Question on Coin Moulds
April 26th, 2010 | 
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I really need some help here folks, LOL
I made a mould of a coin it’s one sided.
I then tried my first go at melting the pewter on my BBQ. It melted fine. Quite easy. It was liquid and runny. As soon as I poured it into the mould it looked like this on demould.
HELP!!!!!!!! It was windy and I have a little ladle I am using. Iv’e tried 3 coins. I haven’t got any talcum or graphite powder. It also looks like my mould is showing pinholes bin a couple of places but overall it is good. It was windy and I was outside doing it at night. Can you help me please?
Answer:
Hi, It is a lttle hard to see if the mould has reproduced the detail etc without air bubbles but assuming that is OK pre warm the mould by casting a few coins and discarding them. Then dust the mould with graphite powder and pour the pewter at as low a melting point as possible. Do not overheat. All the best Stan Alderson
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If you are happy with the pewter casting which contains air holes (that is entrapped air) then what you are doing is probably OK. However if you want a much better reproduction you need to centrifugal cast.
I have had quite a bit of experience using this method and you get some great reproductions.
Have a look on Google and you may find all the information that you require.
Perhaps not using a coin of the land might be advisable especially if still in circulation, but old coins should be fine.
Good luck
Hi, If you cannot afford the centrifugal casting preocess which most of us can’t although it undoubtedly gives the best results try the following. Pre-heat the mould to 120degrees celsius by wrapping the mould in aluminium foil and place it in the oven before casting. Casting into a cold mould gives results similar to what you have achieved. Before casting dust the mould with either talc or graphite and then clap the mould against something hard to get rid of ant excess powder. Don’t waste ant time but when casting give the mould a tap every now and again to ensure penetration of the hot metal into all corners of the mould and to release any air. Do not overheat the metal. A simple test is to get a match stick and insert it into the metal. If it smokes a lot it is too hot. See how you go. Stan Alderson