Short answer: fill it, don’t sand it
You don’t need to sand a deep scratch. Judge its depth first. For a scratch that has reached bare wood, fill it with a wax fill stick or a harder burn-in stick, scrape it level, then color it to match. Sanding a finish to hide a mark can cut through thin finishes and veneer, so filling is usually the safer choice.
Judge the depth first
The depth determines the method.
- A white or gray scratch is usually only in the finish. It can often be softened or blended with a finish-level product.
- A colored, raw-looking scratch has reached the wood. It needs filling and color.
- A gouge has lost wood. It needs a fill that’s built up in layers and then colored.
Run a fingernail across the mark. If the nail catches, the damage goes deeper than the finish.
Finish-only scratches
If the scratch is only in the finish, use a product made for finish scratches, or a solvent that reamalgamates the finish. How to repair damaged wood finish explains both. Alcohol works on shellac, and lacquer thinner works on lacquer. Test on a hidden spot first, and let the test dry before you judge it.
Restoring the sheen with an aerosol finish of matching sheen, such as satin, semi-gloss or gloss, can help. Check that the finish is compatible with what’s already on the piece.
Filling a deep scratch with wax fill sticks
Wax fill sticks are the easiest way to fill a deep scratch without sanding:
- Choose a stick that matches the wood. If no single shade matches, blend two.
- Warm the stick slightly in your hands, then rub or press the wax into the scratch until it’s a little overfilled.
- Scrape the excess level with a plastic card.
- Buff with a soft cloth.
Wax fills are soft. They suit sides, legs and low-use surfaces, but they can wear away on a heavily used tabletop. Many wax fills also don’t accept a topcoat well, so check the label before you spray any finish over them.
Burn-in sticks for a more durable fill
Burn-in sticks are made of shellac or lacquer resin. You melt them into the scratch with a burn-in knife, then level the fill with a flat scraper, a razor blade or a leveling solvent pad. The result is harder and more durable than wax, which is why it’s often used on tabletops.
Burn-in knives get hot enough to burn skin and scorch the finish. Set the knife on a stand when it isn’t in use.
Matching the color
Few woods match a single crayon or marker, so most repairs need two or more shades blended together.
- Start by matching the base color of the wood.
- Use a slightly darker shade rather than a lighter one. Darker fills tend to hide better.
- Add fine grain lines with a fine marker or touch-up pen, then blend them lightly.
- Test the color on a scrap or a hidden spot first.
Stain markers and touch-up pens can color an exposed scratch, but they don’t fill its depth. Use them after the fill, not in place of it.
The goal is a repair that isn’t noticeable in normal use. Under raking light, most fills show some difference, so an invisible result isn’t a realistic target.
Large gouges
For a large gouge, tinted epoxy putty works better than wax. Fill it, let it cure, then color and grain the surface once it has hardened. Epoxy is a skin sensitizer, so wear gloves and work with ventilation.
Common mistakes
- Relying on home remedies. Walnut meat, oil, mayonnaise and WD-40 can darken a fine scratch, but they don’t fill a deep one. Does WD-40 take scratches out of wood explains why.
- Using only one color. A single shade rarely looks right on wood.
- Expecting a perfect match. Aim for a repair that doesn’t stand out.
- Topcoating a wax fill without checking. Some wax fills won’t accept finish.
- Using a scratch-cover polish as a fill. These wash off and need reapplying.
Safety
Burn-in knives get hot and can burn skin. Alcohol and lacquer thinner used for reamalgamation are flammable, so keep them away from flames. Use aerosol finishes with good ventilation and away from ignition sources, and wear gloves when you work with epoxy.
For scratches that have reached a veneer surface, veneer repair on antique furniture covers the extra care needed, since veneer can’t be sanded the way solid wood can.