+x

 

Hanaldo - 6/19/2021 3:07:21 PM

Ah, that's different then - Crystic Glosscoat isn't a gelcoat, it does cure solid and epoxy can bond to it.

Breaking in moulds is definitely a thing. Though if you can get a semi-permanent tool sealer, then this will treat the chemical and physical bonding sites of a new mould in the same way that breaking them in does. So I never break in any of my new moulds, because they always get treated with a sealer first.

+x

 

Hanaldo - 6/19/2021 12:05:30 AM

+x

 

carbon man - 6/16/2021 8:46:22 PM

I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin 

I think this will be your issue. You can't use epoxy resin behind a polyester gelcoat, it won't bond properly. Gelcoats are designed to not fully cure, and they need the chemical reaction between the gelcoat and the laminating resin to cure and make a strong bond. Epoxy doesn't react chemically with polyester, it is a purely mechanical bond, and because the gelcoat isn't cured properly the mechanical bond strength is very poor.

So your issue probably isn't so much a release failure, but the fact that the surface tension between the gelcoat and the mould is higher than the bond strength between the gelcoat and the epoxy resin. 

Either switch to an epoxy gelcoat, or switch to a polyester/vinyl ester laminating resin.

+x

 

carbon man - 6/16/2021 8:46:22 PM

I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin 

+x

 

KLComposites - 6/18/2021 4:20:19 PM

+x

 

carbon man - 6/16/2021 8:46:22 PM

So Iv had 3 moulds stick on me now. I'm using tr108 wax as it's advertised to reduce fish eye when gel coat goes into the mould.

I have tried exact instructions on tin 8 coats and then leave over night before another coat.

Also tried 5 chem release followed by 2 tr108 wax.

I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin and cure in mould at 60deg straight away for about 8 hours so it gels fast in the event of a leak.

The shiney parts of the mould released just about but everywhere else stuck like s***!

But should I be laying in a layer of fibreglass and pulling that out once cured to break in mould first?

Any help appreciated.

You might be seeing high exotherm and temperatures over what the wax is rated for. Data sheet says the TR108 good to 85C but if you're throwing it in the oven at 60C immediately, your resin might get pretty toasty. 

Try Rexco's partall high temp wax. I had much better luck with it than the TR108. I was also seeing relatively high exotherm at moderate cure temps.

+x

 

carbon man - 6/16/2021 8:46:22 PM

So Iv had 3 moulds stick on me now. I'm using tr108 wax as it's advertised to reduce fish eye when gel coat goes into the mould.

I have tried exact instructions on tin 8 coats and then leave over night before another coat.

Also tried 5 chem release followed by 2 tr108 wax.

I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin and cure in mould at 60deg straight away for about 8 hours so it gels fast in the event of a leak.

The shiney parts of the mould released just about but everywhere else stuck like s***!

But should I be laying in a layer of fibreglass and pulling that out once cured to break in mould first?

Any help appreciated.