---
product_id: 273973810
title: "4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)"
brand: "fiberglass supply depot"
price: "NT$4153"
currency: TWD
in_stock: true
category: "Fiberglass Supply Depot"
url: https://www.desertcart.tw/products/273973810-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed
store_origin: TW
region: Taiwan
---

# 5 min full cure time 4 lb density for optimal buoyancy Ideal working temp 75-80°F 4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)

**Brand:** fiberglass supply depot
**Price:** NT$4153
**Availability:** ✅ In Stock

## Summary

> 🚤 Float, Fill, and Finish Like a Pro — 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 (Quart Kit) by fiberglass supply depot
- **How much does it cost?** NT$4153 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.tw](https://www.desertcart.tw/products/273973810-4-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:** Get fast, reliable results with a quick full expansion and cure time, minimizing downtime on your projects.
- • **Resin-Compatible Finish:** Fully cured foam can be laminated with polyester, epoxy, or vinyl ester resins without melting—ideal for professional-grade composites.
- • **Versatile Multi-Use Formula:** Perfect for soundproofing, insulation, filling voids, and even sculpting or taxidermy—one kit, endless possibilities.
- • **Precision Engineered Buoyancy:** 4 lb density closed-cell foam delivers unmatched flotation and durability for marine and dock applications.
- • **Temperature-Smart Application:** Optimized for 75-80°F to ensure maximum expansion and performance every time you pour.

## Overview

Fiberglass Supply Depot’s 4 lb density expanding pour foam is a two-part polyurethane closed-cell liquid foam designed for superior flotation, soundproofing, insulation, and void filling. This quart kit mixes equal parts of Part A and B to produce ½ cubic foot of foam that cures in just 5 minutes. Engineered for marine and industrial use, it withstands water exposure and can be laminated with various resins, making it a versatile solution for professionals seeking reliable, fast-curing foam with excellent buoyancy and durability.

## 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 (Quart 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 Quart Kit; Consists of 1 pint of Part A and 1 pint of Part B and produces 1/2 cubic foot.
- 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 | B08T255GS5 |
| Best Sellers Rank | #21,150 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #52 in Urethane Adhesives |
| Brand Name | Fiberglass Supply Depot |
| Color | Black, Clear, Yellow |
| Compatible Material | Vinyl |
| Container Type | Bottle |
| Customer Reviews | 4.4 4.4 out of 5 stars (148) |
| 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 | Versatility |
| Part Number | poly4lbqk |
| Specific Uses For Product | Floating Decoy, Taxidermy |
| UPC | 819794022897 |
| Unit Count | 64.0 Ounce |
| Viscosity Level | Medium to High |
| Volume | 1 Quarts |
| Water Resistance Level | Waterproof |

## Product Details

- **Brand:** Fiberglass Supply Depot
- **Item Form:** Liquid
- **Material:** Foam,Resin
- **Special Feature:** Versatility
- **Specific Uses For Product:** Floating Decoy, Taxidermy

## Images

![4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit) - Image 1](https://m.media-amazon.com/images/I/81XhbU5HAlL.jpg)

## Questions & Answers

**Q: What is the cure time?  I see 5 minute until "full expansion" but nowhere on the package do I find the cure time.**
A: Around 30-60 minutes

**Q: If one doesn't use the whole kit how long will the 2 parts last?**
A: As long as you make them.

**Q: would this provide floatation if used in the bow of a kayak?**
A: Yes, that is one of its intended uses. It is a closed cell foam.

**Q: Question any way to pump this? I have a void under a concrete walkway and I need to get it back 4 feet The void is 4x4 and 2 to 6 inches deep.**
A: You only have a brown 30 seconds after you mix the product to put it in the location that you are wanting depending on temperature if you have a mixing tip then you could pump it however it needs to be agitated for 20 seconds

## 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 (Quart Kit)
- Fiberglass Supply Depot 6LB Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boats, Dock Flotation, Carving, Soundproofing, Filling Voids, and Insulation (Quart Kit)
- 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)

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**Shop now:** [https://www.desertcart.tw/products/273973810-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed](https://www.desertcart.tw/products/273973810-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed)

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*Product available on Desertcart Taiwan*
*Store origin: TW*
*Last updated: 2026-07-29*