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Pewter is an ALLOY which means it is composed of more than one metal. Most modern pewter is composed of 96 percent tin and 4 percent copper although there are many variations. It is a soft metal and can be shaped easily by hand tools and machine tools. Due to its low melting point (approximately 230 degrees centigrade) it is suitable for casting. It is a bright material, which makes it popular for the manufacture of ‘silverware’ such as tankards, candlesticks and even jewellery.
Pewter can be purchased as ingots. Because pewter is malleable (soft) it can be cut with a hacksaw easily. When preparing to cast pewter small pieces of approximately 60mm in length are cut. This size will fit comfortably in the ‘bowl’ of a casting ladle, ready for casting.
Before casting can take place a mould must be made. Moulds can be made from a range of materials including MDF, steel, silica sand or even oil based casting sands such as ‘petrabond’. In schools and colleges, MDF is an ideal material and moulds made from this material can be reused a small number of times. An example of a mould is seen below. It has two parts and they are held together with wire or small cramps.
The diagram below shows pieces of the pewter ingot cut to a size suitable for heating in a ladle. Fire bricks have been arranged around the bowl of the ladle so that the heat from the brazing torch flame is reflected back onto the ladle. As the temperature rises the pewter begins to melt and quite quickly forms a molten liquid.
The molten pewter is then carefully poured into the mould. The mould is set in sand in case any of the molten pewter runs down the side of the mould. If this happens the molten pewter will simply stay on the surface of the sand and cool down. The mould should never be placed on a cold surface. If molten metal comes in contact with a cold surface it will ‘splatter’ violently. Anyone close to the area will be in serious danger.
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