To achieve best results in gravity casting there are a number of points to consider (fewer than for machine casting) and we would be pleased to offer advice to anyone experiencing difficulties.
Pewter is an almost perfect centrifugal casting alloy but can be difficult to drop cast (select Pewter S or H1 ) there are a number of alloys which are totally unsuitable for the process and only a few which are especially good. We have listed below a number of alloys which are appropriate for gravity casting.
in alloy selection are:-
CASTING TEMPERATURE silicone rubbers are much more prone to heat damage than the harder black vulcanised rubbers.
TOXICITY for items that are to be handled particularly by children or for applications involving food or drink it is essential to use a lead free alloy.
DETAIL & FINISH - bright polish can be best achieved by pewter some of the higher tin whitemetals can be polished but will dull fairly rapidly all our other alloys are suitable to be plated or painted. Where there is little detail in a mould or where quantity is more important than quality the cheaper alloys can be selected.
Most of the leading manufacturers of military models started out at home in their garage so who knows what you could do, good luck.
PEWTER S pouring
270-315C (Select this alloy for all mould materials except rubber)
Suitable for casting into wood, plaster, sand, metal dies etc.
NOTE FOR RUBBER MOULDS select this alloy where H1 is not strong enough, in this situation this composition overcomes many of the difficulties but for best results great attention must be paid to mould design and accurate temperature control of the metal. Complies with BS5140 (broad description) and ABPC.
We also manufacture a large range of alloys suitable for centrifugal casting, lead free solders.