Oven Australia

Beautiful oven constructed by Ric Galt.  Note the metal roof fabricated from a corrugated steel water tank.

from Bread Earth and Fire (The Earth Oven)

 con't The Earth Oven

 

You’ll probably find some coarse gravel at the top of the slab, but if you wait just a little bit until it starts to set up, you should be able to trowel it fairly smooth. Don’t worry if it’s not perfect, ours wasn’t and it didn’t matter because the rocks we used for the base were all irregular, and these sat on top of the slab. After your slab gets hard (concrete dries fast in hot weather), and it might only take a couple of hours, you should hose the top of it because you don’t want the top to dry very much faster than the interior. Instead of hosing the slab, you could cover it with a tarp to slow down the drying process. No matter what you do, the next day you should be able to knock off the wooden form and start building up. Although your slab feels hard to the touch, it really takes at least a week for it to fully harden. It’s okay to work on it now, but be aware that you should not drop heavy items on it or walk along its very edge. Abbott and Nancy chose to build the oven base with rocks because aesthetically it worked for them and to get the rocks we had to take their canoes up a lovely Maine river where we found them in a pile. We were very fortunate indeed, because the rocks were left over from where giant towers supporting high-tension lines were sunk into the ground.When searching for oven materials, if what you find is not on your property, then it probably belongs to someone else. Get permission before you take anything, even if it’s only a stone or a pail full of sand or clay.The rocks we took for our project were irregular, but mostly flat and not heavy. However, it took multiple canoe trips to get all we needed, and then we had to load them into a wheelbarrow to haul uphill. Canoeing was fun, but hauling the rocks uphill wasn’t, as the rocks seemed to become heavier and heavier.Yes, there are easier ways to get rocks. You might consider going to Big Box to buy them. Some companies that do landscaping will deliver them to your building site, but you must pay for this service. Nevertheless, you might think it’s a great deal (especially after you’ve done the hauling yourself), but shop around. Nobody says you have to use rocks for your base. In fact, building a rock base will take longer than building your oven proper. An alternative would be cement blocks. They are cheap, functional and easy to use. If you don’t like the industrial look, you can stucco the blocks, add a colorant or paint them. If you decide on a block base, then it’s easier to make a square rather than round base, but you can buy curved blocks if you really want a round base.  If you choose to have a square base, the oven can still be round. Obviously, we preferred the rock look.Find the center point of the slab, and with a string and felt tip pen, draw the biggest circle you can and that should give you a diameter of 48”. The circle defines the outer perimeter of your rocks. In retrospect, however, had we centered the rocks over the drawn circle, we would have had more room inside the base for insulation and the top slab. I recommend centering the rocks over the circle. Of course you could have made the slab bigger, but that would have been more work. to be con't

from Bread Earth and Fire (The Earth Oven)

 THE EARTH OVEN
When you’re done filling the hole with gravel, tamp it down by jumping on it or pounding it with a heavy object. Get is as level as possible, and this is where a four foot level proves very useful.

  It’s time to build the form that will contain the wet concrete. The interior measurement should be 48 X  48 inches. You might say, as I have, “Oh, I just need to buy two - 2 X 4 X 8’s. “Sorry, it won’t work. To make your form, the 2 X 4’s need to overlap. So this is what you need: two pieces 48 inches. 2 pieces 51 inches. Use one-2 X 4 X 8 and one-2 X 4 X 10. Cut the wood with a circular saw, radial arm saw, chop saw or hand saw. Take your time, and cut accurately. Measure twice and cut once, and probably you’ve heard that before. Nail your wooden frame together and center it on the gravel bed. Don’t forget to level the form. You don’t want a parallelogram so measure the diagonals. The number should be the same. For such a small area, this should not be hard to do, at least that’s what I tell myself, and yet, I always find myself making lots of adjustments.

 Measuring the diagonals

Let’s mix up the concrete now. By the way, folks often use the terms cement and concrete interchangeably, but they are different compositions. Cement is a building material that is a powder, made by burning a mixture of shale or clay. It is used with water, sand or gravel to make concrete and mortar. Assuming you’ve purchased bags of ready mix concrete, you’ll only need to add water. Yes, it’s possible to buy Portland cement and mix this with the right proportions of sand and gravel, add water, and you’ll have concrete. For a small job, it’s simply easier to buy the ready mix, and that’s what Abbott and Nancy did. This is not a project to do in freezing weather. Concrete will not set up properly unless specially treated.

Assuming you have a large wheelbarrow, dump in a full bag of concrete mix. Cut the paper off the bag after it’s in the wheelbarrow. Don’t breath concrete dust, perlite dust, or clay dust. In fact, try not to breath dust. Wear a dust mask if necessary. On the bag of concrete mix it will tell you how much water to add, but we didn’t go by this. With the garden hose we added a small amount of water at a time, always using our hoes to make a homogeneous mixture. Too much water makes for a weaker mixture. Not enough water makes it hard to pour. If you’re not sure about how much water to add, then go by the instructions on the bag. Fill your wooden form about half way up, making certain that the concrete is flush against the form with no air pockets, and then place the remesh on the concrete.

