--- product_id: 273973809 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 Gallon Kit)" brand: "fiberglass supply depot" price: "£118.33" currency: GBP in_stock: true category: "Fiberglass Supply Depot" url: https://www.desertcart.co.uk/products/273973809-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed store_origin: GB region: United Kingdom --- # 2 cubic feet coverage per kit 5 min full expansion 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 (1 Gallon Kit) **Brand:** fiberglass supply depot **Price:** £118.33 **Availability:** ✅ In Stock ## Summary > 🛠️ Elevate your projects with foam that floats, fills, and finishes like a pro! ## 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 Gallon Kit) by fiberglass supply depot - **How much does it cost?** £118.33 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/273973809-4-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:** Expands fully in just 5 minutes, letting you move fast and stay efficient on every project. - • **Precision Perfect:** Exact 1:1 mixing ratio with a 45-second working window ensures flawless application every time. - • **Temperature-Savvy:** Optimized for 75°-80°F to maximize expansion and minimize waste—work smarter, not harder. - • **Versatile Mastery:** Seamlessly laminates with polyester, epoxy, or vinyl ester resins—ideal for soundproofing, insulation, and sculpting. - • **Float Above the Rest:** 4 lb density closed-cell foam delivers unmatched buoyancy for boats, docks, and more. ## Overview Fiberglass Supply Depot’s 4 lb density expanding pour foam is a 2-part polyurethane closed-cell liquid foam kit that produces 2 cubic feet of high-performance foam. Designed for flotation, soundproofing, insulation, and filling voids, it cures quickly and bonds with common resins without melting. Perfect for professionals seeking reliable, versatile, and efficient foam solutions. ## Description Buy 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 Gallon Kit): Urethane Adhesives - desertcart.com ✓ FREE DELIVERY possible on eligible purchases ## 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 Gallon Kit; Consists of 1/2 gallon of Part A and 1/2 gallon of Part B and produces 2 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 | B08T2195F8 | | Best Sellers Rank | #36,144 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #68 in Urethane Adhesives | | Brand Name | Fiberglass Supply Depot | | Coverage | 2 cubic feet | | Customer Reviews | 4.5 4.5 out of 5 stars (260) | | Manufacturer | Fiberglass Supply Depot Inc. | | Manufacturer Part Number | FBAPOLY4LBGK | | Material Type | Foam,Resin | | Recommended Uses For Product | Flotation, Soundproofing, Insulation, Filling Voids, Sculpting, Casting | | UPC | 819794022934 | | Unit Count | 192 Fluid Ounces | ## Product Details - **Brand:** Fiberglass Supply Depot - **Manufacturer:** Fiberglass Supply Depot Inc. - **Material:** Foam,Resin - **Number of Packs:** 1 - **Recommended Uses For Product:** Flotation, Soundproofing, Insulation, Filling Voids, Sculpting, Casting ## 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 Gallon Kit) - Image 1](https://m.media-amazon.com/images/I/611pMIJrAfL.jpg) ## Questions & Answers **Q: What is the compressive strength of the foam, in PCF?** A: They only give the compressive strength in PSI and that is 78 for the 4lb foam **Q: What is the viscosity of the liquids before they mix?** A: The best way to describe it would be like warm pancake syrup. **Q: i'm new at this..what does density mean i see 2lb..4lb..6lb? thanks** A: Think of it as hardness or strength. The 2lb will be more sponge like 6 will be harder. **Q: Can you use pole foam to insulate the walls of a shop? Does it go thru a heat? Will it blister the tyvek or metal on the outside?** A: It doesn't fill a very big volume like spray foam. It is very liquid and comes out of any cracks. Will set up hard as a rock though. ## 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 (1 Gallon Kit) - Custom Shop Paint Mixing Cups Plastic Measuring Cup Epoxy Resin, Disposable or Reusable, 32-Ounce Quart - Pack of 12 - Graduated, Mixing Ratios, Automotive Painting Acrylic Art Crafts Kitchen - 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) --- ## 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.co.uk/products/273973809-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed](https://www.desertcart.co.uk/products/273973809-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-07-15*