RiverMan Posted December 12, 2014 Report Share Posted December 12, 2014 The last clay I used raised the grain on my wood original despite the fact that I had done a good job of sealing it. I'm curious what type should be used as the clay base for making two part molds. Anyone? Thanks, RM Quote Link to comment Share on other sites More sharing options...
mark poulson Posted December 12, 2014 Report Share Posted December 12, 2014 What type of clay were you using? Quote Link to comment Share on other sites More sharing options...
Travis Posted December 12, 2014 Report Share Posted December 12, 2014 If the grain raised I honestly would still say your master wasn't sealed or the sealer has a high water permeability. I have used most the hobby store clays (sculpey, craftsmart, amaco, etc...). Now I just have hodge podge mound of clay I use over and over. Quote Link to comment Share on other sites More sharing options...
RiverMan Posted December 12, 2014 Author Report Share Posted December 12, 2014 No it was sealed really well. I used a mineral based clay and from what I have been reading it has a significant amount of water in it. After sitting 12 hours or so while the first layer of silicone cured some water eventually got to the wood. Quote Link to comment Share on other sites More sharing options...
Travis Posted December 12, 2014 Report Share Posted December 12, 2014 Ok... then we eliminate the crank wasn't sealed properly. So that leave that your sealer either has a high water permeability, the clay also contains another component that compromises the sealer, or the RTV reacted with the sealer. I use the clays mentioned above for "sealing" I have used Zillsner bullseye shellac,Krylon H20 laytex spray paint, Johson's paste wax, WD40, vasoline, and a commercial mold release in a pump spray bottle (forgot the name), and Smooth-on Mold Max 30. Quote Link to comment Share on other sites More sharing options...
RiverMan Posted December 13, 2014 Author Report Share Posted December 13, 2014 Thank you. Quote Link to comment Share on other sites More sharing options...
mark poulson Posted December 15, 2014 Report Share Posted December 15, 2014 i use a rattle can clear acrylic to seal my wood mold forms and it works. Maybe you need to do two coats. 1 Quote Link to comment Share on other sites More sharing options...
