Hey guys, this is my first post. I have been making a set of moulds to make a carbon fibre wing skin. I started with cutting my pattern out of high density blue foam. I then coated it with a couple layers of coating epoxy with a few scoops of microbeads thrown in to make it thicker and sandable. After sanding it down to a nice smooth finish, I cleaned the surface with the Easy-Lease mold cleaner. I then applying several coats of Easy-Lease release agent (letting it dry for about 15 mins between coats). I then went ahead and applied the gelcoat for the uni-mould process. I put a second coat on after letting the first dry for a few hours. I then let it cure over night. The next morning these wrinkles appeared in the gelcoat right in the middle of the surface. I figured they were only on the exterior. I then proceeded with the coupling coat followed by the reinforcement. The next day when I pried the pattern out there were these worm holes where the wrinkles had been in the gelcoat. They appear to be air pockets but when I put the gelcoat down (both times) the was a generous even coat. I've been following the recomended ratios for the catalyst so I'm right stumped to figure out what I did wrong. I tried a second go using the same process but with waitng a little longer between the steps but I got the same wrinkles in the gelcoat again. Can you help me?

Attempt number 3 was much better with no wrinkles. I went for just applying one coat of gelcoat however when I got it out and polished up, you can clearly see several places where the brush strokes were too thin. I hope this won't be a problem for using the mould with my prepreg. For my fourth attempt I went back to doing two coats of gelcoat although this time I let it cure overnight after each application. It came out with only two very small wrinkles this time so I think I've got it worked out. I still wonder what would happen if I had moved faster with the two coats, giving only a couple hours between each, then going straight to the coupling coat on the same day. I read a post from a guy that did the whole thing in one day so I guess it would be worth a try. Maybe on a smaller part.

The other thing I would suggest is are you sure you mixed thoroughly. Mix well in one cup and then transfer to another cup and mix again with a new stick. I used to get all kinds of problems like you describe until I made this my practice.
Hope this helps.
Fred