Thank you Gordon
I found this from a local store in the states
Tap Plasticsit said this
"TAP Poly-Weld Adhesive: Imagine being able to structurally bond Polyethylene!!! This has been virtually impossible in the past. Now, with a simple
flame treatment and Poly-Weld, one can create strong joints on Low, Medium, or High Density Polyethylene. The famous marine Seaboard®, also a polyethylene blend, can now be joined with Poly-Weld! Use for tank, door, pipe, irrigation, pond, marine, float, & automotive body repairs. Also bonds polypropylene, ABS, PVC, ceramics, rubber, fiberglass, metals, and glass. Exterior-rated. Non-sag formula. "
Does that sound close to what you use?
I wonder what "flame treatment " means ?