I am new to molds and casting, I would like to make a mold from a laser cut wood design and make a coin from that mold. I will be melting metal like aluminum or low temp metals, what would be the best putty for what I want?
Most silicones can handle high temps, I'd go with either the High Strength series or the Plat series - both can handle up to 395 degrees.
As the original will be wood, I'd use the High Strength series and be sure to seal the wood as any moisture will interfere with the mold curing. The Plat is "picky" about what it cures against but the HS doesn't have much that would inhibit it from curing properly. If you want a putty type, I'd go with either the Amazing Mold Putty, regular Mold Putty or the Mold Putty 15 (15 has the longest open time). If you have a lot of small detailing then the HS series would be better as it will get into every tiny crack and crevasse.