Renovation 4th Edition

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Renovation 4th Edition Page 122

by Michael Litchfield


  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

 

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