A Final Treatment That Leaves Your Finish Feeling as Good as It Looks
By Michael Dresdner
It's all well and good for a finish to look great, but if you want a finish that will feel as g<x>d as it looks, you'll need to rub it out.
Rubbing out a finish means working it with a mild abrasive such as pumice or steel wool. The abrasive produces extremely fine, uniform "scratches" that go in the direction of the wood grain, helping to hide both brush marks and the "orange peel" texture common to sprayed finishes. And, while the result will not appear much different from satin lacquer or varnish, it will make the finish feet satin-smooth.
Rubbing to satin is easier than rubbing to gloss. A rubbed satin finish hides a multitude of sins, while a rubbed gloss finish shows every minute Haw. Although you use some sort of abrasive in both cases, the materials and methods for a gloss nib are very different. Rather than "gloss over" this important area of finishing, I'll deal with it in a future column.
Virtually any film-forming finish can be rubbed, as long as the dried film is thick enough to prevent cutting through to the wood. A good rule of thumb is that the film should be at least 4 mils (0.004 in.) thick for even a light nib. That's roughly equivalent to four coats of sprayed lacquer, or two coats of brushed varnish, shellac or polyurethane. Wipe-on finishes, such as drying oils, Danish oil, and French polish, don't need to be rubbed, since they usually go on very smoothly. Waxes and nondrying oils do not form films, so they don't get rubbed either.
For rubbing out, it doesn't matter whether you start with a satin or a gloss finish. But you will get a clearer satin-nibbed finish if you use gloss lac quer or varnish. This is because satin lacquers and varnishes contain "flatting agents"—ultrafine particles of sand or wax that diffract light. If you build up several layers of finish containing these particlcs, the clcar film will start to look cloudy. A gloss finish rubbed to satin will retain more of its original clarity.
Abrasives and Lubricants
There are two common methods used to rub a finish. The more tniditional way is to mix FFFF pumice (sec Sources) with water to make an abra-
sivc slurry. You rub the slurry across the surface with a felt block, replenishing it with more slurry when it stops working, or with water if it gets too dry and crusty. For a higher sheen, you can follow up with another slurry of mineral oil or paraffin oil mixed with rot-tenstone, an even finer abrasive powder.
I prefer the more modern method, using 0000 steel wool or ultrafine nylon abrasive pads along with a rubbing lubricant, such as soapy-water or liquid wax. Finish supply catalogs sell jelled soap-type lubricants with names like Wool-Lube (see
Sources), which are meant to be mixed with water. But any pure soap, such as Murphy's Oil Soap, works just as well. Personally, I like to use paste wax thinned with mineral spirits. Although soapy water cuts a bit faster and leaves your hands sparkling clean, wax adds a layer of protection and leaves the finish feeling slickcr.
Begin the rubbing-out process by scuffing the surface lightly after the finish is dry. Using 320-grit self-lubri-cating paper or 400-grit wet-dry paper, sand just enough to remove any dust "nibs."
When the surface feels smooth you are ready to nib. Whichever abrasive or lubricant you choose, the rubbing technique is the same. For a flat surface, such as a tabletop, hit the edges first with short back-and-forth strokes. Then rub in long, even strokes, the length of the entire top if possible, gradually working from one edge to the other. Keep your hand flat as you
When rubbing, keep your fingers flat on the surface and work with your hand perpendicular to the grain of the wood. This will give you a more even surface and reduce the chances you will cut through the finish, especially at the edges.
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