2# Flotation and Insulation Boat Foam (2023)

Starting From $67.00

AeroMarine Products expanding 2 part pour-in place foam is a closed cell, rigid urethane foam. Our closed cell pour foam works very well as a flotation foam in building and/or repairing boats, barges, docks, canoes, kayaks, pontoons, etc. Additionally, AeroMarine Products’ closed cell pour foam is good for insulating buildings, pools, hot tubs and spas.

Do NOT use our pour foam on inflatables and/or canvas.

**This is a closed cell pour foam only. It is NOT a sprayable foam!

Always wear a respirator or self-contained breathing apparatus when working with pour foam.

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(Video) How to Use Two Part Expanding Flotation Foam and Say NO to Pool Noodles Forever!

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Q. I’m making a pontoon boat from empty 55 gallon drums. How much floatation foam do I need?

A. Each 55 gallon drum requires about 8 cubic feet of urethane foam. Since each cubic foot weighs two pounds, you will need 16 pounds of foam per empty drum. Therefore, it will require about one gallon kit (makes two gallons) per drum.

Q. Can I brush or spray the liquid foam onto a vertical wall to provide a uniform thickness of insulation foam?

(Video) 2 Part Marine Foam (TOTALBOAT) Bayliner Floor Restoration

A. No, the liquid foam will just run to the floor, then rise. You will have a big blob of foam on the floor. It is NOT a sprayable foam.

Q. Is this flotation foam compatible with styrofoam?

A. Yes. It will not “eat” or dissolve styrofoam. If you have a large cavity to fill, you can put some chunks of styrofoam in the cavity to save foam.

Q. How do I know how much foam I need to float my boat?

A. Get your calculator ready, you will need it. A cubic foot of polyurethane will float about 60 pounds of “dead weight”. The wood parts of your boat will probably float, so you don’t need flotation foam to offset that weight. The fiberglass parts of your boat will barely sink, so you really don’t need much foam to offset the fiberglass- maybe one cubic foot of foam per two hundred pounds (or more) of fiberglass hull. The metal parts of your boat are what you really need to account for. A small (4-6hp) outboard may weigh 45-55 pounds. A 50hp outboard will weigh about 200 pounds.

So a 16 foot fiberglass skiff with a 50 horse outboard will need about six cubic feet of urethane foam to keep it afloat. A 12 foot plastic kayak will only need one cubic foot. A 30 foot fiberglass sailing sloop with a diesel engine and lead keel would need about 150 cubic feet of foam. Actually, very few 30 foot keelboats have positive foam flotation, but it’s not out of the question- especially when you consider all of the air pockets that would exist, as well as all of the wood interior components that provide some positive flotation.

(Video) How to pour expanding flotation foam in a boat hull - How to Build a Boat Part 10

Q. Do I need to paint or fiberglass over the floatation foam?

A. You probably should. Polyurethane will absorb a small amount of water, because some of the the cells are open (95%+ are closed, though). Painting or glassing will seal the foam and prevent any water absorption. However, it really shouldn’t be necessary unless the foam is constantly immersed in water, such as in a boat with bilges that are always wet. The foam is not UV resistant, so it must be painted if exposed to sunlight.

Q. Is the polyurethane foam resistant to fuel, oil, and solvents?
A. Mostly yes. It is resistant to splashes of gasoline and diesel fuel, although it will absorb a small amount because no pourable foam can be guaranteed to be 100% closed cell. A strong solvent such as acetone or toluene would eventually break the foam down, but it would take a long time.

Q. What is the maximum exothermic temperature that cured polyurethane foam can reach?

A. 250 degrees F.

Q. What is the maximum surface temperature that cured polyurethane foam can withstand before it begins degrading?

A. 200 degrees F. The foam does not ignite. Under high heat and direct flame, it will char like wood. The foam will break down with continued exposure to excessive heat/flame. The damaged area can be repaired by removing the damaged portion and pouring new foam into the void.

