---
product_id: 282511399
title: "4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1/2 Gallon Kit)"
brand: "fiberglass supply depot"
price: "€ 80.30"
currency: EUR
in_stock: true
category: "Fiberglass Supply Depot"
url: https://www.desertcart.ie/products/282511399-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed
store_origin: IE
region: Ireland
---

# 2-part polyurethane for precision mixing 5 min full cure time 4 lb density for optimal buoyancy 4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1/2 Gallon Kit)

**Brand:** fiberglass supply depot
**Price:** € 80.30
**Availability:** ✅ In Stock

## Summary

> 🚤 Float, Fill, and Fortify with Foam That Means Business!

## 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 (1/2 Gallon Kit) by fiberglass supply depot
- **How much does it cost?** € 80.30 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/282511399-4-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 5-Minute Cure Time:** Get your projects moving fast with quick foam expansion and setting.
- • **Resin-Compatible & Durable:** Laminates seamlessly with polyester, epoxy, or vinyl ester resins without melting.
- • **Precision Engineered 4 lb Density:** Delivers superior flotation and structural support without compromise.
- • **Temperature-Optimized Performance:** Ideal working range 75°-80°F ensures consistent expansion and strength.
- • **Versatile 2-Part Polyurethane System:** Mix equal parts for flawless soundproofing, insulation, or buoyancy.

## Overview

Fiberglass Supply Depot’s 4 lb density expanding pour foam is a high-performance, 2-part polyurethane closed-cell liquid foam designed for boat and dock flotation, soundproofing, insulation, and void filling. This 1/2 gallon kit produces 1 cubic foot of foam that cures in just 5 minutes and can be laminated with various resins without damage. Engineered for professionals, it offers water resistance, rapid expansion, and temperature-optimized application for reliable, durable results.

## 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 (1/2 Gallon Kit): desertcart.com: Industrial & Scientific

## 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 1/2 Gallon Kit; Consists of 1 quart of Part A and 1 quart of Part B and produces 1 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 | B08T21WRF9 |
| Best Sellers Rank | #124,005 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #165 in Urethane Adhesives |
| Brand Name | Fiberglass Supply Depot |
| Color | Clear |
| Compatible Material | Vinyl |
| Container Type | Can |
| Customer Reviews | 4.6 4.6 out of 5 stars (16) |
| Full Cure Time | 5 Minutes |
| Item Form | Liquid |
| Item Package Quantity | 1 |
| Manufacturer | Fiberglass Supply Depot Inc. |
| Material Type | Foam,Resin |
| Number of Pieces | 2 |
| Other Special Features of the Product | soundproofing, insulation, buoyancy, laminating with certain resins without melting |
| Part Number | poly4lbhgk |
| Specific Uses For Product | Flooring, Boat, Dock, Insulation, Soundproofing |
| UPC | 819794022910 |
| Unit Count | 1 Count |
| Viscosity Level | High |
| Volume | 2 Quarts |
| Water Resistance Level | Water Resistant |

## Product Details

- **Brand:** Fiberglass Supply Depot
- **Item Form:** Liquid
- **Material:** Foam,Resin
- **Special Feature:** soundproofing, insulation, buoyancy, laminating with certain resins without melting
- **Specific Uses For Product:** Flooring, Boat, Dock, Insulation, Soundproofing

## Images

![4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1/2 Gallon Kit) - Image 1](https://m.media-amazon.com/images/I/61wUzR2lvBL.jpg)

## Questions & Answers

**Q: i'm new at this.what does density mean i see 2lb 4lb 6lb? thanks**
A: The higher the number, the higher the density equaling stronger flotation.

**Q: How well does this hold up to exposure to water? Applied to the bottom of a boat rear swim platform, for example, to reduce noise?**
A: Not good exposed to the elements.

## 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 (2 Quart Kit)
- 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)
- 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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**Shop now:** [https://www.desertcart.ie/products/282511399-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed](https://www.desertcart.ie/products/282511399-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed)

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*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-07-15*