Cooling Epoxy and/or Primer slightly?

[thinwater]

Originally Posted by Tupaia

We have done repairs in 35+ degrees, using slow hardener, the only thing that needed cooling was us.



Pick your time of day, morning, evening or middle of the night depending on humidity and have 2 people, one mixing and one applying, using constant stream of pre-measured small mixes. Have everything else laid out and ready, clamps, spare gloves, mixing sticks, etc.



It sounds like you are glueing stuff together so should not be a problem but be wary of very large thick repairs as it can result in fires.



I used a super slow hardened recently in more temperate climes and it took 3 days to completely cure.

He makes a good point. I've used fast hardener in 30-35C by cooling the resin/hardner first. As long as the layers are not thick it works fine, if you are organized enough to go through the pot in a few minutes. But you are limited to a few layers of biax or the equivalent.

[EngineerRetired]

Asking those that have done this. Wouldn't the temp difference between resin and substrate cause an issue as the resin comes up to ambient temp? It would seem there would be a rapid expansion at the bond layer and that can't be good.

[Franziska]

Funny enough we had an old fridge sitting under the boat which we were about to give away.

Worked a charme!

We mixed small batches and prewetted the Biax with it. Brushed some of the mix on the wood before and than applied layer after layer. Max thickness was 4 layers. All good.

[Jim Cate]

Originally Posted by Fore and Aft

Franziska thanks for the laugh. A 30 degree day is hardly worth a mention down under. Slow hardener and a bit more speed/planning on the job should be fine.
Cheers

Ha! A little further "down under" (southern Tassie) it's more a problem of getting the damn stuff to ever go off, even with fast hardener! Maybe that's why there is such an interest in traditional timber boats here... no epoxy worries!

Jim

[thinwater]

Originally Posted by EngineerRetired

Asking those that have done this. Wouldn't the temp difference between resin and substrate cause an issue as the resin comes up to ambient temp? It would seem there would be a rapid expansion at the bond layer and that can't be good.

Not a problem. The epoxy comes up to temperature in less than a minute, long before the curing process proceeds to any extent. Do the heat transfer math.

[thinwater]

Originally Posted by Franziska

Funny enough we had an old fridge sitting under the boat which we were about to give away.

Worked a charme!

We mixed small batches and prewetted the Biax with it. Brushed some of the mix on the wood before and than applied layer after layer. Max thickness was 4 layers. All good.

Good. That's not very thick. However, at 6-8 you will start having heating problems, and above that slow cure is vital.