I was driving in my car with Husband and 18 year old son. I shouted "HYPERTUFA!" and they just stared at me like I was nuts :)

I have been brainstorming about building Halloween props for this fall. I want to make tombstones, since the styrofoam ones from the SpiritStore are pitiful. It suddenly hit me that I might be able to make hypertufa tombstones, they would be light enough to move in and out each season, and durable enough to last.

How thick can I make a slab? How heavy would a 24x36x3 slab be? Could I put in a styrofoam core to make it thicker without adding weight? Before it is totally cured can I carve in my writing and designs?

I assume I can just nail together a wooden frame, line it with plastic, pile in the hypertufa. Put in 2 pvc pipes (so 2 rebar in my ground could slip in to keep it upright).

Am I on the right track? Am I crazy?
Thanks