{"product_id":"west-system-colloidal-silica-filler-for-epoxy-2-oz-non-sag-thickening-additive","title":"West System Colloidal Silica Filler for Epoxy — 2 oz Non-Sag Thickening Additive","description":"\u003cp\u003e\u003cstrong\u003eWest System 406-2 Colloidal Silica is a finely powdered thickening additive that turns WEST SYSTEM epoxy into a creamy, non-sag paste for fairing, filleting, and vertical\/overhead applications.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eWhen working with epoxy, controlling flow and body is essential for neat, durable results. The 406-2 Colloidal Silica filler from West System is formulated to thicken epoxy resin and hardener blends, creating a stable, off-white paste that resists runoff and improves handling. Made in the USA and specifically compatible with WEST SYSTEM epoxy systems, this additive lets you tailor viscosity for tasks that require a heavier-bodied mix without changing cure characteristics.\u003c\/p\u003e\n\n\u003ch3\u003eHow does West System 406-2 stop epoxy from running on vertical or overhead surfaces?\u003c\/h3\u003e\n\u003cp\u003eAdding a small measured amount of 406 colloidal silica increases the mixture’s internal structure, producing a non-sag paste that clings to surfaces. This makes it easier to apply fairing or fill coats on vertical hulls, keels, or overhead areas without drips.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCreates a paste-like consistency that holds on vertical surfaces.\u003c\/li\u003e\n  \u003cli\u003eReduces sag and runoff for cleaner placement.\u003c\/li\u003e\n  \u003cli\u003eWorks with both resin and hardener blends for consistent handling.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat thickness and appearance can I expect after mixing 406-2 with WEST SYSTEM epoxy?\u003c\/h3\u003e\n\u003cp\u003eWhen mixed in appropriate proportions, 406 colloidal silica produces a creamy, off-white paste that stays workable for shaping and fairing. The additive increases body without significantly altering cure time or final strength when used as directed with WEST SYSTEM epoxy.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eTurns liquid epoxy into a stable, cream-colored paste.\u003c\/li\u003e\n  \u003cli\u003eMaintains structural integrity suited for fairing and filleting.\u003c\/li\u003e\n  \u003cli\u003eEasy to sand and finish once cured to desired hardness.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow much 406-2 should I add and when should I mix it into the epoxy?\u003c\/h3\u003e\n\u003cp\u003eStart with small increments and blend until you reach the desired consistency — a little goes a long way. Add the powder after fully mixing the resin and hardener so the thickener disperses evenly and you avoid lumps.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAdd gradually and hand-stir thoroughly for uniform texture.\u003c\/li\u003e\n  \u003cli\u003eMix into fully combined resin\/hardener to ensure proper integration.\u003c\/li\u003e\n  \u003cli\u003eAdjust quantity to achieve light paste for fillets or thicker body for fairing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill using 406-2 affect the epoxy’s cure or strength?\u003c\/h3\u003e\n\u003cp\u003eWhen used as a viscosity modifier in recommended amounts with WEST SYSTEM epoxy resins and hardeners, 406 colloidal silica customizes handling without fundamentally changing cure characteristics or structural performance. It primarily alters rheology to improve placement and finish work.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompatible with WEST SYSTEM epoxy systems for predictable results.\u003c\/li\u003e\n  \u003cli\u003eDesigned to modify handling, not to replace structural fillers.\u003c\/li\u003e\n  \u003cli\u003eUse in conjunction with other WEST SYSTEM fillers for specialized strength or bulk needs.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho this is for: West System 406-2 Colloidal Silica is aimed at boatbuilders, repair technicians, composite fabricators, and DIY enthusiasts who need controlled epoxy body for fairing, filleting, patching, or any application requiring non-sag behavior. It’s especially useful when working on vertical or overhead surfaces, when a creamy, sandable finish matters, or when you need predictable handling with WEST SYSTEM resins and hardeners. If you require bulk structural fill or gap-filling with high compressive strength, consider combining 406-2 with other WEST SYSTEM fillers to achieve the desired mechanical properties.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can 406-2 be used with any epoxy?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: 406-2 is formulated for WEST SYSTEM epoxy systems; it can work with other epoxies but best results occur when used with WEST SYSTEM resins and hardeners.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Is 406-2 suitable for sanding after cure?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes — mixed into epoxy it cures to a creamy off-white paste that sands well for fairing and finishing tasks.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"West System","offers":[{"title":"Default Title","offer_id":55164006891863,"sku":"B0000AY1OC","price":34.1,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/west-system-406-2-front-packaging.jpg?v=1790348752","url":"https:\/\/britishgarage.co.uk\/products\/west-system-colloidal-silica-filler-for-epoxy-2-oz-non-sag-thickening-additive","provider":"British Garage","version":"1.0","type":"link"}