--- product_id: 680856745 title: "Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill" brand: "fiberglass supply depot" price: "€ 363.23" currency: EUR in_stock: true category: "Fiberglass Supply Depot" url: https://www.desertcart.hr/products/680856745-fiberglass-supply-depot-4-lbs-density-expansion-foam-2-part store_origin: HR region: Croatia --- # 2 cubic feet coverage for versatile flotation 45 sec working time, 5 min full expansion 4 lbs density for robust support Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill **Brand:** fiberglass supply depot **Price:** € 363.23 **Availability:** ✅ In Stock ## Summary > ⚡ Elevate your projects with foam that’s fast, firm, and fiercely versatile! ## Quick Answers - **What is this?** Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill by fiberglass supply depot - **How much does it cost?** € 363.23 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/680856745-fiberglass-supply-depot-4-lbs-density-expansion-foam-2-part) ## 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 - • **Rock-Solid Support:** 4LB density foam engineered to withstand moderate loads, perfect for gas tank supports and deck reinforcement. - • **Rapid Reaction Time:** Mix and apply with a swift 45-second working window and full expansion in just 5 minutes—maximize efficiency on every project. - • **Multi-Functional Mastery:** Ideal for flotation, soundproofing, insulation, sculpting, casting, and filling voids—one foam to rule them all. - • **Seamless Resin Compatibility:** Fully cured foam laminates flawlessly with polyester, epoxy, or vinyl ester resins without melting—engineered for professional finishes. - • **Temperature-Savvy Performance:** Optimized for 75°-80°F working temps to ensure precise expansion and minimal waste—control your craft with confidence. ## Overview Fiberglass Supply Depot’s 4LB Density Expansion Foam is a high-performance 2-part polyurethane closed-cell foam delivering 2 cubic feet of durable, buoyant, and insulating material. Designed for professional-grade flotation, soundproofing, and structural support, it cures rapidly and bonds seamlessly with common resins. Perfect for millennial managers seeking reliable, multi-use solutions that combine efficiency with premium results. ## Description This 4LB density foam is suitable for most float applications that require more support than that of 2LB offers. This foam is recommended for use on gas tank support and some deck areas. Choose this density if you think the foam will need to withstand small to moderate loads. The density of 4LB also works well in floating bait or taxidermy applications, as well as many other sculpting, casting, notching and other filling applications. ## Features - Flotation Foam is a 2-part polyurethane foam that when mixed in equal parts and put into place, this foam will be soundproof, insulate, or provide extra buoyancy. - 4 lbs. 1 Gallon Density Polyurethane Flotation Foam 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 with any type of polyester resin, epoxy or vinyl ester without melting. - 4LB density also works well in floating bait or taxidermy applications, as well as in many other sculpting, casting, carving and other filling applications. - All expansion rates and times provided are temperature critical. Temperatures below 75 °F will decrease the expansion rate, therefore requiring more foam. The ideal working temperature is 75° to 80° F or higher. Accurate measurement 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 | | Brand Name | Fiberglass Supply Depot | | Coverage | 2 cubic feet | | Customer Reviews | 4.4 4.4 out of 5 stars (255) | | Manufacturer | Fiberglass Supply Depot Inc. | | Manufacturer Part Number | FBAPOLY4LBGK | | Material Type | Foam, Resin | | Number of Items | 1 | | Number of Packs | 1 | | Recommended Uses For Product | Flotation, Soundproofing, Insulation, Filling Voids, Sculpting, Casting | | UPC | 819794022934 | ## 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 ![Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill - Image 1](https://m.media-amazon.com/images/I/41biA3dE6uL.jpg) ![Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill - Image 2](https://m.media-amazon.com/images/I/519cSzhqfkL.jpg) ![Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill - Image 3](https://m.media-amazon.com/images/I/41cVcze5RmL.jpg) ![Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill - Image 4](https://m.media-amazon.com/images/I/41z05kTc6bL.jpg) ![Fiberglass Supply Depot 4 lbs. Density Expansion Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Acoustic Insulation, Void Fill - Image 5](https://m.media-amazon.com/images/I/41S-u-+aQ2L.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.hr/products/680856745-fiberglass-supply-depot-4-lbs-density-expansion-foam-2-part](https://www.desertcart.hr/products/680856745-fiberglass-supply-depot-4-lbs-density-expansion-foam-2-part) --- *Product available on Desertcart Croatia* *Store origin: HR* *Last updated: 2026-09-30*