Chris Green wrote:

I've never found it *easy* to stick edpm

The last time someone asked, I suggested evostik contact adhesive, when
I tried it using some offcuts left from when I did my roof it stuck, but
not very well.

The epdm came with some tins of primer to use before glueing, which
presumably 'breaks through' the low surface energy and lets the glue get
a grip.

Unfortunately the primer is not the sort of stuff you can keep around,
it had a short shelf life and dire warnings not to open it until you
were ready to use it as it would go off to a useless gel within 24 hours.