for this and that; this may be true if you get into making name plaques etc For the type of work you will be doing in your home foundry set up, I would say that the green sand that you have, will be fine for most casting that you undertake If you look after it, keep it clean It will last a long time

I still use a base stock of green sand that I bought over 10 years ago, it has had additions of NEW olivine sand & some binder, (Bentonite) but, apart from that, it is still the same stock It has been used for Aluminium and Bronze with very satisfactory

results And provides a high class of finish to the casting

Oil Bonded Sand

The very best sand for very fine detailed work, such as plaques, nameplates art castings etc, readily available from various foundry suppliers, it is well worth your while to check this product out The free ebook Petro Bond you received with this ebook, will make a good edition to your foundry library, read it and learn about this excellent moulding sand

Other methods of sand moulding include CO2 gas & sodium silicate to harden sand moulds Cold set resins are also used in large foundries, we won’t be

covering any of those systems in this e book, and later on you can contact suppliers

to obtain info on these products if you wish

Eleven steps for sand moulding

The Moulding Bench

Your moulding bench needs to be a well constructed piece of equipment, the bench

is just as important as having well made mould boxes The illustrated bench above has been in service for a number of years, much hard pounding and ramming of moulds has been done on it, I would love a dollar for every pound of sand rammed into a mould on this bench! Don’t skimp on this item, having a good bench may make the difference between making good or terrible sand moulds If you’re like most metal casters, you will be spending lots of time at the bench, so make it as easy to work with as you can

Step one: Select Patterns & Mould boxes

The tools & items for sand moulding

• Mould box; Mould bottom board, & another false board to the right, with patterns and gates are ready to set up

• Above the mould board is the hand-ramming tool, draw spikes, and a thin vent wire (Bicycle Wheel Spoke)

• Top right hand corner is the screed bar, a container of graphite-parting powder), water spray, and a funnel, which is used for shaping a pouring basin in the mould sprue hole, after removing the sprue stick

The following sequence explains the eleven steps involved in making a green sand mould The process is not difficult; with some practise the whole thing will become second nature to you It is easier than you think to ram up some moulds and pour

your own castings

Step two: Setting the pattern on the mould board

The pattern is set on the mould board with a false follow board; the piece extending sideways will form the in-gate channel The follow board and in-gate is secured to the bottom board by small steel pins imbedded into the patterns & in-gate and line up with matching holes in the bottom board

The pattern is used to create a cast Aluminium spring cap The cap locates a coil spring and the strut rod of an automotive rear suspension The “T” piece is attached to the steel core The groove in the pattern will form a green sand core to create a recess for the coil spring

Looking carefully at the centre of the pattern a “T” bar is visible; the “T” bar is

screwed into a steel core, which will be held captive in the sand mould When the mould is poured, the steel core will produce a “D” shaped hole in the casting The steel core is pressed out when the casting has cooled down, leaving “D” shaped hole

in the casting

Step three: Ramming the drag mould

The drag has been placed upside down over the pattern and bottom board, sand has been rammed into the box, and part of the “T” bar is still visible During the first stages of ramming the mould make sure the sand is rammed and tucked into the outside edges of the mould box Continue to ram evenly all over the mould, test with the fingers and thumb’s to check the sand hardness, Keep adding sand until the box

is full & ramming is complete Screed of any excess sand before the next step

Step four: Turning the mould box over

After screeding of the excess sand from the mould box, turn it over, the box is now

the right side up (Pins up) If you check step two you will see that the false follow

board is now on the top Take the drawer spikes and twist them into the false board, give it a slight rap and withdrawer from the mould carefully Leave the in-gate pattern piece in the mould; this will be removed later Sprinkle some parting dust, graphite, or talcum powder over the sand before moving onto the next step

It pays to work slowly & carefully when you are moulding as the slightest mistake or damage done to the mould will see you starting all over again This would be

annoying to say the least

Step five: Preparing for ramming the cope

False board has been withdrawn and put aside The pattern is now exposed; the gate pattern piece will remain in the sand mould for the time being Parting dust (Fine Graphite) needs to be sprinkled over the pattern and sand mould at this stage Note the steep bevel left from the false board, this is essential to make sure that the cope & drag easily Part Company when the time comes to remove the pattern and in-gate

in-Step Six: Ramming the Cope mould

The cope box is sitting atop of the drag box; the sprue stick has been pushed into the sand a little to make it sit upright while more sand is placed into the mould box Sometimes a riser is essential to feed metal back into the casting as it cools, but for this casting it is not essential, as the wall thickness is much the same all over the casting (Always feed to the heaviest part of the casting) Keep placing the sand into the box, and keep ramming until the box is full, and you have achieved a nice even hardness all over the sand mould

