Metal Casting Zone

First of all, Hi! I have been doing sand casting for about 7 years but my newest project demands that I make a more efficient setup. Ok, my friends and I play a lot of poker and I thought it would be really neat to have some metal chips so I drew up a design and had it minted. I have a few of the finished products but they want about 3 bucks per chip and at 500 chips I don't really want to shell out 1500 for a chip set. I started casting them in my sand setup but I can only run one at a time so it would take me about 3 months to complete. So, my question is, what kind of mold should I make to do this a little quicker? I want to pour copper, Brass and probably zinc (or some other cheap silvery metal). Are these metals too hot for reusable molds? What other kind of mold can I use to do this in a timely manner?

Thanks!

Im becoming a big lover of lost wax, i think this is a perfect project for it.
Make up a bunch of wax patterns then cast them all at the same time. the other choice
may be a silicone mold, Its iffy of how high a temp it will withstand though, it might hold up to a thin zinc casting but even zinc has a higher melting point then the silicone is rated for. pewter might be another choice.

Ya, initially I was thinking pewter but since the cheapest pewter I can find is 12 bucks a pound I would like to stick with something cheap like Al or Zn at .50 per pound.

I have been kicking around the idea of setting up a vertical sand mold where the chips would stand on end and the sprue is on top. I could set about 5 up and could probably hold it with clamps. I would still have to ram up 100 molds but its a lot better than 500.

I wonder if you could make a plaster mold off the chip and pour directly into it? bed the chip in clay and pour the plaster fight on top of it, dry, flip over and the pour the other side. would need some sort of release agent pva would probably work.

You could also make your own pewter, 9-10 % copper 90% tin and a pinch of antimony.
a home plumbing store is a good source for tin, just read the labels on thier solder most are 95% tin with a pinch of antimony.

Anything you do like this will require a lot of setup or long casting sessions. Here's a link I like to go to for ideas. They did a bunch of these little medallions by stacking mold after mold. This whole site is great, I want to try the cup spoon and saucer someday. This site is very educational and they sell suplies too.

www.foundry101.com/Head%20Start%20Medallions.htm

Hi Goldy

Simple and easy way is to have your poker chips done in white/metal pewter,Then have them electroplated if required make up one perfect master and have a few production masters done of this , or make 5 perfect chip masters and have a spin casting mould made of these. I manufacture items similar to this regularly. Find a medallion company or badge company, they should know of a spin caster that could do this. If you were close to me Australia LOL I would get you to post the chip master to me. Johncast

DO NOT CAST INTO PLASTER. plaster has way too high a moisture content and will explode extremely forcibly due to the rapid expansion of steam. the only way to cast into plaster is to do a traditional ludo mold that is kiln fired and poured hot.

bronze and al are way too hot for a silicon mold, but you can cast some pewter alloys into silicon molds, so i'd go that way. pewter is pretty cheap right now too.

another option is to make a plaster or silicon mold off your minted coin, and then cast waxes out of that.

then tree it up and do a burnout.

and yet another. make a silicon mold, cast a bunch of resin copies of the coin, and make 2-part sand molds, you can then just scratch the sprues into the sand and drill your gate.

I have never had trouble with plaster explosions. I mostly do zinc though which is not that hot.

admittedly I am new at this, but all of my casting have been in plaster. Brass, CU and AL. at first I did have a problem with too much moisture and I had one mold crack slightly, but no explosion. the real key I think is to dry your mold in an oven for several hours before you pour. heating the mold just prior to the pour has helped me also.

I would go with lost wax, making a number of wax patterns to cast at once.

Just my $.02 YMMV