James Freeman on mon 1 mar 10
BOREDOM ALERT! Very, very long. If you are not interested in wood
finishing, CLICK AWAY NOW!
The next step up in durability are wiping varnishes. These are sold as tun=
oil, penetrating oil, antique oil, waterlox, furniture refinisher, and a
number of other names. Despite the names, none of them are oil finishes,
and none contain tung oil. They are usually a mixture of varnish, linseed
oil, and mineral spirits. The secret to getting a good finish with wiping
varnishes is to apply many successive coats, and to work the surface with
very fine sandpaper, steel wool, or a grey scotchbrite pad between coats. =
typically apply 4 or 5 coats, lightly sanding between the first two coats
with 320 grit sandpaper, and between the subsequent coats with a grey
scotchbrite. After the final coat is completely cured (I usually wait a
couple of days), treat the surface to a coat of paste wax applied with a
grey scotchbrite, then buff with a soft cloth. To my eye, wiping varnishes
give the nicest, silkiest finish, but they are not very durable. They are
fine for most surfaces other than table tops. Though they do build a
protective film, it is a particularly thin one. The biggest upside to
wiping varnishes, however, is the ease of refreshing or touching up the
finish if need be. Additional coats can be added to freshen the surface at
any time. Most of my work is finished in this way. My own preference is
for Minwax Antique Oil, but they are all very similar.
For the best protection, a film finish is called for. Though it is much
maligned, I prefer polyurethane, but with a slight twist. The typical
plastic-coated look of polyurethaned furniture is not the fault of the
finish, but rather to an insensitive or uninformed application. A satiny
surface is the key to a natural look, but therein lays the catch. The
secret to a good satiny polyurethane finish, as counterintuitive as it may
sound, is to use gloss poly, not satin. Satin varnish is nothing but gloss
varnish, but loaded with mineral dusts as opacifiers. It is these dusts
that settle to the bottom of the can, and have to be constantly stirred bac=
into suspension. These mineral dusts act to scatter reflected light, thus
simulating a satin finish, but also cause the finish to look cloudy and
washed out. They can also prevent you from ever achieving a truly smooth
surface. I typically apply 3 coats of clear gloss poly, letting each coat
cure overnight, and lightly sanding with 320 grit paper between coats.
After my final coat is completely cured, I pound the surface down with past=
wax and a grey scotchbrite or 0000 (four aught) steel wool. Keep working
the surface with the pad or steel wool until the glass is gone, and is
replaced by a satin surface. Buff the wax with a soft cloth, and enjoy the
silky, smooth finish. For a richer wood color, I typically apply a single
coat of wiping varnish to the sanded wood as my first coat, then the next
three coats with poly. The wiping varnish adds a depth that I personally
enjoy. Side note: Do not use water-based polyurethane. First, it often
isn't really polyurethane at all, and second, they tend to have a blue cast
to them, which really give an unnatural and unattractive look.
The silkiest finish of all is a French polish, done with shellac and oil.
Applying a French polish is an artform in itself, and requires years and
years of study and practice, and literally months to apply. It is
expensive, time consuming, and not very durable, but it is stunning.
One last thing: Avoid wood stain if at all possible. Wood stains typicall=
contain both a dye and a pigment. The pigment is a particulate, and is the
sludge at the bottom of the can. This pigment gets into the wood pores, an=
also forms a dull, lifeless, obscuring film on the surface of the wood. If
you must color the wood, use an aniline dye. These are available as powder=
and as concentrated liquids, and are either water or alcohol soluble. I
prefer the liquid type for cleanliness and convenience. The alcohol based
dyes will not raise wood fuzzies as will the water based dyes, but if you
followed my double sanding approach this will not be much of an issue, and =
quick pass of the grey scotchbrite will remedy the situation.
Well, I have probably bored you to death by now, so I will shut up. I hope
this little writeup answers some of your questions.
All the best.
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
On Mon, Mar 1, 2010 at 10:44 AM, Eleanora Eden wrote:
> A friend of mine is hoping to sell bread boards and other wood
> wares. I have seen very silky wood finishes. I have been asking
> around and getting tips here and there.
> Any wood workers on this list willing to share their expertise on
> this front? My dad did great wood finishes and I know he swore by
> rotten stone. I have used it but have not gotten the fine finishes he
> got or that I am seeing in the galleries.
> Bellows Falls Vermont