Treated polyurethane finishes are effective protection for furniture or floors. If you want to remove a polyurethane coating, you will need to use a chemical stripper in a well ventilated area.
Part 1 of 3: Choosing a polyurethane stripper
Step 1. Observe your workspace before choosing a chemical stripper
You should wait to use the stripper in a well ventilated area that is neither too hot nor too cold. You should use ventilators and protective clothing throughout the process.
Step 2. If the area you are working in is poorly ventilated, use a water-based product
It will take longer to strip the polyurethane, but this product will be less harmful.
Step 3. Take a stripper
If you want to do the project in a very ventilated area, choose a chemical stripper that contains methylene chloride and wear a protective mask. This product is a known carcinogen, but it is very effective in removing polyurethane.
- If you are worried that the surface you are going to be working on will contain lead paint, you are better off using these strippers instead of sandpaper or a heat gun. Lead is more toxic when heated.
- Avis is a popular brand of polyurethane stripper.
Step 4. Consider purchasing a natural stripper
Otherwise, take a soy-based one if you're worried about the stripper's effects on the environment. You will need to use more product because it will be more volatile than chemical strippers.
Step 5. Use white spirit on the laminate or polyurethane coated surface
This petroleum based product is safe on laminate. You can find some odorless or with a slight odor.
Part 2 of 3: Prepare
Step 1. Move your furniture into the garage or outdoors
If you are working on a floor, open all doors and windows. Avoid working in direct sunlight.
Place a tarp under the object to avoid killing weeds or making a stain
Step 2. Wear long pants and a long-sleeved t-shirt
Buy thick rubber gloves to avoid contact with your skin.
Step 3. Protect yourself
If you are using a chemical stripper that contains methylene chloride or white spirit, purchase a face shield and safety glasses. Read the label for precautions and the degree of ventilation required.
Step 4. Purchase plastic putty knives to scrape off the polyurethane
You will also need very fine iron wool (or grade 0000).
Part 3 of 3: strip the polyurethane
Step 1. Spray the stripper onto the object's surface or apply it with a brush
Only apply it to an area that you can strip in about 15 minutes. Work in sections 1 meter wide, one after the other.
Step 2. Wait 15 minutes or the time recommended on the label
If you have evaporation problems, apply the stripper and cover it with a layer of parchment paper.
Step 3. Slide your putty knife over the surface of the object
Follow the grain of the wood. Wipe off the polyurethane with a rag or on the edge of an empty plastic yogurt pot. Continue until you have removed the entire layer of polyurethane.
Step 4. Apply another coat of stripper if there is still polyurethane
Otherwise, use paint to remove. Do not pass steel wool between two applications. Continue until the surface under the polyurethane is visible.
Step 5. Use fine steel wool
This will allow you to remove the polyurethane from wood engravings or crevices. Apply the stripper, wait and run the steel wool in the direction of the grain of the wood to remove the layer of varnish. Use the plastic putty knife as much as possible before using the steel wool.
Step 6. Soak the rags and steel wool in water
This makes it possible to prevent an outbreak of fire. Then take the water to a hazardous waste disposal area in your city, along with the remnants of the stripper. Do not throw rags and chemicals directly into the trash or down the drain.
Step 7. Pass the piece of furniture with steel wool
Do this after you've removed all the varnish and paint. Your furniture is ready to be repainted.