Polishing Lacquer

[Russell Neyman]

Robert Baccus and I had a dialogue on another thread about this [http://www.sawmillcreek.org/newreply...703&noquote=1] and I thought it was worthy of a separate discussion.

I have used lacquer for years on turned projects as well as my casework. As with cabinet shops, I like it because it dries very quickly (helps in a dusty environment, and my shop is very dusty), can be rubbed out (again, with dust around) and it is a very hard finish. Another advantage is that colors and tints are available in rattle cans, making blending and accents easier. Properly applied to about 6-10 coats, it can be glassy smooth.

So what about polishing?

As Robert pointed out, you need to be sure you have plenty of build and that it's well-cured before subjecting it to a polishing process. After multiple coats have dried for a week, I wet sand to 400 and then apply McGwier's Medium Cut auto polish, rubbing it with an extra white diamond buffing wheel (linen?) I purchased from Beall. I use fairly low speed, about 900-1000. The results have usually been good, but occasionally I blow through and have to start over.

But I wonder: should I switch to lambswool? Should my speed be adjusted? I never painted cars, so this is unknown territory for me.

[John Coloccia]

IMHO, one week is not long enough drying time for lacquer. At least 2 weeks, and longer would be better, especially if your technique/schedule aren't perfect and there's a chance you trapped a bit of lacquer thinner in there. If you sniff it, and it stills smells even faintly like lacquer thinner, you have a ways to go.

I generally sand dry with 3m FreCut to P600 or higher. Then if I feel like it, I wet sand with a higher grit, but that's usually not necessary. I think when you stop at 400, you leave a lot of work to do on the wheel, and heat is your enemy. You want to do as little as possible on the wheel. A drop of mineral oil spread on the surface of your piece will help you keep cool also.

[John Keeton]

Russell, I would think 400 would cut thru a few coats of lacquer quickly, leaving little in the way of finish that could successfully withstand buffing or polishing.

With any finish that is going to be buffed to a gloss, I usually do it in two stages - several coats, then level with 600 wet, and then several more coats, 600 and then 1200, lightly sanding with plenty of liquid, then buff.

Another option for you is to do 3-4 coats of brush on lacquer, wiped on, then even out with 0000 or 1200, then spray on a few coats of Krylon Matte acrylic, level it with 600, then 1200 (I do it dry) and then buff. The acrylic seems to be a much harder finish that dries to be sanded in under 15 minutes, and seems to withstand the leveling process better. It produces a nice finish with a good feel to it, and will buff to a nice gloss (even though it is a matte finish.) I also use it to produce a matte or satin finish by rubbing it out with 0000 after sanding to 1200.

With the lacquer and acrylic combination, I can get a nice finish on a piece in an hour or so. Like others have noted, I buff finishes pretty quickly, notwithstanding all credible advice to wait!

[Russell Neyman]

Thanks for the input. John K, are you saying that you don't wait several days with the acrylic application? I'm surprised that the two finishes are compatible. If you like the look and sheen of acrylic, why not just go with that?

[John Keeton]

I don't wait several days to polish/buff any finish. I am not advocating that for the masses, but it works for me and always has. I think the secret is to have a feel for the finish and how much one can stress it in buffing. I am not taking issue with those that wait several days, or a month - that works for them and is what they should do. I just don't have the patience for that, so please withhold the attacks!!!

The acrylic spray doesn't seem to work well for me as a "filling" finish - it is a film finish. The brush on lacquer can be wiped on while on the lathe, buffed on the lathe with 0000, and repeated several times in a matter of 30 minutes, or so, if conditions are good. The result is a "filled" finish that has some limited depth to it. Then, adding a few more coats produces a base that can be leveled. I have used lacquer and the acrylic with complete compatibility - each over the other, several times, with no issues.

[Tom Sherman]

John, a quick question, are youusing NC or WB lacquer.

[Prashun Patel]

Finishing a turned piece is a little different from a flat one; the same rules about application and wait times don't necessarily apply from one to the other. The speed of the spinning lathe allows fast and even application and buffing that are not possible on flat pieces.

Turners are often able to get extremely clear, polished surfaces with poly, where a lot of flat worlders struggle can't get poly to look clearer than plastic.

It remains true that a hard surface polishes better than a soft one. Soft finishes become harder as they cure. But on some finishes, you can compensate for this by polishing more aggressively*. This is the case with lacquer and poly varnish. Also, there are lacquers and there are lacquers. Some cure hard very quickly.

It is also not necessarily true that you you require a thick build to get a polished surface. To get a polished surface, you need a FLAT surface. The easy way to do that is to put on a thick film that can be leveled and polished without burning through. But a thick film requires more time to dry. If you level the finish as you apply it by applying it with an abrasive, or fill the pores beforehand, it's possible to lay on a final finish coat that is ultra thin and can be polished to a high sheen.

IMHO, film thickness should be a function of how durable you need the piece to be - not the sheen you desire.

* edit: Some finishes shrink as they cure, which causes a nice level surface to buckle and settle into pores ever so slightly enough to reduce the sheen; it's another reason people say to wait until cure to buff. But the extent to which this happens varies with different finishes and different woods. Again, all this is just to say that the EASY way is to apply thick, wait, then level, then polish. But it isn't a requirement for all finishes on all woods.

