Lacquer and Buffing

[Cody Colston]

I asked this elsewhere but didn't really get a satisfactory answer, so I'll query you folks.

What is the process for applying and buffing a lacquer finish? If oil is applied first, how long should I wait before applying the lacquer and then how much longer before buffing?

I attempted to buff a bowl that had a coat of tung oil and 3 coats of spray Deft with 24 hours between all coats. The lacquer melted and gummed up making a horrible mess. I need some advice. ;)

Cody

[Bob Noles]

Cody,

Tung oil (true tung) needs a least a couple of weeks to dry (cure) properly before applying the finish coat.

[Greg Savage]

Cody, There is no real need to apply an oil finish before applying lacquer. If you do want to go with an oil, you really need to wait for a full cure. This could be several days or even a month, depending on what type of oil finish are using.

Depending on what type of lacquer you use, and how thick it is applied, your cure times will vary greatly. If you use Nitro cellulose lacquer, the cure time could be as much as 30 days before you can safely buff the finish. Catalyzed lacquers, on the other hand, can be wet sanded and buffed within hours (even minutes) of application. When using lacquer out of a spray can, the thickness of each coat is very uneven and heavy. Most likely your problems of gumming up and creating a general mess were because the lacquer finish was applied too thick (and not fully cured) over tung oil that was not fully cured. The lacquer never really had a chance to get a good hold. Also, don't get too aggressive with your buffing. This will cause too much friction, creating too much heat, causing you're lacquer to melt

A decent spray system would be a nice investment if you wanted to pursue lacquering your pieces. After each coat, you should scuff sand with 320 grit. Three nice coats should be plenty with sanding between each coat. After the final coat, wet sand from 600 grit to possibly 1500 or 2000 grit with mineral spirits as your wetting agent. Once this is accomplished, gently buff, as you normally would(tripoli and white diamond...no need for a wax coat). Where you start with your wet sanding all depends on how well you applied the multiple coats.

I hope this helps.

[Anthony Anderson]

Greg, Good advice. However, 24-48 hours would be enough cure time for lacquer before buffing, if your shop is constantly >70 degrees and humidity is reasonable. After the last coat has cured I would start with a final sanding of 1200, then 1500, and last 2000. I would do all of the final sanding by hand, and not on the lathe, as you have more control of how much finish you remove. What are you using for "burn cream" (polishing compound)? 3M Finesse-It II works very nice. Put some on a cloth and touch it to the piece (Won't take much pressure if you final sanded with 2000) You will have a finish that looks like glass. Make sure to keep compound on your cloth to reduce the amount of friction/heat buildup. Finish up with 3M Microfinishing compound. These compounds are very easy to use and contain no wax, which is important because you may need to recoat, also the finish will continue to "breathe" (purging gases) as it cures. Wax will prevent the "breathing process" and can cause checking. I would not put an oil under a laquer, that's just me. If you want the color, you could try some diluted stain to tone the wood, then clear. I have recently tried the Transtint dyes and very happy with the results. You can mix with distilled water, or denatured alcohol. Both of these would dry quickly, and allow you to go to lacquer in a few hours. HTH, Regards, Bill

[Greg Savage]

Greg, Good advice. However, 24-48 hours would be enough cure time for lacquer before buffing, if your shop is constantly >70 degrees and humidity is reasonable. After the last coat has cured I would start with a final sanding of 1200, then 1500, and last 2000. I would do all of the final sanding by hand, and not on the lathe, as you have more control of how much finish you remove. What are you using for "burn cream" (polishing compound)? 3M Finesse-It II works very nice. Put some on a cloth and touch it to the piece (Won't take much pressure if you final sanded with 2000) You will have a finish that looks like glass. Make sure to keep compound on your cloth to reduce the amount of friction/heat buildup. Finish up with 3M Microfinishing compound. These compounds are very easy to use and contain no wax, which is important because you may need to recoat, also the finish will continue to "breathe" (purging gases) as it cures. Wax will prevent the "breathing process" and can cause checking. I would not put an oil under a laquer, that's just me. If you want the color, you could try some diluted stain to tone the wood, then clear. I have recently tried the Transtint dyes and very happy with the results. You can mix with distilled water, or denatured alcohol. Both of these would dry quickly, and allow you to go to lacquer in a few hours. HTH, Regards, Bill

As a guitar builder, If I'm using nitro, I won't even thing about a full blown rub-out for 3 or 4 weeks. I've just blown through too many edges with very light buffing.

I have nearly ceased using nitro because I don't have those perfect temp/humidity conditions.

[Ernie Nyvall]

Cody, wht rpms are you using to buff? I buff lacquer, but with a light touch between 1000 and 1500 rpms. I make several fast trips around tthe bowl so as not to get it hot.

Ernie