The term "Crazy Glue" is often used as a generic reference to cyanoacrylate ester (CA). This adhesive is available in viscosities that vary from thinner than water to thick as honey. The thicker versions are advertised as gap-filling. CA is brittle and best used in sheer because it has poor peel strength. CA degrades over time and after approximately 25 years has half its original strength. If you use a thinner-than-water CA in an application that fails, subsequent attempts to re-bond the materials may require arduous effort to remove the brittle CA that wicked everywhere. Failure to remove the CA in a failed joint means subsequent adhesives will bond to the brittle CA and not the (usually) much stronger base material.
When epoxy is used to join fiberglass panels in a production environment, a filler like phenolic resin, glass beads or chopped fiber is often used to ensure that no voids are left in the joint. If you decide to buy resin at an auto parts store (not recommended for several reasons), make sure you are getting epoxy resin and not the more brittle polyester resin that is often sold there. Polyester resin kits will come with a very small bottle of water-thin catalyst, while epoxy resin is typically provided in two viscous parts mixed in a 1:1 (or other) ratio.
@Tcab, it is difficult to tell from your picture whether two separate pieces of fiberglass failed at an adhesive joint or whether the fibers of a single part have delaminated. A delamination would likely be best repaired with epoxy resin, while a failed adhesive joint would more likely be best repaired with an elastic adhesive like
Sikaflex. A flexible adhesive is very likely to survive repeated shocks without failure. Note that Sikaflex is neither silicon (a very hard and brittle element) nor silicone, but a polyurethane adhesive.
