You have a bigger problem than the gelcoat being too thick. Gelcoat tends to be brittle, but it should not "friable", i.e. crumble like a cookie, no matter how thick. You may have too much pigment in the resin. Pigment will weaken the resin. Also, check the age of your gelcoat resin. Some resins have a poor shelf life.

> I was wondering what could go wrong if you apply gelcoat too thick?

> What could make gelcoat turn out powdery?

> I had a couple places on a boat recently popped that had cracked gelcoat.
> I flaked a couple pieces off and they crumbled in my hand.