During the mould ramming procedure, test the hardness of the sand with your thumb or finger’s Proper ramming of the sand should be considered correct when you can only make

a small impression with your thumb when pressed into the sand, if you can push your thumbinto the sand mould without too much pressure then it is not rammed hard enough Trial anderror, along with general experience will soon indicate when you have it right

Step Seven: Screeding and venting the mould

Tip

Venting the green sand moulds is an important step Push the vent wire through the sand until you can feel the wire touch the pattern, with a little practice you will get it right (Use a normal bicycle wheel spoke as a vent wire)

If you have rammed the mould evenly all over, the resistance felt as you push the wire through the sand should be the same all over the mould

Now that the ramming is complete, the mould can be screeded of and the mould can

be vented all over to create an escape route for the steam and gasses generated during the pouring of the mould After you have done all this, clean the excess sand from around the mould boxes and of the bench and put it back in the bin The mould boxes are nearly ready to take apart so that the patterns and in-gate piece can be removed and the moulds closed again ready for the liquid metal!

Quick Tip

The funnel is used to make a pouring basin at the top of the sprue This makes the pour much easier to do, and you won’t spill metal

DON’T try to pour molten metal through the funnel; you wouldn’t be that silly would you?

Step eight: Making the pouring basin

The sprue stick has been removed to allow the small plastic funnel to be pushed down into the hole; this will create an excellent pouring cup that will prevent spillage and lost metal

Step nine: Removing the Pattern

Rapping a pattern such as this with an internal green sand core can be difficult to extract with out breaking the internal core

The groove in the pattern must be dead smooth and polished with graphite to give the walls a slippery surface

Two pattern draw pin screws are used to carefully lift the pattern from the sand mould A pattern like this will try your patience!

Before pulling the mould boxes apart they must be rapped to make sure that the sand will part from the pattern surface, a sharp rap on each corner of the mould box with a hammer or lump of wood is usually enough to release the moulds In the

picture above the drawer spikes have been turned into the pattern The pattern has

to be rapped carefully also Special rapping tools are available that look like big tunning forks, the tools are placed around the drawer spike and rattled backwards and forwards quickly to vibrate or rap the pattern This has the effect of slightly

enlarging the pattern cavity in the sand, enabling easy withdrawal of the pattern (Most Times)

Step Ten: Withdrawing the pattern

Notice the green sand ring (core) formed by the pattern

Incorporating green sand cores in the pattern design eliminates the need to make baked sand cores

It is not always possible to do this though Put some thought into your pattern making to save having to do extra work

Withdrawing the pattern has been successful in the picture above Sometimes a part of the pattern will lift some of the sand with it, creating problems, the mould may have to be re-done again if it is really bad, or it may be possible to repair the small break, as you gain more experience you will be able to make an informed decision as

to what is the correct path to take Before closing the mould ready for pouring gently blow out the mould cavity to clear any loose sand particles and other matter

Step Eleven: The tools; & the final castings produced

Above you see all the tools used to produce the two castings to the right, the skills take a little learning before full confidence is gained, and that only comes with

practise The metal for the castings was melted in a gas-fired furnace in less than forty minutes; the ramming of the moulds took only 10 minutes Just imagine how long you would wait to have these done at a commercial foundry… if you could find one that would do it for you!

By learning to do your own metal castings you not only save your self-lots of money you also have much more control over the total process

Once you become confident with the whole metal casting process, you will no longer have to wait for someone else to do the job for you

Just crank up the furnace, ram your sand mould up and just do it your self You can easily see that green sand casting is not that difficult to do I did not have anybody to stand by my side to teach me the techniques of “Green Sand Casting”, it would have been great to have this luxury, but most people have to learn the hard way I.E… Self-teaching and much experimenting

Read & read again if you have to get the moulding steps planted in your mind Or print out these pages and keep them by your side to refer to as you practice your moulding

Thought For The day

"Do not follow where the path may lead

Go instead where there is no path

and leave a trail"