Quick Comparison

Settings2# Flotation and Insulation Boat Foam removeOne-to-One Silicone Mold Making Rubber - 1 Quart removeBar Top/Countertop Epoxy removeAeroMarine Concrete Molding and Stamping Rubber removeAM 128 Brushable Silicone Rubber remove2lb. Flotation and Insulation Foam - 1/2 Gallon Kit remove
PriceStarting From $67.00$59.00Starting From $89.00Starting From $75.00Starting From $71.00$72.00
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DescriptionLow Density Flotation and Insulation Foam (2# per cubic foot). This expanding boat foam is closed cell, rigid foam.It doesn't have quite as good properties as AM 128 shown above. However, it is ideal for most mold making applications. AM 125 silicone mold making rubber cures in less than two hours. This molding RTV rubber is great for first time mold makers. PLEASE NOTE: Do NOT expose AM 125 to any moisture; moisture ruins it! Re-cap the containers immediately after pouring. Store AM 125 at 72F/room temperature. AM125 has a 60 day shelf life once you open the containers.AeroMarine Products' 400/21 Epoxy is a new super clear epoxy that provides a clear, hard, glass-like surface on wood or concrete.AeroMarine Concrete Molding and Stamping Rubber This is a tough black rubber similar in feel to a car tire. It is used not only for concrete or cement stamping mold, but also for making hard durable rubber parts for machinery or automotive applications.Brushable Silicone Mold Making Rubber, RTV Molding Rubber. Brushable silicone for making thin wall 'glove' molds. Clings to a vertical surface.
  • AeroMarine Products 2# density polyurethane pour foam.
  • Closed-cell: Does not react to splashes of oil or gasoline and does not absorb water.
  • Designed for positive flotation, cavity and void fills, and insulation.
  • ½ gallon kit; include one quart each of Part A and Part B.
  • 2 lbs. per cubic foot density.
  • Yields 2 cubic feet.
ContentAeroMarine Products expanding 2 part pour-in place foam is a closed cell, rigid urethane foam. Our closed cell pour foam works very well as a flotation foam in building and/or repairing boats, barges, docks, canoes, kayaks, pontoons, etc. Additionally, AeroMarine Products' closed cell pour foam is good for insulating buildings, pools, hot tubs and spas. Do NOT use our pour foam on inflatables and/or canvas. **This is a closed cell pour foam only. It is NOT a sprayable foam! Always wear a respirator or self-contained breathing apparatus when working with pour foam.This is a simple, 1:1 mix Silicone Mold Making RTV designed for beginners to mold making. AM 125 has a mix ratio of 1:1 by volume and is sold by volume, not weight.Made in USA! PLEASE NOTE: You must use a heat gun (NOT a hair dryer!) to remove surface bubbles from the #400/21 Epoxy. *You must accurately calculate the size of your project and the amount of epoxy that you will need!* Please see our coverage chart near the bottom of this page for guidance. If you are applying our epoxy over a porous surface, you may need to use more epoxy to obtain your desired coverage. *Epoxy is NOT UV resistant. It will yellow in sunlight. DO Not mix the entire amount of resin and hardener together all at once. It will cure in your mixing container! Our customer,Tule Peak Timber, located in Southern California, is a great source for custom table tops and slabs!This is a tough black rubber similar in feel to a car tire. It is used not only for concrete or cement stamping mold, but also for making hard durable rubber parts for machinery or automotive applications. ** Please note: If you are using AeroMarine Products Concrete Molding and Stamping Rubber for making concrete molds and/or stamps, it works for basic concrete or cement shapes without undercuts or fine detail.** For fine detail concrete or cement molds, please use either our"Mold Making Latex" or our"AM 128 Brushable RTV Silicone" This 1:1 by volume mix ratio polyurethane rubber is used for making molds for concrete and/or cement. The smallest container in the picture contains a mold release which is included with each small kit. **You must mix, apply and cure AeroMarine Products Concrete Molding and Stamping Rubber in a humidity-controlled environment.

Instructions for AeroMarine Products' Concrete Molding and Stamping Rubber 75A Urethane

Use between 65° and 75°F in a humidity-controlled environment. AeroMarine Products Concrete Molding and Stamping Rubber 75A Urethane is moisture-sensitive. Use only clean plastic or metal mixing utensils and containers. Do not use paper or wood. Re-cap the bottles immediately after pouring the amount you are going to use. Shake both A and B bottles very vigorously to disperse the product about 30 minutes before pouring. Measure out A and B in 1:1 by volume ratio. Use our Double Mix and Pour method: Pour into a clean container. Mix well for 60 seconds. Do not scrape the sides of the container because it will contaminate your mix ratio. Pour into a second clean mixing container and mix again thoroughly for 60 seconds. Pour within 5 minutes of final mixing. If you are pouring layers of Concrete Stamping Rubber 75A Urethane, let each layer fully cure before pouring subsequent layers. 75A Urethane bonds very well to itself.

