How to Repair a Cracked or Chipped Bathtub

Step 1: Gather Your Supplies

You’ll need several types of products to repair cracks, chips, scratches, and other types of surface damage for bathtubs. Grab your personal protective equipment (PPE), a filler (White Water Resistant or Longstrand Fiberglass), a tube of hardener (blue or white), a flat application tool (like a plastic putty knife or putty spreader), and a sandpaper repair kit to get started.

Pay close attention to color. Choose fillers and hardeners that match the color of your bathtub.

Step 2: Clean the Damaged Area

It’s important to clean the area around the crack. Use cups of water from the sink and a sponge or sandpaper to complete this task. Remove wax, soap scum, oil, and other contaminants from the tub’s surface.

Be sure to dry the area thoroughly before moving on.

Step 3: Put on Protective Gear

As with any refinishing or construction project, you need to wear protective gear. The bathtub repair process creates dust, and the materials used can give off toxic fumes.

Put on gloves, goggles or safety glasses, and a dust mask or cartridge respirator. Wear long sleeves and closed-toe shoes as well.

Step 4: Sand the Crack

Use sandpaper to sand the damaged area, both the crack or scratch in the tub itself and an approximately one-inch radius around the chip.

This sanding process helps remove any jagged edges or glass fibers that may be protruding from the crack.

Step 5: Mix the Filler and Hardener

Following the instructions on the product labels, mix the filler and hardener until you reach the desired consistency, taking temperature into account.

Mix the two materials thoroughly to ensure homogeneity. The longer you stir the mixture, the better the end result will be. However, once the mixture is homogenous itwill begin hardening, so don’t delay.

Step 6: Apply the Mixture to the Damaged Area

Using the flat application tool, apply the filler and hardener mixture to the crack, chip, or scratch. Work it into the damaged area, getting into all the crevices. Keep filling the crack until it is at a level slightly higher than the surface of the tub; you will sand it down later after it fully cures.

Step 7: Wait for the Material to Harden

After the mixture is applied, allow it to harden. It may take up to 30 minutes to fully harden.

Step 8: Sand the Surface

When the filler is dry and hardened, carefully sand the repaired area to eliminate unevenness on the surface of the tub. This process is important in order to ensure a smooth finish.

Don’t hesitate to apply pressure while sanding but try not to scuff the surrounding area or oversand, otherwise you’ll have to mix and apply more filler.

Step 9: Paint and Buff the Repaired Area

You will need to paint the chip repair to match and blend in with the rest of the tub. The original NAPCO coating used to refinish the surface will work well here, but you may have to color match the spot repair if it’s the original surface or one you haven’t refinished before.