This is my first time working with fiberglass. I'm working on a small fender for my race car. Ultimately, I'd like to do these and some other parts in carbon, but it seemed wise to spend some time practicing and learning with cheaper materials.
I made a mold of an existing fender using tooling gelcoat, fiberglass cloth and polyester resin. That worked really well, and I'm happy with the mold.
But, my first part did not turn out so well. In most places where there are relatively sharp bends, I'm getting large (1"-2" long) voids, which I assume are due to air bubbles forming where the 225g fiberglass cloth separates from the mold while curing.

Any suggestions on how to address this? Should I be using CSM instead of cloth? I've seen mention of others using spray adhesive to keep the glass in place, but I'm not sure how that might affect the mold release. (I'm using spray PVA.)

Original part (which was cleaned up after this shot, before working on the mold):


Top outside edge. The voids are clearly visible.



Leading edge with some clay and stuff still hanging on.