Adjusting to Changing Temperature as You Spray

As the day warms up, think about adding more retarder. October 3, 2007

Question
I was spraying some ML Campbell Polystar the other day, and ran into some trouble. In the morning, everything I was spraying looked great - nice even pattern and finish from the gun. As the day went on, the temps rose up to mid 80's, and I started having trouble with orange peel. I couldn't figure out why this was happening. I assumed it was the gun, which is a relatively new gun to me - an Accuspray 19 conversion hvlp. Since I have owned this gun, I have had a lot of trouble getting a consistent finish with it, so I figured for sure that it was the gun that was causing the trouble, except that I actually got good results in the morning.

I am wondering if others find this kind of trouble when spraying throughout the day? Do you need to adjust for the temperature? I thinned the finish a little at the end of the day, and it seemed to help some, but I wasn't sure if that was the right thing to do.

This was my first time spraying this particular finish, and I should mention it was tinted white. However, a couple of months ago I was spraying Enduro tinted white and was having the same problems, and that was when the doors were shut and the heat was on...

I am still trying to figure out if this gun is not working properly, or if I am doing something wrong. Prior to this gun I used a Turbinaire for 10 years and never had this kind of trouble with inconsistency and orange peel. Thanks in advance for any thoughts on this!

Forum Responses
(Finishing Forum)
From contributor J:
I had the same problem just last week while spraying lacquer. I added retarder to slow it down and that fixed it. The higher the temp, the more you have to slow it down to compensate for the faster drying.


From contributor A:
Adding the retarder was the most logical choice to make. But sometimes you don't need to do that because when the temps rise, your paint warms up, causing the viscosity to drop. If your paint is lower in viscosity, you can turn down your atomizing air and sometimes get the same results, as opposed to adding a slower solvent. Just throwing that out there as another possible solution.

From contributor T:
Yesterday I was spraying a 10' ft lobby desk with M L Campbell Krystal. I usually use standard lacquer thinner, but with the air coming in and the booth running, I reduced it with 10% flow enhancer #2 retarder and 5% care reducer and barely had time to get around the desk. It came out fine. It was 10 in the morning, 75 degrees, 80% relative humidity. It really helps to adjust your reducers.

From contributor C:
I have found thinning lacquer with auto grade urethane reducer gives much better results. It was suggested to me by a paint rep that's also a chemist. It's the only way I thin my lacquer now. Much better results!
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