> Dan. I'am confused. Both West system and system Three in there technical
> manuals describe the use of cab-o-sil as a thickener recommended for
> bonding and gluing. West's rates only the glass fibers as better. System
> three mentions that the viscosity of mixed epoxy is not high enough to
> make a good adhesive. They also recommend the use of cab-o-sil for gluing.
> Who is right here?

> Larry C.

> PS/ Where is Kern Hendrick when you need him?

West and System 3 are right about Cabosil. The resins used by boatbuilders are so low in viscosity that they will run right out of a scarf joint, leaving a joint consisting mostly of air. Saves some weight of course, but subject to premature failure :^( Generally a mix of 1 part resin to 2 or 3 parts by volume of Cabosil will give an adhesive with enough wetting ability to completely fill the surface profile of the wood, without running out onto the floor when you're not looking. Increased brittleness of the mix is not significant, because even neat resin is many times stronger and more brittle than the wood it's bonded to. The microspheres are intended for lightweight, nonstructural fairing compounds; it's the spheres that break, not the epoxy.