How long should gelcoat take to cure?

[adrianreeve]

Hi there, I have a quick question about Gel coat. Been repairing a small knock in my rear wing this weekend. Fibreglass all good, then put the gel coat on top of the repair. I did this yesterday afternoon, and the gelcoat is hard, but the surface is still tacky, meaning that I can't sand and puta second coat over the first. how long should it take for the gel oat to go off? I'm reasonably sure I added the correct amount of activator.

Cheers

Adrian

[MarkB]

To do repairs like that you should either use top coat which is sometimes called flow coat or add a percentage of wax solution to the normal gel coat. It will never cure hard.
Your best bet is to dig out the gel then redo it but put some thing like acetate or anything plastic that won't stick to it to seal it so the air can't get to it........Or just use resin pigmented to suit as this will cure and is easy to flat off and polish up.

[MarkB]

By the sound of it it is low as you mention needing another coat?...Try covering the second coat with a plastic bag then seal the edges to keep the air out.

Gel cures on a mould face because there is no air, the surface you lay up on is tacky as this allows the resin to do it's chemical thang and join forces with the gel and stick like sticky stuff to blankets.......But if the gel is left too long and loses it's tackyness then there is every chance the chemical James Bond bit won't work properly.

It's not rocket science but it is a black art......:)

[adrianreeve]

Cheers Mark

[robo]

Also the gel coat as a repair wont be getting a good cooking from the f/g lay up so it might pay to give it a gentle warming. Just thoughts.

Bob