AW Extra 8/15/13 – Easy Rub-Out

Easy Rub-Out

Three quick steps to a silky-smooth finish.

By Kevin Southwick

Brushed-on finishes such as varnish provide
superior protection, but they dry so slowly, airborne
dust and renegade hairs are almost sure
to settle on the damp surface. Fortunately, the
process I use to remove these minor imperfections
is both fast and simple—the
table top shown here took less than 10
minutes to complete—and it leaves
the finish looking and feeling like
nobody’s business. Th e trick is
to apply a low-sheen finish,
let it dry thoroughly and
then use a gentle touch
and the appropriate
fine abrasives to
rub it out.

 

Rubbed-out vs. hand-rubbed

While the terms are similar, a “rubbed-out” finish and
a “hand-rubbed” finish are distinctly different. Abrasive
rub-out methods are typically used on film-building finishes
that are susceptible to debris getting stuck in the film
as it dries. A hand-rubbed finish usually refers to a wipe
on/rub off process that does not involve building a film
above the surface of the wood.

Rubbing a film finish with fine abrasives allows you to
subtly control how light is reflected, for a warmer, more
inviting and refined appearance. Using fine abrasives to
remove minor imperfections in the finish will also give
your project an elegant feel that makes it hard for people
to keep their hands off .

Most rub-out methods include difficult, labor intensive
processes with a fairly high level of risk that problems
will occur. For example, the first step in many of these
methods is “leveling the finish” to remove all the wood
texture. This step is risky because it’s so aggressive. For
anyone, even an experienced finisher, rubbing through
the top layer of finish or even right down to the wood is a
distinct possibility.

My rub-out method carries almost no risk, because
leveling the surface isn’t required. Leveling is only really
necessary when the goal is a high-gloss sheen, as in a
“piano finish.” My method produces a satin sheen.

 

Start with satin varnish

It’s important to start with a satin- or flat-sheen varnish,
so that the pores and low spots in the texture of the wood
don’t appear shiny aft er the finish has been rubbed out.
Th e table shown here is made of figured cherry that has
been finished with General Finishes Arm-R-Seal satin
polyurethane, applied with a foam brush (see Sources, below). Th is product flows out nicely due to its thinner
viscosity, so there are no visible brush marks to remove.

Tip: If your satin varnish is thick enough to leave brush
marks, try thinning it at least 25%.

I’ve applied three coats everywhere but the top, which
has a fourth coat because it will be subjected to more
wear and tear. Unfortunately, my dog stopped by to check
things out while the last coat was still wet (Photo 1).

Before rubbing out the finish, you must allow it to dry
for at least three days in optimal conditions (above 60 F
with relative humidity at 50%), but it’s better to wait a
week. Allow even more time when the relative humidity
remains above 80%.

 

Silky-smooth in three steps

This rub-out technique has only three steps. There’s no
reason to worry about the confusing range of abrasive
sheets, pads, powders and compounds used in more
involved processes. All you need is satin Arm-R-Seal,
400 grit or finer sandpaper, a felt sanding block, good quality
steel wool (made by Liberon or Briwax), and
a few drops of dish soap. These products are available
online or at woodworking specialty stores (see Sources).

Step 1: Remove dust nibs, hairs and very small imperfections
above the surface.
Very fine sandpaper is the
most effective tool for shearing off these buggers, because
it’s important not to remove any more of your carefully
applied finish than necessary. Use 400 grit or finer sandpaper
cut to one-quarter sheet size (not torn with rough,
scratchy edges). For consistent cutting action, wrap the
sandpaper around a soft , pliable sanding block. The best
blocks for this job are made of felt or neoprene rubber.
(Neoprene blocks of assorted density and pliability are
available through automotive suppliers.)

Sand very lightly with the grain to shear off dust and
hairs (Photo 2). Th is process requires very little pressure—
maybe as much as the weight of your hand. It feels more
like dusting or gentle cleaning than sanding. It doesn’t take
long, either. Two or three strokes will oft en do the trick.

Applying the minimum amount of sanding pressure
keeps the sanding scratches as small as possible. Pushing
down harder than necessary creates bigger, deeper
scratches that require more work to remove in the steps
that follow. Feel the surface as you go and stop sanding as
soon as it feels smooth. Completing this step on an average-
size dining room table should take between five and
ten minutes.

In all three steps of this process, it’s best to work carefully
to within about 1/2" of the edges to avoid cutting
through (Photo 3). Then finish the work around the edges
separately and cautiously (Photos 4 and 5). Consistency is
very important for an even sheen. Wipe the surface clean
with a damp cloth. You should see a consistent visible
scratch pattern that shows on the high spots in the texture
of the wood.

