---
product_id: 627153513
title: "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)"
brand: "fiberglass supply depot"
price: "R$3394"
currency: BRL
in_stock: true
category: "Fiberglass Supply Depot"
url: https://www.desertcart.com.br/products/627153513-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed
store_origin: BR
region: Brazil
---

# 2-part polyurethane, perfect mix ratio 5 min full cure 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 (2 Quart Kit)

**Brand:** fiberglass supply depot
**Price:** R$3394
**Availability:** ✅ In Stock

## Summary

> 🛠️ Elevate your projects with foam that floats, fills, and finishes flawlessly!

## 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 (2 Quart Kit) by fiberglass supply depot
- **How much does it cost?** R$3394 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.com.br](https://www.desertcart.com.br/products/627153513-4-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 up to 15x in volume and fully cures in just 5 minutes for fast project turnaround.
- • **Buoyant & Durable Support:** 4 lb density foam engineered to withstand moderate loads—ideal for boat decks and gas tank flotation.
- • **Versatile Application Range:** From soundproofing and insulation to sculpting and taxidermy, this foam adapts to your creative and functional needs.
- • **Seamless Laminatable Surface:** Compatible with polyester, epoxy, and vinyl ester resins without melting—perfect for custom finishes.
- • **Precision Mixing & Temperature Sensitive:** Optimal performance at 75-80°F with a 45-second working time—ensures consistent, professional results every time.

## Overview

This 4 lb density, 2-part polyurethane expanding foam kit delivers superior buoyancy and structural support for boat and dock flotation, soundproofing, insulation, and creative applications. It expands rapidly, cures in 5 minutes, and can be laminated with various resins without damage, making it a versatile, professional-grade solution trusted by makers and pros alike.

## Description

This 4LB density foam is suited well for most flotation applications that require more support than the 2LB offers. This foam is recommended to be used when supporting gas tanks and some deck areas. Choose this density if you feel that the foam will be required to withstand minor to moderate loads. The 4LB density also works well in floating decoy or taxidermy applications as well as many other sculpting, casting, carving and other filling applications.

## 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 |
| Brand Name | Fiberglass Supply Depot |
| Colour | Clear |
| Compatible Material | Vinyl |
| Container Type | Can |
| Country of Publication | USA |
| Customer Reviews | 4.6 4.6 out of 5 stars (15) |
| Full Cure Time | 5 Minutes |
| Item Form | Liquid |
| Item Package Quantity | 1 |
| Manufacturer | Fiberglass Supply Depot Inc. |
| Manufacturer Part Number | poly4lbhgk |
| Material Type | Foam,Resin |
| Number of Pieces | 2 |
| Other Special Features of the Product | Laminatable without Melting |
| Specific Uses For Product | Flooring, Boat, Dock, Insulation, Soundproofing |
| UPC | 819794022910 |
| Unit Count | 1 Count |
| Volume | 2 Quarts |
| Water Resistance Level | Water Resistant |

## Product Details

- **Brand:** Fiberglass Supply Depot
- **Item Form:** Liquid
- **Material:** Foam,Resin
- **Special Feature:** Laminatable 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 (2 Quart 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.com.br/products/627153513-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed](https://www.desertcart.com.br/products/627153513-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed)

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*Product available on Desertcart Brazil*
*Store origin: BR*
*Last updated: 2026-09-03*