-Ralph Waldo Emerson -

Green sand & baked sand cores

After mastering the art of moulding and casting with solid patterns I suggest you try your hand at creating hollow castings, such as bearing blocks or large round collars with a hole in the middle Very often a pattern can be constructed so that when the mould is made The pattern will create its own green sand core (As discussed

earlier) I have had several instances, where it was possible to build this feature into the pattern Much time can be saved by doing this, as there is no need to make a separate core box for the core Having to make core boxes is time consuming, but quite often you have no alternative

Making your own core rods:

Dry silica sand and some raw linseed oil, a small percentage (1.5 to 2 %) is poured

in with the sand and then it is mixed very thoroughly to coat all the sand particles with the oil The core sand/oil mix is then rammed and pushed into the core box The

inside of the core box has to be finished very smoothly just like your patterns, so that the green cores can be knocked out easily on to a core plate, ready for the drying oven

Bake the cores in an old domestic electric oven Set it at about 280 deg C and bake until the cores are a nice dark brown colour (DON’T bake them inside the house, as the oil burning off while baking gives of a strong odor.)

Another way to make your cores is to use a steel core box like a piece of pipe that has been cut along it’s length, you can use this to make and bake the core, just

remove one half when baking, When finished slide or tap the core out of the half pipe

If you produce a core over 1’ thick, it will need a vent up the middle, so that vapor from the oil in the core can escape to the atmosphere during the bake Bake the core until it is nice light brown colour A green or undercooked oil core can create

problems (blows) like a steam blow from wet mould sand Do not warm the cores before you set them in your mould box, they must be cool when you pour The vent through the middle of the core will also vent vapor out of the core during the pour

Note

The pattern is set up using a false follow board On the left is the ingate; the pattern is sitting

in a recess on the follow board The follow board & the in-gate both have small steel pins protruding from the bottom to locate securely on the bottom mould board After the mould is rammed up the mould box is rolled over; the false follow board will then be on top Check the moulding step procedure for more detail

Green Sand Cores

Close up of Pattern

Spring Cap & Pattern

Casting & pattern example

Here’s an example of a casting formed with its own green sand core, the deep core groove around the inside was created by the pattern, ample taper was provided to make sure the pattern, pulled from the sand properly The pattern on the left (above) shows the groove in the pattern The internal groove must be dead smooth and

polished with graphite before the sand mould is rammed up before using a pattern such as this

Two or three layers of shellac have been applied to the pattern followed by rubbing & finishing with steel wool etc

Using sand & steel cores

The casting above is for a spring cap for a “lotus Élan” Notice the “T” bar in the

centre This is attached to a steel core, which is used to make a perfect hole with a

“notch” for the strut rod The “T bar” acts as a keeper to hold the steel core captive in the sand while the pattern is rammed up and when the pattern is carefully removed

from the sand mould The steel core is pressed out later when the casting has

cooled

When using steel cores in sand moulds, condensation becomes a problem, very

often by the time you get around to pouring, the steel core has acquired a layer of

moisture over it

How to prevent core steam blow

When the molten metal is poured into the mould, the moisture on the steel core is

going to cause a steam blow, which will destroy your casting

To prevent moisture, smear a fine layer of engine oil over the core, make sure it is

thoroughly covered, now dip it into a tin of powdered graphite and make sure the

graphite has covered the entire core where the molten metal will come into contact

Do not touch the core with your fingers once this is done; place it carefully in the

mould

Note

Notice where the arrows are pointing, (LHS) this

is the steel core in the drag part of the mould, it isemi circle in shape & attached to a wedge shape tail or holding piece The steel core creates a 1/2

s -circle slot in the casting for a cork gasket, which

is compressed between the timing chest & the sump pan when the engine is assembled

(Graphite has been applied to the steel core

is held between the cope & drag upon closing the ) This ould

ty

pump The cope part of the mould is no

mThe internal sand core is also held the same way, the tall protrusion on the core locates in a cavi

in the cope, and this is called a core print The

casting is for an engine timing cover chest; the white sand core creates the internal water way to

shown

t

The internal sand core was made in a core box

with a silicate & veloset hardener This method

is a very quick way to make sand cores Cold se

Automotive Timing Chest Mould

Green sand mould with steel core &

silicate sand core

Baked sand core rods ready-made core rods

The cores in the above photograph were blown and baked in commercial core

making equipment

There is no shortage of small foundry operations that supply other foundries (your

foundry) with ready-made sand cores; there will come a time when you don’t want to make your own cores The cost of buying 5/8” Dia ready-made cores is not

expensive (under $1.00AU), the rods come supplied in 18” lengths, allowing you to

cut them into whatever size you require for the job at hand

Resin Coated Silicate Sands

Using cold set resins, mixed with the silica sand can also be used to make cores These resins allow you to work the sand for a short time until it starts to go of

