If you discover a fist‑sized hole or large crack in your fiberglass shower or acrylic bathtub, you don’t have to replace the entire unit. Tub Repair Company makes a Large Wall Repair Kit that can handle holes up to roughly four inches in diameter and non‑weight‑bearing cracks up to nine inches long. This guide explains how to use that kit to restore your tub or shower, saving you the cost of professional replacement.
Why choose the Tub Repair Company Large Wall Repair Kit?
The kit is engineered for holes and cracks in fiberglass or acrylic showers and tubs and even rusted spots in porcelain‑coated metal tubs. It comes with marine‑grade materials and an easy color‑matching system. Most repairs take about 2 hours total work time over the course of 24 hours.
Unlike many two-part epoxy patch kits, this system uses reinforced fiberglass putty, a fine‑finish filler and a color‑matched topcoat to create a durable repair that can last longer and look better.
What’s in the kit
The Large Wall Repair Kit contains almost everything needed for a robust repair:
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Marine‑grade short‑strand fiberglass putty and hardener – forms the structural patch.
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Fine‑finish putty filler and hardener – fills surface imperfections for a smooth finish.
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Preval spray system plus back‑up cartridge – applies the color‑matched coating.
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Color‑match coating system and wipe‑on primer – match almost any tub or shower color.
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Abrasives – 80 and 120‑grit hook‑and‑loop discs for shaping; 1000, 2000 and 3000‑grit paper for fine sanding.
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Miscellaneous supplies – acetone, putty spreader, rubber gloves, mixing cup, mesh tape and stir sticks.
The kit weighs about 5 lbs and measures 12 × 7 × 7 inches. You’ll also need some basic power tools and safety gear described later.
Recommended equipment
Besides the items provided, gather the following tools:
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Respirator (not just a dust mask) – grinding and spraying create dust and fumes.
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5 inch orbital sander and vacuum – to shape the patch and keep dust down.
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Power drill with drill bits – for mixing and prepping.
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Scissors or box cutter – to trim mesh tape or cut fiberglass patches.
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Blow dryer – speeds up drying after cleaning.
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Paper towels, extension cord, trash can – for cleanup and convenience.
Step‑by‑Step Procedure to Repair a Fist‑Sized Hole
1 – Prepare the damaged area
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Safety first: Put on gloves, eye protection and a respirator. Work in a well‑ventilated space to avoid inhaling dust and resin fumes.
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Clean: Wipe the area with acetone to remove soap scum, oil and debris, dry it thoroughly using a blow dryer.
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Remove damaged material: Use a utility knife or grinder to cut a bevel around the hole, removing any weak or loose fiberglass. Sand 2–3 inches around the hole with 80‑grit sandpaper to roughen the surface; wipe away dust.
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Install mesh tape support (if needed): For holes larger than a screw hole or pencil, insert the provided mesh tape over the hole.
2 – Apply Fiberglass Putty and Finish Putty
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Mix the fiberglass putty: Following the kit instructions, combine the marine‑grade short‑strand fiberglass putty with the supplied hardener. Mix only as much as you can spread in about 3 minutes, as the putty begins to set quickly.
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Apply to the hole: Use the putty spreader to pack the mixture into the hole. Overfill slightly so you can sand it flush later. The fiberglass strands reinforce the repair and restore structural strength.
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Allow to cure: Let the putty set until firm. Cure times vary with temperature but generally take about 30 minutes to an hour before sanding.
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Sand Fiberglass Putty: Sand the fiberglass putty fairly smooth, feathering out the edges with the 80 grit sandpaper.
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Apply Finish Putty: Apply the finish putty using the same hardener and mixing like you did with the Glass Putty. You will have around 90 seconds to apply this once mixed. Let it cure for 15 minutes before sanding.
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Sand the Finish Putty: Once cured sand the Finish Putty using the 120 grit sandpaper. Sand it smooth and feather out the edges.
3 – Shape and smooth the patch
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Sand the cured putty: Use your orbital sander with 80‑grit then 120‑grit discs to sand the repair flush with the surrounding wall. Vacuum or wipe away dust between grits.
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Check the surface: Run your hand over the patch. If you feel low spots or pinholes, mix a small amount of fine‑finish putty and spread it over imperfections. Let it cure, then sand it flush. Repeat until the repair is smooth and level.
4 – Color‑match and mix product
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Match the color: Follow the kit’s color‑matching directions. Mix the supplied paint resins into the mixing cup until it matches your tub or shower. Test on a small hidden area before spraying. Test your acetone in a discrete area to make sure there is not a negative effect on your surface. This can be the case on plastic.
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Mix the paint product: Measure the paint resin using the glass jar of the spray system. First add the paint resin then add the catalyst and reducer. The minimum ratio should be 4 parts resin; 1 part catalyst; and 2 parts reducer. This is the minimum ratio and you can be over on the catalyst and reducer.
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Use the Preval spray: Fill the Preval sprayer with the color‑matched coating. Hold the sprayer about 6–8 inches from the surface and apply light, even coats. Multiple thin coats yield a better finish than one heavy coat. Allow each coat to tack up before applying the next.
5 – Final sanding and polishing
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Wet sand: Once the color coat heals (wait at least 24 hours), wet‑sand the repaired area and the surrounding surface with 1000‑, then 2000‑ and finally 3000‑grit paper. Use water to lubricate the surface and sand in circular motions.
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Polish: Wipe the area clean and apply rubbing compound or the kit’s polishing bar to restore gloss. Buff with a cloth or a buffer until the repair blends with the original finish.
Project timelines and cure time
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Active repair time: 2 to 3 hours (including sanding and spraying). The kit recommends allowing up to 2½ hours if it’s your first time.
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Cure time: Allow 24 hours before exposing the repair to water. Resin and coatings need time to harden completely. Trying to rush the curing stage can weaken the repair.
The Tub Repair Company’s kit is designed for non‑weight‑bearing repairs. If your damage is on a floor or a weight‑bearing section of a tub, use the company’s Floor Crack Repair Kit instead. Likewise, structural damage larger than about a softball will require additional Glass Putty which can be purchased on your way to checkout.
Repairing a fist‑sized hole in a fiberglass shower is an achievable DIY project with the right tools and a quality repair kit. Tub Repair Company’s Large Wall Repair Kit provides marine‑grade putty, color‑match coatings and everything you need to restore structural strength and appearance.
By following proper preparation, mixing, sanding and finishing techniques, you can complete a durable, long‑lasting repair in a few hours over a couple of days and enjoy your tub or shower again without replacing the entire unit.