Comment on Advice for fire pit construction
user134450@feddit.org 2 weeks ago
do you want natural rock or is synthetic also ok? also do they need to be resistant to freezing water as well? its not clear if there will be any kind of roof above…
very conservative answer would be something like granite, diorite or similar dense rock.
if you have protection from water you can also use more porous rocks like sandstone.
h0rnman@lemmy.dbzer0.com 1 week ago
Either is fine, I’m trying not to break the bank on it though. The pit will be outside, below a high canopy but not covered/roofed. I’m also not sure where I’d even find some of the more esoteric rocks. Would chipped marble work here?
user134450@feddit.org 1 week ago
marble is less resistant to heat but might work if it’s not directly in contact with the ambers and a little away from the fire. Chemically it is CaCO~3~ and if you heat it enough it will start to decompose to CaO and CO~2~ and crumble. It is a similar process to what you would see in a cement kiln :); not exactly stable but also not dangerous if it happens outside.