Laying Remesh

You can easily bend and fold the remesh so it will fit inside the form. It provides strength to the concrete. You don’t want the remesh on the bottom of the concrete slab, and you don’t want it sticking up through the top. If it’s on the bottom or top, it will add no strength to the slab. Position it so that it remains in the middle of the slab.

Now continue filling the form with concrete until it’s slightly higher than the top of the form. As you pour, jab into the concrete so you won’t have any voids in the slab. Don’t fill half the form, break for lunch, then come back to finish the slab. Depending on the weather it could set up very fast. Your slab will be better if you finish the job without taking a break.

Rinse off your tools because the concrete will harden on them, well, like concrete, and it will be extremely difficult to remove. Fill up a plastic pail with water, and leave your tools in it. Be sure to thoroughly rinse off your wheelbarrow.

 Now you have to “strike off” or screed the slab you have just poured. Look at the photo. This is easiest done with two people. Rest a two by four on the wooden form, and with a sawing motion move it across the form. If you look carefully at the photo you’ll see that our two by four has been spliced together. This is not a good arrangement, but we had to make the splice because yours truly never could measure or count properly, and nobody wanted to make another trip to the store. To screed the slab, use a two by four by eight. No splices please. For the purposes of this book, folks who are not innumerate checked all my numbers.

to be continued

--

Purchased Clay

 mixing clay

Recently I have completed an earth oven that was made with clay purchased from a pottery supply store. The clay was extremely easy to work with. We mixed it with a hoe, one part clay with three parts sand in a wheel barrow and it was much, much easier that stomping the clay to smithereens with one's feet. The cost of the clay was minimal ($30.00) and the consistency was excellent. Building a circular oven with a 31" floor diameter, 15" dome height, 4" thick walls, we used about 125 pounds of clay. The type of clay we used was  fireclay (Hawthorne 40 mesh). If you happen to live in Maine, you can buy it in Portland. However, with kids present, you might want them to do the barefoot-in-the-mud dance.

stomping clay

from Bread Earth and Fire

 THE EARTH OVEN con't

 

Assuming you don’t have to buy any tools for the job, the cost of materials is relatively small considering what you’ll be getting. Abbott and Nancy spent about $250.00 on materials. Labor was free.No matter how careful and neat you are, expect the area where you’ll be doing your work to look like a construction site because that’s what it will be. Don’t leave nails sticking up in boards, and don’t leave tools on the ground where someone could step on them. Always think about your safety and the safety of others. Spread a couple of your tarps.After deciding on a spot for your oven, stake out the area. You’ll be pouring a concrete slab, 48 X 48 inches, but the area you stake out should be at least a foot bigger all the way around, or 60 X 60 inches because you need to give yourself some wiggle room. Now start digging. Abbott and Nancy dug down about one foot, and that seemed about right. Place the sod and topsoil in a pile away from the construction site, or it will just get in your way. However, save it because it’s alive, rich in nutrients, and after the sods decompose, you can shovel what remains into your garden or place around shrubbery. Fill your excavation with enough gravel so that when you pour your slab, it will be as high as your own mowed lawn (if you have one) or higher. You don’t want your slab to be underground.
to be continued

Name Change

I just changed the name of this blog to:
http://ibreadhunter.blogspot.com/
I thought it would be easier for me to remember.
Stu

Mud and Foil

 successively layers of overlapping foil being applied

Here's a photo of an oven I worked on this past weekend. The baker does not want a cover over the oven, and this presents a real problem in protecting it from the elements. An unprotected mud oven in the northeast might disintegrate rather quickly so we decided to wrap the mud dome with aluminum foil. Any water that got to the foil would theoretically just drain down the side. Perhaps over the insulation we'll wrap the oven with another layer of foil become applying the stucco. There are some who say an oven needs to "breath," but after a mud oven has been fired to 1,000 degrees F., the dome becomes rock hard and the ability to breath seems to be a moot point.
There will definitely be an update on this oven.

from Bread Earth and Fire (The Earth Oven)

 baking in the rain

The Earth Oven (con't)

Let’s assume the oven you’re going to construct will be for home use, and you are definitely not going to operate a bakery. If you construct a very large oven, it will be a waste of space, materials, and use too much firewood to heat up. A large oven will also take longer to build and contribute unnecessarily to global degradation. You won’t need the Taj Mahal of ovens. However, an oven that’s too small will be difficult to maneuver pizzas and breads. The Meaders decided on a circular oven with a 22.5-inch floor diameter.

For the purposes of this book, when I refer to the floor, hearth or deck, I am referring to the same place. It is there where your breads sit to bake.

