Need help with shrink

Hey I’m having trouble with gel coat repair patches shrinking I suspect it’s due to too much heat from buffing but I figured I’d ask someone more familiar with this stuff than I. I catalyze correctly and wait a nearly 24 hours before I sand and after I buff it to a polished shine I notice it always sucks in a little I’m away from work currently but I will get pictures posted tomorrow any help or advice is appreciated
Thanks
Brad

 

That is barely enough time for the solvents to evaporate. If you want to speed up the cure, use a heat lamp.

 

I just mentioned the shrinking issue in another thread. Depending on the type of polyester you are looking at 2% or more of linear shrinkage (5-13% volumetric). Seems like everybody using a common, basic kind of PE is dealing with it. Among the solutions is to compensate for it beforehand or to use special (i.e. more costly) resins or additives.

 

I usually lay a thicker than necessary coat of gelcoat and sand it down after. The other solution is to finish with a gelcoat/Duracote mix and spray the last coat on.

 

I believe we use a vinyl ester gelcoat I always apply it thicker than needed and sand down I’m going to try the heat lamp thanks for the advice.