Michael Dresdner » rubbing out

Pen polish

Michael — Mon, 08 Nov 2010 14:00:07 +0000

Q: I am new to pen turning. Can you recommend some finishes?
A: It depends largely on the pen material. Obviously, cast acrylics need no finish and can simply be buffed. Ditto for very hard or resinous woods, like rosewood, ziricote, bocote, cocobolo, lignum vitae, ebony and even boxwood. For other woods, I tend toward simple finishes; just wax, or wax over boiled linseed oil or wipe on varnish. For a very durable finish, I also like either cyanoacrylate (CA), or a combination of boiled linseed oil and CA. The CA will instantly cure the oil into a hard solid film. Using paper towel applicators on the spinning lathe, apply a thin coat of one, then the other immediately. Add as many coats as you like, sanding for smoothness when necessary. Once cured, which takes only minutes, this finish will buff nicely.

Pumice problems

Michael — Wed, 16 Jun 2010 14:00:52 +0000

Q: When using pumice stone and linseed oil to rub out slight discoloration in an inlaid dining table I encounter little spots forming. The discolorations do disappear.
A: First, if you must use pumice (and there are far better alternatives), pair it with a non-drying oil such as mineral oil, not linseed oil. As for the spots, if they are tiny and in the wood pores, it simply means you are packing pumice into them. You can remove it by scrubbing with a soft bristle brush and wiping.

In the buff

Michael — Wed, 28 Apr 2010 14:00:12 +0000

Q: Can I buff waterbased acrylic and be able to get a fair shine?
A: Certainly, assuming you started with gloss acrylic. However, it will be much easier, and you’ll get a much better shine, if you wait until the finish is not just dry, but cured. Waterbased finishes generally take about a month to cure.

Wax won’t abrade

Michael — Tue, 20 Apr 2010 17:00:13 +0000

Q: I have a can of Butchers Bowling Alley clear paste. Is this the same as automotive compound?
A: Nope, not even close. It is wax. You stopped short of the entire name of the product; Butcher’s Bowling Alley clear paste wax. As its name suggests, it is pure paste wax, which is a combination of plant and animal waxes mixed with solvent to keep it in an easy to use paste form.
By contrast, automotive rubbing and polishing compounds are mixtures of abrasive grit in a ready to use paste. This is the same abrasive grit used on sandpaper and grinding wheels, and it will abrade away part of the surface of the finish. Using it to remove surface scratches is the same process as sanding, but the paste form allows you to work with very fine grits without clogging, which can happen with ultra fine sandpaper. Of the two, rubbing compound is coarser, and polishing compound finer grit.

Scratches, away!

Michael — Mon, 19 Apr 2010 17:00:00 +0000

Q: Our regularly used dining table was refinished in dark brown, high gloss lacquer and shows superficial surface scratches with use. Is this is normal?
A: It is for lacquer, which has only moderate scratch resistance. To make things worse, scratches show more readily on gloss surfaces. Lacquer does have good stain resistance, but not good heat resistance, another issue that often affects well used tables. Thus, it is not usually my first choice for such a table. On the positive side, lacquer buffs out easily, so you can remove the fine scratches with automotive polishing compound whenever they bother you. Otherwise, consider using a tablecloth to keep the finish looking new.

Poly who?

Michael — Fri, 09 Apr 2010 17:00:48 +0000

Q: I just had an oak dining table refinished in a dark brown, shiny poly finish. It looks great, but only after two weeks I am seeing dozens of little superficial surface scratches everywhere. Do you think this is normal?
A: Fine scratches on the surface of a gloss finish are certainly common. Of course, a lot depends on what, exactly, the finish is. Poly may be shorthand for polyester, polyurea, polyvinyl, or one of five different categories of polyurethane. Each has different durability characteristics, so your expectations of scratch resistance would be different for each one.
At this point, there are two questions you should ask. The first is whether or not the finish is fully cured. Most oil and waterbased polyurethane coatings take up to a month to cure fully, and may be more scratch resistant after that time. If the finish is not cured, you might want to wait until it is, then rub out the scratches and bring back the original gloss using automotive polishing compound. Better yet, have your finisher do it.
The second, assuming the finish is fully cured, is can I live with this level of surface scratching? If not, go back to your finisher and ask what options are available from him or her. While any gloss finish will show scratches, some types are certainly more susceptible than others.

