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Fiberglass Supply Depot

Fiberglass Supply Depot 4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)

  • Based on 55 reviews
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Availability: In Stock.
Fulfilled by Amazon
Arrives Thursday, Apr 30
Order within 4 hours and 7 minutes
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Features

  • Flotation Foam is a polyurethane 2-part foam that, when mixed in equal parts and poured in place this foam will soundproof, insulate, or provide extra buoyancy.
  • 4LB. Density polyurethane flotation Foam Quart Kit; Consists of 1 pint of Part A and 1 pint of Part B and produces 1/2 cubic foot.
  • Once fully cured this foam can be laminated over with any type of polyester, epoxy or vinyl ester resin without melting.
  • The 4LB density also works well in floating decoy or taxidermy applications as well as many other sculpting, casting, carving and other filling applications
  • All expansion rates and times given are temperature critical. Temperatures below 75 F will lower the expansion rate therefore requiring more foam. Ideal working temperature is 75 to 80 F or above. Accurate measuring of these products is extremely critical. Working time before foaming: approx. 45 seconds Time before full expansion: approx. 5 minutes

Features

  • Flotation Foam is a polyurethane 2-part foam that, when mixed in equal parts and poured in place this foam will soundproof, insulate, or provide extra buoyancy.
  • 4LB. Density polyurethane flotation Foam Quart Kit; Consists of 1 pint of Part A and 1 pint of Part B and produces 1/2 cubic foot.
  • Once fully cured this foam can be laminated over with any type of polyester, epoxy or vinyl ester resin without melting.
  • The 4LB density also works well in floating decoy or taxidermy applications as well as many other sculpting, casting, carving and other filling applications
  • All expansion rates and times given are temperature critical. Temperatures below 75 F will lower the expansion rate therefore requiring more foam. Ideal working temperature is 75 to 80 F or above. Accurate measuring of these products is extremely critical. Working time before foaming: approx. 45 seconds Time before full expansion: approx. 5 minutes

Brand: Fiberglass Supply Depot Inc.


Material: Foam,Resin


Compatible Material: Vinyl


Item Form: Liquid


Color: Yellow, Black, Clear


Package Dimensions ‏ : ‎ 8.27 x 5.43 x 3.7 inches; 2.84 Pounds


Date First Available ‏ : ‎ January 14, 2021


Manufacturer ‏ : ‎ Fiberglass Supply Depot Inc.


Best Sellers Rank: #32,802 in Industrial & Scientific (See Top 100 in Industrial & Scientific) #42 in Urethane Adhesives


#42 in Urethane Adhesives:


Customer Reviews: 4.3 4.3 out of 5 stars 55 ratings


Brand: Fiberglass Supply Depot


Material: Foam,Resin


Item Form: Liquid


Color: Black, Clear, Yellow


Item Package Quantity: 1


Compatible Material: Vinyl


Item Form: Liquid


Container Type: Bottle


Viscosity: Medium to High Viscosity


Full Cure Time: 5 Minutes


Water Resistance Level: Waterproof


Item Package Quantity: 1


Volume: 1 Quarts


Brand Name: Fiberglass Supply Depot


UPC: 819794022897


Manufacturer: Fiberglass Supply Depot Inc.


Unit Count: 64.0 Ounce


Material Type: Foam,Resin


Color: Black, Clear, Yellow


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Apr 30

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Great product! Directions a bit off.
This works great and made a nice, firm filler that I needed for a place on my kayak. It was easily sand-able and paintable. It is firmer/stiffer than the spray foam you buy in cans at the home improvement store. Just be aware that the directions are a bit off. In the video we watched online, it looked as if it foamed up instantly, and the directions said to count a number of seconds and no more before pouring. Our experience was that it took a bit longer for it to foam up, and we wasted some that poured through some holes in the cavity we were trying to fill. I would say an extra 10-15 seconds would have worked better. ... show more
Reviewed in the United States on August 3, 2024 by Julie M.
    • Expands quickly
Review Image by Thomas Lewis
I created a rear wing which was hollow and needed to strong as it is active and used as an air brake so I needed to fill it with foam. The 4 pound foam was perfect but calculating the internal volume was difficult. To be sure I wasn't going to come up short I added a little extra and did two pours. Because of the shape I couldn't see where the first ended so I proceeded to do the second pour. As soon as I saw it I had like 2 seconds before it over flowed. All good as I planned for this and could just cut the excess off. So be warned and prepared if you mixed too much. It sticks to everything and there is no stopping it. My wing now is as hard as a rock and strong so it worked well for me. ... show more
Reviewed in the United States on January 4, 2024 by Thomas Lewis
    • Works as described!
I purchased this product to secure a fuel tank in a boat. It worked perfectly. I carefully followed the instructions, adding part A to part B (not the other way around), working in an ambient temperature of about 70 degrees Fahrenheit. It expanded slowly over a few minutes and did not "explode" as described by others. The instructions emphasize the mixing order, and I suspect that is the key to avoiding disaster. ... show more
Reviewed in the United States on October 21, 2024 by Richard
    • 2part foam
The foam is exactly what I needed. It worked perfectly. Awesome product.
Reviewed in the United States on March 6, 2026 by Clara Adams
    • Taxidermy work
Used for taxidermy purposes. It's a denser foam that does not expand as much as the lighter weight foams, but it has been great for form alterations etc Might be a waste to use for habitat work as you'd get more expansion from the lighter weights.
Reviewed in the United States on March 5, 2025 by joe j.
    • Good stuff!
Follow the instructions and work quickly. The foam pours easily after mixing and expands rapidly. Worked perfectly to fill and seal a baseboard area of my pole barn. Best I can tell, the estimated volumes are accurate.
Reviewed in the United States on April 25, 2023 by WTX Geo
    • Solidifies and foams up in a span on 8 seconds
Instructions were unclear and also we're not included so I started off slow poured some in at equal amounts of both solutions with nothing happening so I poured more started to mix and get thick but still barely forming so I figured I'd put all of it into a four gallon bucket started to see it mix more turned around for about ten seconds to prep the area on the wall to fill and I turn back around and it's all just a solid bucket of useless hard unmailable foam no choice at this point but to throw it all away wouldn't recommend if you plan to shape it in any way shape or form ... show more
Reviewed in the United States on October 28, 2023 by matt
    • great product
works well with a great expansion rate.
Reviewed in the United States on March 30, 2025 by Dirtfly

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