I've only used Raka once in the last year. It was about 90-95. It went off fairly fast, but I didn't have any problem. Just mix up small batches and get it out of the cup onto the boat. Once it's on the boat you'll have much more time to work other small batches up to it and meld them. If it starts to cure in the cup, toss it...and mix a smaller batch. I would definately not start applying epoxy until the temperature is static, or on the wane. I had no choice this morning and as it got hotter did see a few small bubbles that I had to brush out on the underside of my deck. No biggie...looks good. This is not a time to go fast...but a time to work smart. I think people make too much of this chemical bond stuff, but with the Raka I would think you have probably 48 hours. With the stuff I'm using probably 72 hours. BUT...I do try to put on fill coats the next day. Many, many boats have gone much longer between coats. Oh...anytime it's light enough to see...whether by sun, or light bulb, it's light enough to do your stuff.