Mr.Chemist...Paint/cold weather

[gert]

What effect does a cool shop have on the oil based paint that has been stored there for the last 3 months? Is there an ideal "pot" temperature for paint when it is being applied? I do have an electric blanket but I'm not alowed to get paint on it.

[thechemist]

All chemical reactions go slower in colder weather.

Solvent evaporation must take place before chemical curing gets well along, and solvent evaporation is a more nonlinear function of temperature.

Solvent evaporation rates also determine how the material holds a wet edge, and how long before it is "dry to dust".

Chemical curing takes place by reaction with the oxygen in the air, so you must have air available under the drape. In other words, it's gotta be spaced away a few inches.....

In other words, It should work, I think, but will be REALLY slow.....

[PugetSound]

I have successfully used oil based paints which I have stored in my cold shop all winter -average winter temp about 47 (F). As for painting during cold weather, it can be done ......

Talk to the manufacturer about cold weather painting with their product or, better yet, contact N.A.C.E. (National Association of Coating Engineers) regarding cold weather painting. Information you should be looking for is things like preferred Surface Temperature and Humidity as well as minimum air temperature. Some paint formulations are specifically designed to work at colder temperatures. Toward this end, you might want to consider epoxy paints as there is an incredible variety. (I recently had to use a special type of epoxy paint which was designed to be applied underwater! This is how they accomplish below the waterline touch-up painting on aircraft carriers)

Try applying a heat lamp to the surface to be painted until the surface temp is about 75 (F). Raising the air temperature in the shop is an easy way to lower the relative humidity (if needed).

If you cannot manage the recommended painting conditions, then back off and wait for a better day. The last thing you want to have is a boat covered with a gooey mess that now has to be removed because it will never cure right. Oil based paints are probably more forgiving than epoxy systems but check out the environmental requirements anyway.

[This message has been edited by PugetSound (edited 11-13-2001).]

[rob]

UNlike latex, oil based paints don't mind cold storage. My shop here in vermont routinely fluctuates betwean single digits at night and 50-60 when I get the stove cranked up. The paint there doesn't mind at all...in the can. If you do have to heat the shop to get the painted surface to dry, I advise doing it well before the application, especially on natural wood that has not been previously well sealed, other wise the air in the wood fibre expands and outgasses through your film creating bubbles or areas more prone to blistering down the line. Also intial heater start up tends to kick up dust when the convection currents are at thier strongets.