PU Resin Optimum Temp for Viscosity and Cure / Gel Time

General Discussion
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Hi all
Firstly, thanks to all the contributors on here. This forum is amazing. I’ve used it a lot!

So, having built a number of boards now, always using PU resin, when it comes to glassing, I’ve experienced (as I’m sure many if you all have too!) everything from a leisurely glassing session to a frantic, panic induces haze where the resin has kicked much quicker than I needed it too!!

My question therefore is

What tenperature do the glassers and makers out there think its best to get the resin to before catalysing? I’m based in the UK so my ambient temps in Winter are lower.

I’m going to have to warm up the resin and want to find the optimum balance between viscosity and cure time…runny enough to laminate with enough time to comfortably glass a board without panic. I realise the resin kicks much more quickly in the pot that once being spread on the board.

I have bought a meat thermometer and will warm up the resin slowly on an oil filler heater and will aim for 18 degrees Celsius i think unless i can get some pearls of wisdom here. I will update this thread with my findings but hope someone has some knowledge beforehand.

All the boards I’ve laminated thus far, I’ve taken no info on resin temp other than if its runny enough to laminate!

Also, the room temp will be about 20 Celcius.

Thanks in advance!

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Hello Ed, welcome to the forum.
I would look to the TDS (technical data sheet) for the resin and shoot for whatever they call ‘lab’ temp, where they take their viscosity readings and working time, usually somewhere like 22-25C (72-77F). If you go warmer than that, the heat will speed the reaction along with the MEKP and it might result in one of those ‘exciting’ glassing sessions.

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Green light, Fiberglass Supply and others have a chart on their website that you can print and hang on the wall .

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Good shout. I’ll take a look. That’s a good idea I hadn’t thought of…will report back!