We felt this would be a good size for pizzas as well as breads, but I don’t think you should build anything smaller than this. An oven this size will easily bake four loaves of bread or one or two pizzas at a time, although I personally like baking one pizza at a time. Baking pizzas and breads are always done separately. A pizza should take less than three minutes to cook, and with some help, you can crank out enough pizzas so your garden party of twenty folks will have no reason to complain.

Now we were ready to come up with a supply list, but when you do your oven, it’s not necessary to have all the materials on hand, although it does help.

You can buy most of the materials you’ll need at Big Box, but they won’t have clay, perlite, firebricks, straw, and sawdust. The firebricks are easily found at a masonry supply store. The Perlite and straw you will find at a garden supply store, and the sawdust you can get free from someone who does woodworking. You might find Perlite at big box, but if you do, it will probably be packaged in small bags, and it will be very expensive. It will be much more economical to buy Perlite in large bags. Vermiculite is a similar insulator, and if you can’t find Perlite, than use vermiculite; they are quite similar. Clay can be dug for free if you know where to look, or it can be purchased from a pottery supply store...

to be continued

from Bread Earth and Fire (The Earth Oven)

     The Earth Oven

 
     Abbott, aged 72 is an artist, 16 mm filmmaker and art professor. Nancy, aged 70 is a potter and French teacher. Working with them was a rewarding experience for me. They really are living proof that numbers don’t add up to anything. Senior citizens? What’s that? None around here. And there were no testosterone-charged young men to move 80 pound bags of concrete mix (although that would have helped), nor did anyone help them get the rocks up the hill to the building site. They did it all themselves with just a little help from me, and they celebrated their 50th wedding anniversary in 2008.      Every step in the process, every peek around the corner was an adventure for them because they had never done this before. “Please don’t do anything until I get back,” was a common refrain if someone had to run an errand. When the job was finished and the first rustic pizza was taken from the blazing oven, we all had to laugh considering what everyone went through to get to that final stage, but of course it was all worth it.      After the initial decision had been made to construct an earth oven, they had to decide where it should go. The size of the footprint is not really that much different between a small and large oven so the choice of location will remain the same. We’ll only be talking about outdoor locations because constructing an oven indoors poses some challenges that are beyond the scope of this book. Abbott and Nancy wanted an oven that would be close to their home, visible from the deck, but not pose a fire hazard. Although the oven would be raised off the ground, we still wanted to find a well-drained location because here in New England, frost in the ground could cause the oven to heave up in the spring and create some real problems, such as cracking and shifting the oven off level. Even after finding what we felt would be the best location, we would still dig down below grade for as least one foot and fill the space with gravel.

     The theory was that if any water did get in under the oven, the gravel would allow it to drain, and there would be no or very little freezing under the oven. If you were totally fanatical about preventing frost problems, then you would have to dig a hole about two feet deep, fill it with gravel and then lay in rigid foam insulation that extended six inches beyond the perimeter of the oven base. A slab would then be poured right on the foam. Or you could excavate a hole below the frost line that could be four feet deep and fill that with gravel. There was no way we would follow these alternative paths. We were willing to take our chances with the least demanding approach, and you should be able to as well. We simply dug a hole, filled it with gravel and then poured our slab.

That said, to really cover all your bases, I think it would be a good idea to get some advice from a local masonry contractor. Simply visit a masonry supply store and inquire. From my experience, folks really want to help out. Have a photo of the type of oven you’re planning to build so the person you’re talking to can relate it to your project.      If you are fortunate enough to live in an area where the ground does not freeze, is solid and has good drainage, then all you’ll have to do is level the surface and pour your pad, but more about that later. In fact, depending on the type of oven base you’d like to have, you might not even need to pour a pad.to be continued

from Bread Earth and Fire (The Earth Oven)

 searching for the perfect oven spot

Chapter 1

THE EARTH OVEN

Building the earth oven has been adapted from my book “Earth Oven Adventure.” It is the story about Abbott and Nancy Meader who built an oven in their backyard. Although they had some assistance from friends and me, Abbott and Nancy really did the bulk of the work. And there was a lot of work involved. If you can’t or don’t like moving heavy materials around, then you shouldn’t be building this type of oven. Of course you could always have someone build it for you or help you with it, but if you personally get involved in the physical part of the process, I believe you'll have a greater appreciation for your earth oven. You don’t have to be a mason or someone with special skills. All it takes is desire and not minding the mud you’ll have on your hands. You can use this section of Bread Earth and Fire as a template for constructing your own earth oven. All the information you’ll need will be right here for a 22 1/2 inch hearth diameter oven. I’ve chosen this size because I’ve already made some ovens with this hearth diameter, and they’ve worked out really well. If you want to change the dimensions, then your material quantities will change accordingly, but the basic principals remain the same. Consider reading Build Your Own Earth Oven by Kiko Denzer. He more than anyone else made this low-cost method of oven construction available to everyone.
to be continued