Making Progress in Montana

[JoeT62]

Sharon -

I am also thinking of the 42" oven, and I think my calcs may be off? In another thread, James uses this formula:

For width:

If you are building a 42" Pompeii oven, you have 42 (floor)+9 (walls)+10 (insulation)+1 (enclosure wall) = 62".

For depth:

The 42" Pompeii oven works as follows. 42 (floor)+9 (walls)+6 (vent floor)+5 (rear insulation)+.5 (one wall)+12 (landing)=74.5".

A 62" should give me that, and leave me space on the right to put the grill (my current plan), but if I need to go to 72", I'll relocate the grill.

I should have paid more attention in geometry...

[swripley]

Joe,

1” for enclosure? What are you enclosing with? If you are planning a stuccoed dome that might be right, I didn’t look into that. I plan to frame in with metal studs and 1/2” Hardibacker so planned minimum of 8” for my enclosure walls, which brought me to a minimum hearth width of 69”. 4 ½ concrete blocks ended up being 70 ¼ inches, so I went with that. Then to figure how far to extend the hearth beyond the angled front corner I found the center point and framed in to go 45” beyond (69/2+10.5). Basically, I laid out a trial run of the floor and determined that would work.

S

[JoeT62]

Yeah, that enclosure estimate is probably too low. Thanks for the help! I'm off to Home Depot tomorrow to buy lots of block!

[DrakeRemoray]

I used metal studs and concrete board, but did not want to add the complete 8 inches, so I built almost a window in the studs at the widest part of the oven to save myself a few inches. That way, the enclosure only added an inch to the widest part of the oven. The picture might make this make sense.

[Archena]

So, the concrete board became the sheetrock?

[swripley]

DrakeRemoray,

Thanks for the photo! A couple of questions…what size is your oven? It doesn’t look like you left room for any insulation other than your thermal blanket, how many layers did you use? Any pointers on securing the thermal blanket? What roofing material do you plan to use? Did you cast your vent? This is something I plan to do and would love any pointers you have to pass on.

S

[DrakeRemoray]

Swripley,
There is a thread about my oven here:
http://www.fornobravo.com/forum/f8/d...-oven-633.html (Drake's 38" Oven)
Post #42 starts to talk about the vent. Let me know if you have questions after you look at that...

As to insulation, There is about 2" of blanket and about 2" of loose vermiculite on the parts where the oven is widest. I ran the oven this weekend on Saturday AND Sunday. The enclosure got about 10 degrees hotter at the widest part, where the fire was sitting...not bad...

Drake

[JoeT62]

10 degrees is not bad - perhaps I'll stay with the bigger oven. Plenty of time to decide yet.

[swripley]

Drake,

Hugely helpful! Thanks. Marcel's post to you got me thinking...(M) If I were making a casting such as yours for the re-bar included vent that gets quite hot, or for the re-bar included lintel that supports weight, I'd probably use a similar mix as recommended for refractory mortar for your dome bricks but I would substitute gravel for 3 or even 4 of the 8 parts sand: e.g. 4 parts sand, 4 parts gravel, 3 parts cement, 2 parts fire clay...


I have a few bags of Quickcrete Ready Mix left over from the structural poor. Anyone have an opinion on whether or not I could add fire clay to that and use to cast my lintel and vent?

Sharon

[swripley]

Disregard my question about ready mix and fire clay. After posting it I dug further and came across wlively's post on Casting Vent that many of you participated in. I then got on the phone and found a local supplier that has KS-4 in stock for what seems like a pretty resonable price. So I think I will just go with that.

S