[John Keeton]

John, a quick question, are you using NC or WB lacquer.

Tom, this is the lacquer I use.
5GDT.jpg
And, this is the acrylic spray.
135715.jpg

Also, I should note that I agree fully with Prashun's comments! Having a flat finish is critical when you produce a gloss. Otherwise, every defect will be seen. And, it doesn't take a thick finish, but the leveling must occur evenly and with care to avoid thin spots that will not withstand buffing.

[Roger Chandler]

Man........I love threads like this one! Such a treasure trove of information. Keep this type of discussion going from time to time, it helps us novices in finishing to hear from the experts among us!

I would love to be able to look over John K's shoulder and watch him finish a piece like he is talking about here, and also do the same watching Prashun finish one...........that would be worth a big steak dinner, my treat!!!

[Jon Prouty]

Man........I love threads like this one! Such a treasure trove of information. Keep this type of discussion going from time to time, it helps us novices in finishing to hear from the experts among us!

I would love to be able to look over John K's shoulder and watch him finish a piece like he is talking about here, and also do the same watching Prashun finish one...........that would be worth a big steak dinner, my treat!!!

totally agree - one of the best threads I've seen in a long time. I would love to see a video of John K finishing a piece (hint hint).
Jon

[John Keeton]

It really isn't that exciting, guys! Like everyone else, I have gone thru a bunch of finishing techniques trying to find the fastest, easiest, etc. In the end, it has boiled down to about 3-4 processes for me, depending on the desired result and the wood being used. The lacquer/acrylic method is used frequently for a fast, natural looking finish with a pleasant gloss or sheen. For a deep, high gloss, glass like finish, I still prefer WOP - usually over BLO and shellac. It is just a much longer process. But, I still buff the final coat the following day.

I wish I had back all the money I spent experimenting!

[Royce Wallace]

I'm pretty much like John, except I use spray can off the lathe-- finally sanding is 600gr followed with Mirlon 448gr finish material, (by Mirka in lieu of steel wool) & I hand buff with hand work ending with Meagires buffing compound and usually use their yellow wax--I can finish in one day-- I have tried many finishes and for almost any reason that works best.
I still like oil for myself, but it does not achieve the same gloss that lacquer will present.

[robert baccus]

Like royce said there are many lacquers out there. I switched from nitrocellulose to Mohawk precat. years ago. A totally different cat. First on goes the heavy bodied SS which is made to level and seal the wood. Two coats straight out of the can. Light dry sanding with foam pads followed by Two coats of PC lacquer. It is made to be sprayed full bodied with no thinning and 2 coats is plenty. This stuff catalizes over time and gets many times harder than nitro. Follow this by wetsanding with 220 foam pads after a couple of hours. You can stop here and Steel wool in some wax for a perfect semi-flat finish or go to a wet pad with Meagires compounds( several grits for different sheens) to a glass finish. And you can easily go back to semigloss. At the end of spraying lacquer and while still soft you can do a light overspraty with retarder which will lay down the orange peel sometimes to a perfect gloss finish. An old auto trick---lightly. Reatarder is just a very slow drying thinner which is what Deft is known for. They take a lacquer and thin it with retarder which allows the brush marks to flow out. You also get a thinned product with less solids and slower drying times. Retarder in the can or rattle can should always be handy when using lacquer. It also prevents/treats fogging which is water vapor condensing in the cold fast drying lacquer thinner. If you have high humidity or fogging add the stuff to your spray gun or be ready to overspray fogging with a rattle can.. Meagires is a very good brand and they do label their bottles with the grit of compound(several) and their yellow waxes are great too. This takes longer to type than to do. Like above this is a film finish and will easily hide sanding marks up to 180 grit is you use pads which are. less aggressive. If you really want to cry notice that your recently lacquered hot rod(20 coats) turned foggy overnite. Don't ask. Again I sand,polish and wax on the lathe with a drill used only for sanding. It is almost impossible to have a burnthrough with compounds while spinning on the lathe. Cars are polished with high powered disc machines with liquid compounds only. There are many opinions and methods out there--I'm lazy and I like near perfect finishes without excessive witchcraft or labor. Materials and methods improve every day. Heavy bodied SS and retarder are a must for lacquer work. Check out how guitars are finished. Try a test--sand out a piece of walnut to 220, add SS, light sand with 220 and add finish. Leave 1/2 the board with no SS and observe the results. Testing beats opinions--mine too.

[John Keeton]

Bob, I have seen pics of some of your high gloss work, and you achieve a great finish! I wish I could justify the expense and cleaning hassle of a spray setup. But, for one piece at a time, it seems like it would be a too much of both. Do you wait and do several at once?

[Dennis Ford]

Bob, I have seen pics of some of your high gloss work, and you achieve a great finish! I wish I could justify the expense and cleaning hassle of a spray setup. But, for one piece at a time, it seems like it would be a too much of both. Do you wait and do several at once?

Having seen Bob's set-up, I will jump in here. He does beautiful work but his spray guns are NOT pretty. Cleaning lacquer out of small spray guns is not really necessary, just shoot a little thinner through it and hang it on the wall (Do not try this with poly).