Trim Repair: How to Fix and Revive Trim
Updated: May 05, 2023
Renew dull trim in one weekend.
Renew the lustrous appearance of stained and varnished woodwork without the messy stripping process. We show you how.
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A full day
Step 1: Start with a thorough cleaning
Photo 1: Remove old paint spots
Soften old paint along the edges of trim and stained baseboards with alcohol. A rag wrapped around a putty knife lets you scrub the trim without slopping alcohol onto the wall.
You can dramatically improve the appearance of stained baseboards and varnished woodwork without all the work and mess of a complete stripping and refinishing job. We’ll show you a much easier process here—and you may even be able to eliminate some steps if your woodwork is in better shape than ours. Just gather the supplies in a 5-gallon bucket and tackle the renewal project one window or door at a time whenever you have a few spare hours. Start in a corner or in an inconspicuous area—better to learn from your mistakes there than on the front door.
The first step in renewing your woodwork and stained baseboards is cleaning it to remove grease and grime and create a contaminant-free surface for the new finish. Wash the woodwork with a TSP substitute. Use just enough cleaner to wet the surface. Scrub with a sponge dipped in the cleaning solution. Then rinse with a sponge and clear water and wipe off the wood with a dry rag.
If there’s paint slopped onto the edges of your trim or spattered on the surface, now’s the time to clean it off. A rag dampened with denatured alcohol will remove most paint spatters (Photo 1). Alcohol won’t harm most finishes, but it will dissolve shellac. Don’t worry if some of the finish comes off. You can touch it up later (Photo 7). Protect the walls with masking tape to prevent the alcohol from damaging the paint. For tougher paint spatters, use a fine synthetic abrasive pad (such as a 3M Wood Finishing Pad) dipped in denatured alcohol.
Step 2: Scrape and sand badly damaged areas
Photo 2: Scrape eroded areas
Scrape away badly weathered finish. A carbide paint scraper removes the old finish much faster than sandpaper. But be careful not to gouge the wood.
Photo 3: Bleach out dark stains
Bleach away deep stains that scraping or sanding won’t remove. You don’t have to scrub; just let the oxalic acid penetrate and lighten the stain.
Photo 4: Sand bleached areas
Sand the bleached wood after it dries. Start with 120-grit sandpaper. Then sand with 180-grit. Vacuum the dust before staining and finishing.
Window stools and other areas exposed to moisture and sunlight may need to be completely refinished. In spots such as these where the wood is discolored and the finish worn away, you’ll get the best results by scraping and sanding to expose bare wood (Photos 2 and 4).
If the wood has dark water stains that scraping and sanding won’t remove, you can remove them with oxalic acid (Photo 3).
Caution: Wear protective gear, including goggles, rubber gloves and a long-sleeve shirt, when you work with oxalic acid. Mix the oxalic acid in a plastic container. Add 1 oz. of oxalic acid powder (about 2 tablespoons) to 1 cup of hot water and stir it until the powder dissolves. Then brush the solution onto the stain with a disposable sponge brush and let it work for 20 minutes. You can repeat the process to further lighten the stain. Wipe the bleached wood with a sponge and clear water. Then neutralize the oxalic acid by applying a solution of 3 tablespoons of borax to 1 gallon of water with a sponge. Finally, rinse the bleached wood with water again and let it dry overnight. Then sand it with 120-grit followed by 180-grit sandpaper (Photo 4) and stain it to match the rest of the woodwork.
Step 3: Roughen the finish and fill small holes
Photo 5: Roughen the old finish
Rub the wood with an abrasive pad to create a slightly roughened surface for the new finish. Vacuum the dust from the surface before wiping on a new coat of finish.
Photo 6: Fill holes
Fill holes with perfectly matched putty. Just knead different colors together until you get an exact match.
To make new finishes stick well, slightly roughen the old finish first (Photo 5). Synthetic finishing pads are the best choice because they conform to profiles and aren’t as aggressive as sandpaper. Buy medium and fine and experiment in an inconspicuous area. Use the pad that roughens the finish without removing any stain.
