I cut pour holes in the silicone mold halves, then strapped two pieces of wood to them with rubber bands. I mixed up the resin and slowly poured it into the molds. I then placed the molds into the pressure chamber, sealed the lid, and began pumping air into it with the air compressor.
Something was wrong. I could hear air leaking out of the chamber and the pressure gauge was staying at zero. I tightened the lid more but the air was still escaping. The resin is a slow-cure so I had about 10 minutes after mixing it to get it pressurized. I removed the lid of the chamber and immediately noticed that the rubber seal on it had come loose. I pushed the rubber seal back into place, put the lid back on, and again pumped air into the chamber. The gauge started rising.
When it got to 50psi the safety release activated. I was shooting for 60psi. Apparently the factory had set the safety valve incorrectly. I got a wrench and adjusted it so it stopped releasing air, then removed the air hose from the chamber. It was pressurized. I let the molds sit in there for 4 hours.
I depressurized the chamber and removed the molds. Moment of truth time. I undid the rubber bands and pulled the molds apart. The resin parts actually looked really good. I used a dremel tool to cut off the pour hole extrusion, then sanded down some of the excess resin that had seeped into the seam of the molds.
Yay! The process had been a success. I spent the rest of yesterday getting more molds ready, including a 3-part mold for the pelvis. I hope to pour a bunch of parts this evening.
