Iron foundry basics
Practical Action
Pattern Making
Patterns, which are simply copies of the shapes of casting required are made of wood. Preferably a
hard wood is used and finished with a covering of good quality, water-resisting varnish or paint. This
helps to resist damage to the mould when withdrawing and also tends to be less affected by
moisture picked up from the moulding sand which is always damp.
Figure 17: Split wooden pattern halves located by dowels
Patterns should be made very carefully to the required dimensions, but allowing (1 % of length)
oversize, to compensate for the shrinkage of metal as it cools.
Patterns are usually in two halves, which are correctly aligned to each other by the use of dowel
pins. More advanced patterns made of metal, cast-iron, brass, aluminium alloy, or white metal can
be used, but these are more difficult to produce, because of the accuracy required and are
therefore more costly. It is much easier and quicker to work with wood than metal, though of
course, the metal patterns are more durable (Fig. 17).
Equipment Required
Core Boxes
Wood
To requirement – made locally
Patterns
Small oven for 520°F
(270°C)
Moulding Boxes
Moulders Tools
Peg Rammer
Wood
To requirement – made locally
Metal/wood
For baking cores
Various sizes
Wood/Metal Locally Made
Flat Rammer
Wood/Metal Locally Made
Strickle (wooden
(Straight edge)
Wood
Locally Made
Vent Wire
16g wire
Purchase locally
Trowel
imported
Ex UK
Available locally
Sieve (or riddle)
3/16” mesh
imported
ex UK
Available locally
Conclusion
Readers are reminded that this profile is not intended as a technical instruction, but only as a
guide or introduction to the lower levels of the foundry industry. For those interested a list of
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