You must use a mold release when pouring AeroMarine's Concrete Molding and Stamping Rubber 75A Urethane against another surface. AeroMarine Products' Mold Release (sold with the smaller sized kits) is the standard release for this product. To release the concrete easily from the mold, you can also use motor oil or castor oil.

AeroMarine concrete molding and stamping rubber is a tough rubber that resembles a rubber shoe heel. AeroMarine's Cement Molding and Stamping Rubber also an excellent choice for making clutch and brake pedals, motor mounts, or door trim rubber for automobiles. DO NOT USE ON HUMAN OR ANIMAL SKIN!


  • Low viscosity
  • Convenient volumetric mix ratio (1:1)
  • Rapid set time
  • Low odor
  • Excellent base for epoxy/polyester resins
  • Readily accepts paints, stains and finishes
  • Approvable under U.S. Coast Guard Regulation # 33 CFR 183.114

Physical Properties:

  • Parallel to Rise Compressive Strength: 40 psi
  • Tensile Strength: 30 psi
  • Shear Strength: 30 psi
  • Flexural Strength: 50 psi

Room Temperature Features of Resultant Product

  • Cured Density: 2 lbs/ cubic foot
  • Compressive strength: 40 psi
  • K-factor: 0.22
  • R- Value: 7 per inch
Additional information
Weight4 lbs
Weight6 lbs
(Video) Pouring Expanding Foam


What foam is best for boat flotation? ›

Closed-cell foam has a higher compressive strength and dimensional stability than open-cell foam, which means it acts as a better insulator while also being more resistant to water and air leakages. Because of this, it is far more suited for marine applications, particularly flotation.

Can you use spray foam for boat flotation? ›

If you are a boat owner, you need to be aware of boat flotation. Closed cell foam is an ideal product to use for buoyancy, and Versi-Foam® is one of the easiest closed cell foam kits to use for this purpose. A boat's job is to float.

Does putting foam in a boat help it float? ›

Flotation foam acts as a life jacket for your boat. If the vessel is punctured and develops a hole or leak, it will still take on water, but the flotation foam will significantly slow the rate at which the boat sinks.

How much foam do you need to keep a boat afloat? ›

Placement of buoyancy

At least 50 percent of the foam should be placed in the sides of a boat (gunwales) and high in the hull so the foam crosses the water line and the boat remains stable if flooded. Buoyancy should be distributed along the length of the boat in proportion to the distribution of weight in the vessel.

How thick should foam be in boat seats? ›

While it is true that higher density foams have more longevity, densities of about 1.4- 1.8 are considered industry standards for boat seats.

Which foam is most buoyant? ›

While floatation foam is mostly known for its high buoyancy, not all buoyant foams are created equal. There are many other foam properties to take into consideration.

Is expanding foam good for boats? ›

TotalBoat Marine Flotation Foam is great for filling voids, especially under decks. It's thermal and sound-proofing abilities make it ideal for a number of other insulation and flotation applications. 94% closed-cell foam structure lets it maintains buoyant pressure even after prolonged exposure to water.

Does foam make a boat more stable? ›

By increasing the amount of quality marine flotation foam on board the boat will sit a little higher in the boat which will improve stability.

How do you make a boat float better? ›

The easiest way to make a vessel float better is by modifying the shape of the hull, and the easiest way to test a hull is to make a miniature version and see how it performs. A hull's shape can help a boat displace more water and fill the gap made with air, which has a smaller density than water.

What is the best material to float on water? ›

A thin, inflatable object like a rubber raft is an ideal way to trap air for floatation. Styrofoam works well too because consists mostly of trapped air. It may not be very strong however (and the rubber raft may have strength or stability issues as well). Balsa wood is also mostly trapped air.

Does spray foam add buoyancy? ›

Most spray foams used in home insulation are too dense to be used for any kind of buoyancy.

Can foam filled boats sink? ›

It should give you enough time to reach safety, radio for help and wait for rescue, or make it to shore before the boat goes under. If you have enough foam, that boat literally will not sink. Flotation foam is there to delay and/or prevent a boat from sinking. Think of it as a life jacket for your boat.

What weight should I float? ›

In the case of water, an object with a density less than 1 g/cm3 will float.

How much weight capacity do float pods add? ›

Features and Benefits: Up to 200 LBS of Extra Flotation. Reduces Engine Laboring. Reduces Fuel Consumption.

Do you need special foam for boat seats? ›

As a general rule, the best foam for boats is a quick-drying foam with medium firmness. The quick-drying foam will help prevent mold and keep your cushions lasting longer. Medium firmness is a good option when it comes to cushioning comfort. There are two types of foam, open-cell, and closed-cell.

