Where is cab-o-sil typically used?

Cab-o-sil, also known as fumed silica or silica aerogel, is a white powder used in composite applications primarily as a thickening agent and reinforcement filler. One of its key characteristics is its ability to improve the viscosity of resin systems without significantly increasing their weight.

When applied to radius or fillet areas in composite construction, cab-o-sil enhances the structural integrity by providing better adhesion and reducing sagging. Its thixotropic properties allow it to hold shape and create smooth transitions at joints and corners, which is crucial for both aesthetic and structural purposes. This capability makes it especially suitable for applications in composite materials where the creation of strong, well-defined fillets is necessary to distribute stress evenly.

The other options focus on properties or uses that do not align with cab-o-sil's intended functions. For example, it does not contribute to transparency or color in resin or gel coat applications. Additionally, it does not function as a mold release agent, a role typically fulfilled by specialized coatings designed to prevent adhesion during the molding process.