How to Remove Thompson’s Water Seal from Wood?

Thompson water sealer protects wood from water damage by penetrating the wood and sealing the pores. Since the sealer penetrates the wood and is waterproof, it’s impossible to refinish the wood without removing the water sealer first. But how do you remove a sealer that penetrates the wood and even more important, how do you remove the sealer without damaging the wood?

To remove Thompson water sealer from wood, you can use a liquid chemical-based paint stripper. The liquid stripper will gradually penetrate the wood and dissolve the sealer from inside the wood.

You can also use a hairdryer or heater to gradually melt the Thompson water seal before using acetone or denatured alcohol to remove the leftover sealer. Sanding with 180-220 grit sandpaper also works to remove Thompson water sealer.

This post reveals more effective and safe methods to remove Thompson water sealer from wood. Let’s dive in.

Can You Remove Thompson Water Seal Without Removing Paint Underneath It?

It’s possible to remove Thompson water seal without removing the paint underneath. To do this, you need to sand the water sealer off with 220-grit sandpaper while keeping tabs on the sealer coat. Immediately you notice that you have completely removed the Thompson water sealer, you should stop sanding so you don’t sand off the paint underneath.

If you do this carefully enough, you won’t remove the paint. The worst scenario here is that you’ll remove or scratch the top layer of the paint and this is a good thing as it allows you to apply a new coat that will make the paint look fresh.

You can also remove the Thompson water sealer without affecting the paint underneath it by using a paste-like paint stripper. In this case, you’ll apply only a light coat of the paint stripper directly on the Thompson water sealer and leave for about 20 minutes. Then you’ll strip the sealer and apply another light coat. Then again, wait about 20 minutes before stripping the sealer. You’ll need to continue this cycle until all the Thompson water sealer has been removed and only the paint underneath is left.

This method is more reserved for professionals because it takes some experience with paint strippers, especially the chemical-based paint strippers to know just how much to apply without affecting the paint underneath the sealer coat.

You should know that in most cases, you’ll cause scars on the paint underneath or remove part of it but you don’t need to panic if this happens. Instead, just touch up the top layer of the paint with a fresh thin coat to revive the paint finish.

How To Remove Thompson Water Seal? (3 methods That Work)

Thompson water sealer is a waterproof coating. Since the sealer is waterproof, it is resistant to almost every paint removal method that you can try. However, the 3 methods discussed below will work to remove Thompson water sealer easily. Here are the 3 methods:

  1. Use a liquid chemical-based paint stripper to remove the Thompson water sealer.
  2. Sand off the Thompson water sealer with medium or fine-grit sandpaper.
  3. Use a heater or hairdryer to melt the Thompson water sealer before using acetone to dissolve and remove it.

Let’s discuss these methods in detail.

1. Use a Liquid Chemical-Based Paint Stripper

Use a Liquid Chemical-Based Paint Stripper

A good and quick method to remove Thompson water seal is to use a liquid chemical-based paint stripper. Liquid chemical-based paint strippers contain active paint removing chemicals like methylene chloride.

Since the paint stripper is in liquid form, it will penetrate the sealer coating easily where the paint removing chemicals will dissolve and remove the sealer in the wood and on it.

For this method, you’ll need these tools and supplies:

  • A brand of liquid chemical-based paint stripper
  • A pair of work gloves
  • A face mask (for breathing protection)
  • A paint scraper
  • Paintbrushes
  • Clean rags
  • Mineral spirits
  • A wire sponge

Here is a guide for this method:

  1. Wipe the Thompson water sealer with a clean rag to remove dirt and debris.
  2. Apply the paint stripper directly on the sealer – you can wipe on, pour on, or brush on the chemical-based paint stripper.
  3. Leave the paint stripper to dry on the Thompson sealer for 20-30 minutes.
  4. After the stripper has dried, scrape it off with a plastic putty knife.
  5. Use a wire sponge over the wood to remove leftover Thompson sealer.
  6. Wipe the surface with mineral spirits to neutralize the paint stripper chemical.
  7. Leave the surface to dry.

Tip: Ensure to put on a pair of gloves and a face mask when working with a paint-remover.

2. Sand The Thompson Sealer Off Of The Wood

Sand The Thompson Sealer Off Of The Wood

Another method to remove Thompson water sealer is to use sandpaper. The idea here is to grind the abrasive side of the sandpaper against the Thompson water sealer. Doing this will gradually scratch off the sealer from the surface. If you are working on a large surface, it’s advised to sand using a portable sander.

For this method, you’ll need these:

  • 180-220 grit sandpaper
  • A vacuum or duster
  • A pair of gloves
  • A face mask
  • Rags

Here is a guide for this method:

  1. Wipe the Thompson sealer to remove dirt.
  2. Sand the Thompson sealer off with 180 grit sandpaper.
  3. Keep sanding until all of the Thompson sealer is off of the wood.
  4. Finish the surface with 220-grit sandpaper.
  5. Remove dust and allow the wood to settle.

Tip: While sanding, always keep watch on the wood to know if you have removed the sealer completely. This helps you to prevent over-sanding the wood.

3. Use a Hairdryer and Acetone

Use a Hairdryer and Acetone

The third method is a two-in-one process that involves melting the Thompson sealer first and then dissolving it with acetone after. The combination of both methods will remove the sealer from the surface. For this method, you’ll need these tools and supplies:

  • Acetone
  • A hairdryer
  • Rags
  • A paintbrush
  • A plastic putty knife
  • A nylon bag
  • A pair of gloves
  • A face mask

Here is a guide for this method:

  1. Wipe the wood with clean rags.
  2. Plug in and turn on the hairdryer.
  3. Set the hairdryer between 80 and 100 degrees Fahrenheit – start low so you don’t burn the wood.
  4. Slowly move the hairdryer around the Thompson sealer for about 10 minutes.
  5. Check if the sealer is bubbling or melting – when this happens, turn off and unplug the hairdryer.
  6. Pour some acetone into a clean bowl and soak a rag in the bowl of acetone.
  7. Leave the surface for 20 more minutes (you can pour little acetone on the surface if you are dealing with many coats of Thompson sealer).
  8. After 20 minutes, take out the damp rag and use it to wipe the sealer repeatedly to dissolve it.
  9. When the sealer is dissolved, scrape it off of the surface with a plastic putty knife -put the scraped sealer in a nylon bag.
  10. Re-apply acetone on leftover Thompson sealer and leave for 15 minutes before scraping off.
  11. Wipe the wood surface with a clean rag.
  12. Leave the wood to dry.

Tip: You can also use denatured alcohol if you don’t have a bottle of acetone. You should also know that some reports claim that a degreaser like can also be used to remove Thompson water sealer safely. So, you can try it out but start with a small surface first to see how the surface and sealer react before using the degreaser on the entire surface.

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