Is higher density foam better? ›

Denser foams are more durable and tend to outlast lower-density materials. They are less susceptible to sagging, and also more resistant to accidental damage and tears. Higher-density foams generally conform closer than low-density foams and thus offer better pressure relief than lower-density foams.

What material is best for covering boat seats? ›

Breathable woven fabrics or luxurious vinyl and faux leather upholster fabrics are popular for boat interiors. Examples of these fabrics include Sunbrella Upholstery, Bella-Dura, Nauga Soft, EverSoft and Ultraleather®.

What type of foam absorbs water? ›

Open cell foam has a higher possibility of absorbing water than closed cell foam, which can lead to degraded performance, especially for thermal applications. While engineers do not necessarily strive for perfect vapor impermeability, the free flow of water can be detrimental to a structure and can trap water.

How much buoyancy foam do I need? ›

Use 62.4 lb per cubic foot for specific gravity of fresh water. Use 2 lb density Foam For flotation. Use 60.4 lb per cubic foot for dry weight supported by 2 lb foam.

What is marine grade foam? ›


These marine polyurethane foams provide structural strength with moisture resistance, enabling boat designers to replace wood components with a top-quality, non-decaying product. This product is fully compatible with fiberglass-laminating production methods.

What kind of foam do you use in a boat? ›

Marine Floatation Foam

This type of marine foam is known for its high buoyancy, which makes it ideal for use in boats and other sea-faring vessels. This type of foam should also be durable and able to strongly adhere to substrates.

Are Expanding foams waterproof? ›

Moisture-curing, self-expanding foam adheres to all common building materials. Resistant to water, heat and ageing. Ideal for filling large holes, voids, gaps around window and door frames and around exterior pipes.

What to put on bottom of boat to make it faster? ›

Speedcoat-49 began as a water-drag-reducing hull coating for power boat racers, but now it is highly coveted by all sorts of boaters that not only want to go faster, but also use less fuel, and provide an easy to clean, non-stick surface against pond slime, algae, and fouling.

How long will expanding foam last? ›

Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!

Why do mortgage companies dislike foam insulation? ›

The hardened foam can also warp wooden beams. This has led to many mortgage and equity release firms refusing to lend to homes with this type of loft insulation.

What is the strongest expanding foam? ›

1. Best Expanding Foam—Loctite Spray Foam. For most small cracks and gaps found around the home, you can rely on Loctite's Tite Foam. This polyurethane-based product can bond to many materials and withstand UV rays.

Does marine foam absorb water? ›

Because our time-tested marine foam for boats do not absorb water, General Plastics' marine polyurethane products do not rot, warp, bow or delaminate. Our HDU marine-grade foam serves as core material for building transoms, hulls and bulkheads.

What's more buoyant air or foam? ›

Hello Wenceslaus Muenyi, air must be lighter than foam and less dense. But to contain the air you need a super-light container or bubble, a light-weight balloon. this would definitely float higher/better than the equivalent volume of foam.

What should you not do before a float tank? ›

Don't shave or wax on the day of the float as the mineral laced solution that helps you float can irritate tender skin. Eat only a light meal before your float session as a large meal just before you float can cause noisy distractions. Avoid stimulants such as caffeine and alcohol on the day of your session.

Are foam filled dock floats better? ›

Dock floats are an essential component of a dock because they support and hold it. Foam-filled, robust foam drums work as the best option for most docks while hollow ones that are light and less expensive may be more suitable to your needs if you're on a budget or looking for something temporary.

Why does a boat float but I sink? ›

If the downward gravitational force is less than the upward buoyancy force then the object floats, otherwise it sinks. That is, if an object weighs less than the amount of water it displaces then it floats otherwise it sinks. A boat floats because it displaces water that weighs more than its own weight.

What items can you gently float on water? ›

List of some items that float on water:
  • Piece of paper.
  • Wood.
  • Balloon.
  • Plastic bottle.
  • Ice.
  • Boat.

How much weight does spray foam add? ›

Closed cell spray foam is extremely dense, approximately 2 lbs. per square foot., and that density is what makes it such an effective insulation.

Is boat foam flammable? ›

Yes, spray foam — like all foam plastic materials — is flammable.

