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Curing too fast

Posted: Tue Jul 07, 2015 6:42 pm
by frankp
How does one prevent the glen-l 2-part epoxy from setting to quickly? We are getting about 5 minutes before it hardens. Unfortunately we have the "fast cure" hardener. Any suggestions other than the obvious? I have three containers of the hardener and would rather use it before ordering more. Any help or advice would be appreciated. Thanks!

Re: Curing too fast

Posted: Tue Jul 07, 2015 9:47 pm
by chugalug
:D Try putting it in paint tray spreading it out and cool it down.I liked the slow hardener better-had a longer work time.If you mix the epoxy with fast hardener and keep it in small cup ,it hardens up fast and gets really hot.don't burn yourself!! Glen-L has an awesome video on fibreglassing. :D

Re: Curing too fast

Posted: Fri Jul 10, 2015 5:39 pm
by mrintense
Two other things you can try. First, keep the resin and hardener in the house when not using it. This keeps it cooler when you need to mix some up. This will help a little. The other thing is to do what Tim suggested (chugalug) but also if you have something larger you can lay the tray in, put some ice in it and lay the tray on top. This will also slow down the curing a bit.

However, with fast hardener, it is going to cure faster. If you can, try to keep your batch sizes small.

Re: Curing too fast

Posted: Fri Jul 10, 2015 9:07 pm
by chugalug
:D read somewhere you can mix hardeners(fast and slow)might help out some if you get some slow hardener.

Re: Curing too fast

Posted: Sat Jul 11, 2015 8:23 am
by jamundsen
use the slow hardner. I had the same problem and ended up building a plastic covered shed like a greenhouse inside my hangar that I airconditioned. That worked pretty well. Of course the FLorida sun in the summer didnt help any.

Re: Curing too fast

Posted: Sat Jul 11, 2015 12:51 pm
by chugalug
:D I fibreglassed my boat last winter when the temp outside was -25 ! if the epoxy was setting up to fast,all I had to do was open both windows in boatshed :lol: :lol:

Re: Curing too fast

Posted: Sat Jul 11, 2015 3:04 pm
by Bob Perkins
Epoxy cures by generating its own heat (exothermic reaction)

The thicker it is in all directions (like in a cup vs. a pie plate) the more heat it generates.. heat = cures faster.
It is the exact opposite of latex paint... a gallon of opened paint will stay wet for hours/days.. put it on a wall and it dries very fast..
Mixed epoxy is the opposite.. thin stays wet... thick generates heat and cures fast!

so - spread in a pie plate to make it thin- it generates less heat on its own that way.

Also - just keep it cool - fridge - ice chest - etc..

and of course.. use slow harder if it is an option..

HTH

Re: Curing too fast

Posted: Sun Jul 12, 2015 12:38 pm
by frankp
Gentlemen - thanks for the advice!!!! Presents some interesting challenges while building a boat in Arizona where the ambient temperature is well over 105 all the time... Appreciate the feedback. The slow hardener arrived this week too.

Re: Curing too fast

Posted: Sun Jul 12, 2015 2:03 pm
by Bill Edmundson
Frankp

Another trick is to get two aluminum pie pans. Freeze some water in one then nest your resin pan in that. But, small batches is a key.

Bill

Re: Curing too fast

Posted: Sun Jul 12, 2015 3:31 pm
by mrintense
Frank,

I understand the heat problem. It regularly gets over 100 here in the Austin area starting around August. Even at lower temps, I have to strategically plan when I want to do epoxy work. When I was installing the plywood skins, It was a constant race to get completed before the epoxy begin to setup.

I can tell you that when you get to it, keep the jobs relatively small and have everything ready to go before you start. Practice any steps that might be a bit unclear. You'll probably have to do a few early (as in "O Dark Thirty") sessions on some jobs. If you can get a portable air conditioner, that helps tremendously with the comfort levels.

Good luck.

Re: Curing too fast

Posted: Mon Jul 13, 2015 5:41 pm
by bob smith
Although I did it solo, in retrospect a helper making up small batches as you are ready for them would make for an easier time of it.
"Honey, can you come out here for a minute?"

Re: Curing too fast

Posted: Mon Jul 16, 2018 6:19 pm
by monitor
With temps in the 90s in Kentucky, I have been slowing small batches of epoxy down by nesting a solo cup inside a INSULATED solo cup. Chipped ice and water goes in the insulated cup, just a small amount. Be sure to mix your batch in this setup. The glue thickens like ice cream and mixing the silica is even easier in the thicker glue. Lasts as long as on a 70 degree day and it gives you an excuse to raid the ice box occasionally! :)

Re: Curing too fast

Posted: Tue Jul 17, 2018 4:33 pm
by mrintense
One thing to do as often as possible is do jobs in small batches. Leave the large jobs for cooler temps like in the morning. Or break the larger jobs down into smaller jobs if possible. For planking plywood sheets of course this is not possible and the early morning option is your only real choice. Having someone on hand to mix small batches for you can alleviate this problem