CABOSIL THICKENING AGENT – Fumed Silica (aka Cabosil) is an extremely fine powder used to thicken virtually every liquid material. It is typically used to thicken resin, paint, dyes, and even water.  It is great for making fillet putty, thickening epoxy for a better glue consistency, and for use below the waterline. Resin mixed with Fumed Silica (Cabosil) is an ideal product for repairing the blisters that are so common on fiberglass boats.
 
 
It is used in approximately a 1:1 ratio to the mixed resin by volume.  This will provide a consistency similar to vaseline. You may use more or less to suit your application. It adds a milky white color to the resin.