Generally only available in 20 litre drums or larger, so it is not really feasible for the home founder to do this until some sizeable production runs are planned There are several foundry companies that supply these products

Foseco, a worldwide foundry supply house, has many different kinds of products to

cover every foundry situation It is well worth your while to investigate using these products, as they are easy to use and give very repeatable results with all types of metal casting applications Ask for the information sheets to be sent to you

There is no, one, correct way to do things with foundry work If three different

foundries were visited you would find that they all have different ways & methods of doing things You will discover certain methods that will work well for you

The idea is to get “REPEATABLE RESULTS”, It helps to make notes as you work on

your projects, don’t rely on your memory for details If you don’t go near your foundry work for a month or two, you might be lost if you can’t remember a certain process or method that you used to get a particular result

An easy way to create special shaped holes in castings is to make up steel cores in the lathe; they are then set in the pattern before you start ramming up When the mould is complete, and the pattern extracted, the steel core is held captive by the sand After the pour is complete and the casting has been retrieved from the sand, you can cut the gates and runners off

The steel core is then pressed out of the casting I use this method to make the spring caps, which are shown in a previous discussion The method is quick and easy, and works every time The steel core is smeared with oil and dipped into a container of graphite powder (The graphite coating prevents condensation on the steel core, which will blow when the hot metal hits it)

Captive Nuts

Can remain, as part of the casting, a simple way to achieve this is to turn up the nuts

or threaded collars on your lathe to the required size For secure retention in the casting, machine some grooves on the outside edge, then locate the nuts in the mould where required

The molten metal will run into the grooves during casting When the metal cools, it will shrink even tighter onto the captive nut, they are not likely to pull out of the

casting (The buttons or nuts also act as heat sinks or chills on the metal)

After this operation, holes can be drilled and threaded into the captive nuts to the size

to be used as anchors in the object that you have made Several captive nuts or plugs could be installed into the one casting if you wish

Don’t be to generous with the graphite powder when installing captive nuts into castings, remember you need them to be held securely, too much graphite may help

to release the nuts if under a heavy load

Note: The author does not have a financial interest in the company of Foseco

Building your gas-fired furnace

Construction Notes

Many ideas can be gleaned from this photograph The rolled former can be seen which is set up ready to start placing the refractory into the wall cavity

The steel supports are welded to the 2’x1/8”straps formed around the drum Wood plugs have been turned up on the lathe to create holes in the refractory for the burner & also the exhaust port on the other side of the furnace

The tall column is for the levers & sliding brackets to be attached for removing the lid safely from the furnace

A sub frame was constructed to mount the whole unit on so that the furnace can be moved around or stored away out of

the road (The next section deals with building this furnace.)

Please note:

This overview of building the gas-fired furnace was left in this ebook to quickly show

you some details, the full project is dealt with in depth in the next section

Go there now

Please click the link above to that section if you wish, or click on the bookmark tab to view all headings

Rear Side View

The furnace shell is made from an old drum, note the rolled sheet metal former used

to make the furnace walls The wood plugs create the holes for the burner pipe and exhaust pipe Put lots of grease on the plugs to help removal

Roll some 2” X 1/8” steel straps to go around the drum shell to weld supports and

other fixtures to Make up some plates to hold the burner inside & outside the

furnace, held together with bolts Lots of details are clearly visible here Your furnace can be scaled up or down to suit your operation

Roll the sheet metal Former

The size you elect to roll the former will be dictated by your crucible, allow about 2” of area between the furnace wall and the crucible sides Sheet metal rollers are ideal for performing this operation, enabling a perfect circle to be formed

You will need to secure the former with some self-taping screws, to hold it at the diameter that you require for your furnace It may be two or three days after ramming

or pouring the furnace walls before you remove the former, so you need to be able to collapse the former before you can remove it from the furnace

The furnace featured here was built from scrap materials scrounged from around the workshop; you can use secondhand steel and discarded materials to make yours also The dearest part of the whole furnace construction will be the refractory for the walls, floor and furnace lid, don’t skimp on this, high quality refractory will outlast any cheap or inferior materials,

