Glueing EPDM Rubber at Temperature / Water

Hi there,
Can someone please help me with a problem I am having.
I have a rubber U shaped extrusion approx 12mm x 2mm gap x 4mm rubber
thickness.
It is easy to obtain in EPDM, but I could probably get it in Neoprene.
It is sponge rubber.

I am trying to glue this extrusion into a circle to make a gasket. The
circle has a diameter of 200mm.

I have tried cyano (works great, but cant handle the 100C temperature
and 20% ethanol / water mixture)
I have tried epoxy (doesnt stick)
I have tried several contact glues (They fall apart after a short time)
I have tried Rema Tip-Top SC4000 which is the best so far, but it still
seems to slowly fall apart.
I have tried all this on EPDM sponge - would the SC4000 work a lot
better on Neoprene sponge?

I would prefer to have it vulcanised, but it seems no-one wants to do
it because it requires a mould.

Can someone help me work out how to do this? I need to do several
hundred. I am located in Geelong (near Melbourne) Australia.

Any other groups I can post to? Thanks a million.
Greg

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