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johnt 05-20-2013 11:13 PM

Stand Dimensions for 42 in Oven
I'm trying to calculate how big my form and stand should be. I have the chart on the downloaded oven plans v 2.0, but I see if I just follow the recommended width of the stand for example, it has it being 65 inches. Should I assume that the extra inch from what might be 4 8x8x16 blocks down to spacing in between the blocks? The depth recommended is 78 in, but I can't figure out how to get that easily without cutting blocks. Should I be scared of cutting blocks or just make my stand bigger so I don't have to make cuts?
Thanks in advance for any help.

SCChris 05-21-2013 07:24 AM

Re: Stand Dimensions for 42 in Oven
John, if your vision is to enclose the oven with an oven house then going bigger on the size of the stand is less important than if you want an igloo. I went with an enclosing house to get the advantage of additional insulation and I wasn't completely comfortable with waterproofing a free standing igloo without some roof structure overhead. What needs to be calculated in to get your minimum stand are;

The oven floor diameter, plus the thickness of the brick in the dome times 2, plus the thickness of the insulation times 2, plus the thickness of the containing wall structure that will sit on the stand times 2.

So I have a 42 inch oven with 4.5 inch thick brick walls covered by 4 inches of insulation and the walls of the oven house are 4 inches.

42+(4.5*2)+(4*2)+(4*2)= 42+9+8+8 = 67 inches.

The steel stud structure, the exterior walls of the oven house, can be used to contain insulation, and I did this, so I was able to stay within the 65". You just need to be a bit careful about where the studs are placed in the walls so you have the space for the insulation. The front to back dimension is the width plus whatever you add in terms of the oven entry and landing.

That's how I did it, cutting concrete blocks wasn't needed in my case.


johnt 05-21-2013 08:03 AM

Re: Stand Dimensions for 42 in Oven
Hi Chris,

That makes more sense and I think I will try and do the same with the enclosure instead of dome, but I still don't quite get the math. If you had a 65 in stand, but your materials add up to 67, does that mean you placed the studs surrounding the spots where the dome meets the stand at it's closest point so you might have a couple less inches of insulation at that point? Also, if you stand was 65 inches wide, how did you get that number if you used 8x8x16 blocks.

Thanks so much,

SCChris 05-21-2013 08:11 AM

Re: Stand Dimensions for 42 in Oven
The void of the exterior, 2X4, wall includes some of my dome insulation. This is the reason for the 65-67 difference. The difficulty of this configuration is really about stud placement so that you have the support structure not interfering with the insulation. I guess the thing I wanted to point out is the exterior wall and how it ultimately relates to the oven insulation.


johnt 05-21-2013 11:25 PM

Re: Stand Dimensions for 42 in Oven
Wow, I've been through the thread of your oven and those pictures really tell the story. I'm sure it's been done in so many ways, but the pictures really help a beginner. Can you tell me how the metal frame is attached to the stand? If you had it over, would you have made the stand slightly bigger to allow more room or did it matter? If possible, do you remember your stand dimensions? Sorry to latch on, but that oven is exactly what I am after.
Thank you so much,

SCChris 05-22-2013 06:43 AM

Re: Stand Dimensions for 42 in Oven
The stand size was fine for my oven and although it could have been bigger, functionally larger would not have added any benefit. What would be called the bottom plate of the stud wall was attached with masonry screws, found at Lowes. The kit contains a drill bit and special screws and it works well. Since the sheeting, Hardie Backer, attaches to the stand and runs up and ties to the stud wall everything tightens up nicely. When you buy your studs buy the thicker gage, the better product. The cost isn't higher but the product is less flimsy and will hold up for your great grand kids better..

I'm including a link for a thread that Brickie started, you'll find it a gold mine of tips and modifications.


johnt 05-22-2013 10:46 PM

Re: Stand Dimensions for 42 in Oven
Hi Chris, I'll definitely be looking at the link, but when you refer to kit, do you mean the one from Forno Bravo? I don't see a kit that offers that size of stand. I see the Cucina series, but nothing seems to be close to our dimensions unless you modified it. The cost of the bigger kit looks to be $1050. Speaking of that, did you find there were certain things much better ordered from Forno Bravo or could you find everything elsewhere. Those 18 x 18 tiles look nice to have on the floor and the insulation on the floor and around the dome looks good to buy here. Maybe even all the fire bricks too, but what do you think. I don't see the metal stud kit you have anywhere on here.
So just to give me an idea on an example of how there are no cuts on the stand, if your stand is 65 in and each block is 15 5/8 in, 4 of them would add up to 62.5 in so did you just have the extra 2.5 in made in the transitions from block to block with a little mortar in between? I'm just paranoid I make the foundation or the stand too small and then have to add to it or make the oven smaller.

SCChris 05-23-2013 09:23 AM

Re: Stand Dimensions for 42 in Oven
Regarding the "Kit". I found that I could source what I needed closer to home and because this avoided the shipping cost of the kit, the overall cost was better. I see you're close to Boise so I'd bet that you can find most everything local. The bits you might not find are going to be the rigid insulation and the ceramic blanket. These items can be found at a foundry supply or a commercial/industrial insulation business.

The rigid insulation board is something I wouldn't compromise on. Vermicrete is fine if you have no other choice, but compared to the insulating properties of the rigid insulation, inch for inch, it doesn't compare. The cost issue has some merit but I feel that this is one of those “pay me now or pay me later” situations.

The ceramic blanket allows a tailored wrap of insulation on the dome so less air movement around the dome and therefore is better insulation than other materials. I didn't use ceramic blanket but used mineral wool bats instead. I minimized air movement around the dome by wrapping mineral wool bats around the dome and stuffing the voids with torn off bits. The manufacture of the mineral wool bats is Roxul but I'll bet there are several out there. This material is generally mandated where fiberglass is not sufficiently stable in heat. Places like backing a fireplace box is where this insulation is mandated. I found this at the White Cap commercial building supply store.

Once I finished positioning these bats, I filled the rest of the space with unlined fiberglass, attic, bats and ultimately filled the rest of the space with loose vermiculite. All of this insulation has allowed me to fire for pizza on a Saturday evening, shut the door at 10PM and come back on a Monday afternoon and find a 375F oven ready for whatever I want to do with a hot oven.


johnt 05-23-2013 09:43 AM

Re: Stand Dimensions for 42 in Oven
And the steel stud structure? Can you reveal where I might source that? Thanks

mrchipster 05-23-2013 09:53 AM

Re: Stand Dimensions for 42 in Oven

Originally Posted by johnt (Post 153506)
And the steel stud structure? Can you reveal where I might source that? Thanks

Any lumber supply, lowes, Home Depot, Menards, etc. can supply it. It is a standard building product in commercial buildings.


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