Spraying Lacquer/humidity questions

Rocks · #1 08-10-2009, 03:53 PM

I'm at the stage of spraying clear lacquer and the can says not to spray when its over 60% humidity. Right now the humidity is 80% and will probably stay over 60% for at least another few days. The house is air conditioned but of course I can't spray in the house. Can I spray outside and then bring the body back in right away to let it dry in the AC? I'm only taking the body out, doing a light coat and bring it right back in to hang dry, would this still be a problem?

bassteban · #2 08-10-2009, 03:56 PM

I've not done guitars or basses but I'd be concerned w/going from one environment(outdoors)to a radically-different one(indoors, AC)so quickly.

mikeyswood · #3 08-10-2009, 04:07 PM

No!

The lacquer is hygroscopic and sucks in every bit of water it can. Find a dry spray booth, or wait a few weeks until the humidity falls. Your patience will be rewarded by not having to sand and start over. Trust me.

Jools4001 · #4 08-10-2009, 04:07 PM

Quote:

Originally Posted by Rocks

I'm at the stage of spraying clear lacquer and the can says not to spray when its over 60% humidity. Right now the humidity is 80% and will probably stay over 60% for at least another few days. The house is air conditioned but of course I can't spray in the house. Can I spray outside and then bring the body back in right away to let it dry in the AC? I'm only taking the body out, doing a light coat and bring it right back in to hang dry, would this still be a problem?

No you can't. When you spray, you're laying down fine 'atomised' particles of your finish on the surface. If the humidity is too high it'll pull in microscopic water particles and the water in the air will find it's way into the finish It'll go cloudy and milky and no amount of sanding (short of sanding it all off) will make it go away

Rocks · #5 08-10-2009, 04:13 PM

Thanks everyone for the quick replies. Just my luck the summer has been perfect for painting until I get half way through my project. The woman is getting upset that the body has been hanging from the kitchen ceiling for over a week now and I'm chomping at the bit to get her off my back (she is far meaner than I am).

tjclem · #6 08-10-2009, 06:25 PM

I no longer spray lacquer but I have been lucky in having poly lightly fog and bringing it indoors and it clearing up. This did not work with lacquer though.......t

Rocks · #7 08-10-2009, 06:30 PM

Would this be a good time to use some polishing compound to smooth everything out or am I better to wait until the last coats of the clear?

Musiclogic · #8 08-10-2009, 06:57 PM

just remember when spraying lacquer, high humidity creates blush, humidity trapped in the finish. You can use Behlens blush eraser if you get blush, but it will only do so much, wait it out until the humidity drops, like Michigan, it's Ohio, and the weather changes constantly.

teej · #9 08-10-2009, 10:11 PM

I like lacquer for it's usually fast dry time, but as others have said, it's a real pain in humid conditions. I really need to start using poly again.

Rocks · #10 08-10-2009, 11:56 PM

I'm kind of at a standstill here waiting for the humidity to go away, would this be a good time to give it a good once over with polishing compound? Or should I wait until all the clear coats are done?

teej · #11 08-11-2009, 02:53 AM

You could probably sand between coats.

Rocks · #12 08-11-2009, 11:17 AM

Quote:

Originally Posted by teej

You could probably sand between coats.

Sand but not polishing compound? Just checked, its 87% humidity again today.

tjclem · #13 08-11-2009, 11:58 AM

You are going to be waiting a long time. You don't want it to blush on you. Try in early fall.......t

gyancey · #14 08-11-2009, 02:29 PM

Also nitro lacquer offgasses for quite a long time - even though it dries to the touch relatively quickly you'll quickly find that you don't want it in the house for a few days at least, if not longer.

Rocks · #15 08-11-2009, 04:21 PM

Quote:

Originally Posted by gyancey

Also nitro lacquer offgasses for quite a long time - even though it dries to the touch relatively quickly you'll quickly find that you don't want it in the house for a few days at least, if not longer.

This isn't nitro, it is acrylic lacquer. Can anyone answer my question about polishing compound?

Rocky McD · #16 08-11-2009, 04:42 PM

I live in Texas and the humidity changes a lot from morning to afternoon. Usually it is much less humind in the late afternoon. If you will get a meter and keep track of the humidity during the day, I think you can work in the painting on most days. In the summer, we usually go from 80% in the am to 40% in the pm.

Rocks · #17 08-12-2009, 02:34 PM

OK, I'll try my question one more time. Is it safe to use polishing compound to smooth things out while I am waiting for the humidity to drop?

mikeyswood · #18 08-12-2009, 02:54 PM

As long as it is cured you will be fine.

tjclem · #19 08-12-2009, 03:06 PM

Quote:

Originally Posted by Rocks

OK, I'll try my question one more time. Is it safe to use polishing compound to smooth things out while I am waiting for the humidity to drop?

I guess I just don't see why you would want to. Use 600 or 800 grit paper

Rocks · #20 08-12-2009, 06:00 PM

Quote:

Originally Posted by tjclem

I guess I just don't see why you would want to. Use 600 or 800 grit paper

Because every time I have tried finer grades of sandpaper it clogs up way too fast and I don't mind sitting here hand rubbing my bass, I can do it for hours.