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GRP curing in "cold" weather
smart51 - 13/6/08 at 04:56 PM

I'm struggling to get my fibreglass to go off. I've tried upping the catalyst to 3% and 4% but with little joy. I've resorted to the hot air gun to warm it up a bit and help it on its way.

A few days ago when the weather was hot, it was going off really quickly. My garage is unheated but it is a fairly mild day. Cool for June but not cold at all.

What can I do to speed things up a bit?

clairetoo - 13/6/08 at 05:23 PM

quote:
Originally posted by smart51
What can I do to speed things up a bit?

Just warm the garage a bit - not a good idea to heat f/glass to cure it as , when heated gell coat expands , but on cooling it will shrink to slightly smaller than it was before heating .
This can cause all sorts of distortion.......

indykid - 13/6/08 at 05:46 PM

tent off a section with polythene sheets from b&q or something like that.

it can be a pain to warm a whole garage but to warm a few square metres isn't so much bother.

tom

chrsgrain - 13/6/08 at 05:52 PM

Use UV activated resin - means you have to work under artificial light to lay up - but doesn't go off at all - then open the doors / take it outside and goes off in a couple of ticks, no matter how cold - its great!!

Chris

turbodisplay - 13/6/08 at 05:57 PM

could moisture be the problem? I had that when it rained outside working in the garage, water in theair stopped the end closer to the door curing.

Darren

smart51 - 13/6/08 at 06:05 PM

UV resin sounds like fun. Shame I've just bought loads of the normal stuff. I'm not warming it up much, just enough to cure in a couple of hours. I'll give making a tent a go.

twybrow - 13/6/08 at 06:59 PM

Sounds like the dodgy resin/catalyst then... Hand layup resin should go off with 'summer catalyst' no problem at all @ 2-3% (by volume) in a un heated garage at this time of year.

stevebubs - 13/6/08 at 07:45 PM

Patience is a virtue...

Where did you get your resin/catalyst from ?

chrsgrain - 13/6/08 at 08:20 PM

Sorry - badly written post. The UV activating stuff is catalyst to go with normal resin, use it in place of normal catalyst.

May even have a bit lying about somewhere....

Chris

smart51 - 13/6/08 at 09:37 PM

quote:
Originally posted by stevebubs
Patience is a virtue...

Where did you get your resin/catalyst from ?


After letting it sit for about 8 hours, I scooped it all off the board I've been using as a "mould" Previous batches could be forced but this wasn't having it.

The resin and catalyst were both from Polyfibre in Birmingham. I've had the same stuff before and had no problem. Probably just a bad lot.

twybrow - 13/6/08 at 09:59 PM

Was it polyester you bought or epoxy?

smart51 - 14/6/08 at 07:14 AM

quote:
Originally posted by twybrow
Was it polyester you bought or epoxy?


Polyester. Low styrene emissions polyester, the same as the last lot I bought.