unexpected loss of heat big problem?

[JLIMA]

My workshop has electric heat but the wind the other day knocked it out in the middle of putting fiberglass on the hull. I know it needs a certain temp for the epoxy to cure fully but is 2 days well bellow 40 deg Fahrenheit going to really muck things up to the point that I need to redo it or will bringing up the temp after the wires are repaired tomorrow allow it to fully cure. For what its worth it's been 34 hours and it went into the 20's last night and everything is still quite tacky still....

Be happy it is tacky!

That way your layup does not make any trouble accepting the following layer.

Leave it as cold as possible until you can provide a proper curing temperature again. Then go ahead with the job.

Don´t worry it cures thouroughly, once heated again.

Regards
Richard

[JLIMA]

Ah thank you I may breathe again so all is not lost ....

Originally Posted by JLIMA

Ah thank you I may breathe again so all is not lost ....

You can even have won a few days off! Nothing lost.

In fact, I like cold layups. It makes dead sure you get a proper primary bond.

[Man Overboard]

So can you purposely work in colder temperatures, say 50º (122ºC); and then kick up the shop temp when you are ready to do a full cure. For instance, when you are doing a large layup that you want to vacuum bag, and want more time for layup and bag prep?

[alan white]

Yes. Crank on the heat when you're done.

Originally Posted by Man Overboard

So can you purposely work in colder temperatures, say 50º (122ºC); and then kick up the shop temp when you are ready to do a full cure. For instance, when you are doing a large layup that you want to vacuum bag, and want more time for layup and bag prep?

Ähh, yes, and no.

No, in case you really meant 122°C ! Although some creatures will survive that, the guy on the job will not!
50° Fahrenheit is only 10°C, and that is a perfect temperature to do a entire hull in one go!

So, yes!

Richard

[Petros]

Usually lower temperatures has the effect of slowing the reaction. It is conceivable that it will eventually cure even at the lower temps (though I would not want to test that on a large structure). Though there is the risk of contamination of the surface if it is stays sticky too long.

Originally Posted by Petros

Usually lower temperatures has the effect of slowing the reaction. It is conceivable that it will eventually cure even at the lower temps (though I would not want to test that on a large structure). Though there is the risk of contamination of the surface if it is stays sticky too long.

Always lower temp. slows down the reaction.

The curing can be severely effected when it sits too long at low temperatures, and finally cures at the surface. There is no guarantee that it cured fully to the quality it would have when cured at the recommended temperature!

But that will not happen here, we are talking days, not weeks or months.

Regards
Richard

[Man Overboard]

Originally Posted by apex1

Although some creatures will survive that, the guy on the job will not!

Ha ha, Ya I don't know why that didn't stand out as being wrong. I accidentally converted 50C to F, (and then posted it as C) instead of the other way around.

[Herman]

That is the nice thing about epoxy. At lower temperatures it does not reach a full cure, and everything bonded to it will achieve a good bond. After all bonding is done, crank up the temperature and postcure the whole part.