Pre-Release / Alligator Problem

[Itchy&Scratchy]

Can also be caused by gelcoat that is too thin , thereby resulting in undercuring and wrinkling.

[Itchy&Scratchy]

Xander, you havent by any chance got your hands on one of those godamn awful silicone release waxes have you that they made a few years ago.

I remember we tried them when they were around and they caused this type of problem as well.

[Landlubber]

....most likely the thin gelcoat as I & S suggested....

[Landlubber]

....you do not get a name like that unless you have played with the product......poor bastards.

[Xander]

No, I've got a good wax. It's the temperature, mix ratio and thickness of application that's causing me grief. Hopefully I can correct for all three in one more attempt or else I'm gonna try a different approach to my project. Thanks for all the advice.

[Landlubber]

No morries mate, just leave a beer in the fridge.

[pescaloco]

Originally Posted by Xander

By the way - thanks for the Southern California Weather Report! I am not at all jealous. Well, maybe a little.

Sorry..........................

[tunnels]

Originally Posted by Xander

Building a box. I am using unwaxed polyester gelcoat. Don't have spray equipment so I am applying the gelcoat with a brush (which is why I need to apply two coats). My mold is made of melamine with clay fillets in the corners and some tuck-tape covered wood. The first application goes on without a problem but when I apply the second coat, major pre-release takes place. It's happened twice now and I don't know what the issue is. The first time, I waited a few hours for the first coat to begin curing before the second coat was applied. After seeing the results (which occur within 20 minutes of applying the second coat) I suspected a hot mix so I corrected for the second attempt by using less catalyst and waited longer for the first coat to cure. Still no success, both attempts failed with almost identical results. Room temperature is a little low, around 13ºC / 15ºC but that's normal for me and I've never had cure problems before. This is becoming an expensive mess. Any suggestions?

Firstly do you understand what causes these problems ?? If you understand the problem you can work out the amswers for your self .
Prelease is caused by the product you are making shrinking away from the mould ! ok ? so what causeing that problem ??
Alligator problem , this can be cause by thin gel coat (SPECIALY IF YOU ARE BRUSHING )/ undercured gelcoat- (not enough catalyst) (ratio to low ) or a slow brew on the second coat of gel .
General rule for gel coating is first coat at 1.5 % of catalyst /second coat at 2% catalyst and let cure at 20C over night !!