Renovation 4th Edition
Page 122
never use ammoniated clean-
have become dull and grimy may just need a
ers to wash old woodwork with a
good washing. Using a damp rag, rub Murphy®
clear finish. if the finish is shel-
Oil Soap onto a small section and wipe it dry
lac, ammonia, which is strongly
quickly. If that clouds the surface, stop; but if
alkaline, will dissolve it.
it brightens the woodwork, keep going.
524 Chapter 18
Scuff-sand and touch up? If a clear finish
remains dull after a test-wash or is worn
looking, scuff-sanding and a new application
of the old finish may do the trick.
Will new coats adhere? If painted or clear
finishes are cracking, peeling, or otherwise
coming off, new coatings won’t stick. To test
adherence, use a utility knife to lightly score a
1-in. by 1-in. area into nine smaller squares
(like a tic-tac-toe array). Press a piece of duct
tape onto the area and pull up sharply: If two
or more little squares pull off, you should strip
the paint or finish.
What’s that Finish?
to identify a finish, rub on a small amount of
the test solvents in this list, starting at the
top of the list (the most benign) and working
In this 1920s house, the homeowner wanted an older look for the cabinets. So
after spraying three coats of oil-based enamel, the painters rehung the doors
down until you’ve got your answer. When
and rolled on a final coat . . .
applying solvents, wear rubber gloves, open
the windows, and wear a respirator.
Oil. if a few drops of boiled linseed oil
soak into the woodwork, you have an oil fin-
ish: tung oil, linseed, Watco, or the like. if the
oil beads up on the surface, the woodwork has
a hard finish, such as lacquer, varnish, or shel-
lac. keep investigating.
denatured alcohol. if the finish
quickly gets gummy, congratulations! it’s shel-
lac, which will readily accept a new coat of
shellac after a modest sanding with an abra-
sive nylon pad or 220-grit sandpaper. older
woodwork with an orange tinge is often
shellac-coated.
mineral spirits (paint thinner). this
will dissolve wax immediately. dampen a rag
and wipe once. if there’s a yellowish or light
brown residue on the rag, it’s definitely wax. if
your woodwork finish has an unevenly shiny,
runny appearance, suspect spray-on wax.
lacquer thinner. this solvent dis-
solves both varnish and shellac, so try dena-
tured alcohol first. if alcohol doesn’t dissolve
the finish but lacquer thinner does, it’s varnish.
Acetone. this one will dissolve varnish,
too, in about 30 seconds. but if acetone doesn’t
affect the finish, it’s probably polyurethane.
. . . which they then lightly tipped off with a dry brush, intentionally leaving
very faint brushmarks.
Painting
525
striPPing Methods
mOTher naTure’s strippers
Test-strip small sections of woodwork to see
which method—or combination of methods—
Solvent-based paint strippers, which usually contain methylene chloride (dichloro-
works best for you.
methane) are effective, exceptionally smelly, and (according to the Centers for
metal scrapers with straight edges work well on
disease Control and Prevention) probably carcinogenic. not surprisingly, the plethora
flat surfaces without too many layers of paint or
of green building products now include a range of solvent-free chemical strippers.
clear finish. A scraper with changeable heads
none of this new batch of strippers removes finish as aggressively as solvent-based
enables you to scrape varying contours. For best
strippers, but if you’re patient, repeated applications will get the job done. in general,
results, hold the scraper head roughly perpendic-
gel strippers work more effectively because they adhere better—especially to vertical
ular to the surface and pull the tool toward you.
surfaces—and don’t dry out as quickly. Note: many of these eco-strippers tout their
Caution: Sharp scraper heads can easily gouge
safety for indoor use, but make sure there’s adequate ventilation anyhow. Some
wood, especially softwoods like fir and pine,
names to look for: Smart Strip®, ready-Strip®, Citristrip®, multi-Strip™, Fastrip®,
whose contours may be obscured by thick paint.
and lift Off®.
heat guns soften paint so you can scrape it off.
Heat guns can remove many layers of paint, but
stay alert when using them. Maintain a constant
distance from the surface you’re stripping, and
keep the gun moving so you don’t scorch one
spot. Using a heat gun on shellac and varnish
gets tricky because they have low kindling tem-
peratures and tend to burn when heated; first, try
stripping them with metal scrapers.
Never use a heat gun next to glass—for exam-
ple, on window muntins—because you could
crack the glass. Heat guns can also ignite dry
materials within walls, so stop using guns well
before the end of the workday so woodwork can
cool. Before you leave for the day, sniff around
Solvent-free paint strippers are typically less aggressive than solvent-
for smoke or anything that smells hot.
based varieties—and a lot less smelly. Wear a respirator, safety glasses,
gloves, and long sleeves when using any paint stripper.
