100 gm or 1 Kilo Fumed silica powder (often known by brand names like Cab-O-Sil or Aerosil) is an ultra-fine additive used to thicken epoxy, polyester, and vinyl ester resins. It creates a thixotropic, non-sagging paste perfect for vertical applications, filling gaps, and creating fillet putty Thixotropic Properties: It transforms liquid resin into a thicker paste that stays on vertical surfaces without running, yet flows easily when stirred or brushed. Gelcoating: Adding about 2-3% by weight creates a gelcoat consistency, while up to 3%+ can be used to form structural filler pastes Best Practices & TipsSafety First: The powder is extremely lightweight and easily airborne. Always wear a dust mask and protective gloves when handling.Mixing Ratios: For general anti-sag properties, start with a low ratio of about 0.7% to 1% by weight of the resin.