proper humidity for painting

[Just Mike]

I know that the ideal is about 60% humidity to spray paint but is there a lower limit to paint? My room in the basement was 39% this morning while outside, it's 63%.

Too dry, yes? I'm guessing that that's why my paint cracks - because it's drying too fast.

Get a humidifier and set it on low for a while? Maybe set a pot of water on my radiator (it's rather cool down there)?

 

[Grendels]

Sorry Mike, I can't help you with this one. I have the opposite problem, too much humidity. Right now it is 54% outside, and that is a very low day. It is usually near 80%.

I do spray indoors under air conditioning. Because of this my conditions are pretty regulated, and I don't have a problem with moisture. Other than what the water trap on my compressor picks up.

 

[Just Mike]

the water trap collects in-line moisture like a spit valve on a brass instrument. It's the moisture that combines with the atomized paint between the nozzle and your subject you want to worry about.

The constant pressurization and discharge of air in the tank causes condensation. I don't think you have to worry about it with a diaphragm model.

 

[Elm City Hobbies]

Any compressed air, either from a tank or direct from a diaphragm compressor will have a tendency have moisture in the line, which is where the water trap comes into it.

Its not so much a problem if you are using acrylic paint, because well....its acrylic, the water will just add to the paint mixture, if anything it will thin it slightly more, but probably not enough to be noticeable.

Its when you are painting Enamel or Lacquer that the moisture will cause havoc.

 

[sunsanvil]

Too dry, yes? I'm guessing that that's why my paint cracks - because it's drying too fast.

I doubt dry air is your problem, at least that would be my last guess when it comes to cracking. What type/brand of paint are you using, how much and with what are you thinning?