My WFO design

[shuboyje]

If it's good enough to make pottery, with all the complicated glazes (thats COMPLICATED), simple bottom - top heat calculations at a relatively low temp should be easy.  I like the crossdraft, U-shape supply with adjustable vent.  It's close in concept to the LBE.  Can you take some pictures of the other potter's ovens?  Are they much different?

I'm really looking forward to seeing how it turns out, with you and Meesh collaborating.  I live in an area with lots of good clay, plentiful firewood, and my wife used to make pottery in a little kiln - I'm thinking of giving this a try too.

Pottery and pizza are very different things. Pottery kilns take a long time to heat with the goal being an even temperature throughout.  That's not what we are after with pizza.  For home use getting the hearth to 900F in an hour and a half like you can in a black oven is going to be the design challenge.  Not saying it can't be done, but it will take design work to get the heat down to the floor.  Reverb furnaces for melting metal are also very similar to this.  They require lots of design for a throat that directs the heat down on the hearth.    

[shuboyje]

I want to say again that I really appreciate the suggestions, collective wisdom, and the discussion here. My design has changed quite a bit because of everyone's input.

It's a lot of fun isn't it.  Nice to run across somebody who doesn't think people are being jerks, just trying to help.

[pizzaneer]

It's a lot of fun isn't it.  Nice to run across somebody who doesn't think people are being jerks, just trying to help.

Second that!

[adios pantalones]

It's a lot of fun isn't it.  Nice to run across somebody who doesn't think people are being jerks, just trying to help.

Absolutely. I'm confident that I can "make stuff hot" as well as the next guy- but that doesn't mean I can build a proper appliance for making pizza, blowing glass, or smelting ore.

Talking about where the heat goes makes me think of my early struggles in firing my kiln properly (everyone ruins pots in learning a new kiln)- but it turns out that a tall chimney can be made to suck fire down low in a kiln (I used to over fire the bottom stacks). Slowing the fire (using the damper) gets more heat up top. I'll run a couple test fires to learn this "kiln" as well.

(making stuff hot)

[adios pantalones]

pizzaneer- here's some shots of my kiln. The firebox is a "Bourry box"- 40" wide wood is suspended above the coal bed- primary air is sucked through the wood charge, so it effectively burns upside down. The fire gets superheated as it approaches the coal bed. The firebox shot shows the "throat" area as well. This firebox design has a number of advantages,including the ability to put a lot of wood in, and that the wood shields you from the intense heat in the kiln (some other designs will catch you on fire from radiative heat if you aren't careful).

The pic with me loading shows the flue area- the vent to the chimney. They go all the way across to even flow, and I have "passive dampers" that I can use to direct heat left and right to even out a firing.

The fire pic is me next to the firebox during a "reduction" cycle- getting the burn to be inefficient at certain times actually helps with clay and glaze colors. With the draft slowed way down, the gases produced by the heating wood create a back pressure, and the hot gases combust when they hit air.

[scott123]

AP, I'm confident that you're going to have no problem getting the heat out of your setup.

Btw, speaking of kilns and pizza (and reduction), have you seen this?

http://www.pizzamaking.com/forum/index.php/topic,15696.0.html

[Tscarborough]

The idea of improving upon 5000+ years of baking experience seems to be a bit of a waste of time to me.  If you are trying for a new type or style of cooking I can see it, but realistically, the problem was been solved and refined to a high degree.  What is the point?  Do you want to have a combo kiln/oven?

[adios pantalones]

The idea of improving upon 5000+ years of baking experience seems to be a bit of a waste of time to me.  If you are trying for a new type or style of cooking I can see it, but realistically, the problem was been solved and refined to a high degree.  What is the point?  Do you want to have a combo kiln/oven?

No, I just want to have fun.

I admit that I have that damn Cindy Lauper song in my head now.
I hope to have a combo oven and smoker.

[pizzaneer]

pizzaneer- here's some shots of my kiln. The firebox is a "Bourry box"- 40" wide wood is suspended above the coal bed- primary air is sucked through the wood charge, so it effectively burns upside down. The fire gets superheated as it approaches the coal bed. The firebox shot shows the "throat" area as well. This firebox design has a number of advantages,including the ability to put a lot of wood in, and that the wood shields you from the intense heat in the kiln (some other designs will catch you on fire from radiative heat if you aren't careful).

The pic with me loading shows the flue area- the vent to the chimney. They go all the way across to even flow, and I have "passive dampers" that I can use to direct heat left and right to even out a firing.

The fire pic is me next to the firebox during a "reduction" cycle- getting the burn to be inefficient at certain times actually helps with clay and glaze colors. With the draft slowed way down, the gases produced by the heating wood create a back pressure, and the hot gases combust when they hit air.

SEE? I TOLD you guys, this is more complicated than pizza!  Man, a pizza- making kiln...  not since the days of the old coal-fired bread ovens that were adapted for pizza.  Ground-up design, and someone who is welcoming input into how to make an ideal cooking situation for pizza.  C'mon you WFO ppl!

[Tscarborough]

In my opinion, it is not worth the effort.  You end up with an appliance that is "OK" for the multiple uses, but not optimized for either.  Better to build the smoker next to the oven, or the fireplace next to oven, or the grill next to the oven, rather than try and bastardize a combination that is a compromise of both.

[adios pantalones]

AP, I'm confident that you're going to have no problem getting the heat out of your setup.

Btw, speaking of kilns and pizza (and reduction), have you seen this?

http://www.pizzamaking.com/forum/index.php/topic,15696.0.html

That's pretty funny. They'd have a hard time firing too much pottery in it after making pizzas- the elements get stuff condensed on them and corrode at high temps.

If you ever get a cheap electric kiln on Craigslist to experiment with- watch out- some low fire glaze chemicals are volatile. You could have a heavy metal condensing out on your cheese

[adios pantalones]

In my opinion, it is not worth the effort.  You end up with an appliance that is "OK" for the multiple uses, but not optimized for either.  Better to build the smoker next to the oven, or the fireplace next to oven, or the grill next to the oven, rather than try and bastardize a combination that is a compromise of both.

I appreciate the words, and you may be right- except that "the effort" is the fun of it for me.

I could be more efficient in the boudoir too, I suppose  

[Tscarborough]

Yes, if that is the aspect that interests you then full speed ahead, Damn the torpedoes!

[scott123]

That's pretty funny. They'd have a hard time firing too much pottery in it after making pizzas- the elements get stuff condensed on them and corrode at high temps.

From the glow of the red emanating from the kiln, it looks to me that they're running these at pretty high temps. Do you think the elements might be corroding now?

[adios pantalones]

From the glow of the red emanating from the kiln, it looks to me that they're running these at pretty high temps. Do you think the elements might be corroding now?

I think elements are always in the process of oxidizing. If they run these at a high setting they will likely fail earlier than elements in a system designed for pizza, but they may have a good service life- I couldn't say.

There are coatings that you can put in a kiln that help reflect heat and resist corrosive atmospheres, and coatings for elements that will help them resist corrosion. Some fairly respected people make amazing claims about "ITC 100" and "ITC 213" slashing their electric bills and saving element life.