Chavant clay and fiberglass molds

I have been doing some reading on making fiberglass molds. One thing has me concerned. The curing of the resin causes heat. With the chavant clay being oil based, will there be any distortion to the original sculpture? I am going the Chavant route even though it is a 3 foot tall figure because I will not have the available time to spend each day to use WED clay. Would rather get some research done before hand so I can figure out the best way to cast the creature. It needs to be flexible, so a hard mold is needed. Any ideas? Anyone use the Smooth On product line of silicones? Thanks. Matthew


  • Hey Matthew sorry i didn't see this earlier. you should only be using the fiberglass for support, with the inner mold silicone (i like smooth on oomoo, it doesn't require degassing) . The process is called matrix molding or matrix transfer molding. 

    Hope this helps
  • Thanks Chris. I have only worked with hydro stone / ultra cal molds for foam appliances and that was 25+ years ago. So I am learning new tricks here. In the rod and cable puppet tutorial, since the end product is silicone, is this too a matrix mold? Do you have any recommendations on what might be some good sources for more info on this? I took a look at the tutorials, and I did not see anything that looked like it covered this process. Thanks again Matthew
  • Hi Mathew, I've been using epoxamite by smooth-on for a couple of years now to make molds, very much like fiberglass but no odor and the cure time is rather long, several hours, so there really isn't the heat problem encountered with fiberglass, I've used this with wed clay and chavant clay with no problems, with water based clays make sure you seal the clay thoroughly or the epoxamite takes forever to cure.  I used the epoxamite 102 medium set for the werewolf head that I am using in an upcoming indie film, you can see it on my website at or on the kickstarter page at

    I used dragonskin pro for the skin and also thinned the dragonskin pro and added the silc pig pigments to paint the skin.  I have also had success with foam latex in the same molds.

  • Hi Charles, thanks for that info. I do like the smooth on products. Was not aware of the material you are using for the molds. I will go check it out. Matthew
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