underwater epoxy repair putty

Underwater Repair Epoxy


This versatile 2-part underwater marine & boat epoxy repair putty fills voids, patches holes, and seals leaks on aluminum, fiberglass, wood, steel, and even concrete for impact- and abrasion-resistant repairs. It cures completely (even underwater) in just 6 to 8 hours at 70°F. A must-have for any boat's emergency toolkit.

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  • Two-part marine epoxy repair putty creates permanent bonds on fiberglass, aluminum, steel, wood, and concrete surfaces at, above, and below the waterline
  • Easy to mix, use, and apply in an emergency—in or out of the water
  • Thick formula won’t sag on vertical or overhead surfaces
  • Cures completely in 6 hours at 70°F in air or in salt or fresh water—even underway
  • Cures to a rock-solid, hard surface that stops leaks and resists impacts and abrasion
  • Once cured, can be drilled, machined, or tapped
  • Prevents wood from deteriorating and weakening; prevents corrosion from forming on metals
  • Non-shrinking, non-sagging putty is great for reliable, permanent repairs on boat hulls, docks, and much more
  • Size: Available in a 2-Pint Kit, 2-Quart Kit, or 2-Gallon Kit. Each kit contains equal parts Part A resin and Part B hardener.
  • NOTES: TotalBoat Underwater Epoxy Repair Putty is not for use in potable water systems. Cured putty is not suitable for sanding.

Make emergency repairs without hauling out

Discovering your floor hatches floating to the tune of your shrieking high-water alarm can wreck a relaxing trip in a heartbeat. When bad things happen on a boat, they can happen really fast, requiring immediate action to reverse the situation, or at least keep it at bay. The more time you spend on your boat, the greater the chances are that some day you’ll be faced with a disaster that threatens your boat’s ability to stay afloat.

Prepare yourself with an emergency toolkit that includes TotalBoat Underwater Repair Epoxy. It lets you make repairs without hauling out first because it can be applied underwater to patch, fill, and seal leaks in aluminum, fiberglass, wood, and steel hulls.

Mix it, apply it, and cure it underwater—even underway

When we say underwater, we mean underwater—for mixing the two components, applying the putty, and letting it cure. Of course, it works just as well in air above the waterline, too. Either way, it’s easy to mix—just wet your gloved hands, grab equal-sized chunks of Part A and Part B, and combine thoroughly. Mix as much as you think you’ll be able to use in 30 minutes. Keep the putty wet while mixing it. This isn’t hard to do if you’re underwater, but if you’re working with it out of water, the second you feel it sticking to your gloves while mixing, wet your gloves and keep mixing. The putty is ready to use when it becomes a consistent, dark green color.

In an emergency, our Underwater Epoxy Putty gives you a generous working time of up to 30 minutes at 70°F, which gives you enough time to slap it on the repair area, smooth it out, mix more, apply, and smooth, to build up a thickness of 1/8″ to 1/4″. It’ll begin firming up in about 2 hours at 70°F, and is super-sticky enough to stay where you stick it, and will cure properly, even while your boat is moving through the water returning to a safe harbor.

Rock-hard, reliable repairs on everything from boat hulls to pier supports—and much more

This versatile epoxy repair putty cures completely hard in 6 hours at 70°F—in air or underwater. It creates a high-strength, extremely hard surface that protects against impacts and abrasion, making it ideal for repairs to hulls, docks, pilings, sea walls, buoys, concrete barriers, and many other wood, steel, aluminum, fiberglass, and concrete structures. While it’s protecting repaired surfaces from impact damage and water intrusion, it’s also preventing new corrosion on metals and further deterioration on concrete and wood.

More TotalBoat products for your emergency toolkit

TotalBoat Underwater Repair Epoxy Putty plugs leaks, patches holes, and reshapes surfaces to rebuild them, and it comes in three convenient sizes to tackle large and small repair jobs. Don’t leave the dock without it. Other indispensable TotalBoat products for your emergency toolkit should include TotalBoat FlexEpox flexible epoxy adhesive and TotalBoat TotalFair epoxy fairing compound.

