Hi,

Feel free to share some pictures, but I'm not sure I can help much beyond what I already showed in the video.

Hi. Sorry the forum doesn't send email notifications, I should add that.

From the pictures it looks quite tricky to build that. Simply hollowing out a coin is not going to be enough.

It might be possible to produce a die, which molten silver could be cast into, to produce the enlarged coin, that could then be hollowed out.

Another option is CNC machining and hardening a punch with the scaled coin design, and stamping a silver blank.

There might be a way of taking a silicone mould of the original coin, then scaling it up slightly somehow. You would probably need to do multiple negative/positive cycles to end up with something that is bigger and can take the heat of molten metal. If it doesn't have to be silver, you could try pewter, which has a very low melting point. It might even be possible to cast pewter directly into a silicone mould.

Hmm, ok. There must be a way of expanding the coin without damaging the face of it then.

You could try hollowing out the coin, and then pressing it over a mandrel just slightly bigger than the hollow. This might take several goes on progressively bigger mandrels before it's expanded enough, and you would definitely want to anneal the coin between each pressing. It will be very difficult not to rip the rim, but if done carefully it might work.

Another option is to expand the coin before hollowing it out. If you put a silver coin in a hydraulic press, but sandwich it between sheets of soft metal like lead or copper, you should be able to squash the coin without ruining the design. Again you might want to do this in stages, annealing it between each go.