close to breaking ground

[Blacklab]

As of late summer 2014 I was bit by the oven bug. With all the reading I have done lately I almost feel smart, all most. Here's my oven Idea tell me what you think please. Or should do different. Breaking ground in the next couple days

Base will be cider blocks and home brew refractory 4inch thick

39 inch cooking floor. Want to go into it not out of it Red clay bricks (free)

Build sand dome to specs, cover with wet newspaper.

will have chimney and brick arch

Cover with fire clay 1 part clay 3/4 parts sand. 3/4 inches thick?

Let cure

Wrap in 8# blanket 50sf secure with chicken wire.

Cover with 3/4 inches home brew refractory let cure

Build small fires over period of 2/3 weeks depending on weather.

Thanks for all the insight guys/gals

[david s]

Re: close to breaking ground

I guess that will work. I think your clay and sand inner layer will not be very strong. Because of the high clay content expect plenty of shrinkage and cracking.You would get a better result from using the home-brew mix: sand, clay, lime, cement 3:1:1:1

Cider blocks??

Keep your fingers crossed that your solid red bricks will be suitable for the floor. They may be or they may not be, you won't be able to tell until you start using it.If you lay them loose you can always replace them.

Make sure you insulate under your floor. If cost is a factor use vermicrete (vermiculite or perlite and cement 5:1) Alternatively, if you can afford it use calsil board.

[Blacklab]

Re: close to breaking ground

David thanks for the feed back I appreciate it As for the clay dome I assumed that is what I wanted to start with. Then add banket and homebrew. I can very easy change to all home brew with blanket. I will insulate the floor with Portland cement and perlite 4 inches thick 1 part Portland 5 parts perlite? Great idea on laying the red brick loose. Fire brick it's very hard to find and costly. I'll keep looking though. The cider block will be the base for the oven. Anything else? I'm all eyes......lol Thank you!

Blacklab
alias Mike

[SableSprings]

Re: close to breaking ground

Welcome to the forum Mike. I've referenced/linked a build below that you might find useful.

http://www.fornobravo.com/forum/f43/...oven-9380.html

I'm not sure why you want to use homebrew for the slab on top of your cinderblocks...concrete/rebar is much stronger and pretty cheap. The 3/4" thickness of your dome seems way too thin...especially if you want to do any breads or long term baking. I'd be thinking more along the lines of 3" thick as a minimum (3"-5" for extended baking capabilities). Then your insulating blanket, chicken wire, & either stucco or waterproofed cement for an outer covering (don't need home brew refractory for the outside, but of course it will work). Remember that you can cover your dome with 10:1 perlcrete for insulation if the cost of the insulation blanket is too high for your budget.

As David noted, I'd also be cautious using the red bricks on the floor. I was able to find used firebricks for my dome, but chose to bite the bullet and buy new firebrick for my hearth floor...after all, it's going to be what my food/bread/pizza is actually cooked on. Old red bricks were fired at a higher temp and will last longer-with less spalling than new bricks...and you sometimes just don't know what you've got until you've put them into use.

David's suggestion of placing the bricks loose on the floor for easy replacement is great...just remember to put a thin sand bed between the perlcrete insulating layer (or insulation board) and the hearth bricks to help leveling. Also, leave a little gap between the dome and the hearth bricks so you actually can get a failing brick out fairly easily (the little perimeter gap will quickly fill with ashes, so the bricks won't wander).

[Blacklab]

Re: close to breaking ground

Thank you Sable Springs for the welcome and insight

Well I thought I was on the right track.

Doesn't the slab have to be insulated under the fire brick? If not I can do rebar.
red clay brick free fire brick $5 each
Sand dome
home brew? I can go 5 inch's thick
blanket it's in the mail 1x24x25
chicken wire
? stucco, Portland cement? how thick 3-5

Thanks for not letting me run this thing in the ditch

Blacklab
alias Mike

[Laurentius]

Re: close to breaking ground

The slab itself is not insulated, but insulation should be placed between the slab and the hearth(fire bricks). This will isolate the heat within the oven, to keep it from migrating into the slab, which would make it unmanageable or controlled. This is called a heat sink.

