Cabosil® Fumed Silica – Epoxy & Paint Thickening Additive

Cabosil® fumed silica is a high-performance thickening agent designed to modify the viscosity of epoxies, resins, paints, and coatings. This ultra-lightweight, fine powder transforms thin liquid materials into smooth, non-sagging pastes, making it ideal for crack filling, filleting, bonding, fairing, and vertical or overhead applications.

When added to epoxy, Cabosil creates a thixotropic (non-drip) consistency, allowing the material to stay exactly where it’s applied without running or sagging. It’s commonly used for concrete crack repair, structural bonding, marine repairs, fiberglass work, and industrial coatings, where strength, control, and precision matter.

✔ Key Benefits

• Excellent thickener for epoxy, resins & paints

• Turns liquid epoxy into a smooth, workable paste

• Lightweight, ultra-fine fumed silica powder

• Improves sag resistance for vertical & overhead use

• Ideal for crack filling, bonding, fillets & repairs

• Compatible with most epoxy and coating systems

Cabosil® blends easily and allows you to customize viscosity—from slightly thickened to peanut-butter-like consistency—giving you complete control over your application. A small amount goes a long way, making it a cost-effective and essential additive for professional contractors and DIY users alike.

How to Use Cabosil® with Epoxy

Cabosil® fumed silica is added after epoxy resin and hardener are fully mixed. Slowly sprinkle small amounts of Cabosil into the mixed epoxy while stirring continuously. The material is extremely lightweight, so add gradually until the desired consistency is achieved.

For light thickening, add Cabosil until the epoxy reaches a syrup or honey-like consistency. For crack filling, bonding, or vertical repairs, continue adding until a paste or peanut-butter-like texture forms. Once mixed, apply using a putty knife, metal trowel, or notched trowel as needed.

Mixing Tips

• Always mix epoxy resin and hardener first

• Add Cabosil slowly to avoid clumping or dusting

• Use only small amounts — a little goes a long way

• Wear gloves and a dust mask during mixing

• Apply immediately after mixing for best workability

Cabosil does not change cure time when used properly and is compatible with most epoxy systems. It allows you to customize viscosity for precise control, making it an essential additive for professional repairs and DIY applications.

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Maximum transit times may take 10- 12 days for Hi, PR, and AK

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