--- product_id: 20049723 title: "WEST System® 404 High-Density Epoxy Filler | Strong Structural Thickening Additive for Epoxy Resin Bonding and Filleting | Made in the USA" brand: "west system" price: "€ 158.60" currency: EUR in_stock: true reviews_count: 9 category: "West System" url: https://www.desertcart.be/products/20049723-west-system-404-high-density-epoxy-filler-strong-structural-thickening store_origin: BE region: Belgium --- # High-density strength boost Gap-filling, non-slumping paste Proudly made in the USA WEST System® 404 High-Density Epoxy Filler | Strong Structural Thickening Additive for Epoxy Resin Bonding and Filleting | Made in the USA **Brand:** west system **Price:** € 158.60 **Availability:** ✅ In Stock ## Summary > 🧪 Elevate your epoxy game with strength that sticks and fills like a pro! ## Quick Answers - **What is this?** WEST System® 404 High-Density Epoxy Filler | Strong Structural Thickening Additive for Epoxy Resin Bonding and Filleting | Made in the USA by west system - **How much does it cost?** € 158.60 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.be](https://www.desertcart.be/products/20049723-west-system-404-high-density-epoxy-filler-strong-structural-thickening) ## Best For - west system enthusiasts ## Why This Product - Trusted west system brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Gap-Filling Powerhouse:** Creates thick, non-slumping mixtures that bridge large gaps without sagging. - • **Maximize Bond Strength:** Enhances epoxy adhesive power for hardware & stud bonding under high cyclic loads. - • **Versatile Compatibility:** Works seamlessly with multiple WEST SYSTEM epoxies for tailored project needs. - • **Precision Viscosity Control:** Adjust thickness from slurry to dense paste by varying filler amount—no air traps. - • **Trusted Marine-Grade Quality:** Formulated by industry leaders since 1969 for structural and marine-grade reliability. ## Overview WEST SYSTEM 404 High-Density Epoxy Filler is a premium, USA-made additive designed to thicken epoxy resin for superior structural bonding and gap filling. Ideal for hardware bonding and filleting, it reduces creep and sagging, ensuring durable, high-strength joints compatible with multiple epoxy systems. Perfect for professionals demanding marine-grade reliability and precision control over epoxy viscosity. ## Description Product description WEST SYSTEM Fillers modify the consistency of epoxy, greatly increasing its versatility for a wide array of applications Syrup Consistency (unthickened resin/hardener mixture or "neat" epoxy) CONSISTENCY: Unthickened epoxy, syrup CHARACTERISTICS: Drips off vertical surfaces USES: Coating; wetting out surfaces before bonding; applying fiberglass, graphite, and other reinforcing fabrics Catsup Consistency (slightly thickened) CONSISTENCY: Slightly thickened epoxy, slurry CHARACTERISTICS: Sags down vertical surfaces USES: Laminating or bonding flat panels with large surface areas, injecting into holes with a syringe Mayonnaise Consistency (moderately thickened) CONSISTENCY: Moderately thickened epoxy mixture, creamy CHARACTERISTICS: Clings to vertical surfaces; peaks fall over USES: General bonding, filleting, hardware bonding Peanut Butter Consistency (maximum workable thickness) CONSISTENCY: Maximum thickness epoxy mixture, dense CHARACTERISTICS: Clings to vertical surfaces; peaks stand USES: Gap filling, filleting, fairing, bonding uneven surfaces Versatile, reliable WEST SYSTEM products WEST SYSTEM offers high-quality epoxy resins, hardeners, fillers, and additives. Developed by our in-house chemists, our formulations are proprietary, structural, and marine grade. These epoxies have set the standard for epoxy quality in the marine industry and beyond since 1969. WEST SYSTEM Product Selection Guide How to choose the right WEST SYSTEM Epoxy products for your project 1. Start with 105 Epoxy Resin, the basic ingredient of all WEST SYSTEM Epoxy compounds. Use 300 Mini Pumps for convenient and accurate metering. 2. Mix with one of four WEST SYSTEM hardeners. Select a hardener for its intended use and for the cure speed best suited for your job in the temperature range in which you are working. 3. Add one of six WEST SYSTEM fillers to thicken the mixture as needed. Select a filler for its handling characteristics or cured physical properties. Or, add WEST SYSTEM additives to provide specific coating properties. WEST SYSTEM pigments can be used to change the epoxy's color. Pigments for tinting epoxy 501 White Pigment 501 White Pigment is an epoxy-based liquid colorant used to tint the epoxy mixture white, providing an even, white color base for the final finish system. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional paint or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigments will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 1.5 gal of epoxy. Adding a coloring agent to WEST SYSTEM Epoxy is frequently done to make colored castings, highlight an epoxy-coated surface, act as a colored base coat for paint, etc. Without exception, adding pigment will weaken the cured epoxy mixture to some degree. Use very small amounts of pigment, about 5% by weight. As a result, thin films of colored epoxy are somewhat transparent. It usually requires several coats to make the film opaque. 502 Black Pigment 502 Black Pigment is an epoxy-based liquid colorant used to tint the epoxy mixture black, providing an even, black color base for the final finish system. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional paint or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigments will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 1.5 gal of epoxy. 503 Gray Pigment 503 Gray Pigment is an epoxy-based liquid colorant used to tint the epoxy mixture gray, providing an even, gray color base for the final finish system. