On Tue, Feb 14, 2012 at 7:48 PM, Lee Mulvogue wrote: > > Get some proper moulding Addition-Cured RTV silicone, like Dow Corning > Silastic S-2 or similar. =A0They are initially expensive, I think I paid > about $80 for 1.1kg, but they would make a mould that is reusable > hundreds, if not thousands, of times, and readily flexible so your > parts just pop right out in 2 seconds flat. =A0Available in different > shore hardnesses, choose one that's flexy enough to pop your part out, > and has a high tear strength. =A0You don't even need a release agent, > but a quick spray of a proper release agent can greatly extend the > life. We've used Smooth On Mold Max 60 to make some molds for urethane encase par= ts. http://www.smooth-on.com/a59/Mold-Max%3D-60-Higher-Heat-Resistant-Silicone/= article_info.html They have lots of grades available (you may not need 60). I think it was around $100 / gallon. We used MDF that was then varnished to make the negative mold for the silicone rubber. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .