How to Fix Scratches on a Polyurethane Finish? (3 Methods)

When your polyurethane finish starts to develop scratch marks, the lustrous finish that you once enjoyed will turn dark and ugly. So how do you fix scratches in a polyurethane finish?

To fix light scratches on a polyurethane finish, you need to wipe the scratched spot with mineral spirits. Then buff the light scratch with wax that has the same color or shade as the existing polyurethane finish.

If the scratch is deep, you’ll need to sand the scratched spot and fill it with a scratch-repair polyurethane pen. If the scratched spot looks darker than the surrounding finish, it means that the scratch has affected the wood. In this case, you need to strip the polyurethane, repair the scratch with wood filler, and re-stain the wood.

This post reveals all you need to know about fixing scratches on a polyurethane finish. Let’s dive in.

Why Is Your Polyurethane Scratching?

The main reason for scratches on your polyurethane finish is wear and tear. Over time, your polyurethane finish will begin to develop scratch marks due to friction, dropped items, pencil marks, and the like that the polyurethane finish is exposed to.

However, that’s not the only cause of scratches on a polyurethane floor. Here are other common reasons why your polyurethane finish is scratching:

1. Pet Claw Marks

One major reason for scratches on your polyurethane finish is your pet. If you have pet cats, dogs, or even reptiles, the claws of your pet can easily scratch your polyurethane finish.

This is very common but not limited to polyurethane finishes on floors. For instance, your cat can easily pounce on your polyurethane finished desk and scratch the finish. The safest way to avoid this is to trim your pet’s claws frequently.

2. Kids Toys

Your children’s toys can also scratch your polyurethane finish. Dragging the toys across the floor or table causes the toy to scratch the polyurethane. Luckily, scratches that occur from kids’ toys are usually surface scratches and can be fixed easily.

3. Aggressive Cleaning Chemicals

Cleaning or exposing your polyurethane finish to aggressive chemicals can cause scratches on your polyurethane finish.

In this case, the chemicals don’t scratch the polyurethane finish directly. Instead, the chemicals dissolve the polyurethane paint causing it to become softer. When this happens, your polyurethane finish will develop scratches from even the faintest touches because the finish has gone soft.

4. Using The Wrong Sandpaper

Using the wrong sandpaper on your polyurethane finish can also cause scratches. You are required to sand between coats of polyurethane with 320-grit sandpaper.

If you used coarse or medium-grit sandpaper like 120-grit to sand between coats of polyurethane, the finish will reveal scratches. Sanding the top coat with the wrong sandpaper will also cause scratches.

5. Filthy Polyurethane Finish

When your polyurethane finish is filthy, it can develop scratches. This is very common with polyurethane-finished floors. When there are dust nibs and sand grains on the polyurethane finish, you can push and drag the sand grains into the polyurethane finish as you walk over the floor. This will cause scratches.

6. Using Abrasive Cleaning Attachment

When you clean a polyurethane finish and you use abrasive or spiky cleaners on the finish, you can cause scratches on the polyurethane. That said, stay away from hard brushes especially.

So, can you touch up polyurethane? Let’s find out.

Can You Touch Up Polyurethane?

You can touch up the polyurethane finish only if the polyurethane has a surface scar. If the mark has only affected the surface of the polyurethane finish, you can touch up the finish with an extra coat of polyurethane or with a scratch-repair polyurethane pen.

However, if the scratch or scar is deep or has penetrated the wood, you can’t touch up the polyurethane because the scar is too deep for the touch-up to cover or fix.

You can touch up by applying a fresh coat of polyurethane over the existing finish. The new coat fills and covers the affected spots. However, you’ll need to sand the existing polyurethane finish before adding a new coat. The purpose of sanding is to remove grime and bumps on the existing polyurethane so the new coat can stick properly.

You can also touch up polyurethane by using a scratch-fix PU pen or a scratch-repair polyurethane marker. These markers are filled with a mix that fits all types of clear coats. You just need to pick the pen that has the same color or shade as your existing polyurethane finish. This way, you can touch up the polyurethane without anyone knowing you fixed it.

However, you should know that you can only touch up light errors in a polyurethane finish. If you have a deep scratch or mark on your polyurethane finish, it’s best to sand the polyurethane. If the scratch goes through the polyurethane to the wood, it’s best to strip and re-stain the wood.

How To Fix Scratches On Polyurethane Finish?

It’s very easy to fix scratches on a polyurethane finish. But before you can fix the scratch, you need to know what type of scratch it is. If it’s a surface scratch, you can easily touch up the polyurethane. If it’s a deep scratch, you’ll need to sand the polyurethane.

Here are tips to help you know what type of scratch you are dealing with:

  1. Is the scratched spot looking darker than the surrounding finish? – It’s a very deep mark and you’ll need to strip and re-stain the wood.
  2. Is the scratched spot the same color as the surrounding finish? – It’s a surface scratch and can be touched up.
  3. If the wood stain is affected – It’s a film scratch and sanding is required.
  4. Wipe the scratch mark with mineral spirit and if the scratch comes off – it wasn’t a scratch but a stain.

