---
product_id: 273973810
title: "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)"
brand: "fiberglass supply depot"
price: "VT22169"
currency: VUV
in_stock: true
reviews_count: 8
category: "Fiberglass Supply Depot"
url: https://www.desertcart.vu/products/273973810-fiberglass-supply-depot-4-lb-density-expanding-pour-foam-2
store_origin: VU
region: Vanuatu
---

# Closed-cell waterproof foam 5 min full cure time 4 lb density for superior flotation 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)

**Brand:** fiberglass supply depot
**Price:** VT22169
**Availability:** ✅ In Stock

## Summary

> 🛠️ Float, fill, and fortify—foam that means business!

## Quick Answers

- **What is this?** 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) by fiberglass supply depot
- **How much does it cost?** VT22169 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.vu](https://www.desertcart.vu/products/273973810-fiberglass-supply-depot-4-lb-density-expanding-pour-foam-2)

## 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

- • **Fast & Efficient:** Fully cures in just 5 minutes, letting you move quickly from application to finishing.
- • **Buoyant & Durable:** 4 lb density foam delivers unmatched flotation and structural strength for marine and outdoor projects.
- • **Precision Pouring:** Two-part polyurethane system with a 45-second working time ensures controlled expansion and minimal waste.
- • **Multi-Use Masterpiece:** Ideal for soundproofing, insulation, sculpting, filling voids, and even taxidermy—engineered for pros who demand more.
- • **Versatile Compatibility:** Laminates seamlessly with polyester, epoxy, or vinyl ester resins without melting or damage.

## Overview

Fiberglass Supply Depot’s 4 lb density expanding pour foam is a two-part polyurethane closed-cell liquid foam designed for rapid curing and superior buoyancy. Perfect for boat and dock flotation, soundproofing, insulation, and filling voids, this quart kit produces 1/2 cubic foot of waterproof, sandable, and paintable foam that bonds with common resins without melting. Engineered for professionals seeking precision and durability in demanding environments.

## 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

Review: 2part foam - The foam is exactly what I needed. It worked perfectly. Awesome product.
Review: Expands quickly - I created a rear wing which was hollow and needed to strong as it is active and used as an air brake so I needed to fill it with foam. The 4 pound foam was perfect but calculating the internal volume was difficult. To be sure I wasn't going to come up short I added a little extra and did two pours. Because of the shape I couldn't see where the first ended so I proceeded to do the second pour. As soon as I saw it I had like 2 seconds before it over flowed. All good as I planned for this and could just cut the excess off. So be warned and prepared if you mixed too much. It sticks to everything and there is no stopping it. My wing now is as hard as a rock and strong so it worked well for me.

## 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 | #31,363 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #69 in Urethane Adhesives |
| Brand | Fiberglass Supply Depot |
| Brand Name | Fiberglass Supply Depot |
| Color | Black, Clear, Yellow |
| Compatible Material | Vinyl |
| Container Type | Bottle |
| Customer Reviews | 4.4 out of 5 stars 126 Reviews |
| Full Cure Time | 5 Minutes |
| Item Form | Liquid |
| Item Package Quantity | 1 |
| Manufacturer | Fiberglass Supply Depot Inc. |
| Material | Foam , Resin |
| Material Type | Foam,Resin |
| Package Information | Bottle |
| UPC | 819794022897 |
| Unit Count | 64.0 Ounce |
| Viscosity | Medium to High Viscosity |
| Volume | 1 Quarts |
| Water Resistance Level | Waterproof |

## Product Details

- **Brand:** Fiberglass Supply Depot
- **Color:** Black, Clear, Yellow
- **Item Form:** Liquid
- **Item Package Quantity:** 1
- **Material:** Foam,Resin

## Images

![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) - 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

## Customer Reviews

### ⭐⭐⭐⭐⭐ 2part foam
*by C***S on March 6, 2026*

The foam is exactly what I needed. It worked perfectly. Awesome product.

### ⭐⭐⭐⭐⭐ Expands quickly
*by T***S on January 4, 2024*

I created a rear wing which was hollow and needed to strong as it is active and used as an air brake so I needed to fill it with foam. The 4 pound foam was perfect but calculating the internal volume was difficult. To be sure I wasn't going to come up short I added a little extra and did two pours. Because of the shape I couldn't see where the first ended so I proceeded to do the second pour. As soon as I saw it I had like 2 seconds before it over flowed. All good as I planned for this and could just cut the excess off. So be warned and prepared if you mixed too much. It sticks to everything and there is no stopping it. My wing now is as hard as a rock and strong so it worked well for me.

### ⭐⭐⭐⭐⭐ Great product! Directions a bit off.
*by J***. on August 3, 2024*

This works great and made a nice, firm filler that I needed for a place on my kayak. It was easily sand-able and paintable. It is firmer/stiffer than the spray foam you buy in cans at the home improvement store. Just be aware that the directions are a bit off. In the video we watched online, it looked as if it foamed up instantly, and the directions said to count a number of seconds and no more before pouring. Our experience was that it took a bit longer for it to foam up, and we wasted some that poured through some holes in the cavity we were trying to fill. I would say an extra 10-15 seconds would have worked better.

## 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)

---

## Why Shop on Desertcart?

- 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016
- 🌍 **Shop Globally** — Access 737+ million products across 21 categories
- 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price
- 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members)
- 🔒 **Secure Payments** — Trusted payment options with buyer protection
- ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews

**Shop now:** [https://www.desertcart.vu/products/273973810-fiberglass-supply-depot-4-lb-density-expanding-pour-foam-2](https://www.desertcart.vu/products/273973810-fiberglass-supply-depot-4-lb-density-expanding-pour-foam-2)

---

*Product available on Desertcart Vanuatu*
*Store origin: VU*
*Last updated: 2026-05-07*