Ive used UHMW-PE as edging for 10 boards then ran out.
So what i did this time was take my 15mm thick foam blank and mark out the the outline, then routed a 8mm deep x16mm wide groove (freehand with routher) along the outline.
Then i filled it with epoxy, slightly overfilled. Make sure you do it on a perfectly level table!
I trimmed it level with foam using a router that rides in a transverse carrier that is in turn on flat longitudinal rails.
Milled/sanded down top deck to shape. Was fast and easy, lowcost
I would suggest putting some microfibres in there too.