---
product_id: 423761958
title: "4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)"
brand: "fiberglass supply depot"
price: "53217 kr"
currency: ISK
in_stock: true
reviews_count: 5
category: "Fiberglass Supply Depot"
url: https://www.desertcart.is/products/423761958-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed
store_origin: IS
region: Iceland
---

# 2 cubic feet coverage per kit 5 min full expansion time 4 lb density for superior flotation 4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)

**Brand:** fiberglass supply depot
**Price:** 53217 kr
**Availability:** ✅ In Stock

## Summary

> 🛠️ Expand your possibilities with foam that works as hard as you do!

## Quick Answers

- **What is this?** 4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit) by fiberglass supply depot
- **How much does it cost?** 53217 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.is](https://www.desertcart.is/products/423761958-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed)

## Best For

- fiberglass supply depot enthusiasts

## Why This Product

- Trusted fiberglass supply depot brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Rapid Expansion & Cure:** Expands fully in just 5 minutes, letting you work fast without sacrificing quality or control.
- • **Seamless Resin Compatibility:** Can be laminated with polyester, epoxy, or vinyl ester resins without melting—ideal for custom finishes.
- • **Versatile Multi-Use Solution:** Perfect for soundproofing, insulation, filling voids, and even sculpting or casting projects.
- • **Precision-Engineered Buoyancy:** 4 lb density closed-cell foam ensures unmatched flotation and durability for marine and dock applications.
- • **Temperature-Optimized Performance:** Designed to perform best at 75°-80°F, ensuring consistent expansion and reliable results every time.

## Overview

Fiberglass Supply Depot’s 4 lb density 2-part polyurethane pour foam delivers 2 cubic feet of closed-cell foam designed for boat flotation, soundproofing, insulation, and filling voids. It cures quickly within 5 minutes, is compatible with multiple resin types, and offers professional-grade performance optimized for ideal working temperatures.

## Description

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 (1 Gallon Kit) : desertcart.co.uk: DIY & Tools

Review: Awesome stuff, I used it to fill holes used from animals going under my cement driveway and walkway. Fantastic results and hardens like a rock
Review: Works well. Be quick and ready for it, it expands quickly and will come for you if you're not prepared to control it.

## Features

- Causes skin irritation.
- Harmful if inhaled.
- May cause allergy or asthma symptoms or breathing difficulties if inhaled.
- May cause an allergic skin reaction.
- May cause damage to organs through prolonged or repeated exposure (respiratory tract).
- May cause respiratory irritation.
- 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 1 Gallon Kit; Consists of 1/2 gallon of Part A and 1/2 gallon of Part B and produces 2 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

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B08T2195F8 |
| Batteries Required? | No |
| Batteries included? | No |
| Best Sellers Rank | 1,123,626 in DIY & Tools ( See Top 100 in DIY & Tools ) 41,492 in Adhesives & Sealers |
| Coverage | 2 cubic feet (volume coverage) |
| Customer Reviews | 4.3 4.3 out of 5 stars (243) |
| Date First Available | 14 Jan. 2021 |
| Item Package Quantity | 1 |
| Item Weight | 4.82 kg |
| Manufacturer | Fiberglass Supply Depot Inc. |
| Manufacturer reference | FBAPOLY4LBGK |
| Material | Polyurethane Foam |
| Part number | FBAPOLY4LBGK |
| Product Dimensions | 25.4 x 22.86 x 15.24 cm; 4.82 kg |
| Size | Gallon Kit |
| Special Features | Soundproofing, Insulation |
| Specific uses | Boat, Dock |

## Product Details

- **Brand:** Fiberglass Supply Depot
- **Manufacturer:** Fiberglass Supply Depot Inc.
- **Material:** Polyurethane Foam
- **Recommended uses for product:** Flotation, Soundproofing, Insulation, Filling Voids, Sculpting, Casting
- **UPC:** 819794022934

## Images

![4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit) - Image 1](https://m.media-amazon.com/images/I/81ySuM57MmL.jpg)
![4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit) - Image 2](https://m.media-amazon.com/images/I/8189VtbwU2L.jpg)
![4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit) - Image 3](https://m.media-amazon.com/images/I/71Gbm9XW+IL.jpg)
![4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit) - Image 4](https://m.media-amazon.com/images/I/71Jn4WV0S0L.jpg)
![4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit) - Image 5](https://m.media-amazon.com/images/I/81mbAHsaZfL.jpg)

## Questions & Answers

**Q: What is the compressive strength of the foam, in  PCF?**
A: They only give the compressive strength in PSI and that is 78 for the 4lb foam

**Q: What is the viscosity of the liquids before they mix?**
A: The best way to describe it would be like warm pancake syrup.

**Q: i'm new at this..what does density mean i see 2lb..4lb..6lb? thanks**
A: Think of it as hardness or strength. The 2lb will be more sponge like 6 will be harder.

**Q: Can you use pole foam to insulate the walls of a shop? Does it go thru a heat?  Will it blister the tyvek or metal on the outside?**
A: It doesn't fill a very big volume like spray foam. It is very liquid and comes out of any cracks. Will set up hard as a rock though.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by L***E on 18 October 2025*

Awesome stuff, I used it to fill holes used from animals going under my cement driveway and walkway. Fantastic results and hardens like a rock

### ⭐⭐⭐⭐⭐ Review
*by R***H on 8 March 2025*

Works well. Be quick and ready for it, it expands quickly and will come for you if you're not prepared to control it.

### ⭐⭐⭐⭐⭐ Review
*by A***H on 28 July 2025*

It worked perfectly to replace floatation foam in a boat

## Frequently Bought Together

- 4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)
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- 6 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boats, Dock Flotation, Carving, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)

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**Shop now:** [https://www.desertcart.is/products/423761958-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed](https://www.desertcart.is/products/423761958-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed)

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*Product available on Desertcart Iceland*
*Store origin: IS*
*Last updated: 2026-03-14*