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Mold Making and Resin Casting

Once this has set for 4 hours, you can now break down the mold box to begin the process of pouring the other side. Once the sides are removed, put them to the side, as we will re-use them for the second pour. Turn your half poured piece over and set it back on the same base (Fig 20). Start removing the clay bed. The clay bed will come off fairly easy.

You will find that you still have some clay bits adhering to your proto type. Use your flat scraping tool to gently remove the bigger pieces and a toothpick to remove bits from any detail (Fig 21).

Now, as before, use your brush dipped in alcohol to dissolve the remaining clay bits and residue right down to the silicone seal at the prototype. Be careful not to pull on the prototype itself, thus breaking the seal or you will have silicone from the second pour run down the seam where we don't want it.

Now rebuild your mold box in the same manner as before. Next, use a brush dipped in petroleum jelly and liberally apply it to the surface of the cured silicone (Fig 22). This is very important. Silicone bonds to itself and without this barrier, your part will be locked into a cube of silicone.

Try to be careful about getting Vaseline on your prototype. It won't hurt anything but can fill in fine detail so wipe any excess off with a clean brush.

We are now ready for the second pour. Mix silicone as described before and pour. In 4 more hours, we can begin making duplicates of our master.

After the second pour has cured, break down your mold box. Gently separate the 2 halves of the mold (Fig 23). They should come apart pretty easy here but you may have to coax it a bit.

Now remove your prototype.
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