The furnace you see here has been in service for many years, it has virtually been maintenance free all this time A burner needs to be constructed, A piece of black pipe 1 ¾” to 2” in Dia and about 16” long will make a nice burner, again the details are all revealed in the ebook mentioned above, There is no Rocket science involved with this, but you need to take care with certain things to make the burner easy to light and adjust to the optimum heat out-put for your furnace,

Furnace lid lift arrangement

Furnace layout

Furnace Notes

Building a gas-fired furnace is really just a lot of common sense and straightforward planning of the order in which you do the construction

The biggest problem facing most people is designing and building an efficient burner

The burner (LHS of furnace) designed for the furnace shown in this picture, is simple but highly efficient

It does not have an external flare or a fine jet, which is unnecessary The gas line pressure runs

at almost zero LP gas is fed from a 100lb tank through an adjustable regulator A 6 Kilo melt can

be done in less than 35 minutes from a cold start

This image shows the general arrangement of the furnace body, wheels and the lifting lever

lid-The lugs on the main upright are quite visible lid-The lid and the support rods are bolted

to these, the ends of the rods are threaded with nuts either side of the lugs Which allow the lid to be adjusted for proper fit on top of the furnace walls

There are no hard and fast rules for the size of your furnace; it will all hinge around

the size of the crucible that you choose Always allow at least 2” of free area

between the furnace wall and the crucible So size up or down depending on what you want I built this furnace from ideas of my own after studying other furnaces

Pour the floor of the furnace first Make the furnace floor 3” (75mm) thick

The steel former is rolled to the correct diameter, it is held in place with some wood wedges as the refractory is poured in (Refractory can be rammed also) don’t forget

to drill holes in the bottom and the walls of the drum shell to let water drain from the refractory When the walls have air dried, remove the former carefully

You will marvel at the simplicity of the burner design, which is a highly efficient

design and not difficult to build Please move forward to that project to read more about it

Every dimension and component of the furnace is outlined for you in imperial & metric, no need for guesswork or trying to workout the sizes of things to make, it is

all explained in plain English for you

Hours of work have been spent laying out an easy path for you to follow to help you construct a furnace that will last you for years in your home foundry operation

Scrap metal: what to melt

Aluminium

Most hobby caster’s are never quite sure what kind of scrap they should melt for their castings The best source of Aluminium metal is scrap cylinder heads, inlet manifold castings, & gearbox casings if you can be bothered stripping, & cleaning the muck of them Try to source your metal privately, or from engine repair workshops Scrap metal yards will rip you off when they find out what you are up to

Beware also of mixing Magnesium in with your scrap, it may catch alight during melting, it is impossible to put it out

To Identify magnesium scrap metal, the metal looks grey in colour Polish a small area with emery paper Then apply a small drop of 1 % silver nitrate to the

polished surface A black stain will appear on the metal Aluminium will not stain

Other sources of scrap metal could be from old machinery castings such as wheel hubs, casings & cover plates etc, If the item is painted and your not sure if it is

Aluminium or not, just place a magnet on the metal, if it sticks, leave it there, as it’s probably cast iron

Now, I can hear you asking how on earth does one melt a cylinder head in the little old crucible I’ve scrounged from another metal caster

Method 1

The idea is to take your cylinder head to a machine shop or someone who has a good sized power hacksaw, or better still a metal band saw, ask them to cut the cylinder head into small chunks to fit into your crucible!

Quick Tip

Getting good scrap will be the biggest problem for hobby metal casters Most will not be prepared to buy metal from a commercial supplier Melting your own is the next best thing If you stick with what I have said to melt you wont go far wrong Don’t concern your self with metal compositions yet; leave that for the experts to sort out

All you want to do is have some metal casting fun!

