just got one how long after glassing before i can turn it on? any other usefull info? thanks paul
they put out quite a bit of water vapor as a byproduct of combustion, so I’d consider that too. What kind of temperatures are in your shop, currently? doc…
generally about 50-55 if i have the heater on and the radiators before i can get it up to about 65ish.
Okay, so this isn’t going outside the range that resin will harden in - though it’ll take longer. That’s not necessarily a bad thing. And the heat is more for your comfort than for anything else. Wait until the resin is fairly hard ( and the fumes pretty much gone ) before you fire up the space heater. I’d also note that fir sanding and polishing cool temps are good, both in letting you wear enough clothing so that dust and stuff are not on your skin so much and in keeping the glass cool while you’re doing it. doc…
Whats the range poly resin will harden? how cold is too cold?
Poly resin, strictly speaking, will go off pretty cold, though there are resins and resins and resins - all ‘polyester resins’ are a mix of several chemicals that are catalysed by MEKP or something similar . There’s more variables such as thickness of lamination, how much catalyst you’re willing to use, exactly what kind of polyester resin you’re using and so on. Sunlight has an effect, humidity, that sort of thing. Resin gives off heat ( exothermic reaction ) as it hardens, so that can drive the cure time one way or another. I have gotten resin to harden, though it did take a while, at 40 F or maybe a little lower. It’s a question of how long you’re willing to wait. Epoxies are a little different, there’s low temperature hardeners available for some epoxy systems with far more data available. I was looking for a chart of hardening times vs temperature and found nada, but I did stumble across http://www.netcomposites.com/education.asp?sequence=2 which is worth a look, doc…
was wondering this…how cold is to cold for a UV lay up to go off. Providing that the sun was your only source of UV light. Say for instance that you had your garage heated a bit, at around 50, but the temp outside was actually oh say a balmy 35 degrees. Do your lay up and open up the garage door and bam klet that sweet winter sun do it’s thing. i would imagine that it wouldn’t real make that much of a adiffference as long as your resin was kept warm prior to glassing. by the way, i was polishing off a gloss this weekend in 40 degree weather. NICE!!! Winter is fun Drew
Uhmmm…one thing aboout the winter sun is it’s sending its light through more atmosphere, so it might be the relative UV level is down some. I wonder if there’s a correlation between the altitude and the speed resin cooks off at. I seem to recall that many chemical reactions will proceed slower in higher pressure and faster in lower pressure - all other things being equal. doc…
Up here in Oregon, it takes about 10- 20 minutes on a cold December day to kick off the uv resin.
I work for a gas utility and come across this subject quite a bit. First of all , you do not want to use an unvented space heater as they have the capability of producing CO which will put you to sleep and you’ll never see your board again! If the heater is vented to the outside then the only thing that you will get from it is heat. If it has a standing pilot that is exposed to the vapors in the room you will have a reaction between the flame and the vapors that will smell and could possibly be toxic. So if you are going to use a heater the flame should be completely sealed from the air in the room. A forced air heater is the best as it draws its combustion air from outside and exhausts its products of combustion to the outside using a vent from the appliance. These are just answers to the safety concerns. Anymore questions, please feel free to ask or email me at .