|silicon in tin|
|tin wall with clamp|
I have mentioned this silicone before Platsil 71-20 RTV Silicone Rubber mix 1 x 10 ratio Part A and Part B, use vinyl gloves (not latex) measure carefully down to grams for volume (can't fluctuate by 5% or more or error) used scale to weigh exact grams of each, scraped and mixed both together very thoroughly. Note: I don't know how you can do this and keep it such a perfect mix without using the gram scale (thanks Deb). You have a 30 minute window once it is combined to get it all mixed and into your tin walled off area.
|mold material is white so picture difficult|
After setting for a minimum of four hours the tin is removed and based upon marks left you slit the rubber to allow your original clay to escape. On the dog I placed a crimped piece of tin as a shim between his ears (thanks for the idea of crimping it Walt) where I would know exactly where to cut the mold material.
This shows the mold after removing everything and at this time you need to decide whether or not you are going to give it more support by making a plaster mold over the silicon for support, I opted not to because of the size. To do a plaster support just move your tin frame out a bit and make your basic plaster, fiber glass mold over it and let dry. Often this keeps your wax from moving during pour or set up and creating weak spots or cracks.