How to Remove Polyurethane From Antiques

Polyurethane is a sturdy synthetic varnish that dates to the 1950s. If you own an older wood antique that was refinished with polyurethane, you may wish to replace the modern varnish with an authentic finish from the antique’s own era. Although sanding may seem like a straightforward way to remove varnish, mechanical sanders can damage fragile antiques and are difficult to use on ornate or oddly shaped pieces. Therefore, it’s usually preferable to use a chemical paint stripper designed for synthetic varnishes. The most efficient polyurethane strippers contain a very hazardous chemical called methylene chloride, which typically works in 30 minutes or less. Safer alternatives are available, but they take much longer to work and often require multiple applications. If you decide to use methylene chloride, read and follow the manufacturer’s safety warnings carefully.

Screwdriver
Slip joint pliers
Low-tack painter’s tape
Safety gloves
Safety glasses
Charcoal-filter face mask
Chemical-resistant apron
Paint stripper
Brush
Paint scraper
Coffee can or other metal waste container
Nylon scouring pads
Brass-bristle brush
String
Butter knife
Paint-stripper solvent
Cleaning rags

Instructions

- 1
  Diagram or photograph the placement of knobs, hinges and other removable parts for easy reassembly after stripping. Remove doors, drawers, hardware and other components and set them aside to be stripped or cleaned separately. Protect areas you don’t want to strip by masking them with low-tack painter’s tape.
- 2
  Place the antique on a thick layer of newspaper to catch drips and stripped varnish. Ensure adequate ventilation and put on safety gear.
- 3
  Brush a thick layer of paint stripper evenly over the polyurethane coating as directed by the manufacturer. Brush in one direction only, covering no more of the antique’s surface area than you can strip in approximately 10 minutes. Let the paint stripper attack the polyurethane for the specified amount of time. Do not allow it to dry.
- 4
  Test the polyurethane by rubbing it gently with a scraper. If the varnish comes up easily, the wood is ready for stripping.
- 5
  Scrape the varnish from the wood, following the grain and taking care not to gouge or otherwise damage the surface. Scrape away from your body, pushing the stripped varnish into a coffee can or other metal container. Scrub the varnish from rounded areas with a nylon scouring pad, again taking care to follow the grain. Clean crannies and crevices gently with a brass-bristle brush, a string or the rounded end of a butter knife.
- 6
  Wipe the antique down with a cleaning rag to remove stripper and varnish residue. Examine all surfaces carefully. Reapply the paint stripper as needed to remove any remaining patches of varnish.
- 7
  Remove stripper and varnish residue with a clean nylon scouring pad soaked in the type of solvent specified by the paint stripper’s manufacturer. Let the antique dry completely before sanding it.

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