How do you clean a foam boat floor? ›

How to Clean Foam Flooring on Your Boat the Right Way
  1. Step One - Vacuum Bulky And Loose Dirt. ...
  2. Step Two - Pour Clean Water Over The Deck. ...
  3. Step Three - Combine Deck Cleaner With Warm Water. ...
  4. Step Four - Scrub Boat Deck With Only A Bristle Brush And Approved Deck Cleaner. ...
  5. Step Five - Rinse With Clean Water. ...
  6. Be Careful!

Can you float too much? ›

While you can float every day without harm, we find that the relaxing effects of a one-hour float typically last beyond that day. For best results, we recommend regular sessions, and many clients find that floating once or twice a week provides the most benefits.

How many times a week should you float? ›

Most patients see the benefits of using float therapy around two or more times a week, and even more positive results from long periods of routine use. The number of float sessions could differ depending on your reasons for choosing float therapy. For some people, once a week for 2 months is plenty.

What is the best shape for a boat to float? ›

In addition, the shape of the boat is very important. A flat bottom is best, with sides to keep out the water and a large surface area that touches the water. Boats with lots of surface area are very wide, with lots of space inside.

Can you sleep overnight in a float tank? ›

Yes – dozing off in a float tank is possible, although it's surprisingly unlikely. What is common, however, is reaching a state of hypnagogia, or otherwise put, the space in between wakeful alertness and sleep.

Can you fall asleep in a float pod? ›

So the short answer is yes – you can fall asleep in a float tank, although you may be mistaking nodding off for reaching a deep, meditative state! Still, it's common to have questions. Especially if you're new to floating. We're sometimes asked if sleeping through a session is a waste of your float.

What is the difference between float and float pods? ›

The main feature of our float rooms is that extra ceiling space! We carry the same float pods at both of our locations. The float pods are also located inside of a larger private room, but they are free-standing float tanks. The pods have a clam-shell-like shape.

What type of foam does not absorb water? ›

Dry Fast Foam

It is non-water absorbent and won't mold, rot or mildew. It is very resilient and buoyant, with an open-cell structure. Dry Fast Foam is used for filtering or padding that is subject to high amounts of liquid.

What is the best material for boat cushions? ›

We typically recommend Marine Sunbrella for most boat cushions but the upholstery Sunbrella is an option for your boat interior if you want more pattern and color options. In addition to popular Sunbrella, marine cushions can be made of high quality marine vinyl, Phifertex mesh, faux leather and/or Ultrasuede.

Can I fill my boat with foam? ›

Like thermal tanks, boats also benefit from the advantages of using polyurethane as a large cavity filler. In the case of boats, filling the hull with polyurethane ensures insulation and buoyancy.

What makes a good boat float? ›

Metal boats can float when their density (which is defined as mass per unit of volume) is less than that of water. In addition, the shape of the boat is very important. A flat bottom is best, with sides to keep out the water and a large surface area that touches the water.

What happens if foam insulation gets wet? ›

Does spray foam absorb water? Yes, there are open cell spray foams on the market that will absorb water, but that doesn't mean they all do. The spray foam used here at RetroFoam of Michigan does get wet and water even moves through it, but it doesn't trap moisture indefinitely. This means it will dry out.

What kind of foam is waterproof? ›

Generally used for packaging, Ethafoam is a type of versatile closed-cell polyethylene foam that is water-resistant. At high density Ethafoam is waterproof as well as being impervious to most chemicals, mildew and rot.

What type of foam is waterproof? ›

In short, closed cell spray foam is waterproof while open cell spray foam is not. This is because closed cell spray foam insulation is a denser material, while open cell spray foam is lighter and expands more.

What is the best boat cushion? ›

The Best Boat Cushions for a Comfortable Boat Riding Experience
  • 1 Flowt Type IV Throwable Flotation Cushion – Best Overall.
  • 2 Stearns Utility Flotation Cushion – Most Affordable Option.
  • 3 Seachoice Emergency Marine Foam Flotation – Great Value.
  • 4 Airhead Type IV Throwable Cushion – Best Throwable Cushion.
14 Nov 2022

What should you put on boat seats to protect them? ›

Never use tarps to cover your boat.

Applying a vinyl protectant after each cleaning will further extend this protection. These sprays contain ingredients that absorb UV light and repels dirt and oils that can cause cracks or leave your vinyl looking dingy and discolored. We recommend: 303 Aerospace Protectant.

What is the best filling for seat cushions? ›

Foam wrapped in a layer of fibre (SupaWrap) is the most recommended seat cushion filling as it provides the support of foam and the softness of fibre, it is also cheaper than feather wrap.


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