I am getting some problems with some minor imprinting onto the tooling surface of molds. It is not the fiberglass of the mold printing through, but rather the weave of the carbon that I lay into the mold to infuse that actually prints into the surface of the mold a bit. Any ideas what causes this? Is it a result of the epoxy that I use not having a high enough hardness?
I get that too, a bit. Especially if I use the mould too soon after having made it, or if I don’t postcure it (which I don’t most of the time)What surface coat are you using?
That’s the thing, I don’t have access to post cure, but I did leave it for quite a few days before using it and it was also under a heat lamp for quite some time catching some rays:D
I have not been using a suitable surface coat, I’m still searching for one. I have been using the same resin as a surface coat that I have been laying up the rest of the mold with.
Obviously I’m not using the best things for the job but that’s casue I’m still searching, but I would like to get a good idea of why this imprinting happens? Is it to do with the “hardness (barcol)” of teh reasin or what?
thanks for the reply jj.
Use the right materials.
Your resin is softening from the exotherm of curing parts, and either the mold materials or the layup is distorting the surface.
Ya that’s what I thought too, I am searching…
calcium carbonate is your friend 
I add about 1 tablespoon full to every 2ounces of surface coat mixture. It really does make the resin much harder.
I know, I beleive you and it’s already on the way:D it should tide me over unitl I find a proper surface coat…
That doesn’t make the resin harder, it just makes the surface harder.