For chemical strippers, a rule of thumb is the
stronger and smellier the chemical, the faster it
will strip paint or finish. Methylene chloride
(dichloromethane), for example, will soften mul-
tiple layers in 10 to 15 minutes. Fortunately,
there is an emerging family of solvent-free strip-
striPPing saFelY
pers that, although not as aggressive, will strip
Before stripping woodwork, read “Painting
effectively given enough time and reapplications.
Safely” on p. 510 and “Lead-Paint Safety” on
They are easier on the environment and your
p. 514. Many of the concerns when stripping are
lungs, but adequate ventilation is still important.
P R O T I P
the same as those when painting. Most important, Follow application recommendations on the con-
wear a respirator with replaceable filters. Also
tainer label. By the way, gels and semipaste strip-
wear rubber gloves, goggles, and a long-sleeved
if you’re using water-based
pers are best for vertical surfaces. Even when
finishes, use damp rags to wipe
shirt. Lay down plastic tarps (or layers of news-
brushed on thickly, they won’t run.
dust off surfaces, rather than
paper) to protect floors and capture paint debris,
Chemical strippers require patience and care.
tack rags. because tack rags are
mask off areas you’re not
stripping, and make
Use a rag to cover the cap before opening the
typically pieces of cheesecloth
sure you have adequate ventilation. Even if a
container so stripper won’t splash on you. Pour
treated with varnish to make
chemical stripper is relatively odorless and
stripper slowly into a work pail, and close the
them sticky, they leave a faint,
claims to be eco-friendly—keep it off your skin
container immediately so it won’t spill if the
oily film that water-based coat-
and out of your lungs! Read instructions for all
container is bumped or knocked over. As you
ings may have trouble adhering
stripping chemicals before using them, and if
apply stripper, brush away from yourself. To
to. tack rags are fine, however,
you’re using a heat gun, have a fire extinguisher
avoid tracking stripper throughout the site,
if followed by oil- or solvent-
close by.
replace plastic tarps as they become fouled with
based finishes.
softened paint. Or lay down newspaper, which is
cheap and easy to roll up before stuffing it into a
garbage bag.
526 Chapter 18
dry well before test-staining or finishing. When a COMMON CLEAR-
patch is so hard that your thumbnail can’t gouge
FINISH PROBLEMS
it, the putty’s dry enough to sand.
sanding. If the woodwork is in good shape and
doesn’t need filling, just scuff-sand it (sand it
lightly) with 220- or 320-grit sandpaper before
applying a clear finish. More likely, you’ll need to
use several grades of sandpaper, starting with
80 grit or 100 grit to sand down tool marks or
dings, moving on to 150 grit, and ending with
180 grit or 220 grit. Always test-sand an area in
an out-of-the-way place, and always use the least
This hand scraper comes with six interchangeable
abrasive paper that will still be effective.
stainless-steel blades, which will fit most contours you’re
Sand sections completely with one grit before
likely to encounter.
switching to another, even if you think an area is
smooth enough. If you switch from 120 grit to
Once your tarps or newspaper are in place,
150 grit while sanding a baseboard, for example,
brush on stripper liberally. A 1⁄8-in. to 1⁄4-in. coat-
it may have two different shades when you stain
ing of stripper should stay wet long enough to
or finish it.
Orange peel, often seen near
soften all the layers of paint or finish. To make
If there’s a lot of woodwork to sand, use a
kitchens, is caused by airborne
sure that slower strippers stay moist, press a
palm-size power sander (also called a block
cooking oils.
sheet of lightweight plastic (polyethylene) right
sander) for the first three sandings, and finish
onto the stripper-coated woodwork; the stripper
up by hand sanding with the wood grain, using
won’t dissolve the plastic. Periodically lift an edge 180-grit or 220-grit garnet paper. Wrap sandpaper
of the plastic and try scraping off the paint. Be
around a standard blackboard eraser or a scrap
patient: Remove the plastic only when the soft-
of 2x4 to hand-sand flat areas; sandpaper
ened paint scoops off easily. Until then, leave the
wrapped around a dowel works well on concave
plastic on.
areas. After sanding, wipe or vacuum the surfac-
Although renovators usually use a wide spack-
es to remove the dust.
