--- 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: "£207.80" currency: GBP in_stock: true category: "Fiberglass Supply Depot" url: https://www.desertcart.co.uk/products/282511397-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed store_origin: GB region: United Kingdom --- # 45 sec working time, 5 min full expansion Closed-cell foam for premium insulation 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 Gallon Kit) **Brand:** fiberglass supply depot **Price:** £207.80 **Availability:** ✅ In Stock ## Summary > 🛠️ Expand Your Possibilities with Every Pour! ## 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?** £207.80 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/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 - • **Seal & Soundproof:** Closed-cell structure locks out moisture and noise for a quieter, drier space. - • **Float Above the Rest:** 4 lb density foam delivers unmatched buoyancy for boats and docks. - • **Speed Meets Precision:** Quick 45-second working window ensures efficient, mess-controlled application. - • **Versatile Crafting Power:** Perfect for sculpting, casting, filling voids, and even taxidermy projects. - • **Temperature-Savvy Expansion:** Optimized for 75-80°F to maximize expansion and minimize waste. ## Overview Fiberglass Supply Depot’s 4 lb density, 2-part polyurethane expanding foam kit offers 4 cubic feet of closed-cell foam designed for flotation, soundproofing, insulation, and filling voids. With a rapid 45-second working time and full expansion in 5 minutes, it’s engineered for precision and versatility in marine, craft, and construction applications. Temperature-sensitive expansion ensures optimal performance between 75-80°F, making it a must-have for professionals seeking reliable, high-performance foam solutions. ## 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 (2 Gallon 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 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 ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B08V5BV9V9 | | Best Sellers Rank | #79,073 in Arts, Crafts & Sewing ( See Top 100 in Arts, Crafts & Sewing ) #315 in Sewing Pillow Forms & Foam #444 in Craft Foam | | Brand Name | Fiberglass Supply Depot | | Coverage | 4 cubic feet | | Customer Reviews | 4.6 4.6 out of 5 stars (496) | | Manufacturer | Fiberglass Supply Depot Inc. | | Manufacturer Part Number | poly4lb2gk | | Material Type | Foam,Resin | | Model Number | 819794022927 | | Number of Items | 2 | | Number of Packs | 2 | | Recommended Uses For Product | Flotation, Soundproofing, Insulation, Filling Voids, Sculpting, Casting | | UPC | 819794022927 | | Unit Count | 1 Count | ## Product Details - **Brand:** Fiberglass Supply Depot - **Manufacturer:** Fiberglass Supply Depot Inc. - **Material:** Foam,Resin - **Number of Packs:** 2 - **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 (2 Gallon Kit) - Image 1](https://m.media-amazon.com/images/I/61Vgv9wS7SL.jpg) ## Available Options This product comes in different **Size** options. ## 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) - 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/282511397-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed](https://www.desertcart.co.uk/products/282511397-4-lb-density-expanding-pour-foam-2-part-polyurethane-closed) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-10-18*