Fill holes left by nails or screws with soft wood putty. Wood putty is available in many colors that you can blend for a perfect match. Application is easy. You just push it into the hole and wipe it off (Photo 6). There’s no sanding required. Buy several shades of putty, ranging from dark to light, that are similar to the color of your trim. Then mix them to match the wood surrounding the hole. Push the putty into the hole and wipe off the excess with your fingertip. Then remove residue from around the hole by wiping over it with a clean rag. If your woodwork has filled nail holes that have darkened and no longer match, pick the old filler out and replace it with soft putty. Buy water-based putty if you plan to use water-based polyurethane.
Step 4: Apply stain to hide dings and scratches
Photo 7: Apply matching stain
Hide scratches, chips and worn away finish with a fresh dose of stain. Then wipe the woodwork with a clean rag to remove the excess stain. Let the stain dry overnight.
Completely refinishing the area may be the only way to make flawless repairs to badly damaged doors, windows and moldings. But you can greatly improve the overall appearance of worn or damaged wood with less drastic measures.
Disguise large areas where the stain is worn away by dabbing stain over the light areas to blend them in. The patched area may not match exactly, but at least the spot will be less obvious. Or simply wipe the surface of the wood with a rag dipped in stain to fill in small scratches and imperfections—you’ll see a big improvement (Photo 7). Wipe the stain on. Then wipe off the excess with a clean rag. Allow the stain to dry overnight before you apply the finish.
One of the trickiest parts of a wood restoration project is finding stain to match. You can pry off a small piece of trim and ask the paint department to mix stain to match. Some paint stores and home centers offer inexpensive sample packets of stain. You can choose several samples that are close to the color of your wood and experiment in a hidden area to find the best color match. Then buy a larger container. Another approach is to buy two or three cans of stain that are close to the color of your woodwork and mix them to get the right color. Use an eyedropper and disposable plastic cups to mix small batches until you get the proportions right. Keep notes so you can reproduce the results in a larger batch.
Step 5: Apply the fresh finish
Photo 8: Wipe on polyurethane
Restore the shine with a fresh coat of polyurethane. Wipe on poly gives you a faster, smoother finish with less mess than brush-on poly.
The final step in your trim renewal project is to apply a fresh coat of finish. Wipe-on polyurethane is a good choice because it’s fast and easy to apply. You simply wipe it on with a soft rag and let it dry. Each coat is very thin and dries quickly. You can recoat in two or three hours if you want a thicker finish for extra protection. Several coats of wipe-on polyurethane are required to equal the thickness of one coat of brushed-on varnish, but it’s easier to get a smooth, drip-free finish with wipe-on poly.
Fold a cotton rag to create a pad. Then dip an edge of the pad into a container of wipe-on polyurethane and press it against the side to wring out the excess. Wipe the polyurethane onto the wood in long strokes in the direction of the wood grain as you would if you were using a brush.
For window stools or other trim exposed to sunlight, consider using spar varnish. Spar varnish has built-in ultraviolet protection and is more flexible, so it holds up better in areas exposed to sunlight and water. Experiment on a scrap of trim or in an inconspicuous area to see if the slightly amber tint darkens the color too much. When you’ve completed all of the steps above, your woodwork will look like new and be protected by a fresh layer of finish. If you don’t have time to do an entire room from beginning to end, just tackle one door or window whenever you have a few spare hours. You’ll be done with a room before you know it.
Round Up Your Supplies
You’ll need the materials and supplies listed in “Additional information” below for a basic wood renewal project, including several for refinishing window stools and removing stains. Most of the tools and supplies are available at paint stores, full-service hardware stores and home centers. Visit an art supply store for the artists’ markers. Oxalic acid is available online at rockler.com or at woodworking stores and some hardware stores and lumberyards.
Faux Wood Patch
Dings and dents too large to fill with soft putty present a unique challenge. If you can’t replace the wood, the next best thing is to patch the damage with filler and color the patch to match. Use hardening-type filler like Durham’s Rock Hard Water Putty. Apply the filler carefully with as little excess as possible to minimize sanding. Let the filler dry and sand it smooth, being careful to avoid sanding away the finish on the surrounding wood. Then use felt tip markers to “paint” the patch to match (photos below). Art supply stores are the best source of markers—you’ll find endless shades of brown. Most other stores carry only one or two. The repair won’t be perfect, but you may be surprised by how inconspicuous it is from a distance.
Required Tools for this Project
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
Required Materials for this Project
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.
Originally Published: January 07, 2019