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional paint or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigments will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 1.5 gal of epoxy. Additives for modifying epoxy 420 Aluminum Powder 420 Aluminum Powder will increase the hardness and abrasion resistance of the coated surface and improve its moisture resistance. 420 provides limited protection from ultraviolet light in areas that will not be protected with other coatings and can be used as a base for subsequent painting. Cures to a metallic gray color. Add to mixed resin/hardener at the rate of 5%-10% by volume or 1.5 tablespoons per 8 fl oz of epoxy (10 strokes each of resin and hardener from 300 Mini Pumps). 36 oz of 420 will modify up to five gallons of mixed epoxy. 422 Barrier Coat Additive 422 Barrier Coat Additive is a proprietary blend designed to further improve cured epoxy’s moisture exclusion effectiveness. 422 is used as a barrier coating additive to help prevent gelcoat blistering in polyester fiberglass boats. 422 also increases the epoxy’s abrasion resistance. Cures to a light gray color. Add to mixed resin/hardener at the rate of 15 to 20% by volume or 3 tablespoons per 8 fl oz of epoxy. 16 oz can of 422 will modify approximately half a gallon of mixed epoxy. 423 Graphite Powder 423 Graphite Powder is a fine black powder that can be mixed with epoxy to produce a low-friction exterior coating with increased scuff resistance and durability. Epoxy/graphite is commonly used as a low-load, low-speed bearing surface, as a coating on rudders and centerboards, or on the bottoms of racing craft that are dry sailed. It does not provide antifouling qualities. The epoxy/graphite mixture cures to a black color. Add to mixed resin/hardener at the rate of 10% by volume or 1.5 tablespoons per 8 fl oz. of epoxy. 12 oz can of 423 will modify approximately one gallon of epoxy. Review: Epoxy filler - Nice addition to west epoxy, thickens mixture and fills gaps, just as advertised. Review: great products - west system is great products ## Features - High-density epoxy thickening additive for strength – Made in the USA WEST SYSTEM 404 High-Density Filler is used to maximize epoxy’s adhesive properties in hardware bonding and other applications where high cyclic loads or maximum bond strength are required. - Excellent for hardware and stud bonding – Even small amounts added to epoxy resin and hardener reduce creep in the cured epoxy, making this filler well suited for hardware, fastener, and stud bonding applications. - Creates strong, non-slumping epoxy mixtures – Mixed with epoxy, this filler produces a gap-filling adhesive capable of forming structural fillets or bridging large gaps without sagging, reducing the need for tight joinery. - Compatible with multiple WEST SYSTEM epoxies – 404 High-Density Filler can be blended with WEST SYSTEM 105 resin and 20X hardeners, G/flex 650 epoxy, or G/5 five-minute adhesive and cures to an off-white color. - Viscosity controlled by filler amount – The amount added determines epoxy thickness, from a loose slurry to thicker mixes. For best results, use only enough filler to bridge gaps without trapping air and avoid overfilling the mixing cup. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0006JJAU6 | | Best Sellers Rank | #100,891 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #128 in Wood Filler | | Brand | West System | | Brand Name | West System | | Color | off-white | | Compatible Material | Wood | | Container Type | Aerosol Can | | Customer Reviews | 4.7 out of 5 stars 106 Reviews | | Included Components | FILLER HIGH-DENSITY 43 OZ | | Item Form | Paste | | Item Package Quantity | 1 | | Item Type Name | West System Filler | | Item Weight | 16 Ounces | | Manufacturer | Gougeon Brothers, Inc. | | Material | epoxy; filler | | Material Type | epoxy; filler | | Model | 404-45 | | Other Special Features of the Product | Strong | | Part Number | 404-45 | | Special Feature | Strong | | Specific Uses For Product | Carpentry, Gap Filling, Hardware Bonding, Repair, Structural Fillets, Woodworking | | UPC | 811343011413 | | Unit Count | 43.0 Ounce | | Viscosity Level | High | | Volume | 219 Milliliters | | Warranty Description | Limited Warranty | | Water Resistance Level | Water Resistant | ## Product Details - **Brand:** West System - **Item Form:** Paste - **Material:** epoxy; filler - **Special Feature:** Strong - **Specific Uses For Product:** Carpentry, Gap Filling, Hardware Bonding, Repair, Structural Fillets, Woodworking ## Images ![WEST System® 404 High-Density Epoxy Filler | Strong Structural Thickening Additive for Epoxy Resin Bonding and Filleting | Made in the USA - Image 1](https://m.media-amazon.com/images/I/71wtb8ECQOL.jpg) ## Customer Reviews ### ⭐⭐⭐⭐⭐ Epoxy filler *by B***I on December 9, 2023* Nice addition to west epoxy, thickens mixture and fills gaps, just as advertised. ### ⭐⭐⭐⭐⭐ great products *by R***U on December 30, 2025* west system is great products ### ⭐⭐⭐⭐⭐ Great filler *by K***A on June 25, 2025* I use West System products exclusively when doing marine fiberglass repairs/modifications. There are many different filler options, so choose the one that best fits your needs. Mix the resin, add the filler and mix to your desired consistency, then apply. For me, usually similar to mayonnaise works best. Drying time will depend on your choice of hardener and if you've adjusted the resin/hardener ratio. ## Frequently Bought Together - WEST SYSTEM 404-45 High Density Filler 46oz. - WEST SYSTEM 105A Epoxy Resin (32 fl oz) Bundle with 205A Fast Epoxy Hardener (7 fl oz) and 300 Mini Pumps Epoxy Metering 3-Pack Pump Set (3 Items) - West System 406-7 Collodial Silica 5.5oz, off-white --- ## 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.be/products/20049723-west-system-404-high-density-epoxy-filler-strong-structural-thickening](https://www.desertcart.be/products/20049723-west-system-404-high-density-epoxy-filler-strong-structural-thickening) --- *Product available on Desertcart Belgium* *Store origin: BE* *Last updated: 2026-07-14*