Cabosil Use?

[sa7Ndy]

I am just starting cedar strip canoe kit (prospector 16) and am unsure when Cabosil is added to the epoxy. Do I use it for gluing the stem laminations or only if the epoxy is used as a filler? I presume it is not used for the fiberglass step.

[captsvm]

Sandy,

Cabosil is primarily used as a thickening additive and is especially suited to help prevent resins from sagging or running. It is one of the best additives to use to increase bonding strength and gap filling.

It is added, like all fillers, to the epoxy after mixing the resin and hardener. It can be used at any stage of construction, except when wetting out glass for layups. Laminations of wood layers are benefited by adding cabosil to bring the consistency up to that of catsup. Structural wooden members would benefit by a slightly thicker mix, (mayonnaise). For maximum gap filling a mix to the consistency of peanut butter might be required.

All joints should be first primed, (both surfaces), with un-thickened mix, then use the thickened mix to finish the joint. Clamping pressure should be kept to a minimum so the the joint is not starved. Epoxy is at it's strongest when there is a about a 1/64" or so glue line at the thinnest point.

Cabosil can also be used in conjunction with other fillers to stiffen the mix.

Regards,

Patrick