Staining Windows

Staining Windows

Sun, moisture, and weather are hard on windows. Water  may condense on the glass in winter and  puddle on the sill.  You may forget to close the window when it rains.  Then sun streams in and causes the water-weakened finish to buckle and the finish degrades over time. Eventually it is necessary to sand and strip either the whole window frame or parts of it.


Before the 1950s, the clear finish on most windows was shellac, then came lacquers, and now polyurethane coatings are almost standard. Fortunately, you do not need to know exactly what is on your windows because polyurethane will almost always do a good job of covering any surface. You have a choice of oil-base or water-base poly; both work satisfactorily. Exterior spar varnish - made for boats - is especially durable and it can also be used indoors.

Can you strip a painted window frame then stain and varnish it? Yes, but it is hard to do well. You will need to coax paint from the crevices of the trim, the window frame, and all the molding. It might be easier to remove the woodwork and send it out to a dip-and-strip shop than to do it yourself.




Step 1

 Step 1: Evaluate the present finish

Evaluate the present finish

If the window frame is in fairly good condition, you may only need to sand it enough to smooth it and dull the sheen. Begin with 120-grit sandpaper; then switch to 180-grit sandpaper for a smoother surface. If the finish is badly damaged or built up, it is best to remove it. On many newer windows, the sashes pop out: you may have to carefully pry off trim pieces to remove sashes on older windows. Cover the work surface with an inexpensive drop cloth. Brush paint and varnish remover onto the wood following the manufacturer's instructions.  Be sure to provide good ventilation and wear rubber gloves and a vapor respirator. Scrape off the finish with a putty knife. Rinse with the solvent recommended for the remover.


Step 2

Step 2: Fill holes and gouges

Fill holes and gouges

Buy a commercial wood putty that closely matches the stain you are using or choose a stainable putty. Fill in the flaws with the wood putty, and spot-sand when it dries. Remove the dust with a tack cloth (if you'll be using an oil-base finish) or damp paper towel (if using a water-base finish). If you stain the wood, either tinted or stainable putty comes close to a match but it may not be perfect. If you are not going to stain, you can make your own putty. Simply collect a few pinches of fine sawdust from the type of wood you will be patching, mix with quick set epoxy, and fill in any holes. When the epoxy dries, trim off the excess with a utility knife or sharp chisel and then sand. For an extra-smooth finish, do the final sanding with steel wool.


Step 3

 Step 3: Mask the panes, side of the sash and the tracks

Mask the panes, sides of the sash, and the tracks

Masking with tape takes time, but it saves work later. Low-tack painter's tape is easy to remove and leaves little residue; it works well for masking off trim too. There are several types of low-tack tape so read the label carefully and choose the one that best meets your needs. Make sure you mask the two side edges of the sash and also the track; these parts are almost always left unfinished so the window opens and closes smoothly.


Step 4

 Step 4: Apply the stain and finish

Apply the stain and finish

Staining the wood will darken or warm its color, but the color will look even only if you have been thorough in removing the old finish. Window frames made of pine or other soft wood often absorb stain unevenly, causing a blotchy effect. Avoid this by using a gel stain, which will not blotch because it does not soak deeply into the wood. Let the stain dry and apply at least two finish coats; apply three finish coats on the sill which takes the greatest beating. Sand lightly between coats; remove the dust with a rag dipped in denatured alcohol.


Step 5

 Step 5: Remove the masking tape

Remove the tape

Remove the painter’s tape from the glass as soon as the finish begins to dry. If you have not taped off the glass, or if your masking job wasnot quite adequate, draw a sharp utility knife along the edges of each pane, leaving a narrow margin of finish on the glass. Push a window scraper or a single-edge razor blade toward this cut line to remove finish from the glass.