Step 2: Remove the visible scratches from sanding
and replace them with smaller scratches.
For this step you
must have good quality #0000 steel wool that’s specially
made for rubbing finishes (see “Types of Steel Wool,” below). It’s important to cut and fold the steel wool carefully to
create a good, consistently-abrasive surface (Photo 6). An
18" to 20" length of wool folds into an effective four-layer
pad. Use your felt or neoprene block to back up the steel
wool. As with the sandpaper, this provides a much more
even and gentle cutting surface. Work the surface carefully
and consistently to create an even appearance (Photo 7).
As with the first step, this step requires very little pressure.
Once again, save the edges for last. Wipe clean with a
damp cloth. This step should take 10 to 20 minutes.

To rub turned legs or shaped moldings, use the sandpaper
on only the straight portions. On the shaped portions,
skip the sanding and go straight to the steel wool
(Photo 8).

Step 3: Remove the scratches made by the dry steel
wool and replace them with scratches that aren’t visible
to the human eye.
Scratches that are easily visible create
a hazy appearance. Moving from these scratches to
scratches so small they’re not detectable is what makes
this step different from the first two.

Start with fresh steel wool prepared as in the previous step, with the soft felt block to back it up. Mix a couple
drops of mild dish soap or hand soap in a small dish of
water. Use just enough to get some suds going. Dip the
steel wool in the soapy water or just sprinkle drops around
on your surface. Work the wool in a circular pattern using
the same gentle approach as in the first two steps (Photo 9).
Add a drop of soap to the surface anytime you need more
suds. Move across the surface in an overlapping pattern.
After one complete pass over the entire surface, repeat the
pattern two more times, then wipe dry with clean, soft
paper towels. Let the water evaporate and then carefully
assess your progress. Repeat this last step as needed to
create a consistent satin sheen. This step should take 10
to 20 minutes.

Click any image to view a larger version.

1. Embedded hairs and dust nibs are almost impossible to avoid
with film-forming finishes. Removing these imperfections and
creating a smooth, lustrous finish is easier than you might think.

2. Start by sanding very gently with the grain using a felt block
wrapped with 400 grit paper (or finer). Removing dust and hairs
requires only a few strokes.

3. Consistently work the surface while carefully staying about
1/2" from the edges. Sanding gently leaves smaller scratches that
are easier to remove.

4. Sand to the ends using two or three short, light strokes, lifting at
the end of each stroke so you don’t cut through the edge.

5. Sand to the sides, working with the grain and using your thumb
as a guide to keep the abrasive away from the vulnerable edge.

6. Carefully cut and fold good-quality #0000 steel wool to make
a consistent abrasive pad. Folding the wool allows you to renew
the cutting surface by unfolding fresh layers.

7. Remove the sandpaper scratches by working with the grain
using the steel wool. Back the wool pad with the felt block to
create a more consistent rubbing tool.

8. Go straight to the steel wool on the shaped portions of turned
legs and moldings. Be careful to avoid cutting through delicate
edges. It’s OK to sand the flat portions, but stop short of any curves.

9. Finish the job with a fresh wool pad, soapy water and a circular
rubbing pattern. The lubricated wool removes the scratches from
the dry wool and leaves no visible marks behind.

Types of Steel Wool

The fibers in good-quality steel wool are long and very
consistent. That makes it far better for rubbing finishes than
ordinary steel wool, because it provides consistent cutting
action and produces a consistent scratch pattern. It also
lasts longer. Good-quality steel wool is more expensive than
ordinary wool and harder to find (see Sources, above).

Ordinary steel wool has shorter fibers that are visibly
inconsistent. It often feels greasy with residual oil from the
manufacturing process and it has a tendency to crumble.

A quick look at the cutting surface of a nylon abrasive
pad shows that it’s significantly different from good-quality
#0000 steel wool. Although it’s a useful finishing tool, a nylon
abrasive pad isn’t appropriate for the process shown here,
because it doesn’t cut the same way that good-quality steel
wool cuts.

Sources

Note: Product availability and prices are subject to change.

Woodcraft, woodcraft.com, 800-225-1153,
General Finishes Satin Arm-R-Seal, 1 qt., #56606; Norton 3X
Sandpaper, 400 grit, 20 sheets, #29533; Felt Block, #58289; Liberon #0000 Steel Wool, 1/2 lb. roll, #58354.

Rockler, rockler.com, 800-279-4441,
General Finishes Satin Arm-R-Seal, 1 qt. #85F08; Norton 3X
Sandpaper, 400 grit, 3 sheets, #145034; Felt Rubbing Pad,
#38N41; Briwax 4/0 Steel Wool, 1 roll, #844337.

This story originally appeared in American Woodworker April/May 2012, issue #159.