Gel coat question

If I gel coat my carbon fibre parts does the gel coat flex as well as the carbon or does it crack? Thanks!

dont quote me on this as i may be wrong…

If its epoxy gel coat then it should flew with the part,

Polyester gelcoat / vynlester may crack…

all gel coat will crack if it is too thick. never mix poly with epoxy!

i am using epoxy gel coat!

Depends on your gelcoat. You can formulate them for a lot of flex, or to be quite rigid. (mostly the high temp ones are more brittle). Keep in mind that some gelcoats need a good cure before being ductile.

My best guess is to read the datasheet. (not much of a help, I know.)

Why are you using a gelcoat? Just wondering why your using a gelcoat rather than no gel and the first layer being your cloth.

If i use and poly gel coat and resin to make a mold, will it be ok to use epoxy to make parts?

i read somewhere that it is a no no, (i think)… p.s. im still half asleep

It is fine. There shouldn’t be any issues.

You could go for a flex gelcoat, is it more for a cosmetic reason?

And I have made epoxy parts from a poly mould, but if I ever do cross materials like that I make sure my mould is as sealed and shiny and waxed as it’s going to get lol

The wings on my glider (full size) are carbon and it has a Poly gel coat, this appeared to be the norm untill around 2005`ish, the wings flex a fair bit anything up to 4ft at the tips and no cracks yet (it is 19 years old!) The biggest killer is UV and the cold (temps as low as -30C when flying in Lee waves at 20,000ft) wing flex at these temps does crack the gell, I have seen it happen. But I guess your parts wont be flexing at those temps!!!

Thanks for that. Interesting!