Terrain Making – After having several of my OOMO molds fail on me I was bummed out. The ones that failed on me were mostly components that I had built from other kits and used the molds to replicate my work rather than starting from scratch every time. I'm more or less just a hobby caster so I needed to find an expert to help me out. Luckily the TFB Plastics the shop that I usually pick up my supplies from has a really knowledgable staff.
After explaining my issues he suggested using a platinum cure instead of a tin cure silicone. Apparently the tin cure like OOMO is a cheaper silicone that is only supposed to hold up for 50+ pulls if you properly care for your molds. (I got much more that that with my base molds, but anything with undercuts was far less) The product he suggested is called Mold Star which should last for 400+ pulls. I was excited as the OOMO lasted quite a long time and the Mold Star was only $5 more per 1 lb. kit.
Once I got it home and set up my masters I mixed up a batch and used my vacum chamber to removed the air bubbles. Since it has a 50 min pot life I had plenty of time to degas the silicone before pouring. While mixing I noticed the color of this material is the same as the Hirst Arts molds which explains why their molds seem to be much stiffer than the ones I made in my intial runs. I used the 15 Slow version of Mold Star which meant four hours to cure, I decided to leave it overnight just to be sure.
After popping out the mold I'm really happy with how it turned out the material is much stiffer so it should hold up better against the rigors of resin casting.