Hi
I've done all my building in the winter in a climate which can get to -30 C. General rule for me has been to heat things up, do all the coats in one day and then forget about it until the next weekend. Your tent idea would work, leave enough room to move around. Until I started using RAKA, I used fast hardener for everything. Even with the cooler temperatures and slower set time, I didn't get the penetration I wanted with RAKA (some weave still showed). For RAKA, I went to slow for the first coat and fast for the next two. Made for a longer day but a better result. With System 3 and West Systems, fast was fine. I use wood heat and just let the fire go out. With your system, I would let it get to the same stage as you would for re-coating (tack free) before I shut down the heat. We have managed nine kayaks and four canoes in my shop and the only problem was when a batch was not mixed thoroughly enough. No blush on any of the boats. Warm the epoxy first to improve the viscosity and warm the tent first so that the boat is warm for better penetration. In really cold weather, it has taken two weeks before I could sand but, on the plus side, you had a long time where you could scrape easily to get rid of runs etc.
The better option is to insulate the garage -- costs more up front but cuts your heating costs in a major way and makes working in it much more pleasant. To cut heating costs, just put poly on the walls over the insulation and hang a tarp or poly from the ceiling to divide the area into heated and unheated space. Don't know what insulation costs where you are but it's a fast payback here with R20 walls and R40 ceiling. (My shop is R12 and R20).
good luck
don
: I am building in an uninsulated garage and will have to heat it to
: do the glassing. I plan to build some kind of tent around the
: kayak to minimize the space to be heated.
: But heating is expensive. How long is it necessary to heat? How
: much should the epoxy cure before I can turn of the heat? I'm
: not looking for a number of hours (Because it varies between the
: different epoxy-brands), more like at which cure-stage I can
: stop heating.
: The temperature is around freezing at the moment. Without the tent
: (which I haven't made yet) I could only get the temperature up
: to around 14 C (~57 F) with a 2000 W electric heater and a 4200
: W propane heater. But that is too expensive for long term use.
: Btw. does anyone have a description or pictures of a tent-frame
: that is easy to make?

: Palle Dam
: Denmark