Are concrete bricks safe for a brick oven?

Short version: looks like you shouldn't.

Hm.. that seems to be talking about higher temperatures, though? And mostly just that it wouldn't be very durable?

I won't be terribly upset if the cinder block pieces I got for free (because they're pieces) ended up falling apart..

that's the problem I'm running into, that anything mentioning cinder blocks or concrete pieces is talking about making a fire oven, not just retaining heat in a normal one.

Hrm.. guess I"d better not do it for now.

just put the pizza on the rack? should get crispy at 425-450

If you go to HD you can get terra cotta tiles (unglazed) really cheap.

That's probably what I'll do, I just haven't gotten around to it yet.

I looked up Portland cement, which is the main ingredient in concrete blocks. Can't see anything that appears to be toxic. They use cement blocks for outdoor barbecues in state parks.

oh cool