The Necromunda terrain I am working on is largely made out of foamcore. I wanted to effectively hide the edges, and it took me a little while to figure out the best way to go about it. In the end the solution I decided upon was to use 3/16" C channel. Starting at one of the slots and ending at one of the tabs, I laid out the longer sections first, then working the angles. I sealed the edges of the deck with PVA glue mixed with water applied liberally. Once this protective layer dried, I was able to use superglue to attach the C channel to the exposed foam.
Once the edging was completed, I cut some strips of 1/2" thin card and glued them on the platform, top and bottom, flush with the C channel.
The mostly complete section. There will be more plates and rivets (always more rivets), as well as another piece of terrain that will slot into the holes in the center of the deck.
Here you can see the process of applying C channel, thin card, more card, and finally rivets to complete the main detail on these sections. This is where I ran out of C channel. There is a bit more than 17" on this piece. The store that sells Evergreen locally went out of business, so I have to wait for some to come in.
This tower is about halfway done. Once I get more C channel, I can finish the tower up. I think I might try some of the GW technical paints on these projects.