Buffing Question

[Tom Megow]

I had built a mount for my buffing wheel to be lathe mounted.
My research found that i should use a plain wheel on wax/oil finishes.
I am using a Walnut oil/wax/Shellac combo finish.
What should I buff it with, Plain? White Diamond??
Thanks
Tom
Ala

[Michelle Rich]

do not buff shellac..it will melt when it gets warm and stick to your buffing wheels

[Tom Megow]

OK then what should I do? Wet sand with very high grit paper?

[robert baccus]

Try sanding with the 3M foam pads. Always use slightly soapy water. You may not need further finishing if you like a piano finish--just do a light wax job behind the sanding. There is a misconception that buffing means hard wax cutting compounds. This was primarily a metal polishing technique. When doing film finish buffing the proper compounds are water-based as in liquid auto buffing compounds. No heat or burning using high rpm and low pressure. Guess how they shine up a new porche or hotrod which are lacquer or acyric sprays. Shellac or lacquer(which was developed to correct most of shellac's shortcomings) is the same stuff on a bowl or show car.

[Jeff Gilfor]

Wait a minute there!
i use shellac finish for just about everything, and ALAWAYS buff my pieces. The shellac most certainly does not get taken off by the buffing if you are doing it properly.

first thing is, use at least 3 coats of shellac (even if friction polishing) and wait several days before buffing. Even though it feels hard to the touch, it takes a bit longer for the shellac to become truly hard.

second, use LIGHT pressure when buffing. Especially with the harder buffs (tripoli and white diamond). Creating too much heat will indeed burn through the finish. I buff at 1750 RPM... Not faster!

buffing levels the surface of shellac finishes nicely, giving a finish that can rival French Polishing... If done correctly.

here's a bowl I did last week, finished with shellac, and buffed.

[Tom Megow]

that's a nice finish

[Brian Kent]

I have had Jeff's experience after a bad molten shellac lesson - waiting several days, buffing lightly at a medium speed. Not letting the wheel stay in one place a long time.

[Jeff Gilfor]

Thanx. It's my home made friction polish that I've used for years. Made of 1/3 denatured alcohol, 1/3 pure tung oil, and 1/3 hard shellac (chemically altered regular shellac that turns impervious to solvents after a few weeks... Not the same stuff sold by that name by the U-Beaut folks, but similar). Would work just as well with normal 2 pound cut shellac (Zinsser sanding sealer is 2 pound cut out of the can), just won't be as hard wearing.

Like I said. I wait a few days, then buff at 1750 RPM with tripoli, WD, and carnauba. Final coat with Ren wax makes it fingerprint proof (well... Mostly).

[robert baccus]

I'm sure you get a nice finish after all that. You can do all the same with lacquer by noon. Also I finish on the lathe--5minutes wet sanding-5for compounding and 2 for waxing and no danger of banging the bowl on a shaft buffer. The precat lacquers are almost as hard as glass after a few days crosslinking.

[Michelle Rich]

Well Jeff, by disagreeing with me, you proved my point. Shellac when buffed does migrate to the wheels UNLESS one is so gosh darned careful to not induce heat, and "baby" the finish. Now after years of being on these forums I have learned turners want a huge 1,000 lb lathe with 5 hsp, so they can hog off material with a 2" wide gouge made from titanium. Right? So getting those same people to gently buff, seems iffy. Therefore I stand by my recommendation to Tom.

[Tom Megow]

OK I buffed two bowls with the Dr Lab WO/Wax/Shellac finish. Before Buffing when I looked at the bowl in the glare from overhead lights(sorry there is probably a correct term for that) I could see streaks and blotches. They are 99% gone now. Yeah!!
As advised a plain cotton wheel at 1750 RPM's and a light touch did the trick
Thanks y'all.
Now I am getting sucked into the finishing vortex. My sole customer thus far wanted a High gloss finish for her bowl. That is why I bought the shellac component finish. Does lacquer give a higher luster finish than shellac? Is it more skill than finish? What about lacquer and food safety?

[Jeff Gilfor]

I am, and have been a finishing geek for some time. I can definitely induce glazed over eyes in those I start getting all "sciency" with.

Shellac and lacquer are two distinctly different finishes, with two distinctly different "characters." Both are excellent finishes that have been used for ages.

To me, thinned shellac mixed with oil gives a very nice warm shine. If you look at any of my pieces finished that way, you can see the grain patterns in the finish, despite the nice gloss. Of course, the finish can be softened if you prefer.

Lacquer, is a phenomenal finish as well. Of course, it is durable, but it also tends to be a bit too glossy for some of my work. Buyer seem to like high gloss, even if it's a "glassy" look and, for some things, I like that as well. I think that salt/pepper mills look very nice finished that way for instance. For bowls and HF's, I actually like my shellac based finish better though. I will say though, that for some punky woods, or those which do not lend themselves to a friction-type Finnish, lacquer would be my choice.

Lacquer, also most properly should be sprayed. This requires additional equipment and skill (not much, I agree), plus a clean shop. It is a chore, when I need to do that. Some professionals have separate spray rooms or tents for that purpose. Others just throw a blanket over the lathe, and spray while spinning slowly.

I do not advocate using straight shellac. Although it is an ancient finish, with great ease of application, very forgiving, and easy to repair and restore; it is not durable, and does not stand up to use on any utility item. One plus is though, that it's completely non-toxic. The shellac finish I use is a specially modified vesion of shellac, designed to allow crosslinking between the hydroxyl groups once the solvent vehicle has completely evaporated. When mixed with the tung oil, and applied either hand-rubbed, or on the lathe (my preference), the oil draws the finish into the wood, while the shellac seals the surface. There is also a great deal of crosslinkage between hydroxyl groups in the shellac and the oil itself. This creates a super solvent and water resistant finish, that is also extremely flexible, and enhances the cell structure of the wood, which seems to improve any chatoyancy of the wood itself. Getting a similar combination of these characteristics with sprayed lacquer is difficult, if not impossible.

As to the heat stability of the finish, as I said, I buff at 1750 rpm. I do not baby the piece I am buffing! I tend to press fairly hard, but keep the piece moving. Like any buffing operation, you don't want to stay on one spot too long. I have NEVER had any shellac "build up" on my buffing mops, and I've never burnt off the finish as long as I wait until the solvent has completely dried. Lacquer finishes, in my opinion, should be buffed as well to provide the best final surface. Even with lacquer, the recommendation is to wait a day or two until the finish has completely set and dried.

There will always be folks who are proponents of one finish over another, and they all bring up good reasons for their choices. It's like asking a turner which gouge grind is "the best". You'll get as many answers as people you ask.

[Alan Dick]

Jeff,

Could you talk a little about what you do to the Shellac to allow the crosslinking? Is this an off the shelf product or something you mix yourself?

Alan

[robert baccus]

I agree there are many ways of getting a good finish. However when you add in things like time, ease of screwing up, durability, consistency of results, ease of repair stoneage products simply do not compare. Again check out show cars, piano's, and guitar finishing. These people have real money invested in the results. Some turners still use reground files for gouges and swear by them. I do agree that the best finish I've ever seen was a French polish shellac job.