---
product_id: 273973809
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: "2623 kr"
currency: NOK
in_stock: true
reviews_count: 13
category: "Fiberglass Supply Depot"
url: https://www.desertcart.no/products/273973809-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed
store_origin: NO
region: Norway
---

# 5 min full expansion time for rapid project completion 4 lb/ft³ density for superior stiffness 2 cu ft coverage ideal for flotation & insulation 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:** 2623 kr
**Availability:** ✅ In Stock

## Summary

> 🛠️ Elevate your projects with foam that works as fast and 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?** 2623 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.no](https://www.desertcart.no/products/273973809-4-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:** Fully expands in 5 minutes, letting you move fast without sacrificing quality.
- • **Resin-Compatible Finish:** Can be laminated with polyester, epoxy, or vinyl ester resins without melting or damage.
- • **Versatile Multi-Use Formula:** Perfect for flotation, soundproofing, insulation, and sculpting—one kit, endless possibilities.
- • **Precision Engineered Density:** 4 lb density delivers unmatched rigidity and durability for demanding applications.
- • **Temperature-Optimized Performance:** Designed to work best at 75-80°F, ensuring consistent expansion and flawless results.

## Overview

Fiberglass Supply Depot’s 4 lb density expanding pour foam is a high-performance 2-part polyurethane closed-cell liquid foam kit that produces 2 cubic feet of rigid, durable foam. Engineered for boat flotation, soundproofing, insulation, and filling voids, it cures quickly within 5 minutes and is compatible with various resin laminates, making it the go-to solution for professionals demanding speed, strength, and versatility.

## Description

Buy 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): Urethane Adhesives - desertcart.com ✓ FREE DELIVERY possible on eligible purchases

Review: Reacts fast - Excellent
Review: Dense and low expansion - I am used to working with 3lb foam and wanted to try a 4lb foam for a project that needed some extra stiffness. This product didn't disappoint. The volume of foam that it made wasn't as much as a lighter density, but it set off and hardened extremely quickly. I was able to do my project quickly and get it out of the way. Thanks for making it easy.

## 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 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 |
| Best Sellers Rank | #35,578 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #73 in Urethane Adhesives |
| Brand | Fiberglass Supply Depot |
| Brand Name | Fiberglass Supply Depot |
| Coverage | 2 cubic feet |
| Customer Reviews | 4.5 out of 5 stars 262 Reviews |
| Manufacturer | Fiberglass Supply Depot Inc. |
| Manufacturer Part Number | FBAPOLY4LBGK |
| Material | Foam,Resin |
| Material Type | Foam,Resin |
| Number of Items | 1 |
| Number of Packs | 1 |
| Recommended Uses For Product | Flotation, Soundproofing, Insulation, Filling Voids, Sculpting, Casting |
| UPC | 819794022934 |
| Unit Count | 192 Fluid Ounces |

## Product Details

- **Brand:** Fiberglass Supply Depot
- **Manufacturer:** Fiberglass Supply Depot Inc.
- **Material:** Foam,Resin
- **Number of Packs:** 1
- **Recommended Uses For Product:** Flotation, Soundproofing, Insulation, Filling Voids, Sculpting, Casting

## 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/611pMIJrAfL.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

### ⭐⭐⭐⭐⭐ Reacts fast
*by J***Y on May 2, 2026*

Excellent

### ⭐⭐⭐⭐⭐ Dense and low expansion
*by S***V on September 24, 2024*

I am used to working with 3lb foam and wanted to try a 4lb foam for a project that needed some extra stiffness. This product didn't disappoint. The volume of foam that it made wasn't as much as a lighter density, but it set off and hardened extremely quickly. I was able to do my project quickly and get it out of the way. Thanks for making it easy.

### ⭐⭐⭐⭐⭐ Be prepared.
*by M***E on July 4, 2026*

It's it reacts very fast, especially when it's hot out. But it is very solid, takes about 10 minutes to set up completely. It works perfect for fence posts.

## 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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---

*Product available on Desertcart Norway*
*Store origin: NO*
*Last updated: 2026-09-21*