Now that you know the type of scratch mark you have, you can pick a fix for it. Let’s check out the fixes.

1. Touch Up The Polyurethane – For Surface Scratches

Touch Up The Polyurethane

This fix only works for light scratches. Since it’s a light or surface scratch we are dealing with, we can touch up the area to clear the error.

For this fix, you’ll need the following tools and supplies:

  • Scratch repair polyurethane marker/pen
  • Clean rags
  • Mineral spirits
  • A clean bowl

Here is a guide for this fix:

  1. Pour some mineral spirit into a clean bowl and dip a rag in the bowl
  2. Take out and squeeze the rag so it’s damp
  3. Use the rag to wipe the scratched spot on the polyurethane – this removes dirt and can even remove the scratch
  4. Place the tip of the polyurethane marker where the scratch begins
  5. Press the pen to release the content and carefully, trace the pen along the scratch line while pressing the pen
  6. Stop at the end of the fix and wipe the tip of the pen with a rag
  7. Wipe the spot to remove excess polyurethane filler
  8. Leave the spot to dry and sand gently with very fine-grit sandpaper
  9. Remove dust and the scratch mark should be gone.

2. Sand and Touch Up The Polyurethane – For Film Scratches (Scratches not affecting the wood)

Sand and Touch Up The Polyurethane

This method works for layer or film scratches. These are scratches that penetrate the polyurethane but don’t affect the stain or wood.

This scratch is called layer or film scratch because it only affects the polyurethane film and not whatever is underneath. You’ll need to sand down the polyurethane to level the area and get rid of the stain. After, you can touch up the polyurethane to seal the spot.

For this fix, you’ll need the following tools and supplies:

  • Polyurethane paint
  • 320-grit sandpaper
  • Clean rags
  • A paintbrush

Here is a guide for this method:

  1. Wipe and clean the affected spot
  2. Sand down the polyurethane using fine sandpaper – while sanding, always check the wood so you don’t sand into it
  3. When you have gotten past the depth of the scratch, you can stop sanding
  4. Recoat the polyurethane – you have gotten rid of the scratch but leaving your finish like that will wear it quickly so you need to recoat
  5. You can apply up to 2 coats of polyurethane to touch up
  6. Leave the finish to dry

3. Strip and Re-Stain The Wood – For Deep Gouges

Strip and Re-Stain The Wood

This step is for scratches that have affected the wood. These are deep gouges and they are often caused by dropped items and heavy furniture. For this fix, you need to remove or strip the polyurethane finish and re-stain the wood.

For this fix, you’ll need the following tools and supplies:

  • Sandpaper of different grits
  • Wood filler
  • Polyurethane paint
  • Paintbrushes
  • Wood stain (optional)

Here is a guide to this method:

  1. Sand the polyurethane finish down to the wood
  2. Check for and fill scars in the wood with wood filler
  3. Sand the wood using fine-grit sandpaper
  4. Remove dust
  5. Apply wood stain (optional)
  6. Reapply the polyurethane
  7. Allow the finish to dry.

Can You Fix Scratches Between Polyurethane Coats?

Sadly, there is no way to fix scratches between polyurethane coats without removing at least part of the polyurethane.

If you notice the scratch mark while applying the polyurethane initially, then you’ll need to sand the scratch mark off of the affected polyurethane layer using 320-grit sandpaper. Then remove the dust and apply the next coat of polyurethane finish.

However, if you notice the scratch between the coats after the polyurethane has dried, you’ll need to sand down the polyurethane finish because you can’t fix scratches between polyurethane coats after the polyurethane has dried. You should only use very fine-grit sandpaper (320-grit sandpaper and finer) on polyurethane.

How To Prevent Scratches On A Polyurethane Finish?

Here are expert tips to help prevent scratches on your polyurethane finish:

  1. For polyurethane-painted floors, place transparent carpets on the polyurethane to protect it from scratch marks
  2. Don’t drag items across a polyurethane finish
  3. Always use the right sandpaper when sanding polyurethane
  4. Don’t use aggressive cleaners like bleach on polyurethane because such cleaners will soften the polyurethane and make it more prone to scratch marks
  5. Don’t use abrasive pads or cleaners on a polyurethane finish
  6. Don’t use polyurethane in areas that will experience scratch marks like front decks
  7. Wipe and clean the polyurethane regularly so you don’t push dust nibs into the finish

Final Words

In summary, you can fix scratches and marks on a polyurethane finish easily by following the steps revealed above. For light scratches, use a scratch-fix pen to touch up the areas.

For deeper scratches, you’ll need to sand and then polish the area. If the scratched area looks darker than the surrounding finish, you need to strip and re-stain the wood because the scratch has penetrated the polyurethane.

Finally, ensure to take proper precautions to protect your polyurethane finish from scratches. This way, you won’t have to worry about removing scratches at all.

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