It's getting cold here...30's at night, 40's during the day. My attached garage stays about 10-15 degrees above ambient temperature. I's like to do some more fiberglass work this fall. If I use Marinepoxy medium hardener, how long will it take to cure? My guess is several weeks to a month or so for a final cure, but dry to the touch in 24-48 hours. If true, I could still fiberglass parts until it really gets cold. Comments?
Dave
hey Dave,
I built my weekender in my somewhat heated shop during the winter. I also used marinepoxy with the fast hardener. I was mostly able to get it to set up fairly normally at 40 degrees. When I did some glass work that I needed to have set up, I covered the boat with a plastic drop cloth that went all the way to the floor and set up a small electric heater underneath it set on low. Worked like a charm. I had the stuff hard to the touch by morning.
After my recent experience building 5 Scamps, I am more convinced than ever that fall and spring are the best times to work with epoxy. I suppose that for me when it is uncomfortable to work because I'm cold is when I should stop anyway.
Al
I second Al's suggestion about the heater and covering. It would be a good idea to run a couple of tests on scrap wood, at shop ambient, and heated, to get an idea of how long you'll need and what works or doesn't. My guess is that you're probably not going to get acceptable results at 40-50º.
I use oil filled radiator looking heaters. No flame, they don't get too hot, unless you yank out the thermostat and thermolitic switch, like I have a in a couple of mine. The unmolested versions (I have a total of 4, $25 bucks at Wal-Mart) will heat an enclosed space to about 120 degrees, before the thermal switch trips it or the thermostat does the same. Without the electrical regulation, it'll drive the temperature up to about 150, which is good for post curing stuff. I tent what ever and place a thermometer in top of the tent, with a flap. I open or close the flap to regulate the temperature or it trips the breaker in the panel, depending on how closely I'm monitoring it. As far as time trials, don't bother, just keep it hot as long as you can. A half a day will usually cure it enough to sand it, unless you're not able to truly elevate temperatures much. In these cases (really cold weather) just keep it above 75 for 24 hours and you're good to go. If you can keep it above 85, you'll cure hard in 18 or less hours and above 90, 12 hours or less. This is why I really cook things. I can toss some heat at it and it'll be ready to work in the morning.