The Stovebolt Site Forums The Shop Area Paint and Body Shop painting in hot weather question

I have my cab ready to for paint. It has been repaired, primed and sanded and is literally ready to spray finish paint onto. I have single stage Urethane paint, and I'm interested in knowing if it is OK to apply it in this hot weather. It's going to start out each day this week in the low 70s, but will rise into the 90s by mid afternoon. I definately would not paint at the hot point of the day. My question is: would it be OK to paint with the temp in the 70s, knowing that it will get much hotter before the paint is cured?

Yes its perfectly fine. Just mind the humidity. Thats the real pain. Early morning is my choice, for better temps and fewer bugs.

Follow the manuf's instructions on temp and humidity and it should work great. What gun and tip size are you using?

Im definately an amateur. I have a Divilbis Finish Line gun with a 1.3 tip.

Some paints require different primers reducers for different temperature ranges. F'rinstance, one for warm weather, and one for cool weather, etc. Check the spec sheet on your paint.

I would guess you have a copy of the Technical Data Sheet for the single stage paint, if not, get one. Follow the recommended tip size for the HVLP gun you are using. Paint in the morning during the cooler temps, allow the rcommended flash time between coats. I dealt with similar weather conditions last year and had no problems. The AkzoNobel polyurethane single stage I used did not require a reducer. If yours does, be sure to follow the recommended reducer for the approximate temperature range for the environment you plan to spray the paint in. Reducers types are slow, medium, and fast. The type indicates has fast the solvents will evaporate and the paint flashes and starts to cure. I'm an amatuer but had good results with the single stage.

Kevin, he's spraying his final coats. Primer is done.

Mike, check with your paint manufacturer. Most offer different speed reducer/activators for temperature. I sprayed plenty of times at 4 in the morning, knowing that the natural oven will help cure it later in the day. More important, it seems, is not the ambient temperature, but the substrate temperature. I always have a temp gun with me and the moment my surface I'm going to spray, hits the mid 70's, I'll start to apply paint. Checking between coats. Plenty of times the air has been in the 60's, but the metal temp was the proper temp for spraying.

I typed primer, but meant reducer.

Thanks guys for the info. My paint is PPG shop line, and I bought medium reducer. I will double check the data sheet before painting, to make sure that I"m working in the temperature range that's correct for that reducer.

PPG and many others make a high temp reducer. Many call it slow-dry and if you look at the "ingredients" you will see it is a different animal. If there's a chance you'll be painting at 80 degrees or above, I'd use that. All it does is to allow a little more time for your paint to lay down and flow. Slower drying can help you avoid orange peel. Good luck!

If you've already purchased your thinner based on a cooler temperature, most paint lines can also be used with a retarder to slow the process. You don't want things flashing/drying too fast. Check with your PPG rep.