Deciding on a Base

[dmun]

Just a quick question, why cob? As a smith, you must know how important proper refractory materials are to reflect and concentrate heat from a fire.

For you base, it's always best to build on a base of well drained crushed rock, unless you are digging down below the frost line and pouring footings on bare rock.

My 1920's concrete block outbuilding was built on shallow field rock footings, mortared together, but it did crack in a couple of places. I still think you're better off with proper footings of one kind or another.

[Allen]

Hi, thanks for responding.

Originally Posted by dmun

Just a quick question, why cob? As a smith, you must know how important proper refractory materials are to reflect and concentrate heat from a fire.

For a gas forge, refractory like kaowool and ITC-100 play an important part.
For a coal or charcoal fire, refractory plays no part.

I like the look of cob and how its made. Its more of a rustic construction than brick.
Are you saying that cob is that much less efficient than a brick oven that it isn't worth pursuing?
If cob is that bad then we'll have to look at brick construction.

How shallow are the footings on that outbuilding?
Here in Pa., 36" down should be fine for what we want to do. Unless I'm not understanding what you mean.
Allen

[dmun]

If you are going down the 36 inches, then you're under the frost line, and you can build direct on bare ground, no problem.

I'm not arguing against the cobb, I'm just wondering why someone used to managing fires for high heat would make that choice. If you like the look, that's all you need to know.

[james]

One thing about getting the look you want. The oven itself can be brick, alla the Pompeii Oven, but you can finish the exterior of your oven any way you want. You can have the advantages of a real brick oven -- high heat cooking, better heat retention, longevity, etc., and still get the rustic, hand-hewn look on the outside.
James

[geisen]

Pompeii ovens have been around for .......well, as long as Pompeii. I walked through the steets of Pompeii and Herculenium many times and always enjoyed exploring the sidewalk store-front pizza stalls with WFO dome ovens just like we are all making. Yes, their bricks were probably not made with exactly the same materials and I highly doubt they had wet saws, but the basic engineering was the same. Some of them looked like you could just start a fire today, even after being buried by lava dust for generations. Way cool. My avatar is from the pompeii theater. seemed appropriate.

[dazarooney]

Some useful information in here, thanks!

[fljaweiu]

Thanks Verschwindende, look forward to the result.