The best laid experiments!!!!!

 

I have been reading up on making moulds to pour molten pewter into rather than cutting-carving graphite. I read that one could make 'silicone clay' that could deal with molten pewter by mixing room temperature vulcanising silicone with cornflour (1:2 ration). I made enough 'silicone clay' to try to pour a small peace piece and a small heart - as you can see in the above photo. 

A couple of process photos below including my 'clay' mixing tray and the original pieces pressed into the soft clay.

Removing the original from the cured  'clay' resulted in nice sharp moulds. I let the 'clay' cure for 24 hours.

The silicone could not handle the heat as you can see from the photos below.

Maybe it would have worked if I was able to guarantee that the silicone was able to handle a much higher temperature. My next experiment will be with an oil based clay-sand moulding mix.