ling knife or a putty knife to scoop off softened
paint, a wooden spatula with a beveled edge is a
aPPlYing a Clear Finish
near-perfect tool because it won’t gouge the
Clear finishes can be brushed on like paint or
chemically softened wood. Whatever tool you
wiped on and off with a rag or pad—or some
use, unload sludge from your scraper after each
combination thereof. Brushed-on finishes tend to
pass. Use a toothbrush, a nylon potato brush, or
be thick and shiny, whereas wiped-on finishes are
a handful of wood shavings to dislodge softened
thinner and less shiny. As with oil-based paints,
paint from detailed or hard-to-reach areas. Only
use natural-bristle brushes to apply oil-based
occasional spots should need additional stripper.
clear finishes. Use synthetic bristles for water-
Weeping is wood sap excreted
When the woodwork is bare, scrub off the
over decades.
based finishes.
stripper residue with a solvent recommended by
Don’t shake containers of clear finish. If you
the manufacturer. For solvent-based strippers,
do, you’ll entrap air bubbles. Instead, stir them
typically mineral spirits is applied with a nylon
well by hand until the thick, flattening agent at
abrasive pad, then blotted dry with paper towels.
the bottom of the can is evenly distributed. Clear
Follow that with a dilute solution (5% to 10%) of
finishes tend to “skin over,” so pour out small
household cleaner in warm water, and wipe that
amounts into a painter’s pail and replace the can
off with paper towels. Allow the wood to dry
lid promptly. If finish builds up around the rim,
thoroughly—at least a day or two—before filling
the lid won’t seat well. To prevent buildup, use an
holes or sanding. Note: Don’t use steel wool to
old slotted screwdriver to punch slots around the
scrub stripper or remove paint. Otherwise, steel
rim’s recess. These slots will let excess finish
particles can stick in the wood and then rust,
drain into the can, allowing the lid to seat tightly
marring the new finish.
into the recess. If the finish skins over, strain the
finish or discard it.
reFinishing WoodWork
Polyurethanes are favored for wood in kitchens,
Once your stripped woodwork has dried, patch it bathrooms, hallways, and other busy areas. Once
with wood putty that dries to the same color as
cured, they’re tough and water-resistant. And
the unfinished wood. (Putty lightens as it dries.)
Wax buildup is characterized by
they’re easy to apply. Oil-based and water-based
Test a number of putty colors, allowing each to
uneven, shiny sections where
sprayed-on wax has run.
Painting
527
P R O T I P
after stripping with hand
scrapers and a heat gun, don’t
bother with chemicals if you
decide that your old trim is too
beat up or too plain to look good
under a clear finish. sand down
the remaining paint edges, prime
the trim, paint it, and call it a
day. it’ll look great.
You can usually apply oil-based penetrating stains over
After brushing stain on, use a clean, dry rag t
o remove any
previously varnished surfaces, but they can be tricky to
excess. You may need to apply several coats—over several
work with. Test-stain an inconspicuous section. If the
days—to match existing stains, so be patient.
penetrating stain is compatible with the old finish, it
should dry hard overnight.
polyurethanes are equally durable but require
slightly different application methods. For both
types, apply at least two coats, preferably three.
Water-based polyurethanes: Because
staining and sealing:
water-based polyurethanes dry clear, use them
if you want light-colored wood to stay light.
a sampler
Seal woodwork before application, using a
there should be a Ph.d. in stains. there are all-pigment stains that won’t fade (a
diluted finish. Thereafter, brush on full
good choice for window trim), water- and oil-based stains, liquid stains, penetrating
strength. Follow manufacturer recommenda-
stains that both stain and seal, and gel stains that won’t run on vertical surfaces.
tions for drying times. Some water-based
Plus, there are wood conditioners, sanding sealers, presealers, and a plethora of put-
polyurethanes dry quickly, allowing multiple
coats in a day. There’s no need to sand between
ties and wood fillers. if you want to learn more, excellent resources are Michael
coats unless a week passes, in which case, use
dresdner’s Painting and Finishing (the taunton Press, 2002) and Finishes and
a fine nylon abrasive pad. If you want to add a
Finishing Techniques (the taunton Press, 1999).
wax finish, follow recommendations on both
to achieve an even stain on softwoods such as fir, preseal them with a thinned
the polyurethane and the wax cans—both for
coat of whatever the clear finish will be, say, 1 part oil-based polyurethane to
compatibility and drying times.
4 parts mineral spirits. Presealer soaks into the softer parts of the wood and seals
Oil-based polyurethanes: Oil-based
them slightly. but once dry, the surface should still feel like wood.
polyurethanes impart a rich, amber color to
oil-based polyurethane over water-based stains is ok, but do not use water-
wood. So use them if you favor dark wood or a
based polyurethane over oil-based stains. the polyurethane won’t stick.
historic look. They don’t need a preliminary
sealer coat, but they will flow on better if you