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Cursing a white streak?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=23840		 Page 1 of 1
Author:  ayavner [ Thu Sep 17, 2009 10:06 pm ]
Post subject:  Cursing a white streak?
So I sprayed what was going to be the first of 3 coats following my sealer coats. After a little while, I noticed my sides had huge white blotches going around. I think this is from too much humidity, and I know there is some kinda remover I now need to buy in order to make this go away. Question here is do I wait till i get that and spray it on the current coat before continuing?

Or do I go ahead and spray the 3 I was going to do? It will obviously be a few days before I have a chance to get the stuff. Will the white blotches go away as it cures and the humidity dies down?

ARRRRRGH


Adam
Author:  Kim [ Thu Sep 17, 2009 10:09 pm ]
Post subject:  Re: Cursing a white streak?
Just let it dry and it should be fine. You can always spray with straight thinners as well, as it burns in it should let the moisture out.

Cheers

Kim
Author:  matthewrust [ Thu Sep 17, 2009 10:39 pm ]
Post subject:  Re: Cursing a white streak?
Yep... Let it sit in a dry environment and it should clear up. This happens to me all the time when I am finishing furniture in my garage instead of in a humidity controlled environment.
Author:  bluescreek [ Fri Sep 18, 2009 5:57 am ]
Post subject:  Re: Cursing a white streak?
you need a water separator on the air line to start with. Also if you hit too heavy of a coat that can do it ,and last , you don't need 3 coats of sealer . I do 1 coat of sealer , fill it I am using a standard filler . If I use CA as a fill I don't use the 1st seal coat. At most I may do 2 coats of seal but that is rare.
Once sealed , you don't need anymore. With the seal coat you can start the finish. I hit the seal coat with a scotch pad or 0000 steel wool.
Author:  ayavner [ Fri Sep 18, 2009 7:53 am ]
Post subject:  Re: Cursing a white streak?
Just to clarify, i am using the aerosol nitro from Stewmac, so no way to put a separator. It is very humid out, but the sealer coats went on fine (also nitro from SM), so didn't think I would have a problem here.

So seems like wait it out is the thing here? Should I go ahead and scuff it back to help it out? Or just let it sit in the house until its gone?

thanks!

adam
Author:  runamuck [ Fri Sep 18, 2009 8:11 am ]
Post subject:  Re: Cursing a white streak?
ayavner wrote:
Just to clarify, i am using the aerosol nitro from Stewmac, so no way to put a separator. It is very humid out, but the sealer coats went on fine (also nitro from SM), so didn't think I would have a problem here.

So seems like wait it out is the thing here? Should I go ahead and scuff it back to help it out? Or just let it sit in the house until its gone?

thanks!

adam


You will have to wait for the humidity to drop; you don't have a choice since you are using an aeresol

You can sand whenever you want before shooting any more lac. Much of the bloom may disappear once you sand.
Author:  matthewrust [ Fri Sep 18, 2009 8:12 am ]
Post subject:  Re: Cursing a white streak?
Let it sit. I'm probably wrong, but I think the moisture in the finish makes it a little gummy and that will clear up once it dries enough.
Author:  ayavner [ Fri Sep 18, 2009 10:49 am ]
Post subject:  Re: Cursing a white streak?
Does anyone think maybe hitting it lightly with a hair drier might help?
Author:  Steve Kinnaird [ Fri Sep 18, 2009 12:15 pm ]
Post subject:  Re: Cursing a white streak?
Adam, when the sides are dry (which shouldn't take long w/ lacquer) get a rough terry cloth towel and rub that blushed finish hard. Show it who's boss. You'll get most if not all out that way.
Sand a bit for stubborn areas.
Hit it w/ a wee bit of lac thinner for the obstinate zones.
You're not in trouble.
(But get it out before you do any more build coats.)

Steve
Author:  ayavner [ Fri Sep 18, 2009 12:24 pm ]
Post subject:  Re: Cursing a white streak?
Thanks Steve,

Well its finally starting to dry up a bit here in DFW and the sun is intermittenly poking its head out. Maybe by the time i get home, it will have dried up enough. Although its humid out in the shop thanks to no AC, it stays a relatively dry 30-40% in the house, so i always bring my work in when i am done, till i am ready to work on it again, so at least exposure is limited.

