How to Remove Oil Based Stain From Wood

Whether you’ve botched a stain job or are simply refinishing an old piece, this article will give you all the info you need to remove oil based stain from wood. After describing and defining oil-based stain, I’ll tell you how to get past protective coatings to the stain underneath. Then, get step-by-step instructions for three ways to remove oil-based stain. 

What is Oil Based Stain?

Oil-based stain is a liquid wood treatment that enhances the natural appearance of wood and changes its color. Stronger in nature than its water-based counterpart, it can be applied to a wide array of wood types.

Stain is applied with a cloth, brush, or roller.  The stain is applied to the wood, then rubbed in a circular motion using a lint-free cloth or rag. 

Oil based stains that contain a drying oil such as linseed oil provide some protection from moisture and impact damages. The drying oil penetrates the surface of the wood and adheres to the inside of it’s cellular structure, creating a flexible barrier that will repel some moisture and mild impact damage. 

However, stains are usually covered with a clear protective coat, such as polyurethane.

Oil Based Stain Ingredients

Removing oil based stain is a tricky process, made easier if you understand exactly what ingredients it contains. 

The ingredients in oil based stains are:

• an oil base (usually boiled linseed oil)
• dye and/or pigments for color
• solvent (usually mineral spirits)

The oil is responsible for penetrating the top layer of wood. The very fine dye particles or slightly coarser pigment particles adhere to the wood’s surface.

Due to their small size, dyes tend to penetrate more deeply into the surface of the wood, making them more difficult to remove. Pigments, which are larger, usually sit on top of the wood in a manner more similar to paint. This makes them somewhat easier to remove. 

The solvent used to keep wood stain liquid evaporates through consistent exposure to fresh air. As the moisture is carried away, the stain dries. 

Read on for a step-by-step guide to removing  oil-based stain. 

Removing Protective Coatings From Oil Based Wood Stains

As mentioned above, stains do not provide wood with very much protection. Before you can remove oil-based stain, you’ll usually need to remove the protective clear coat. 

1. Apply stripper. Generally, oil-based polyurethane would be used to cover an oil-based stain. Use a citrus-based gel stripper or a varnish stripper to remove polyurethane. Apply the stripper with a brush or roller and let it sit on the wood for the length of time indicated on the container, usually 15 to 20 minutes.
2. Scrape off the coating. The stripper will loosen the clear coat, but it still takes some elbow grease to remove. Grab a plastic scraper and move it in straight lines across the wood. Scrape in the direction of the grain. Hold the scraper at an angle to avoid gouging or scratching the wood. 
3. Wipe off any coating that remains. Use steel wool pads dipped in stripper to get into every crevice of the wood. Wipe in the direction of the grain until all traces of protective coating are gone. You may need to use several steel wool pads as the stripper can clog the fibers. 
4. Wipe down the wood. When you are sure that all the protective coating has been removed, wipe the wood with a clean, damp rag to remove the stripper. Allow the wood to dry for 24 hours before continuing on to the stain removal method of your choice. 

One note: you can apply stain over polyurethane, but it isn’t simple.

Methods For Removing Oil Based Wood Stain

The chemical stripper will help lift some of the color out of the wood. To get all the way down to bare wood, you’ll need to use one of the methods below. 

Reapply a Stripping Product

A second coat of stripper can be applied after the protective coating has been removed. While this may not remove every trace of stain, it can limit the amount of sanding you have to do and save on material. This method is definitely worth trying on carved or detailed areas where sanding is not possible. 

• As in the steps above, apply the stripping product using a brush or roller. Make sure to work it into corners and carvings, using the bristles of the brush to soak hard-to-reach areas. Allow it to sit for at least 15 minutes – some products can take up to 30 minutes, so check the instructions to make sure. 

• The stain should start to bubble and pucker when it’s ready to be scraped off. A scraper can be used to remove loosened stain from flat areas, while a putty knife may be more effective in corners or carvings. For detailed carving areas, a plastic cocktail stirrer can be used. 

• Use steel wool pads to get into tight spaces and for table and chair legs, as well as spindles and banisters. Soak the steel wool in stripper and change the steel wool as needed. Wipe the surface with a new, clean, water-dampened rag and leave it to dry for a full 24 hours. 

Use Oxalic Acid

If you don’t want to lighten the color of the wood, use oxalic acid. 

1. Mix the oxalic acid with water. Oxalic acid crystals come from rhubarb leaves, and are mixed with water to form a color-removing solution. Follow the instructions on the package to mix up only the amount you need. 
2. Apply the mixture. Use a mop for large areas such as floors or decking. For smaller projects, use a brush to apply the oxalic acid mixture. Don’t soak or overapply, and be careful not to apply oxalic acid to any wood you want to stay stained 
3. Neutralize the oxalic acid. Once the color has been removed, mix two tablespoons of borax with a quart of water to form a neutralizing solution. Use a fresh brush or mop to thoroughly cover the affected area, stopping the chemical reaction. 
4. Wash away the borax solution. Use clean water and yet another clean applicator to clear the wood of the borax and neutralized oxalic acid. Allow the wood to dry for 24 hours. 

Use Wood Bleach

Wood bleach will not only remove stain from wood, it will change the color of the wood itself. Because of this, it is recommended only after you have tried a stripper and oxalic acid. 

Follow the same methods listed in the section above to use wood bleach, being careful to take appropriate safety precautions. Don’t worry – once the stain has been removed, you can restrain it to the color of your choice. 

Sand the Stain Away

Dense areas of the wood tend to absorb and retain more stain than less dense areas. When you’ve done all you can, resort to removing the stain with abrasives. 

1. Choose your tool. A power sander such as a belt sander or random orbital sander is a godsend when removing stain from large areas. For smaller areas, use a sanding block. To remove stain from cylindrical objects such as table or chair legs, wrap sand paper around the object. 
2. Choose your sanding paper. Medium grit sandpaper will remove stain while leaving the wood as intact as possible.  An 80 grit sanding paper is best – 100 or 120 is too gentle, and 60 will remove material too aggressively. Sand with the grain, stopping as soon as the color has disappeared.
3. Remove the dust. Use a vacuum cleaner, shop vac, tack cloth, or wet rag to wipe up the dust created as the sanded wood is removed. You should now have bare wood that is ready to be re-stained. 

Conclusion

The first step to remove wood stain is to remove any protective coating with a chemical stripper. A second coat of chemical stripper can be used to remove stubborn stain, with oxalic acid and wood bleach as other methods for stain removal. If all else fails, the wood will need to be sanded down to remove all traces of wood stain.