Painting in colder temps

SpinnerSpinner Member Posts: 450 ✭✭✭
I’ve been thinking about colder temps and colder compressed air and how this effects paints and activators. 
My paint booth is a separate insulated room on the back of the shop. The greater shop is mildly conditioned with a mini split unit. I have my heat and air guy scheduled to install a mini split in the finish room. At the moment, I have an oil filled radiator warming the space. But when I turn the booth on, the cross ventilation drops the temp down to the outside temperature pretty quick. 
But for now when I have been
painting solvent paints, the gun gets cold in my hand. This must of course be coming from the cold
air compressor. 
How does the cold air from the compressor effect the paint and the part?
I have noticed the paint doesn’t “cover” or lay down as well as usual. Sort of an “alligator” like texture to it. 
How is it possible to fix the air temp from the compressor?
From the compressor I have three filters - a refrigerated air dryer at the compressor, a desiccant filter in the finish room, then a filter at the gun. 
So two questions, I guess… the temperature of the sprayed air and the ambient temperature of the room. How do I fix this?


  • WileECoyoteWileECoyote Member, Moderator, Business Ninja Posts: 7,958 El Moderator
    The gun gets cold in your hand because of the expansion of the compressed gas. Its the same function as an air conditioner, compressing gas causes heat, releasing pressurized gas removes heat. The compressed air is not your problem.

    The fact that the solvent in the paint evaporates faster in low humidity air than warmer (more humid) air is the issue. (solvent can be water also in water based paints). The solvent is evaporating out of the coating from the gun to the part faster. You need to lay down more coating to achieve the same effect.
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