painting humidity?

[Brockport Bill 1,668]

the spray paint cans directions caution about "drying time" or the "finish" for primer or final coat if the humidity is high -- and suggests painting preferable below 50-60 percent -- which is often a challenge considering its summer and frequently humid. From everyone's experince -- does higher humidity just cause longer drying........... or should higher humidity be avoided while spraying becuse it will cause adhesion or finish problems or some other quality problem? One company uses the termonology "for best results" stay outside that range.....another company says "may effect finish" ...Your suggestions welcome from whatever results you have had? ..thanks

[rmaynard 15,514]

High humidity will slow drying, and in some  cases cause "blush", which is a white or pinkish look to the finish. 

[Mike'sHorseBarn 2,998]

For best results wait until fall or early spring. When it's humid, paint does terrible things. It can peel too or make it dry with a dull finish. Ask me how I know that 

[squonk 41,151]

Air can only hold so much water. Paint dries by the solvents evaporating. If there is little room for the solvents in the air because of the moisture it will take longer to dry.  Longer drying times gives the pigment a chance to change, get chalky, wrinkle and collect Tse Tse flies and Cottonwood  that's flying around.

[elcamino/wheelhorse 9,324]

Move down here , and trying breathing the humidity . Activities outside end around 10 AM for me. 

[Achto 27,601]

1 hour ago, Brockport Bill said:

Your suggestions welcome from whatever results you have had?

 

If you are relying on solvent evaporation to dry the paint, all of the above statements are correct. Color change, adhesion issues, etc. If you need to paint in high humidity and can swing the extra coin, switch to a urethane primer & paint. Urethanes can only be sprayed with a spray gun, not available in spray cans. Urethane paints chemically dry so they are not effected as much by humidity. For example - If you put a urethane paint mixed with it's activator in a sealed container, it will be solid all the way through in around 8hrs. Urethanes are far superior to enamel's and lacquer's for durability and shine but the price tag can put a dent in your wallet.

Edited July 29, 2021 by Achto

[squonk 41,151]

26 minutes ago, Achto said:

 

If you are relying on solvent evaporation to dry the paint, all of the above statements are correct. Color change, adhesion issues, etc. If you need to paint in high humidity and can swing the extra coin, switch to a urethane primer & paint. Urethanes can only be sprayed with a spray gun, not available in spray cans. Urethane paints chemically dry so they are not effected as much by humidity. For example - If you put a urethane paint mixed with it's activator in a sealed container, it will be solid all the way through in around 8hrs. Urethanes are far superior to enamel's and lacquer's for durability and shine but the price tag can put a dent in your wallet.

You can get urethane in spray cans at Napa and I'm sure at other parts stores as well. They mix the color and put it in the can. Expensive though. Prolly $25 a can now. I've had to use them on occasion with great results.

 

 

 

[Brockport Bill 1,668]

wow - - amazing insights -- i guess i have to wait a few days till lower percent humidity -- of course always other tasks to do in the meantime - just eager to paint -- but waiting makes sense -- thanks all

[ebinmaine 67,599]

The Paint Department here uses mostly Rust-Oleum 2X. 

We have the advantage of being able to spray outside unless raining/snowing or temp below about 20 or so. 

 

She brings the sprayed items into the humidity controlled basement for drying/curing. 

 

[953 nut 55,312]

          If you must spray with aerosol enamels on a humid day you may want to set-up a drying booth with a heater to dry the inside air prior to painting and move the pieces into it (or spray then there) and leave the heat on as long as you can. This will diminish the drying time.

[Gregor 4,846]

I paint in my garage. I have a de-humidifer, and won't paint above 60%. I tried painting lacquer once at a higher percentage. It did dry, but was very dull. My dehumidifier was $150. Worth every penny. It will drop the humidity from 75% to 60, in less than an hour.

[adsm08 2,069]

9 hours ago, squonk said:

You can get urethane in spray cans at Napa and I'm sure at other parts stores as well. They mix the color and put it in the can. Expensive though. Prolly $25 a can now. I've had to use them on occasion with great results.

 

 

 

 

 

That's about right. I had BAPS mix me some stuff up to do a 50/50 on the neighbor's van last summer after she tore a huge chunk of paint off on the mailbox (Don't ask). Primer, color, and clear was $75.

[Brockport Bill 1,668]

I dont understand how its ok to paint in a basement or garage with all the warnings about needing ventalation -- and the vapor dangers -- YUK !! Do people just use an exhaust fan and a mask? I have not even tried indoors .. I thought the room would fill up in minutes with unhealthy vapors?

[Gregor 4,846]

2 hours ago, Brockport Bill said:

Do people just use an exhaust fan and a mask?

Yep

[ebinmaine 67,599]

5 hours ago, Brockport Bill said:

I dont understand how its ok to paint in a basement or garage with all the warnings about needing ventalation -- and the vapor dangers -- YUK !! Do people just use an exhaust fan and a mask? I have not even tried indoors .. I thought the room would fill up in minutes with unhealthy vapors?

 

 

We do the actual spraying outdoors. 

[RandyLittrell 3,884]

15 hours ago, Gregor said:

I paint in my garage. I have a de-humidifer, and won't paint above 60%. I tried painting lacquer once at a higher percentage. It did dry, but was very dull. My dehumidifier was $150. Worth every penny. It will drop the humidity from 75% to 60, in less than an hour.

 

It keeps the tools all non rusty too!! I run one as well! 

 

 

 

 

Randy