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Working with Lacquer

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Forum topic by flyingoak posted 1705 days ago 5112 views 0 times favorited 7 replies Add to Favorites Watch
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flyingoak

68 posts in 1732 days


1705 days ago

Topic tags/keywords: question

Greetings folks,
I have a question about lacquer. I will admit that finishing is my downfall….. I like the use and ease of lacquer but my finishes are not as smooth as I would like. I typically sand to at least 220 grit before application of the finishes. I have read two things about lacquer. 1) that you dont have to sand between coats and 2) you need to sand with 320+ materials between coats but you dont have to worry about the dust because the next coat disolves it.

SO——which one is correct and any additonal tips for working with this type of finish?

THanks,

-- where is the duct tape.....


7 replies so far

View Ger21's profile

Ger21

622 posts in 1755 days


#1 posted 1705 days ago

The top coat will only be as smooth as what it’s going on . If the surface is rough, you need to sand it before spraying.

A little clarification on what you read.

1) Some finishes require sanding between coats so that the finish can “stick” to the finish below it. Without sanding, you won’t get a good bond between coats. The finish will actually grab onto the sanding scratches for a better bond. Laquer, however, will dissolve any laquer finish already on the workpiece, so the multiple coats actually become one single thick coat. So, what you’ve read, actually meant, that you don’t need to sand between coats for the laquer to adhere to the previous coat.

2) For a smooth finish, you definitely need to sand any bumps or dust nibs out of the finish before spraying. How fine of grit you need depends a little on how thick the laquer is. If you can still see scratches after spraying the new coat, then you need to use a finer grit.

While laquer will dissolve the white laquer dust, it’s still a good idea to thoroughly remove it all before spraying. It’s very likely that you’ll have sawdust or other dusts mixed in with the laquer dust that won’t dissolve. And laquer dust in cracks typically won’t be dissolved unless the laquer can thoroughly flow into those cracks before drying. I’ve seen guys spray right over laquer dust, and have usually been able to find a few small spots that didn’t get dissolved.

-- Gerry, http://home.comcast.net/~cncwoodworker/CNC_Woodworker.html

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huff

2795 posts in 1909 days


#2 posted 1705 days ago

Gerry has covered it pretty well for you. Your straight nitrocellous lacquers will “burn in” to the previous coat which simply means that it partically dissolves the preveous coat and becomes one layer of finish. If you are using a pre-catalyzed lacquer or post-catalyzed lacquer, that’s different. Once a coat of finish is dry, the next coat will not burn into the previous. A catalyzed lacquer is a much harder finish and more resistent to heat and moisture. I always sand or block (3M foam blocks) between coats to remove any nubs etc before the next coat. I agree with Gerry, that you should remove all dust before you spray the next coat…..and if you are not satisfied with the final coat, you can rub out the final finish to achieve the smoothness and sheen that you like. It takes some playing around with, but lacquer is very forgiving.

-- John @ http://www.thehuffordfurnituregroup.com

View rhett's profile

rhett

697 posts in 2291 days


#3 posted 1705 days ago

Its hard to truely answer not knowing the type of laquer your using, or the method you are applying it with. Generally speaking any film forming finish will not really benefit from sanding past 150 grit. Your feeling the finish not the wood anytime you apply one. Starting with a sanding sealer is the first step. I don’t know where you do your finishing, but laquer dries fast so it is important to have a warm piece and a warm finish so it can “flow” properly. Sanding between coats with a fine grit sanding sponge works well and you always wipe down the surface free of dust before applying the next coat. You can also mist laquer with laquer thinner to dissolve the top layer and help it lay down.

-- http://planeandsimpleblog.wordpress.com/

View stefang's profile

stefang

12861 posts in 1958 days


#4 posted 1705 days ago

I find that a foolproof method is to sand with wet/dry 600 grit on the last coat. I just dip the paper in water as I’m sanding and wipe up as I go with paper towels. You can also rub out the finish to a silky smooth feel which can be high gloss without that cheap plastic look. I use automotive paint rubbing compound for this last step. If I just want a nice-to-the-touch satin finish I don’t do the rubbing compound bit. I don’t know much about finishing, but I do get a really good result with this method. Depending on the type of finish I either sand between coats or just the last coat.

-- Mike, an American living in Norway.

View Kent Shepherd's profile

Kent Shepherd

2697 posts in 1910 days


#5 posted 1705 days ago

So far, everyone has given great advice. I would add, though, that while my basic method always stays the same, the project I’m working on determines the care I give in the finishing process. I have done several complete new houses and shutters on a professional level. There is no way I could sand between every coat, or wipe down when I do sand. I have always just used my air hose and blown the dust off. What little remains will be melted into the the next coat. I sand the sanding sealer to 180, and that is suffient.

However, my guitars are a different story. I will sand between coats, and will use finer paper, maybe 320, until the last coat or two. Then I will wet sand with 400 to 600 like Mike said. I like to use mineral spirits as a lubricant though.
after the final coat I will hand rubb the finish. If you’re interested, Ill share that too.

Good luck

-- She thought I hung the moon--now she just thinks I did it wrong

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stefang

12861 posts in 1958 days


#6 posted 1705 days ago

I agree with all you said Kent. It does depend on the type of project and I forgot that. What advantages do you get from the mineral spirits? I’ve never tried that before. The only negative I could think about would be the fumes or at least the smell. I’m thinking about white spirit here. Is that mineral spirits? I know they sell white spirit in an almost odorless version, so maybe no problem. I haven’t had any problems with water thus far, but I’m only doing these small projects.

-- Mike, an American living in Norway.

View Kent Shepherd's profile

Kent Shepherd

2697 posts in 1910 days


#7 posted 1705 days ago

Mike, I’ve aso used water before. One reason I quit was just having a hang-up about putting water on a lacquer finish. Water also seems to take a little longer to dry and it must be totally dry before spraying again. It really all boils down to personal preference. There is really nothing wrong with what you’re doing. As far as the difference in “spirits”, I don’t know that it matters. I’ve also used paint thinner and naptha before, which are very similar———I think! A chemist would probably prove me wrong very easily. Anyway, they all work.

I also forgot to mention, on fine work, I use a tack cloth after sanding, before the next coat. On things like guitars or table tops, I get really anal about how I do things. On cabinet work, not so much!

-- She thought I hung the moon--now she just thinks I did it wrong

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