[SableSprings]

Re: close to breaking ground

Doesn't the slab have to be insulated under the fire brick? If not I can do rebar.
red clay brick free fire brick $5 each
Sand dome
***
home brew? I can go 5 inch's thick
blanket it's in the mail 1x24x25
chicken wire
? stucco, Portland cement? how thick 3-5

As Laurentius said above, it's extremely important to insulate your supporting slab from your oven. Maybe this initial construction overview will make it little more clear. I know this will only addresses the first three items of your list ... but you have lots to do before the other items come into play. I'm assuming you have requested/downloaded the free oven plans from Forno Bravo...even though you aren't planning on building a brick oven, the plans include pertinent information that applies to all wood-fired oven types.

1) Foundation slab poured or other type of ground foundation created (oven and stand will be built on this...it's important!)
2) Usually cinderblocks are stacked (dry or mortared) as a base stand on the foundation
3) A form is built on top of the cinderblock stand for a 4" pour of concrete.
4) Rebar is set into the form (often extending into the base stand) and then the concrete support slab is poured.
5) The concrete needs to be cured for a week or so before proceeding.
6) Either an insulating board (2"-4") or a perlcrete/vermicrete layer (4"-6") is placed/poured on top of the concrete support slab where the oven will be placed/built - remember you want this insulation to extend fully underneath not only the hearth bricks, but the oven walls as well. So, if you want a 39" inside diameter oven with 4" thick walls, your insulation pad will be 4"+39"+4"+1/2"+1" = 48" in diameter and it should extend some in front under the landing/oven entrance). Note the 1/2" is to allow for a 1/4" gap around the outside of the hearth bricks, so you can place/replace them more easily if needed and the 1" will give you a little margin of error.
7) Layout & cut hearth bricks (& number them ) on top of the insulation board/layer to fit your design & size specs (some people do this with just a tape measure or cardboard cutout, but I like to actually see the pieces fit).
8) Mark the outside perimeter of the hearth brick layout
9) Remove bricks (or not) & start building your sand form - (use a brick for a thickness guide at the base of your form...)

That's going to take a while, so read the free oven plans & keep reading through the forum...especially the Hidden Treasures I linked below. I'm sure you'll get lots of versions of my initial task/time line, but remember there's lots of ways to a successful project and no perfect "one plan fits all" version.

http://www.fornobravo.com/forum/f2/n...res-15133.html

Firebricks: I don't know where you are in Washington, but if you are near Spokane, try pricing firebrick at Willamette-Graystone there. If that store doesn't work for you, call some local contractors and ask them about getting firebrick...if they include fireplaces in their jobs, they'll have some supplier suggestions for you.

Insulation Batting: Hopefully you'll be able to get 2" thickness over the oven...never know until it's wrapped. If you can't get 2" of insulation from the batting, you'll want to do either more batting or add a layer of perlite, vermiculite, perlcrete, or vermicrete...you never can have too much insulation!

Sorry, didn't mean to ramble on...but it's a lot better to read more & plan carefully in the early stages than it is to try and figure out how to fix a mistake that's now under a hundred pounds of hardened home brew or concrete...

[Blacklab]

Re: close to breaking ground

Thank you guy's!
After reading your post, I've had a couple awe ha moments I appreciate it.
Spokane is about 7hrs ne of me. I do know a couple contractors, that was one awe ha. lol I'll post pics of progress. Weather is perfect and I'm getting excited.

Thanks again for your time an help.
Blacklab
alias Mike

[vertigopilot]

Re: close to breaking ground

Thank you guy's!
After reading your post, I've had a couple awe ha moments I appreciate it.
Spokane is about 7hrs ne of me. I do know a couple contractors, that was one awe ha. lol I'll post pics of progress. Weather is perfect and I'm getting excited.

Thanks again for your time an help.
Blacklab
alias Mike

Blacklab:

I'm guessing that you're west of the Cascades (as I am). You can get firebricks readily (and at reasonable cost) from Mutual Materials with various locations around the state. Get your fireclay from them too. Perlite and vermiculite can by bought readily in quantity from your local farmers' supply.

I just finished my latest oven (a barrel-vaulted design), and will probably build a homebrew cast dome over a sand-form next for a friend. Send me a PM if you'd like to chat about details or come have a look at mine. The oven is always hot and the housebrew cold and bubbly.

-Jim

[Blacklab]

Re: close to breaking ground

Thanks vertigopilot. I already have fire clay rated 2300F 100lbs for $33. I just talked with a contractor friend on the bricks, I'll know price tomorrow. Hell I might just see about getting all my materials through him