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Spraying Lacquer and Humidity
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=18469		 Page 1 of 1
Author:  Wes McMillian [ Wed Aug 20, 2008 10:26 am ]
Post subject:  Spraying Lacquer and Humidity
What's an acceptable humidity range for spraying lacquer? I don't have a spray booth and am having to spray at the open door or my shop. You would know it, normally conditions are perfect - right up until the day I get ready to spray. Right now it's 96% outside! So when will I be ready to spray again? Or is it possible that I could still spray at the door of my climate controlled shop without any issues? I thought about hanging a sheet up at the door and spraying into it? Or would I be asking for trouble?

Maybe I just need to be patient until the weather turns. Or use this as a good excuse to build that spray booth....
Author:  Hesh [ Wed Aug 20, 2008 10:35 am ]
Post subject:  Re: Spraying Lacquer and Humidity
Wes buddy when spraying lacquer excessive RH can cause blushing and this holds true for the first few days of curing too.

So I would only spray in RH of 55%ish or less, less is better, and although I know you know this and because others may be reading remember that the stuff is explosive and an explosion proof fan, if you are not out side, is advisable and or course a respirator too. Spraying outside in an urban area with the possibility of others or pets being exposed should be avoided too.

Sorry for all the safety stuff, nitro is something that I approach with great respect.
Author:  Barry Daniels [ Wed Aug 20, 2008 10:43 am ]
Post subject:  Re: Spraying Lacquer and Humidity
I have always used an exhast fan when spraying lacquer, which is pulling in outside air, so I don't have the exact same conditions as described. In my old shop, the outside air entry point was a screen door at the other end of the shop. I sprayed lacquer several times when it was raining outside with no problems or blushing. But this is obviously dependant on the type of thinner/retarder that I was using. In other words, you can definitely compensate for high humidity conditions by using the right materials.
Author:  Wes McMillian [ Wed Aug 20, 2008 5:12 pm ]
Post subject:  Re: Spraying Lacquer and Humidity
Well, RH dropped to about 65%, so I took the plunge and started shooting. Looks like I'll be alright so far. If not, expect a new nitro post in your very near future!

Thanks for the responses, guys. I don't have any retarder, just had to go with it. Maybe I should have some on hand.

Oh, Hesh, thanks for your concerns. I do take precautions for my health and live in the country, so no neighbors to complain.

Still looking into that spray booth....
Author:  jsimpson [ Fri Aug 22, 2008 1:22 pm ]
Post subject:  Re: Spraying Lacquer and Humidity
ToddStock wrote:
.... If you can hang the guitar in a lower humidity area after spraying, any blush you do get will usually go away after an hour or so unless you've shot multiple coats over an already blushed surface.



Hi Todd, guess what I did outdoors on my lunch break on this very warm, humid, Iowa afternoon? gaah Shot it outside (72% RH), then moved it immediately into the house where the dehumidifier is working overtime (currently 54% RH).

Also I noticed that you could totally see my bracing pattern telegraph through the top about two minutes after I shot it! On dryer days, this never happened...presuming that's humidity too? Luckily, the blushing happened on the last coat, the first went on very smooth.

Will check it out later this afternoon, hopefully will be cleared up by then.
Author:  WaddyThomson [ Fri Aug 22, 2008 1:33 pm ]
Post subject:  Re: Spraying Lacquer and Humidity
Wouldn't you blush if someone took you out to lunch, sprayed your backside, and rushed you back into the house? :oops: gaah :D
Author:  jsimpson [ Fri Aug 22, 2008 1:44 pm ]
Post subject:  Re: Spraying Lacquer and Humidity
WaddyT wrote:
Wouldn't you blush if someone took you out to lunch, sprayed your backside, and rushed you back into the house? :oops: gaah :D


Bada-bing! Ouch! That was a baaaad one, Waddy!

laughing6-hehe laughing6-hehe
Author:  WaddyThomson [ Fri Aug 22, 2008 3:08 pm ]
Post subject:  Re: Spraying Lacquer and Humidity
Sorry! They are all bad! [headinwall]
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