How to Refinish With Polyurethane Over Oil
- 1). Apply oil-based stain to the wood, using the proper paintbrush. Petroleum-based finishes will destroy synthetic polyester and nylon brushes. Select a brush that has natural bristles that can endure exposure to solvents.
- 2). Wipe the oil finish from the wood, using old rags. Use rags that are disposable, as the stain will permanently ruin them.
- 3). Use mineral spirits to thoroughly wash all of the oil finish from the bristles. Never use water on a natural-bristled brush; this will deform the bristles and ruin the brush.
- 4). Leave the oil finish to dry for three hours, before applying the polyurethane finish. Brush the polyurethane over the dried oil finish, using the clean natural brush. Only use a solvent-based polyurethane. Don't use a water-based polyurethane, over an oil finish, or flaking will occur. Brush along with the wood grain for best results.
- 5). Let the first coat of polyurethane dry for two hours. Add a second coat to complete the process.
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