G/Flex epoxy for kayak repair – review

I had to re-seat the plastic hatch rims on a 30-year-old Romany kayak a few months back. The original adhesive had completely dried up and the previous owner had simply installed a few rivets to hold it in place (Photo 1) – suffice to say they leaked a lot.  So, I used a West Systems epoxy product that was new to me, G/Flex 655 Thickened Epoxy Adhesive.  West Systems describes G/Flex as “a bit more flexible than standard epoxies and polyester but much stiffer than adhesive sealants,” and, “ideal for bonding dissimilar materials.”  Sounded perfect for my needs.  I’ve used standard epoxy and polyester resins for past kayak projects, for laying up fiberglass cloth and hull repairs.  But I’ve never had the need to permanently bond plastic to fiberglass.  In short, G/Flex worked great.

Years ago I used 3M 5200 to glue some plastic rings inside the cockpit of a kayak – but that 3M stuff is a different class of sealant composed of polyurethane. It worked fine, but 3M 5200 is mainly used for bedding hardware on motor/sail boats in areas subject to engine vibration and such.  It’s a one-part sealant that doesn’t have quite the strength of epoxy.

For the hatch repair, I roughed up the plastic hatch rims a bit with sand paper to help the epoxy adhere. Whatever adhesive used when the boat was made was a rubberized type that could not be easily sanded away from the boat without cutting into the boat itself (Photo 2). So, I just left the boat's hatch recesses as-is without sanding.  

G/Flex 655 comes already thickened, no need for adding thickeners like most epoxies, and is easy to work with. Just mix the two parts together (comes in two separate tubes), smear a liberal amount on the hatch rims, then press the rims in place. I strapped the hatch rims down during the 24-hour curing time (Photo 3) as a safety precaution because the boat was stored in a communal boathouse where it might get pushed around. But that wouldn't be necessary normally – the G/Flex is so viscous/tacky that the rims weren’t going to move around during the cure.

The result – the rims are Rock-Solid, no leaks and the bond seems super strong.  I’d use G/Flex again if I have to do any adhesive repairs of dissimilar materials (metal/plastic to fiberglass).

Photo 1: Pre-Repair, rivets - someone's misguided attempt to secure rims

Photo 2: Rims removed (rivets drilled out) showing original dried rubber adhesive

Photo 3: G/Flex curing....