I have been making gelcoat+polyester moulds from damaged parts, and I'm being forced to fix the mould surfaces with car body filler, sanding to 1000 and finishing with filler spray primer. After this process, when I have the surface as desired, I made the attempt of using car clearcoat, with really good results. But it don't last smooth many mould uses, it tends to wrinkle and lose strenght.
Parts are made with polyester resin, hand lay up, and room temperature curing.
Any experiences on mould repair or last coat to apply to get a shiny result?