Satin rub primer

Michael — Fri, 26 Feb 2010 17:00:59 +0000

Q: I recently attempted to hand rub the polyurethane finish on a mahogany tabletop that I refinished and was disappointed with the result. The top has three coats of oil based satin polyurethane. The finish had a nice even satin sheen but felt like 220 grit paper. I then wet sanded with 600, 1000 and 1500 grit wet paper wrapped around a felt block, then rubbed with FFF pumice using a felt block and water lube. What did I do wrong?
A: You did not tell me if the finish was sufficiently cured, and that alone can undo your best efforts. Even so, you are going about creating a satin finish in a most difficult way. Here’s a simpler method that may work better.
Wait until the finish cures completely. For shellac and lacquer, two or three days will do; for oil based varnish and polyurethane, try to wait three weeks, and longer if you can spare the time. For waterbased, wait a month.
Smooth the top surface, removing any dust nibs, by sanding lightly with 400 grit self lubricated sandpaper. Sand only enough to remove the nibs – don’t over sand. Dip a pad of 0000 steel wool into paste wax and carefully rub with the grain. Do the edges first separately, as it is hard to rub all the way to the very edge of a surface. Keep your hand flat so you can rub right up to the edge without rounding the steel wool over the corner, which would cause you to rub through the finish. Once the edges are pre-rubbed, concentrate on the bulk of the top surface. Rub in very straight lines side to side, with the grain, across the entire top. Overlap your strokes and cover the entire top with at least six passes back and forth. That will guarantee a uniform fine scratch pattern from the steel wool, and the finish should look like finely brushed brass. Add more paste wax as needed for lubrication.
When you are done rubbing, immediately wipe off all the wax with a soft cloth, but that may still leave enough wax to smear. To remove it, sprinkle the top with cold water. Take a new, clean 0000 steel wool pad and gently go back and forth in the same rubbing pattern. Go over the surface once lightly, then flip the pad and do it again. Use no pressure other than the weight of your hand. The cold water will congeal the wax, allowing the steel wool to remove it. Wipe off the water and admire your work.

There’s the rub

Michael — Wed, 24 Feb 2010 17:00:18 +0000

Q: I find conflicting information as to whether polyurethane can be rubbed.
A: Any finish, including polyurethane, can be rubbed provided it is sufficiently cured. As a rule, the longer the finish cures, the harder it gets and the easier it is to rub. Attempting to rub out a finish that is still rubbery is an exercise in frustration. For oil based polyurethane, I’d wait at least three weeks to rub if at all possible, and four weeks for waterbased.

The clear solution

Michael — Wed, 17 Feb 2010 17:00:34 +0000

Q: I’m finishing a guitar in Krylon Special Purpose clear Lacquer over Satin Nickel Metallic over gray primer. The clear coat has some orange peel. I’m afraid to wet sand and buff it because I previously sanded through the finish at the edges and had to start over with bare wood. Since the finish looks good, I’d like to keep using the spray paint and just change the clear coat. Should I get a compressor spray outfit and spray clear nitrocellulose over the acrylic?
A: That’s one option, but there are others, and better ones at that. For one thing, nitrocellulose lacquer is amber, and will get more amber with time, while acrylic lacquer is clear and stays that way. Thus, even if you were to switch to a spray rig, I would suggest sticking with acrylic clear topcoat, which is available from most industrial suppliers and auto paint stores. However, there’s no real reason to go that far. You can simply add more clear coats the same way you added the first; with an aerosol can. With practice you can spray without orange peel. Working in a cooler room can sometimes help slow the set up time enough to give you better flow out also. Once you have built up enough clear, you can carefully sand it smooth and add more, or if there is enough material, simply rub it at that point. Granted, it takes a whole lot longer, and many more coats, when you are using aerosol cans, but you can still get the same final results and avoid the expense of setting up a spray rig. Just be patient.

Nibs in wipe on

Michael — Mon, 15 Feb 2010 17:00:55 +0000

Q: I’m trying to finish a secretary project. I’ve done part of it with General Finishing wipe on semi-gloss urethane and I guess I got lucky, because now I can’t get the same results without dust and debris setting in. If you do a semi gloss finish is there a way to erase the nibs and have a smooth clean result?
A: Yes, there is a way to erase dust nibs, and I’ve talked about it quite a bit in these pages, but there is also a way to avoid them. You can search for “rubbing” and get more in depth discussion, but for now, let’s go over both options at least briefly.
Any finish that is sufficiently thick can be rubbed out, and that process removes dust nibs. Start by lightly sanding with 400 grit or finer paper to remove the nibs, then restore the sheen by rubbing. You can rub to satin using 0000 steel wool and paste wax, or rub to semi-gloss by replacing the paste wax with automotive rubbing or polishing compound. The pairing of polishing compound with 0000 steel wool gives you a slightly higher sheen than steel wool lubricated with wax.
You can avoid all this by how you wipe the finish. In truth, wipe on finish should be called wipe off finish. If you put it on too thickly, it can pick up dust, but if you wipe it off completely, it won’t. That means you need many more coats to get the build you want, but since each coat goes on and off so quickly, and it is so easy to regulate it if you simply wipe off all you can, leaving only the thinnest layer of residual oil varnish, it’s really no big deal. It will take more time, but not more work.