Supposed to be good on fixing thermal plastics like Poly-3. Anybody use the stuff?

Bought some from Old Town
Two part epoxy in a syringe. It peeled off my poly kayak after a few months and by then one part had completely dried out in the syringe. I’ve had better luck with G-Flex from West Systems. Backed it with fiberglass cloth to keep it from spreading too much.

It’s stayed on the hull for over a year now and the surplus is still in good condition.

I have used G-Flex as well with good initial results. A polyethylene C-1 I repaired with G-Flex has held up well for over a year. I did an extensive repair using cloth (Dynel and E 'glass) and G-Flex on a 3 layer poly Old Town Discovery canoe and it looks good but has not been subjected to the test of time.

It is absolutely critical to prep the hull before applying the epoxy, however. I would start by roughing it up with sandpaper around 80 grit or so. Clean it very well starting with soap and water and then isopropyl alcohol.

The surface of the hull absolutely needs to be flamed with a propane torch and you should make sure that the tip of the inner blue cone of the propane torch flame just touches the hull surface as you pass it over the boat. You don’t want to heat the hull to any extent, but you need to oxidize the surface. Try to apply your epoxy as soon as possible after flame treatment.

Use it all the time
And MA-310 both sold under the trade name Plexus. The stuff is awesome for thermo[formed]plastic boats. But Poly[link]-3 is not Thermoformed and it definitely won’t work on it.

G-flex and proper preparation of the gluing surfaces are your best bet.

Thermoformed plastics
Be careful with the term “thermoformed”. Thermoformed refers to a manufacturing process whereby a plastic sheet is heated and shaped over a mold. It does not imply a specific plastic material.

There are, in fact, thermoformed polyethylene boats. Polyethylene and polypropylene are both thermoplastic polyolefins that have a quite chemically inert surface which is why they are notoriously hard to repair. Because of their nonpolar nature they require an oxidation process (chemical, flame or plasma) to get anything to bond to them.

What boats?

here are a couple
The Old Town Saranac, Saranac XT, and Saranac Angler are all thermoformed polyethylene as this table attests:

This Rogue River square stern is another:

I strongly suspect the Colemans and Pelicans are as well but I don’t think it is worth my time to check into it.

Thermoplastic, is another term frequently misunderstood by paddlers. It refers to a polymer that liquifies when heated and freezes into a solid state when cooled. Thermoplastics include polyethylene, polypropylene, ABS, polyvinyl chloride, polystyrene and many others.

Neither term, thermoformed or thermoplastic, refers to any unique material.