If you don’t intend for it to be hung, but used as a trivet or equivalent you can stick adhesive cork to the back or - I have not done this yet - but you could also dip it into tool dip/plasti dip
You’d need to make a “handle” on the face (I’d suggest a folded over piece of gorilla tape) - dip the tile into a shallow dish of tool dip, and then let it hang dry.
This is a triptych one I designed similar to the free file I linked to above. I meant to post it in Free Files, actually – guess I should hunt it down and do that!
I like the way this gives extra depth to the whole piece. My framing was sort of similar but done in layers instead of as a box. My method doesn’t give the thickness yours does.
Yes, I’ve wondered about that. Or even just embedding the whole thing in resin.
I like the idea that the back should be flat and not visible. Looking at the tiles I’ve got I’m not sure cork would work as they are too bumpy (which figures - its to hold the cement when fixing them down!)
I use self-stick felt from Michaels. I’m hesitant to use a plain tile on a wood surface due to the potential vfor scratching.
I started out using little foam or silicone dots for the corners but I found it quicker to peel & place a felt square vs getting 4 feet placed uniformly. I cut the felt in the GF (sized about an eighth of an inch smaller than the tile).
I did a few hundred tile coasters a couple of years ago for an event and used the felt - but I got it off Amazon in a roll that was 5 or 10 feet long. Lots cheaper than getting a ton of the 12" squares at Michaels. When I’m doing a handful, I still get the felt from Michaels.