Glassing in cold weather

Hello. I have 1 more coat of lam glass to do and am expecting it to only get to 65 deg. tomorrow. I have to glass outside as I have no place inside to do it . Would it work to do the lam coat and then put the board in a heated room for a while . I have a small meter room here at the Apt. complex I could put the board in for a while . I could also put a small heater in there for a while also… Will this work??? I don’t care how long it takes to set up but tomorrow is the only day I have off till Sat. Thanks so much for your help… D.J.

it will go off, it’ll just take longer in a cooler temp. If you can put the board in sunlight, that might help too.

hope that’s of use


Thanks Doc , I getting impatient to get this thing done … D.J.

yah, by all means go for it, strike while the iron is hot, etc. I find that when I get distracted from a project it can take me forever to get back to it.

The other thing is… if it takes longer to go off, say 2-3 days worst case…what do you care, right, cos you can’t get back at it til Saturday. Besides which, my own SWAG ( Scientific Wild-Assed Guess ) is that when resin hardens over a longer period of time, the polymers formed are longer, tougher chains that fast-hardening hot batches. It may not be quite as hard, but by the same token it’s less brittle.

hope that’s of use


Nothing wrong with glassing in the cold. It’ll still be the same board - just take longer to kick. You can always use lamps and such too if you absolutely must.



Using UV cured resin is a great cooler weather alternative. However, if you can only glass outside then that kinda kills the process.


Hah man I’m about to glass in cold weather today too… It’s even colder here though, like 50… I’m gonna see if my mom will let me glass in the laundry room… yes I’m sixteen! Prolly gonna do it outside though which sucks. Put the finbox in at about 8 pm and the next morning it’s still tacky at 9 am! ohwell at least it will give you more time to get the glassing on right, I know I’ll need it…

Ahh… Got it done … Wasn’t too bad . the temp got up just over 60 but it was sunny too so the resin kicked ok … better than I thought .

15-25 mph winds didn’t help though . wondered if it was gonna be a nightmare but it went Ok… Thanks Again for the help… Don J.

Heat the resin up in a double boiler or crock pot. Lam with warm resin.

Faster cures are stiffer and more brittle.

So if you glassed in even colder (30 degrees) would you get an extremely strong glass job even though it might take weeks to harden?

dude. make sure that gas hot water heater/dryer is shut off at the gas line.

Hi Hotcoat,

The way I do it is kinda like the double boiler method mentioned above. I use a “water bath” technique. I just get two tubs, one for the resin and one for the warm water. I fill the warm water tub about 1/4 the way full with [obviously] warm water then i place the resin tub on top of it. this heats up the resin nicely. you can tell the difference in viscosity in about a minute or two. the resin just gets so “slippery”. when it is the viscosity that i want i catalyze it with same amount of catalyst as per warm weather. it makes gelling time more predictable in cold or rainy weather. and I can be doing this outside, not inside the house. I’m not sure if the colder temperature of the board has anything to do with the resin adhering well to the board but from what i notice is that it’s just the same as glassing in warmer conditions.


PS i used to microwave the resin but that just made it incredibly hot. and very little catalyst would send the resin smoking in the tub. it would melt plastic tubs just like that. but it was still easy to work with once on the board. I don’t microwave resin anymore.

Does polyester resin have a dangerous flashpoint? Going to also do some winter glassing in my garage and was wondering about the water heater pilot light and portable heater.

if you’re using catalyzed resin in temps of 60 degrees or lower add a drop of cobalt to the mix.

also, as far as warming the resin a micowave or blow drier works fine, and its probably faster- 20 sec in the micro and your good to go. just make sure you warm the resin before you catalyze it