---
product_id: 282511397
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 Gallon Kit)"
brand: "fiberglass supply depot"
price: "$461.01"
currency: USD
in_stock: true
url: https://www.desertcart.ec/products/282511397-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed
store_origin: EC
region: Ecuador
---

# 45 sec working time, 5 min full expansion 2-part polyurethane, perfect chemical bonding 4 lb density for superior buoyancy 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)

**Brand:** fiberglass supply depot
**Price:** $461.01
**Availability:** ✅ In Stock

## Summary

> 🛠️ Elevate your projects 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 (2 Gallon Kit) by fiberglass supply depot
- **How much does it cost?** $461.01 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ec](https://www.desertcart.ec/products/282511397-4-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

- • **Speedy Setup:** Mix and pour with a quick 45-second working window and full expansion in just 5 minutes.
- • **Float Above the Rest:** 4 lb density foam delivers unmatched buoyancy for boats and docks.
- • **Precision Performance:** Temperature-sensitive formula ensures optimal expansion and fill every time.
- • **Versatile Application:** Seamlessly laminates with polyester, epoxy, or vinyl ester resins without damage.
- • **Soundproof & Insulate Like a Pro:** Closed-cell foam blocks noise and retains heat, perfect for modern living spaces.

## Overview

This 2-gallon kit of 4 lb density 2-part polyurethane expanding foam offers fast curing and superior buoyancy, soundproofing, and insulation. Ideal for marine flotation, filling voids, and crafting, it bonds flawlessly with common resins and performs best at 75-80°F for precise expansion.

## Description

Full description not available

## 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

## Product Details

- **Material:** Foam,Resin
- **Brand:** Fiberglass Supply Depot
- **Manufacturer:** Fiberglass Supply Depot Inc.
- **UPC:** 819794022927

## 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 Gallon Kit) - Image 1](https://m.media-amazon.com/images/I/81eqmB9VuWL.jpg)

## Questions & Answers

**Q: The description says that it can be used as insulation. Do you have a recommended sprayer vendor and/or setup?**
A: think it would be hard to spray..pour it in cavities surrounding a fuel tank .. its water prove and floatation,

**Q: For the 2 gallon 4 lbs. density kit, how many pounds of flotation would it nominally provide?**
A: Buoyancy of 2lb foam is 60lbs of flotation per cubic feet. 
Buoyancy of 4lb foam is 30lbs of flotation per cubic feet. 
Remember this is an approximate number.

**Q: i'm new at this.what does density mean i see 2lb 4lb 6lb? thanks**
A: the weight rating numbers are for how much the foam expands and how much weight it can support.  2lb foam will expand around 30 times its liquid amount and 4lb expands around 15 times its liquid amount and 6lb expands 10 times its liquid amount. for my boat i used 4lb it worked great.

**Q: I am restoring old plaster life-size statues for a museum. Could I use your foam product to cast hands in an alginate mold?**
A: The mold would have to be rigid because as the foam expands it could deform your shape if it wasn't.  Also this stuff sticks to everything so make sure you will be able to get it out of your mold.

## 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 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.ec/products/282511397-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed](https://www.desertcart.ec/products/282511397-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed)

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*Product available on Desertcart Ecuador*
*Store origin: EC*
*Last updated: 2026-02-13*