Aluminium Ingot Stock

Method 2 (My Favourite)

If you happen to have a charcoal forge stored in the corner of your workshop, drag it out and get it ready to do some serious melting Firstly you need a good supply of charcoal (Read… A good large bag full)

You can make it your self Complete instructions are available free at our web site

With a good supply of charcoal, and the right blast, it won’t be long before you will have to pour the melt into your ingot bar

The illustration above shows the shape of the ingot bar that I have used, it was made from a piece of folded heavy gauge metal, the notches were formed from pieces of angle iron cut to fit and welded inside the ingot bar

The ingot bars in the photograph weight about 6 Kilos each When the bar has

solidified, knock it out and get ready to pour the next melt The stacks of ingots in the photo were made in an afternoon’s work… The cost = $00.00 Plus fun time

Melting scrap bronze metal

Sourcing & melting Bronze is going to present another problem for you to solve The heat involved in the actual melting is considerably higher than Aluminium, and the metal losses involved as you melt will also be much higher

Finding suitable sized scrap bronze is going to make you search harder than you would for Aluminium Hunting around junkyards and private places for your metal may well turn up what you require

Probably the best source of good bronze metal is going to be by purchasing your supply from an ingot supply house

Buying it here will give you the exact metal composition that you need, eg Silicon bronze is one of the best types of bronze to melt in your crucible It is easy to cast, and does not present any problems while melting, and needs very little if any fluxing before the pour

It won’t be cheap to buy, but you will know the exact make up of the metal If you were to continue collecting scrap bronze, you will have difficulty determining whether

it is silicon bronze, manganese bronze* or perhaps Aluminium bronze * , gun metal bronze etc All these metals have different fluxing & degassing requirements for melting and pouring Some are just too difficult* for the hobby caster to even attempt

to melt & cast

There is nothing wrong with you experimenting and melting your own scrap, just don’t get too upset if some of your castings are not turning out as good as you may want them to

Try to keep your different metals apart if you can, but with scrap bronze it can be very hard to tell the difference between the mixes used commercially, even for the

professionals! (Without chemical tests & analysis etc)

An excellent source of bronze is buying the sprues and runners from a foundry

involved in casting bronze art castings for sculptors, they will most likely charge you only half the normal ingot cost Art casting foundries use silicon bronze…, which is very easy to melt & pour

At least with buying ingots you will be able to cut them up into small pieces with a power hacksaw, so they will fit easily into the crucible used for melting Cutting up chunks of scrap may give you more headaches than it is worth in the long run Bronze is a lot more difficult to break down into smaller sizes, and bronze castings do not smash easily like Aluminium does

One of the easiest ways to handle larger pieces of scrap bronze is to do all your melting in another type of furnace called the “Cupola Furnace”, these furnaces are the most ancient in operating principle, but are still used today in many places

Cupola furnaces are fuelled by charcoal and require a considerable amount of air blast to create the high heat needed for melting cast iron or bronze

We cannot go into the technical aspects of the Cupola Furnace here, as it would take

a large book to cover the subject

It may be worth your while to investigate this type of furnace as you advance along the metal casting journey

Many hobby caster’s usually end up building one of these after a lot of experience has been acquired with crucible melting, it just seems to be the next step in the long journey

Furnace ignition: Lighting up for the first time

When lighting the furnace for the very first time It is important to “run” the furnace in before doing any serious melting with it The refractory material has to be dried ”very slowly” so that it cures to a hard tough material to enable it to withstand the high temperatures involved with metal casting

The NEW furnace refractory should be allowed to air dry for several days Then and only then can you light the furnace and run it for a maximum of only FIVE minutes and shut it down and let it cool Repeat this procedure until no more steam can be detected issuing from the holes in the side of the furnace Once it is fully cured then you can run it for an hour or so, even do your first melt in it to help vitrify the

refractory and cure it fully

Follow These Steps:

1 Lighting up your furnace for the first time can be a daunting affair If a simple practice is adopted, there is nothing to fear from the lighting up of the gas-fired furnace

2 The easiest way to light up is to scrunch up a small piece of newspaper and push this between the furnace wall & the crucible pedestal (The block that the crucible sits on in the furnace)

3 Light the paper with a match and let it burn for a few seconds

4 Turn the cylinder regulator gas valve on very slowly, only let a small amount of gas flow down the line, a second or two after this you will see & hear a small flame erupt in the furnace with a pop

5 If you are using a vacuum cleaner for the blast, switch it on now, but on it’s lowest setting (some have an adjustable speed control) Bring the air speed up gently until the flame starts to swirl around the inside walls It will be running very rich at this stage

6 Increase the air blast again, but not too much as the flame may blow out As the furnace warms up, and it will very quickly, adjust the Air/Gas ratio until it is

running evenly with a gentle roar Let the furnace run at this low setting for about five minutes to warm up The ideal air/gas mixture is when there is a blue primary flame, leading out to an orange colour flame coming out of the exhaust port

