Metal Casting Made Easy

Complete guide to hobby metal casting.
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.

Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
1
Complete guide to hobby metal casting.

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

Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
2

Complete guide to hobby metal casting.
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

Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
3
Complete guide to hobby metal casting.
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.
T
he 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.
Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
4
Complete guide to hobby metal casting.
Castings from metal.
Bronze & Aluminium items
are the result of
greensand casting.
Produced in the author’s
home foundry.
Greensand casting can

produce quite fine details.
Each of these items
presented their own
particular casting
techniques, especially the
crocodile nutcracker
.


Sand casting techniques.
H
ave 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 intriguing craft.


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.
Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
5
Complete guide to hobby metal casting.
About the author.

M
y 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

machines etc.

As a teenager I went to Tech College and studied all the trade courses I could find, even
attending night classes over many years.

Furthering my studies into foundry work, I now hold certificates in all foundry areas Inc, sand
moulding, core production, foundry practice & pattern making. But I can assure you that the
early days of my casting were done with much trial and error. (Plus plenty failures.)

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.
Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
6

Complete guide to hobby metal casting.
DISCLAIMER.
Foundry work is lots of fun.
Y
ou 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.
Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.

7
Complete guide to hobby metal casting.
A
nother 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.
•
This ebook has been written and compiled as a PDF ebook; it is readable on any
computer platform providing you have the FREE Acrobat Reader installed on your
computer.
•
All images displayed within are copyright of “Coljan Photography” Australia, May
2003
•
International Copyright protects all Images & text appearing in this eBook. Images
are Low - Res, watermark embedded.

•
If you are new to metal casting, please read the book as a whole, and not just in
sections, the more experienced metal caster may choose to read individual chapters
if they are familiar with certain operations.
•
Navigation from start to finish is quite simple, choose any page from the bookmarks
or contents shown, and use the black forward & backward arrows to go from page
to page. You can also enlarge or reduce the font size to fit your computer screen for
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•
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down you will notice a small side bar with all the page numbers shown. This method
can be used to find a certain page very rapidly if you know the page location or page
number.
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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.
== ANONYMOUS
==

Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
8
Complete guide to hobby metal casting.
Moulding and foundry work.

M
oulding 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!


Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
9
Complete guide to hobby metal casting.

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 hand-
ramming tool to the size you require. Two or three ramming tools could be made up
in different sizes to suit the different size mould boxes & patterns you might have.
Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
10
Complete guide to hobby metal casting.


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 glov

The 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
.


Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
11
Complete guide to hobby metal casting.

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.



Water Spray.

Visit your local super market to buy a florists hand pump water spray device. this is a
very handy tool. The adjustable nozzle is used to create a fine mist or a solid stream
of water. Use it to keep the top of the sand moist on a hot day, or use it to wet small
sections of the mould that may have dried out a little. You can use the spray to wet
the sand when setting a sand core. The wet mould sand can be pinched to hold the
core better. Always be on the look out for things that you can adapt to your work.
Quick Tip.
Your moulding bench can be of any size; unless you are limited
with 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.

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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.
Quick Tip.
This Electrolux Vac may look battered about, but it still runs
well, and provides more than enough air for the furnace.
An electronic slide speed control makes lighting up the
furnace a breeze. The old vac would also work equally well
with a charcoal furnace.




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.





Parting powder.



You can buy proper parting powder, I found graphite to be just as good, and some

people use plain foundry talcum powder, which seems to work well. You might need
to use an old sock, to make up a shaker to apply the parting powder. Keep things
simple and inexpensive by using every day products and items in your home foundry.


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.
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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 som
handles 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.

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Making foundry patterns.

B
efore 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.
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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 timber
patterns are expensiv
to

e to make.
T
he 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.
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Pattern draft.

I
n 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
pinholes.


If you are making a pattern that has webs or strengthening ribs on one side of the
pattern, make sure the sections are roughly the same thickness, otherwise the
castings will suffer from tears and shrinkage. Always allow a generous amount of
feed metal to supply the casting as it solidifies.

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.

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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.
W
hat 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
technique will enable you to make accurate complex split patterns, which can be
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Complete guide to hobby metal casting.
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.
T
o 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
yourself many headaches if you do this every time with NEW patterns. As there is
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Complete guide to hobby metal casting.
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
.


T
he 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.
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Complete guide to hobby metal casting.
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.
Quick Tip.
This is the part of foundry work that you look forward to,
checking the success or otherwise of all your hard work.
This casting looks OK at this stage & most do, however after
extracting the casting from the sand, give the casting a
thorough check to make sure there are no cold shuts, miss
runs, or metal pulls, shrinks, caused by insufficient metal feed

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.

T
his 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 &
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Complete guide to hobby metal casting.
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.
Quick Tip.
Sand moulding is very easy when you have patterns,
gates & runners mounted on the mould board.
Ram up of the mould ready for pouring only takes a
few minutes. Always hang the pattern board up ready
for the next round of moulding and casting work.

Mounted patterns & runners.
T
he 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

Casting Mismatch!
This photo shows a classic casting fault; (The mould box has been accidentally
turned around.) This is a casting miss-match, it happens when you don’t have
identification markings on one corner of the mould boxes, a good way to match
mould box corners is to spray a bright colour like red or blue on one corner of the
mould boxes. (cope & drag) A quick check of the corners before starting to ram the
mould as well as before mating up the halves when closing, will tell you if it’s right or
wrong.
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.
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Reconditioning foundry sand.
D
ue 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
1/3

rd 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.

Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
23
Complete guide to hobby metal casting.
Eleven steps for sand moulding.

The Moulding Bench.
Y
our 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.

Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
24
Complete guide to hobby metal casting.

Step two: Setting the pattern on the mould board.

T

he 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.
Written by Col Croucher Australia. You are entitled to one
Printed edition of this ebook, please respect my copyright and intellectual
Property.
25