Plastic Crack Repair?

Someone was asking at a recent pool session about repairing his plastic kayak that has a crack behind the cockpit. Not sure of the exact boat but it is a fairly old Perception WW boat(i.e lonnnnnnng boat). I think it might be an early rotomolded kayak.

Someone suggested that he had attempted repair with some plastic sticks that were heated and melted. However he didn’t think it work very well on what he tried to repair(SOT seating area?).

Someone suggested trying fiberglass repair. However we weren’t very sure on it’s ability to hold over time.

I don’t think the owner really uses it for WW that much. Primarily just a rec kayak for his family and/or friends who want to take it for a spin while he paddles something else.



bad sign
when an old ww boat (or any plastic boat for that matter) cracks behind the cockpit are a sign the boats on it’s way out. this is a thin area and subject to the first plastic failure.

if it’s cross linked it won’t weld. a f/g patch may work or lots of duct tape.


drill small holes at either end of
the crack, and duct tape the hell out of it.

You may also want to retire that one to rolling practice.



“fiberglass” patches will not stick on
polyethelene “plastic” boats. Not with polyester resin, not with vinylester resin, and not with epoxy resin. There’s a reason that many glues are packaged in polyethelene containers.

If one can get at the crack from inside, one can clean the crack (drilling ends OK), abrade it, and then apply several layers of duct tape. One then applies a hot iron to the layers of duct tape. Has been discussed in old boatertalk threads, and a friend has tried it successfully on his old Perception Dancer.

You nailed it. The first thing to do is to drill a small hole at each end of the crack to keep the crack from traveling further. The best adhesive to fix the crack, albeit temporary, is duct tape. If he wants a more permanent fix, clean well, sand lightly and apply a fiberglass patch using epoxy resin. It will PROBABLY hold for a long time.

Thanks for all of the input. Actually I talked to the guy last night and he had already tried the fiberglass method.

I’ll pass along these additional suggesstions.

Thanks Again,


Actually, it will

– Last Updated: Feb-09-04 2:46 PM EST –

Epoxy/glass patches can be made to adhere to polyethylene by activating the surface with an open flame, such as a propane torch. However, the recommended method of repair is welding. Plastic welding equipment is available inexpensively from Harbor Freight.