Shellac was a popular finish many years ago, but it has its challenges. It needs to be applied in the right temperatures, and its drying time needs to be respected to prevent uneven textures. But, shellac is tough and can take forever to sand. When a pair of homeowners needed their woodwork repaired, paint expert Mauro Henrique knew just what to do.
Steps for Removing Shellac from Wood
- Lay drop cloths under the area you’ll be working in. Also apply tape along the walls and any areas you don’t want damaged. Plastic sheeting will provide extra protection.
- Wearing your safety gear, use the paintbrush to apply denatured alcohol to the wood’s surface. Work in relatively small sections (just a foot or two at a time). Allow the alcohol to sit for 1 to 2 minutes.
- After a few minutes, use a paint scraper to scrape the shellac off of the wood. Work slowly and in short passes to remove shellac without damaging the wood.
- Use the painter’s tool, putty knives, and sanding pads to get into the profiles of any trim where the scraper won’t reach.
- Continue applying the alcohol, letting it sit, and scraping it from the wood.
- Once all of the shellac is removed, sand the entire surface with 220-grit sandpaper before vacuuming the area with a wet/dry vacuum.
- Apply the first coat of polyurethane with a paintbrush. Start at the top of the wood and brush in one long stroke all the way to the bottom, maintaining a wet edge between passes. Wait two to three hours before lightly sanding the polyurethane again and applying a second coat. Depending on the wood, it may need three coats.
Resources
Mauro prepped the area by covering the floor with drop cloths and protecting the windows and surrounding walls with Scotch Blue pre-taped painter’s plastic sheeting and painter’s tape.
Mauro removed the shellac by applying denatured alcohol–any type will work. He poured the alcohol into a plastic bowl and used 2-½” to 3” flat chip brushes and then had it sit for a couple minutes before scraping it off.
To scrape the shellac—wear safety glasses, an n95 mask, and disposable gloves.
To scrape off the first, thick layer of shellac, Mauro used a mix of his Warner carbide paint scraper, painter’s multi-tool, 1” to 1-½” putty knives, and a 5-gallon bucket to catch all debris.
After the thickest layer was off, fine grade (#00) and medium (#1) steel wool pads and heavy-duty scour pads were used. Scour pads and a painter’s multi-tool are helpful for grooved areas. Multi-purpose shop rags were used to wipe tools clean of the shellac in between scrapes.
Before adding the new finish, sand the trim with 220-grit sanding sponges and pads. Use a shop vacuum to vacuum up all debris.
Mauro used Varathane Clear Satin Water-Based Polyurethane. He chose a water-based polyurethane to avoid excessive off-gassing because of the young child in the house. Oil-based polyurethane has a much stronger odor, although fewer coats would be needed. The water-based polyurethane will need 2-3 coats, maybe more depending on the wood. Drying instructions will depend on the manufacturer but water-based will dry faster than oil. 2-½” to 3” synthetic brushes were used.
Materials
- Drop cloths
- Painter’s tape
- Plastic sheeting
- Denatured alcohol
- Sanding sponges
- Sanding pads
- Steel wool (#00)
- Steel wool (#01)
- Scouring pads
- Shop rags
- 220-grit sandpaper
- Water-based polyurethane
