Has anyone else had problems with fine detail plastic (both smooth and smoothest) sticking to silicone rubber? A search of the forums turns up a couple of posts where people have experienced this and have believed the problem was caused by the model not being properly cured but I don't think this is the problem. There seems to be some sort of chemical reaction going on between the two materials. First let me say I have been creating silicone rubber moulds for 25 years. I've used many different materials for the master model (wood, metal, resin, plastic, glass, etc) but as long as the surface wasn't porous, I've never had adhesion problems. I wanted a system which produces many moulds reliably and accurately so I had several pieces printed which fit together to make a negative of the mould. I prepared the pieces by sanding and polishing the faces to remove the fine ridging cause by the printing process. Then I assembled the pieces and filled the cavity with silicone rubber. This worked very well for the first 4 or 5 moulds, then the rubber began to stick in places. To cut a long story short, the problem got worse with every attempted mould, until now I have to coat the entire surface with release agent otherwise the rubber will bond so strongly I have to tear it off and scrape the surface clean again! Release agent spoils the intended mirror finish on the mould surface. I don't want to coat the surfaces with sealer because that would upset some very fine tolerances, but I suppose I could try to include a compensation factor for this in my model design if there is no other solution. If the problem was caused by patches of uncured plastic, I would have expected adhesion problems from the first attempt. But actually it was okay at first then got progressively worse - from small patches to the entire surface. It's as though something is changing in the chemistry of the outer surface layer to encourage the silicone rubber to bond with the plastic. It doesn't seem like the surface is becoming porous - I can see no difference under strong magnification between a problem surface and another part of the piece which hasn't ever contacted silicone rubber. Can anyone throw any light on this problem, please? If I can overcome it I will have a very useful technique which I can use for many future moulding needs.