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Lacquer problem / White film on finish?

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Forum topic by rustynails posted 12-04-2018 12:06 AM 408 views 0 times favorited 6 replies Add to Favorites Watch
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rustynails

842 posts in 2951 days


12-04-2018 12:06 AM

I have a problem; I just finished a piece which has black walnut and pine in the project. It was sanded and then just sprayed with Watco Crystal Clear Lacquer (spray can) which I have done a few times now with no problems. I like using this product as it dries fast and you can put multiple coats on in no time.

Well this time it did not turn out, the project started to get a white film in the finish big time. I was spraying in my shop which was about 78 degrees (wood burner Michigan) I also put a new coat on about every 30 minutes. I did put a lot of coats on but that should not make a difference (I believe) any Ideas on what went wrong and how to correct the problem. Sanding off the old lacquer would be difficult as some of the project is 3-dementional.

Thanks Richard


6 replies so far

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CL810

3937 posts in 3410 days


#1 posted 12-04-2018 04:36 AM

The white film is caused by applying another coat too soon or too thick of a coat.

Instructions say to allow 2 hours between coats.

-- "The only limits to our realization of tomorrow will be our doubts of today." - FDR

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rustynails

842 posts in 2951 days


#2 posted 12-04-2018 05:12 AM

I did do it fast between coats and thick…. Does the white go away once it drys good?

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Planeman40

1420 posts in 3183 days


#3 posted 12-04-2018 04:50 PM

What you are most likely dealing with is what is called “blushing” which is common to lacquer. What happens is the fast evaporation of the thinner in the lacquer chills the wet surface causing water vapor in the air to condense on the surface turning the lacquer surface a milky white.

There is a cure. Lightly brush a DAMP brush dipped in lacquer thinner on the surface. Handled carefully, this slightly melts the surface of the lacquer. The trick is to do this so there is just barely enough thinner to melt the surface and then flash off so quickly that the surface can’t chill enough to allow condensation to form.

I learned this more than 60 years ago when, as a boy, I built tissue covered model airplanes using nitrate dope, a type of lacquer. I live in Atlanta, Ga. where the summer temperatures are high and the humidity is wringing wet!

Also, Try lowering the the temperature in the shop. The higher the temperature, the more moisture the air will hold. I suggest applying lacquer at around 70 degrees (F) or lower

-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

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rustynails

842 posts in 2951 days


#4 posted 12-05-2018 02:14 AM

I did try using some straight lacquer thinner and it did take the white off . I am letting it dry for a a few days to make sure nothing comes back. At that point I am going to have to apply more finish due to some of the finish coming off.
Not sure what I am going to use on it more lacquer or maybe shellac or even a urethane

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000

2859 posts in 1321 days


#5 posted 12-05-2018 02:22 AM

Try to respray the lacquer.
It should melt the previous coat and take away the film.

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Rich

4575 posts in 1011 days


#6 posted 12-05-2018 06:45 AM


Try to respray the lacquer.
It should melt the previous coat and take away the film.

- jbay

+1. Another thing to keep around if you use lacquer a lot is an aerosol can of blush remover. It’s a solvent called Butyl Cellosolve that evaporates 64 times slower than acetone, allowing it to not only melt the lacquer, but to keep it from curing before it has time to trap the moisture that causes blush. It’s also useful for areas where you’ve gotten overspray that’s dusty. A quick shot and it smooths out the finish.

-- Knowledge is not skill. Knowledge plus ten thousand times is skill. -- Shinichi Suzuki

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