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Originally Posted by qz33
Thanks for story and the insight into the process. Sometimes the how can be even more intriguing than the final product. I love seeing J Scott Campbell's composition sketches and light box work.
I've been meaning to ask someone in the industry: What's the usual casting process like? After you finish with the clay is it covered in something slick then covered with silicone? Is a fiberglass mold first?
Also it's been said on these forums that PVC captures the most detail. That true? Is there a type of resin you prefer a statue be cast from?
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It's interesting that traditional sculpting and digital rendering aka digital sculpting actually converge in the prototype process. My original must be molded so that three castings can be made. One for production which is not painted and two which are painted. One stays in the U.S. and one goes to China. The one in the U.S. is used to match the Counter Samples the factory sends back after working on establishing the paint process for the edition using the paint master sent to them. Counter Samples are the first pieces made by the production managers at the factory and one or two are sent to DST in this case as a sort of "What do you think? How are we doing?" step. Input is given and the factory proceeds with the production.
In digital work, once the piece is finished and approved, it is printed out in 3-D. That piece is then molded, just as the master I sculpted is molded after approval. Michael Measles, who molds my pieces, sprays a mold release over them so they separate more easily when the mold is cut open. The mold is typically done in silicone rubber and the castings made from that mold are in polyurethane resin, which is strong and slightly flexible. No outside mold, or "mother mold" is made. Michael makes a simple box mold, which uses a lot of silicone, but leads to cleaner seam lines. He could do a "Glove mold" which can be googled, but it's a more thin rubber mold surrounded by a supportive "Glove" on the outside.
Polyurethane is a very expensive resin and so the factory does not use it in production. They use polyester resin mixed with porcelain powder (cold cast porcelain) or polystone, a much cheaper product made from polyester resin and stone powder. Powdered porcelain is a finer material and gives the statue more of a feel of porcelain.
Note that the printer could print out three prototypes, but I think the above is the more common method.
I hope I explained this clearly. Thanks for the question!