Good to know that I need to address this before I get the next coats on, i was a bit unsure on that one. You gotten any of this nasty weather out in your part of TX?

adam
Author:  Daniel Minard [ Fri Sep 18, 2009 1:57 pm ]
Post subject:  Re: Cursing a white streak?
I strongly recommend NOT using a hair dryer or other heat source.
Just a touch too much heat & bubbles will form under your finish. Not fun!
Even putting a lamp with a 60 W. bulb a foot and a half away can cause bubbles in a very short time. Ask me how I know this...
Patience... The blush will almost always disappear.
Don't be tempted to spray any more coats 'till the finish has cleared. You'll just be sealing in the problem.
Author:  ayavner [ Fri Sep 18, 2009 2:28 pm ]
Post subject:  Re: Cursing a white streak?
good to know! I'll wait it out!
Author:  SteveSmith [ Fri Sep 18, 2009 2:44 pm ]
Post subject:  Re: Cursing a white streak?
Daniel Minard wrote:
I strongly recommend NOT using a hair dryer or other heat source.
Just a touch too much heat & bubbles will form under your finish. Not fun!
Even putting a lamp with a 60 W. bulb a foot and a half away can cause bubbles in a very short time. Ask me how I know this...


The same thing happens with Emtech 6000 too [headinwall] Good thing its easy to repair.
Author:  ayavner [ Sat Sep 19, 2009 3:34 pm ]
Post subject:  Re: Cursing a white streak?
Well, the terry towel trick got most of it out, then a light scuff with some steel wool and a couple hours wait, and looks like we're streak-free again!

Thanks, now on to the next coat (now that the humidity is back down to a reasonable level) :D


adam
Author:  Mike_P [ Sat Sep 19, 2009 9:11 pm ]
Post subject:  Re: Cursing a white streak?
ummm...I hate to be the one to inform you, but you should NEVER use steel wool during the finishing schedule (i.e. more coats are still to be applied)...it is pretty much impossible to get every little remnant removed, which means there will most likely be some steel wool trapped in layers of finish, which will eventually start to rust and possibly cause finish failure...finishes are not vapor proof, which means vapor can get to the steel, make it rust which will cause a void in the finish which might cause some issues....
Author:  Steve Kinnaird [ Sat Sep 19, 2009 9:32 pm ]
Post subject:  Re: Cursing a white streak?
ayavner wrote:
Thanks Steve You gotten any of this nasty weather out in your part of TX?

adam


Well, it has been raining all week, but it's hard to call it "nasty" when you've been through a summer of drought!
Rather, it's been wonderful.

Timely, scary reminder there about steel wool. Get a good tack cloth and go over every inch of the guitar before spraying more.

Steve
Author:  ayavner [ Sat Sep 19, 2009 11:15 pm ]
Post subject:  Re: Cursing a white streak?
Not to fear, I did use a good tack cloth and went over the whole thing - don't *think* there's any remnants, at least as far as I can tell, but as you say its impossible to be sure... guess we'll see!

Anyway, got 2 more coats on today, that finishes the first set of 3. No more steel wool for this one, and back onto our regularly scheduled program!

Thanks folks!

adam
Author:  Kim [ Mon Sep 21, 2009 8:28 am ]
Post subject:  Re: Cursing a white streak?
If you are using aerosol cans a good tip, especially for the final coating session, is to let the cans sit in 'hot' (NOT BOILING) water for a few minutes. The heat will thin the lacquer and raise the pressure in the can giving a much finer spray and more even finish with less sputter. If you are working with two or more cans, rotate them in and out of the hot water as you feel the pressure begin to decrees. Just make sure you have a dry rag at hand to wipe each can down as it is taken from the water.

I would not be too concerned about steel wool rusting in the finish and causing failure, this has been known to happen when the wool has been used on bare wood because the fibres catch in the grain, but when used to flat back a finish, any residual fibres easily wipe away or blow right off.

Cheers

Kim
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