FlexEpox creates permanent structural bonds that bend without breaking for quick and easy gluing repairs on fiberglass, metal, plastic, and wood. It has an easy-to-use 1:1 mix ratio, works on wet or damp surfaces, and also cures underwater, making it ideal for hull repairs.

TotalFair is a two-part epoxy fairing compound with a simple 1:1 mix ratio that’s easy to measure, mix, and apply to clean, dry surfaces. Use it to fill voids, and fair, shape, or repair dings and dents in fiberglass, aluminum, steel, and wood surfaces. It dries quickly, and can be sanded in just three hours at 80°F.

All three of these dependable, durable epoxy-based products can be used above and below the waterline, provide excellent moisture resistance, and should be kept on board in case of emergencies.

Underwater Repair Epoxy Specifications:

  • Components: Two
  • Mix ratio: 1 to 1
  • Mixing: Use gloved hands or a putty knife
  • Color (admixed): Dark green
  • Application: Using gloved hands, apply to repair area; use heavy hand pressure to remove air bubbles
  • Application temperature: Above 50°F; (will not adhere and cure properly at temperatures below 50°F)
  • Application thickness: About 1/8″ to 1/4″
  • Working time: 30 minutes @ 70°F
  • Firm time @ 70°F: Approximately 2 hours
  • Full hardness time @ 70°F: Approximately 6-8 hours
  • Important: Always wait for full cure before machining, drilling, or tapping TotalBoat Underwater Epoxy Putty.

TotalBoat Underwater Repair Epoxy Technical Data

Underwater Repair Epoxy Part A Resin SDS

Underwater Repair Epoxy Part B Hardener SDS

Frequently‌ ‌Asked‌ ‌Questions‌ ‌

Can Underwater Repair Epoxy be used for high heat applications like engine building and repair?

While this product is formulated for emergency repairs on boats, similar products have been used by engine builders for shaping intake runners, ports, and manifolds.

Upon curing, can Underwater Repair Epoxy be drilled or sanded?

Once cured, TotalBoat Underwater Repair Epoxy can be sanded, tapped, machined, and drilled.

How long does Underwater Repair Epoxy take to cure?

It takes approximately 6-8 hours at 70°F to achieve a full cure in air or underwater.

Does it cure when applied underwater?

Yes, it cures when applied underwater, making it ideal to use for hull repairs.

Can Underwater Repair Epoxy be used to repair fiberglass blisters below the waterline?

Yes, you can use this Repair Epoxy, but a more common solution would be to use 3M Marine Premium Filler, which is specifically designed to treat gelcoat blister damage.

Can this epoxy be used on aluminum boats or pontoons?

Yes, it can. Underwater Repair Epoxy can be used on aluminum, fiberglass, steel, wood, and concrete surfaces.

Can it be painted over?

No, but it can be overcoated with TotalBoat TotalProtect Epoxy Barrier Coat Primer or 2-Part Epoxy Primer before applying antifouling paint.

How do you apply Underwater Repair Epoxy?

While wearing rubber gloves, spread smoothly on the surface in 1/8” to 1/4” layer using heavy hand pressure to displace water and air bubbles. Smooth off by hand. When starting another handful, start spreading at and away from the previously applied film so as not to trap air bubbles or leave an area of uncoated surface. Step-by-step instructions can be found here.

Can a second coat of this epoxy be applied over a cured first coat?

While only a single application is necessary for most repairs, a second application may be applied after the first has fully cured.

Can you use this in potable water applications?

No, it’s not suitable for use in potable water.

Can this be used to repair leaking swimming pools or koi ponds?

Yes, Underwater Repair Epoxy can be used to repair leaking swimming pools and koi ponds.

How do you know when you have mixed the resin and hardener correctly?

When mixed together properly, the yellow and black epoxy will turn into an olive green color.

What is the working time of Underwater Repair Epoxy once mixed?

Once mixed, the working time is 30 mins at 70°F.

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