I’m kinda new to the composites world. I made a few parts but the last mould I made turned out like this. Not 100% sure why but was hoping someone could maybe give me some ideas.
Alligatoring or elephant skin.
Cause: undercured gelcoat.
How to solve: get to cure the gelcoat better.
Can be done by:
-increasing catalyst amount (between 1.5 and 2.5%)
-increase temperature
-increase wet film thickness
-in bathtub shaped moulds: put mould on the side, so heavy styrene can flow out. gelcoat under styrene will not cure.
-mix better
-apply with more equal film thickness
Thanks for the tips.
Question tho. I let the gel coat sit long enough where if I touched it, my finger would barely leave a mark. I guess I should wait even longer? Is there a thing as letting the gel coat cure too long?
Is this your flange area? I think it looks like this area didn’t get enough gel coat. Maybe sprayed unevenly. Are you using cardboard for flanges?
Fixed it. Hermans tips helped. I think I was just rushing it too quickly. Plus, it was low to mid 60’s when I was doing it. So I over catalyzed, laid the gel coat a little thicker and let it sit over night. Came out good finally.
And in the original picture, below the modeling clay is the part surface. Above is the flange. I brush on my gel coat right now cause I’m to cheap to buy a gun. For flanges, I use aluminum flashing. Very thin and easy to apply with double sided tape, and no prep work needed to make an acceptable parting surface aside from the normal steps.