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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 (2 Gallon Kit)

  • Based on 30 reviews
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Availability: In Stock.
Fulfilled by Amazon

Arrives Thursday, Mar 19
Order within 22 hours and 40 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 2 Gallon Kit; Consists of 1 gallon of Part A and 1 gallon of Part B and produces 4 cubic feet.
  • 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 2 Gallon Kit; Consists of 1 gallon of Part A and 1 gallon of Part B and produces 4 cubic feet.
  • 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


Item Package Quantity: 1


Package Dimensions ‏ : ‎ 12.2 x 12.2 x 6.5 inches; 20 Pounds


Date First Available ‏ : ‎ January 27, 2021


Manufacturer ‏ : ‎ Fiberglass Supply Depot Inc.


Best Sellers Rank: #75,708 in Industrial & Scientific (See Top 100 in Industrial & Scientific) #91 in Urethane Adhesives


#91 in Urethane Adhesives:


Customer Reviews: 4.4 4.4 out of 5 stars 30 ratings


Material: Foam,Resin


Brand: Fiberglass Supply Depot


Manufacturer: Fiberglass Supply Depot Inc.


UPC:


Package Dimensions: ‎12.5 x 12.2 x 6.3 inches


Item Weight: ‎20.2 pounds


Manufacturer: ‎Fiberglass Supply Depot Inc.


Item model number:


Date First Available: ‎January 27, 2021


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Mar 19

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


  • Follow the directions
Good stuff. Works well. Read the direction AND HEED THEM! (It hardens FAST)
Reviewed in the United States on September 20, 2025 by tch

  • Works
Does what it needs to do
Reviewed in the United States on March 10, 2026 by John

  • Works as described
Works exactly as described as long as you follow instructions. I did a test batch and it didn’t turn out so good. I then put on a space heater and made sure the temperature was above the recommended 75-80F and mixed the two compounds as instructed. It worked perfectly for my DIY project, couldn’t be happier as it saved me a lot of headache. A word of warning though it hardens very quickly and becomes hard as a rock. Make sure you prepare the surface and block off anywhere you don’t want it to go. Act quickly and it will turn out well, once you pour there’s no redo. ... show more
Reviewed in the United States on January 31, 2022 by Michigancarguy81

  • This stuff does the job
I was using this to void fill a vintage boat project. This stuff did the trick and was cheaper than some competitors. Listen to the instructions and it will work. After the foam hardens it is very sturdy and won’t be going anywhere. Yes it is somewhat messy but for an efficient way of void filling it was worth it. ... show more
Reviewed in the United States on November 10, 2023 by Joe Meyer

  • Lots of Rigid Foam per Dollar
Great foam, as described, great deal!
Reviewed in the United States on September 6, 2025 by tat

  • Follow All Instructions
This product is real good, and it works real fast. Make sure you have everything set up before mixing parts A & B.
Reviewed in the United States on August 6, 2024 by cthebyrd

  • Good foam
Works as should
Reviewed in the United States on March 16, 2025 by Josh Saville

  • Worked well. Expands a lot!!!
Easy to use. Just make sure you dont mix too much at once. Once mixed, this stuff expands quickly. So, work fast.
Reviewed in the United States on December 14, 2022 by v. palladino

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