# lacquer finish problem



## twak (May 21, 2011)

I am using an aerosol lacquer. I sand the bare wood to 320 grit, apply sanding sealer and sand (sometimes multiple times), when the surface is uniformly flat and true I spray flat black lacquer and finish with a few coats of clear satin lacquer. It is driving me crazy that I continue to end up with some dull areas. I thought I finally had the situation rectified but after a day or so cracks developed and I was able to lift the finish. Does anyone have any ideas as to what I am doing wrong? As I said, it is driving me crazy.


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## billg71 (Mar 25, 2011)

Are you using a lacquer sanding sealer? Cracking and lifting sounds like there's some non-compatible component in the mix somewhere. Or it may just be that you're sanding the wood too smooth for the sealer to grab, try a test piece sanded to 180.

Same brand for all products? Time between coats? How many clear coats? What wood species?


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## twak (May 21, 2011)

billg71, both the sanding sealer and finish are from the same line of Behlen products. Too smooth of a surface would compromise adhesion but it wouldn't account for the dull areas when finsihed or, would it?


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## IC31 (Nov 16, 2012)

Not sure where you are, but often when lacquer turns hazy/milky and lifts it's moisture - either ambient or the wood itself. Also, when you apply the clear coat coat, you will have an application window, possibly as short as a few minutes to maybe 24 hours. Not adhering to that will allow the clear solvents to degrade the base. Then there is that possibility that you have some paint that is degraded ........


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## rwbaker (Feb 25, 2010)

You are buffing the whole thing with 6 to 10k grit polish? Once the lacquer is on it, it might as well be a car.

Baker


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## JOAT (Apr 9, 2010)

What kind of wood. That can make a huge difference at times.


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## randyb01 (Aug 11, 2012)

Aerosol - if you using spray cans from a big box store, the problem may be that it's really not lacquer. Look at the label and if the solvent for cleanup is anything other than lacquer thinner, the product is not lacquer. I just saw a "Lacquer" label that recommended mineral spirits or Xylol for cleanup which means it's oil based, even though it flashes quickly. Clean your piece up by sanding or scrubbing with a solvent, apply a couple of wet coats of dewaxed shellac to seal out any residue from the previous finishes, when dry (about 20 mins or so) sand with 400 grit, tack totally clean, apply lacquer sealer, sand, then black, sand and clear. Lacquer "bites" into the previous coat, so it should never peel off. If you are using spray cans, a small investment for a siphon gun and a small air compressor will make your life much easier. 

If you get "blush" (moisture entrapment), add one drop of castor oil (sometimes two are necessary) to your spray cup, stir thoroughly. This will act as a "blush retarder" causing the lacquer thinner to flash off a little slower. Castor oil is much cheaper than commercial blush retarder. By causing the thinner to evaporate slower, the residual moisture will be evaporated also. You may need it in the black coat, but if you apply the clear within a short period, you should be OK.


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## twak (May 21, 2011)

JOAT, the wood is poplar.


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## Dr Neon (Apr 15, 2010)

Hi Tom. Many good suggestions above. Another is the possibility that you are sanding through your sealer, in places; giving you the randon opportunity for the lacquer to penetrate. I have found that going to 220 grit on the wood gives me a good base. I use 320 or 400 on the sealing layer, and only sand enough to remove the very top 'hairs and sniglets'. Tim


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## bcfunburst (Jan 14, 2012)

randyb01 said:


> Aerosol - if you using spray cans from a big box store, the problem may be that it's really not lacquer. Look at the label and if the solvent for cleanup is anything other than lacquer thinner, the product is not lacquer. I just saw a "Lacquer" label that recommended mineral spirits or Xylol for cleanup which means it's oil based, even though it flashes quickly. Clean your piece up by sanding or scrubbing with a solvent, apply a couple of wet coats of dewaxed shellac to seal out any residue from the previous finishes, when dry (about 20 mins or so) sand with 400 grit, tack totally clean, apply lacquer sealer, sand, then black, sand and clear. Lacquer "bites" into the previous coat, so it should never peel off. If you are using spray cans, a small investment for a siphon gun and a small air compressor will make your life much easier.
> 
> If you get "blush" (moisture entrapment), add one drop of castor oil (sometimes two are necessary) to your spray cup, stir thoroughly. This will act as a "blush retarder" causing the lacquer thinner to flash off a little slower. Castor oil is much cheaper than commercial blush retarder. By causing the thinner to evaporate slower, the residual moisture will be evaporated also. You may need it in the black coat, but if you apply the clear within a short period, you should be OK.


NOTE* If you use caster oil in a spray gun, you are committed to use it every time from then on as it will cause fish eyes thereafter in use with other paints. ALSO, caster oil will forever attract more dust than normal on your finished piece. That's a FACT!!


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## Woodwarrior (Nov 17, 2017)

If you have enough finish coats say 3 or more you can use some corn starch on a damp sponge. It is like a really light 
cut rubbing compound. You can also spray a light coat of lacquer thinner over that area to level out the finish.
Lacquer cracks when you have some contaminant under your finish or there is moisture in between the coats of finish. 
It also will blush if the temp is to cold. I like using pigmented lacquer if i'm going to spray a color finish, It's a 2 part 
lacquer which comes with an activator or catalyst you mix in. I like using a cup gun with a number 80 nozzle. Also, I will use a 
lacquer primer tinted the same color of my finish instead of sanding sealer. For those of you that spray a lot of lacquer finishes, 
You can buy blending solvent which slows down the drying time eliminating a lot of over spray. Just my 02


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## harrysin (Jan 15, 2007)

Have you recently used Silicone spray where you are doing woodwork because that sounds like I once had and I ended up using a different finish. When I want a high gloss colour finish I use a few coats of gloss colour followed by at least two coats of gloss lacquer.


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