7 If the flame blows out SHUT EVERYTHING DOWN INSTANTLY The starting process will have to be carried out again (Put The blower back on to blow

unburnt gas out of the furnace interior, if you don’t do this, any residual gas will

explode and burn you when you go to relight, LPG gas is heavier than air)

8 The furnace will most likely be too hot at this stage, to put your hand in to light the paper with a match, so use a long instrument to light the paper on the second time around

9 Once the lighting sequence has been carried out a few times and you have come

to grips with the behavior of your furnace, lighting up should be a success every time that you attempt to light up

• WARNING: DO NOT leave the furnace unattended while it is running, If there is a

power failure the blower stops, but the gas keeps going, this is a potentially very dangerous situation, It only requires a small amount of LP Gas MIXED WITH

AIR to create a life threatening situation…Read… “EXPLOSION”

Common Sand Casting Faults

Casting Mismatch

This is what happens when you are not thinking what you are doing while

reassembling the Cope & Drag moulds The mould was poured only to find the boxes had been turned around This is the very reason we said to colour match one corner

of your mould boxes to avoid this mistake You think I got mad when I saw this… You bet… Only one solution, scrap the casting (& remelt it), and re-mould & pour it again!

Cold Pour or Cold Shut

The metal was poured way to cold; it cooled even more while traveling through the cool sand and stopped right at the casting cavity Sometimes a low sprue height will also cause this to happen A combination of factors can at times confuse you to what actually caused the problem Some form of temperature control should be used to monitor the exact temperature that you will pour at Usually smaller items have to be poured at higher temps than larger items, simply because larger amounts of hot metal will keep hotter for longer

Quick Tip

Using uncoated steel chills or cores can also cause steam blows A good method I have found to prevent this is to smear some oil on the steel core or chill and then dunk the core in a box full of fine graphite flakes

or powder Place the core or chill carefully in the mould When the metal is poured, the graphite acts

as a barrier to moisture It does not affect the chilling action on the metal

Steam induced Core Blow

This steam blow originated from the sand core The likely cause was the core not baked long enough The core may have absorbed moisture from lying around for too long

The casting is a clutch slave cylinder The steam blow has just destroyed the casting Looking from the outside you wouldn't know what was wrong with it, as it looked quite normal, looks can be deceiving As a pressure vessel this had to be a very good quality casting, steel chills were inserted while moulding along the barrel & at the end

of the cylinder to promote a dense grain structure (Chill effect)

Needless to say, some new cores were made and some fresh moulds were made up and they turned out just fine

Glossary: Common foundry terms

Absorption: Ability of any material to absorb certain gases from the atmosphere

Use a good flux & degasser to purge gasses from molten metal, especially

Aluminium

Aerating: Reworking & reconditioning your moulding sand with hand sieve/Shovel/or

Motorized riddle (A great machine for any Foundry!)

Binder: A material such as Bentonite used to bind sand particles together Foundry

sand and bentonite is mixed in a Muller

Blowholes: Gassy metal due to lack of de-gassing before pouring Can also be

caused by wet foundry sand, sand should not stick to your hand when squeeze tested

Cast: To pour molten metal into the sand mould (Cavity)

Chill: Cast Iron or steel objects used to promote rapid solidification of metal, reduces

porosity Creates very tight metal

Core Shift: The result of a core moving with the pressure of the metal entering the

mould Make sure that core prints on the pattern are the correct size for the core being used

Crucible: You’re melting utensil, quality crucibles are made from silicon carbide

materials, buy the best you can afford (Cheap Clay Graphite items are available also) A make shift crucible can be lined with fire clay

Dross: The rubbish & oxides that form on top of the melt Always degas the metal Fluidity: The ability of a metal to flow freely when in its molten state (Correct

temperature)

Flux: Special powders available from foundry supply houses, helps to remove oxides

etc from the melt (Sprinkle on top of melt to prevent gas pick up from atmosphere)

Gate-In: The last part of the flow channel for the metal before it enters the mould

cavity

Gated pattern: Patterns & ingates mounted to mould board, saves hand cutting of

runners (Rapid moulding system, great technique)

Inclusions: Particles and rubbish in finished casting (Degas metal and blow mould

cavity out)

Ladle: A crucible or refractory lined steel pot used to pour or (ladle metal) from larger

melting device (Pre heat required before pouring)

Melting Point: Critical temperature that metal turns to liquid form (This is not the

pouring temperature.)

