I've done some of both and they both work. But I don't know about which is strongest, most flexible, or other advantages. I do know that the CA is easier, but epoxy is the "professional" choice. Why?

thanks,
Balin

Composites carry the load through the fibers. The purpose of the matrix (either the epoxy or the CA) is to keep the fibers in place.

Most composite failures are not due to fiber failure or matrix failure, but rather flaws in the composite, i.e. voids, unwet fibers, excess matrix material, fiber pull out etc. Many of these problems are not a function of the tensile strength or modulus of the matrix, but of how the composite is formed. Effectively there is no way to really control the properties of a composite well using CA, hence "professionals" use epoxy along with some type of pressure system.

For modeling purposes- i.e. wrap a center section with fiber glass cloth- the same criteria apply. Lightweight cloth may drape over a structure well enough to allow a good bond to the surface, but heavier cloths need to be wet and CA dries too fast. Plus the heat of reaction can cause outgassing which lifts the composite away from the surface.

Summary- use CA with very light cloth for finishing purposes or for joints where ultimate strength is not required. CA is more brittle than epoxy however, so for joints undergoing impact, epoxy remains a better choice. For cloth over 2 oz. plus in weight or so (my weights could be off) CA is a waste of time.

Sam