>>2374719I've always paddled Pyranha, so they're not really weldable.
The best fix we've found is heat gun an ice cream container lid to it, and smear it on with a knife.
Touch it up with the knife as best you can, then just leave it.
It's not pretty, but it works.
Just make sure you drill both ends of a crack to stop it spreading - 2mm bit, right through.
A tidier option I found, though it doesn't last forever, is drill, then gorilla glue a strip of plastic on the inside. Gives me a couple of months of near daily use before having to do it again.
Before gluing, ream out the crack inside a bit, and sand everywhere that will be glued to give it something to hold. I'd send a pic of result, but it's under my seat and it's a pain in the ass to pull out.