Cox at his finest!
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its impossible to spray at anything below 60 and expect good results. my shop isnt insulatd so when i have a complete to do i usually end up spraying at the end of the day (reason why i end up spraying after midnight at times) when the shop heater finally gets the place warm enough. forget the all the solvent pop, peeling issues, and orange peel. you’ll get runs! and if you dont get runs its because you held your gun too far in fear of getting runs which means ur finish will look like a$$!
i believe the optimal temp you wanna be spraying at is 70 or 75 degrees Fahrenheit
I sprayed a pearl white firebird in my booth at 55 degrees for a guy that had bought all cold weather reducer cause he was going to paint it in his garage then changed his mind. He didnt have any extra cash to buy the right stuff so he got what he got. Also only had 2 quarts of clear left to do the whole car . It turned out as good as it could. My poor hand was cold from holding that gun in those temps though
This is a subject I’ve looked at many times and spoke with chemists about it over the years to. I know PPG states not to spray under 60 degree’s as you can stop the crosslinking process and it will not be reinitiated at a higher temperature.
This is for 2k urethanes, the best understanding i have of it is:
You spray your favorite cold urethane product, since you mixed the hardener in the crosslinking process has begun. What you want to happen is the isocyanate to react with the polyol (alcohol) forming a long polymer chain giving you a proper cure. In colder temperatures the polyol is unable to react but the isocyanate group is. As everybody here likely knows isocyanates are very reactive with water, so the iso group reacts with the water (in the air) when it was supposed to react with the polyol resulting in a non-cured coating.
Also the organic peroxide (used in the hardener) is very reactive and doesn’t last long once added to the mix, it can be broken down before it has a chance to react with the polymer at a cold temperature, another cause of no curing.
I can see the negatives to the mixed products not curing in cold temps.
But storage wise, as long as it isn’t freezing and it isn’t extremely hot (40-110*F range)
You should be perfectly fine.Like Jimmo says, it’s the reaction between the Isocyanate and the polyol. Which yes when too cold will either slow or completely stop the reaction between the two. The Isocyanate side will continue to cure with moisture leaving nothing for the alcohol to react with, (Causing it to never cure) But when polyol is returned to the proper temperatures it is fully reactive again. The same applies for the peroxide.
So in my personal opinion, as long as it doesn’t get so cold or hot that it damages the product.
You should be perfectly fine with storage. Just don’t even attempt to spray it in any conditions colder or hotter than suggested.Infact because it’s solvent based. it probably even has a lower freezing point than water. (This is why they aren’t scared to ship Solvent based products during the winter.) thus you could probably safely store it in freezing conditions. (Although I wouldn’t suggest it because none of us want to find a bunch of exploded cans in our cabinets.)
I have to say i agree with rat. When i worked for the yacht co i remember spraying outside when it was snowing out. Once winter past and things warmed up again what i sprayed cured out just fine. Was it the right thing to do, hell no but you couldnt tell them that so they got what they got.
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