Thank you sir! So far, the cheapest I've found is $20 for a 4 cu foot. But I'm loving your blog man! Oven is awesome. I'm a little confused between September and October. You have a hearth stand made of just concrete, then a perlite concrete mix insulating layer, then fiber board, THEN fire bricks?
Thank you. Ive made a surprising amount of local friends with the blog. It's been fun.
Yes. That's what I did. I've got the slab, a 3.5 inch layer of perlcrete (a 2x4 high), two inches of board under the floor. The insulation board was probably unnecessary but I wanted some for inside an eventual door. It also helped with giving me a little flexibility with the height of the oven floor. I bought a box and had enough for the 2 inches under the oven and two inches inside a future door. There is 3 inches of blanket around the oven. When I get the walls up, I'll top that off with some more loose perlite. Seems like the running joke on the Forno Bravo site is no one has ever complained about too much insulation. Without a door, just bricks stacked in front of the opening, I have had very good heat retention. I think the insulated door will improve it. If I did it again, I think I'd go with a 2x6 form for the perlite and skip the board. I'd say the best part of the board was that it was easy to level and there was a nice flat surface you could mark up to start the oven.
The goal was an oven that could heat up in a reasonable amount of time (not a huge mass) but well insulated so I could use the residual heat too. Now if it ever stops raining, I can start the enclosure. I've been stockpiling the materials in the garage. Hope to get started on that soon.
