Reply Cancel Billy Kearney - I am curious about the rocket stove exhaust pipe. Did you also put a chimney there near the front door? I was planning an oven and stumbled on this brilliant blog. Thanks for the inspiration! Thanks so much for sharing, it looks lovely!

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Finding Clay Subsoil Clay subsoil is pretty easy to recognize. I take a pinch of dirt in my palm, spit into it, and mix it with a finger. Silt or organic matter feels floury or crumbly. Clay feels sticky, slippery, and a bit greasy. Wetted, it rolls into snakes between your palms and wraps around your finger. Beware dirt that may contain glass or debris; ask permission where necessary.

When dry, the clay should be hard, not crumbly. Test it. Make bricks and let them dry. See how much they crack and how hard they are. Try mixing dirt with sand, and make more bricks. If they show less cracking and shrinkage, good! Compare and choose the best. Remember what your proportions were. Your Oven Floor The simplest and easiest thing to do is simply to set your floor bricks in a cm in bed of sand, tamped and smoothed into an even, level bed.

No mortar is necessary. The bricks will be held in place by the heavy, solid oven walls. Set your first brick carefully, level and solid. Hold the next brick level and about 2.

Set it flat and firm on the sand. Minimize cracks and gaps. If one stands up a bit proud, tap it down. Sand or whatever should be moist enough to pack into a ball, but not so wet that it slumps. Make a pile on the floor bricks. The form should be a bit higher than the radius of the oven floor. A 69cm 27in diameter oven, with a 34cm 13in radius, should be cm in high. Hold a straight stick level across the top; measure the distance to the floor to get the interior height of your oven.

Write down the number! Mix Mud Use whatever mixture gave you the best, hardest, strongest test bricks. Prepare a pile of dry mix on your tarp. With two people, hold two corners of the tarp each — feet spread, knees bent, elbows down and shoulders back — roll the mix from side to side.

You can do this solo by pulling one end of the tarp over the other, rolling as you go. A longer tarp is easier.

Or just use bare hands and feet and muck around in it. Add water slowly. Take off your shoes, jump in, and do the twist — seriously! As you twist and turn, your feet work like rotating pistons, breaking up the clay and pressing sand into it. Play music! Grab a partner! Pack a hard ball pats from hand to hand. Drop it from breast height. It should hold together. If not, add a little water. Smooth them down flat. Press handfuls of your mix around the base of your sand form.

Use your fingers as a gauge to guide you in maintaining thickness. Make a layer at least three inches thick. You can make it thicker it will hold more heat , but a thicker oven also requires more fuel. Maintain a well-defined edge.

As you go higher, the face of the layer should angle upwards. Your mix was too damp. Rock the board firmly back and forth, up and down, or rub it as if you were polishing. Make it beautiful. Say your dome is Your door should be 0.

Scratch a line in the material where the door will be. Cut a hole just big enough to get your hand in. Dig a narrow channel into the form.

If the mix was moist but not wet, you can dig out the whole form immediately. Cracking due to natural expansion invariably occurs during firing. You can also soak it in water, or screw a sheet of metal to the inside, or wrap it in foil.

He is a sculptor and builder who has been working with cob and earthen materials for 8 years. Ovens in such settings often have a foot or more of insulation; some have baked as much as five pounds of bread for a single pound of fuel burned! But any oven, when insulated around top, bottom, and sides, will hold heat longer and cook more food per pound of wood burnt.

No matter how you use your oven, insulation is important. I strongly recommend it. I became particularly concerned about this issue after seeing some reports from builders making ovens in Africa, where wood is scarce and the where loss of vegetation is replacing forests and fields with deserts.

First a quick review: a masonry oven bakes so well because hot, densemasonry radiates heat evenly into the small, hollow cook space on the inside. At the same time, however, a masonry oven loses heat in every other direction.

In brick, stone, or earth, however, when the rigidly connected molecules heat up, they get excited. In a liquid or gaseous state, that excitement would cause them to flow think volcanoes and lava.

Well, imagine a room completely filled with beach balls. That is, essentially, the principle of conductivity at work, and that is how it moves heat in all directions. In your oven, conductivity moves heat into every material in contact with it, including the earth under your feet. This causes problems, whether you live in a land suffering from over-harvesting, over-grazing, and desertification, or whether you live in a fuel and forest rich area.

We all depend on trees and forest for the air and environment that make life possible. So I hope you might reflect on your relationship to the forest and make some important strategic decisions about efficiency and fuel consumption — and perhaps move closer to the precious and sacred sources of all life. This radiant property of heat is what makes masonry ovens effective, but it can also make them very inefficient.

It takes a lot of wood to heat up that masonry, but if you only cook a single loaf of bread, most of the heat will be lost and wasted. So the trick is to take specific steps to maximize your use of the internal heat of the oven, and to minimize external heat losses. If you do take those steps, and if you bake every day, you can bake extremely efficiently.

On the other hand, if your oven is only used occasionally, and cools down between bakes, efficiency will diminish significantly. But you can still improve it by the same principles of maximizing use and minimizing loss of heat. Then you mix the slip with some kind of coarsely chopped, dry woody material. So make a test ball. When it dries, it should be fireproof lightweight, and it should stay stuck together. A very good additional experiment is to fire your test ball as hot as you can, either in a wood-stove, an oven, or a campfire.

Indeed, this is essentially how insulating fire brick is made. If you were so inclined, you could make such bricks and use them for insulation. And if you have a supply of recycled? Just to prove to yourself the value of the foil, put your hand as close as you can stand to a burning candle. Then put a piece of foil between your hand and the flame. How much closer can you go? Alan Scott, the grandfather of modern brick oven-building, makes very sophisticated hanging slabs of insulated concrete under his ovens.

They further reduce heat loss by using a cleverly engineered air gap to isolate the floor of the oven from the foundation and the ground. For more info, see The Bread Builders, by Scott and Wing In addition, there are groups and individuals working on fuel efficient, low-mass, non-radiant ovens and stoves for use in fuel-poor countries. One of them is Aprovecho Institute, in Oregon, which has some good things posted on their website, aprovecho.


Build Your Own Earth Oven

Finding Clay Subsoil Clay subsoil is pretty easy to recognize. I take a pinch of dirt in my palm, spit into it, and mix it with a finger. Silt or organic matter feels floury or crumbly. Clay feels sticky, slippery, and a bit greasy. Wetted, it rolls into snakes between your palms and wraps around your finger. Beware dirt that may contain glass or debris; ask permission where necessary.


Build Your Own Wood-Fired Earth Oven

Build the Stand -Advertisement- 1. Build a firm base. We used some spare cinder blocks. Keep it level and build the structure up to a comfortable working height for cooking. Prepare a solid floor for your oven.


The Simple Art of Making an Earth Oven

It looks better than the past few efforts, but still not the pounds I was aiming for when I fenced off the 3, sq. The baker is Noah Elbers, who runs a small bakery in New Hampshire. He does participate in the brickoven group on yahoogroups, which is where this comment came from. Here was my schedule and quantities just to give you an idea. I would fire the oven from cold at am. With three stokings a brisk fire most of the time the oven was fully saturated by am.



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