buffing question

Re: buffing question

Mike Schwing from Md.

>Ken, you can do any and all of them. Totally up to you. In fact, I suggest doing exactly that - all of them to see which you prefer.

Some woods buff up wonderfully with no finish - bubinga, walnut, some maple. Just use the tripoli compound and the wax - no white diamond on walnut! Some don't. Almost all finishes aren't really dry when they feel dry, they still off gas for some time (talk to Russ for more detail on this). I wait a week after the last coat of Watco, and a month or more if lacquer. If you can't hold your horses, the buffing job might need repeating after a time. It'll buff up nice a week after your last coat of poly, but might not stay that way for long as the finish still shrinks a bit as it finally dries. If oil isn't fully cured it heats up and becomes gummy.

If you're going to buff with no finish, sand to a higher grit than normal, and burnish with some shavings (maple works best for this) or a brown paper bag. I wish more folks produced finished products with no finish on them, but the buying public expects to see something on bare wood. Bill G. prefers (his words) no finish on his cherry bowls.

Re: buffing question followup

ken chase

>Thanks Mike. The two types of wood in my shop now are mesquite and oak. Would either of these do well with no finish before the buffing process? And..you mentioned burnishing with shavings. How is that accomplished?

Appreciate all the great info you provide

Re: buffing question followup

Mike Schwing from Md.

>I've never turned mesquite - don't know! A guess, but I wouldn't think oak would buff up too nicely on its own.

Burnishing is a process that pretty much seals the wood at the end of the sanding process. Technical details of why escape me.

Done on the lathe, take a brown paper grocery bag (or a handfull of shavings) and hold it against the spinning workpiece. Before too long you'll see a nice sheen develop - if the wood is conducive to burnishing. Some woods have silica and other abrasives in them that do not lend themselves to working well as burnishing material, but maple does not - its great for that and I keep maple shavings around for that express purpose.

Be careful though - too much pressure/heat and you'll not only BURNish but BURN the wood.

Some folks will say that burnishing prevents finish from sticking - they may be right. I'd like to ask Russ to chime in here for more, as I only know that burnishing works, but not really how.

Re: buffing question followup - burnishing

JL

>Think of burnishing as filling the pores and what not on the wood. As you hold the shavings to the wood, they help fill up the pores, holes and crevices. The shavings act as a gentle polishing agent. They abrade the loose wood fibers on the surface of the turning (pore and crevice filling).

As to why the finish won't stick as good - there isn't much for it to stick to. You have a pretty slick surface now that everything is leveled out. You can also "carmelize" the hydroxyls on the cellulosic fibers - this also prevents the finish from sticking.

My $0.02

Re: buffing question followup

Jim D.

>If I remember right, burnishing is a form of polishing. It will not improve a poor sanding job. Basically, it seals the wood poors and the heat draws the natural oils out of the wood to create the polishing. I have heard it can effect the adheasion of certain finishes but i have never had a problem. I used this system when I was turning a lot of pens and finished using lacquer.

Jim D.

Re: buffing question followup

Ed in No.VA

>Mesquite should buff up great. turned a small piece of green mesquite limb wood last week and it shined up with just shavings.

Thanks all for buffing help

ken chase

>Great info. I'm grateful to all

Re: buffing question followup

Russ Fairfield

>True burnishing is a compaction of the wood surface, usually done by rubbing another piece of wood on it. Very hard wood or steel works very well.

What we are doing with fine sandpaper, wood shavings, and grocery bag paper is some combination of compaction, melting the cellulose, and bringing the oils out of the wood, all with the goal of closing the cellular structure of the wood. It isn't as hard as a true compaction of the surface, but the result is similar.

I have been told forever that finishes will not stick to highly polished wood; but I have never had a finish refuse to adhere because the surface was too shiny. It might not get the same penetration, but it will stick to the surface just as well. The benefit is that the wood grain is brighter when the surface is polished than if it were not. Others may get different mileage on this.

Pencrafters are sanding to 12,000 MicriMesh which is a bit finer than 2500-grit sandpaper, and they have no problems with any of the finishes sticking and staying on the surface.

Burned wood, as from a saw blade or router bit is a different story. Finishes will not adhere to burned wood.

Buffing with Tripoli leaves a dark residue in an open grained light colored wood, White Diamond leaves a residue in a dark wood, and excess Wax in any open wood can be a problem. Buff the wood with a natural bristle scub brush to remove the residue after each of the 3 wheels in the buffing system. Don't use a nylon brush because the sharp ends of the bristles will scratch the wood. You might find that the buffing with the brush may improve on the finish off the wax buffing wheel.

Use a toothbrush or a dental pick to remove the gunk from voids in the wood.