The basics I used when starting to learn to make molds was this small collection of supplies.   Pictured here:   -1oz Dart plastic cups  -Plasticine Clay  -Smooth-On Ecoflex 00-30 Silicone  -Small tray with grate
 Here I have taken several of the 1oz cups and placed a small ball of the plasticine clay in the bottom. Once I have done this, I can carefully press each die into the clay. I prefer to place them on a corner so I don’t lose any numbers when I cast. This does result in needing to re-carve the single corners effected on each die.
 I carefully fill each cup with a corresponding amount of silicone. Since each cup it 1oz, I plan for about 8oz of silicone.  This means I have to mix equal parts of A and B for the Ecoflex. 4oz (by volume) of Part A, and 4oz of B. Make sure you mix very carefully and make sure to avoid mixing in too much air.   Silicone can be de-gassed in a vacuum chamber, and this will help reduce bubbles. I have also heard people refrigerate the poured molds for longer curing time and more chance for the bubbles to float to the top. I would advise doing a sample test before trying this out.
 After the silicone has cured, you can carefully pull the mold out of the cup. I then carefully remove the clay base from each mold, and carefully wiggle the die out of the mold. The result is a fresh and new silicone mold ready for casting!
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