Mould: Sand/ Metal/ Clay etc, used to make the casting (Green sand, Permanent

or die cast, Investment casting type of mould)

Moulding Medium: sand used for the mould making process, e.g green sand/silica

sand/ casting plaster, etc

Oxidation: The reaction where an element combines with oxygen to form oxides or

dross etc

Pouring Basin: The top funnel section of the mould I.e sprue

Pyrometer: Special instrument used to determine temperature of molten metal

before pouring

Refractory: Heat resisting material, used in furnace walls, ladles, moulds &

crucibles Cupola furnace pouring spouts etc

Riser: A large head of molten metal used to feed casting as it cools Always feed to

heaviest sections

Shakeout: The operation of removing your castings from the sand moulds

Southern Bentonite: Special foundry quality clay used in the refractory, and as a

binder for green mould sands (Green sand moulds would mould without this

compound)

Judging temperatures by eye

With a reasonable amount of metal melting and pouring experience, you will soon get a feel for the correct time to lift the crucible out of the furnace and pour the

casting

Don’t worry too much if you have some failures; this is just a natural part of the

learning curve that all hobby caster’s go through

There are times when you think the metal is spot on and ready to pour, only to find out that it’s not Experience is a great teacher

Approximate temperature readings only

Looking at hot metal and trying to guess its temperature is really just a guessing game You have to view the hot metal under dark conditions A little difficult if you’re melting metal in bright daylight Aluminium is even more difficult to determine what temperature it is at, because it does not change in colour like molten cast iron or bronze

Aluminium looks silver at solid & looks a silvery pink colour when it’s at full melt The colour can vary with the amount of light in the foundry I still like the pine stick method that I discuss in the book However the most accurate method is with an industrial optical pyrometer You can also make up a thermal couple device and use a cheap multi meter calibrated to determine the temperature of the melt

The meter is made using two pieces of dissimilar Alumal metal; they have been proven to be quite accurate for measuring molten metal, although it can take awhile

to dial in the accuracy

The Home Metal Foundry

Your home metal foundry will be a constant source of satisfaction & amazement to you and your friends As you acquire more confidence with the projects that are attempted, you will find that after a while, people will ask you to cast small items for them

If you feel confident with your skills, by all means, do some outside jobs, whether for fun, or a paid service is up to you

Don’t take on a job if it is outside your foundry skills, it is better to carry out trial and error casting jobs of your own, rather than practice on other peoples work, which may end defeating you and suffer the embarrassment of not being able to do the job Some people will pick up the required foundry skills quicker than others, that’s OK, it

is better to learn at your own pace, rather than rush things through and not grasp the skills and techniques needed to successfully mould and pour your own castings When you become totally familiar with metal casting, everything will become second nature, it is a bit like driving a car, you don’t think twice about what to do next do you? All it takes is practice and lots of learning Don’t be afraid to seek out others that might be doing the same as you Visit mainstream commercial foundries for guided tours; you’re bound to pick up some really good ideas & new technology

I still remember the tour we had of the General Motors Holden Foundry at

Fisherman's Bend, Melbourne, Australia, during a foundry course that I was

undertaking On the last day of the course we were able to take a look at this large fully computerized manufacturing foundry plant

The principles of this large foundry were basically the same as what we were doing during the course, only the scale of the operation was simply huge The memory still lives with me today

Build as much of your own equipment as you can, you will not only save lots of $$$, but the custom-made gear will suit your operation perfectly If you have a reasonable workshop, it should not be too much trouble building your own equipment

In the next section of this ebook we will be taking you through all the steps to build your own gas fired furnace as well as a motorised riddle It’s time to start getting up

to scratch with your metal welding and fabrication skills Your’e going to have a lot of fun

Don’t forget the safety aspect of your craft, Molten metal can be very dangerous and can inflict some nasty injuries, buy the proper safety gear, it’s an investment in you and your own safety Do not allow small children in the workshop during metal

casting operations There will be enough things to look after with out having to worry about small children at the same time

Enjoy the fascinating journey into home metal casting, only your imagination &

creativity will limit the things you can make with this craft

Following this we have some outlines of casting projects completed in the home foundry which you can read about, and perhaps learn some techniques which will help you to further your foundry knowledge These projects were all produced with basic foundry equipment explained in this ebook