Gel coat question?

[craig]

Hi, Quick question about the top coat? I have read that the surface needs to be air tight for the top coat to harden, is this true of all top coats?

I have some gel coat from marlin but this seems to set in the open air.

I want to have a bash at my dash but need it top coating after the resin, so do I need to but some special gel coat?

Cheers
Craig

[alackofspeed]

Mine goes off in open air.

Gel coat is used primarily to ensure mouldings release. If you're doing your dash, you don't need to use gelcoat - just glass it, then use filler to take out the imperfections. That's what I've done with mine, and it seems to have worked pretty well.

[Ric H]

It's true - gelcoat only hardens off completely when sealed in a mold. For coating you really need flowcoat, which is gelcoat premixed with a wax to remove surface tackines. Info I picked up here:
http://www.cfsnet.co.uk/acatalog/CFS...LCOATS_46.html

[alackofspeed]

It'll go off sufficiently in atmosphere without the wax, you might just have to wipe the very top with some acetone (though I've not needed to yet, as I've been deliberately using a bit too much catalyst).

A friend of mine used to work for Sunseeker powerboats, and is a dab hand with gel coat / polyester resin / glass.

He said for repairs (which is all I've been concerned with), you shouldn't use any wax (as it may adversely affect the colour), and use plenty (read excess) of catalyst to ensure enough heat is generated to make the gel coat go off.

[craig]

Cheers guys, John what filler did you use on your dash??

So if I use the blue marlin gel coat supplied I still need to use the catylist I have and mix some in?

Craig

[alackofspeed]

Nowt fancy, just off the shelf filler from Halfords.

Yes you need to add catalyst. It'll be a peroxide catalyst (exact name I can't recall), I think (haven't got a bottle to hand) you should add about 6 drops per 10ml of gel.

[craig]

Cheers, I am going to attempt my dashboard within next few days so hope it goes well

Craig