417, Im sure you know EPDM when you see it. "EPDM" has been used erroneously even by manufacturers to take advantage of the success associated with its name.
The first manufacturer to come out with TPO (Thermoplastic Olefin, yes of course they were a tire company) called their TPO "Heat weldable EPDM"
We in the roofing industry knew this was bunk, and pressed them on it. It was TPO, not EPDM, but they did not want to call it a thermoplastic due to the failures associated with some poorly formulated PVC Membranes at the time.
I say some, because there are some very good PVC membranes that have stood the test of time. I installed thousands of squares of a membrane in the early eighties that originated in Switzerland that are still performing well today, and you can still heat weld to them.
This particular membrane is the only thing that can stand up to the intense solar radiation in the Mideast, from what I understand, and we all know that it is UV that kills roofs.
EPDM is a cured elastomer that is vulcanized under extreme heat and pressure. There are uncured elastomers like Hypalon which cure over time in the presence of moisture and UV.
There was a company in the US that put down millions of square feet of sprayed liquid Hypalon over a polyester mat, right over existing built up roofs, even gravel surfaced ones.
To my knowledge the owner of that company now lives somewhere US Law cannot get to him. "Postcard from Paraguay" Mark Knofler, if you get my drift.
:whistling2::whistling2::whistling2: