Instructables
Picture of Building a WFO (wood fired oven)

In the spirit of off the gridness and in an effort to be more self-sufficient, my wife and I recently tackled a new project at home.  We built a wood-fired oven, or WFO, if you prefer. 

An outdoor wood-fired oven gives us another option for many kinds of cooking.  It also provides a great accompaniment to the barbecue.  The WFO is a lot of fun to built and use.  It provides a lot of feel good factor for having done it ourselves with little money.  Of course, it also makes great tasting food.

We over-researched the subject by reading several books and by searching online before finally building it.  We need not have prepped so much.  Two of the most helpful resources were http://www.traditionaloven.com and the book “Build Your Own Earth Oven, 3rd Edition: A Low-Cost Wood-Fired Mud Oven; Simple Sourdough Bread; Perfect Loaves” by Kiko Denzer.


Materials list and cost:

I used:

less than 1.5 yards of 5/8 minus for the entire project – about $40.

"Urbanite" and large rocks - free.

Concrete block – free from freecycle.

Sand – free from river.

Coarse Sawdust – free from a local lumber mill.

Perlite – about $30 from the hardware store.

Clay – $150.  (It could have been free with more elbow grease)

Material for the door – free from around the property.

 

Total cost:        under $200.


 
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Step 1: Pick your type of WFO

Type:  We discovered that there are several types of WFO’s.  Which is best depends on who is writing the article.  Our primary concerns were the difficulty of the project, the cost of the project, and the look of the project.  A $15,000 brick and marble WFO would look silly sitting next to our farmhouse, would be way beyond our budget, and might be beyond our construction ability.  We decided on an adobe, cob, or clay oven.  They exact material seems to be interchangeable.  Since we are part-time potters, we happened to have a sixty-gallon garbage can full of left over clay from the past couple of years.  We decided to use what we had

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jawnn4 months ago

What kind of clay did you use? Was it a low fire clay?

Have you had any problems with the clay absorbing moisture out of the air yet?

jon ball (author)  jawnn3 months ago

we used a mix of lowfire 04 up to highfire cone 10. we've had many problems with it. The decorative items have all separated. Large cracks (1/2") have popped up here and there. The mouth has lost most of its structure. However, we just keep slapping clay on it to fill in the cracks and keep on going. Cooked last weekend with it. Got it to 1600F inside, still cool outside, flash cooked the first pizzas, kept cooking the rest of the day. It was still warm the next morning. We had intended to rebuild it this summer, but the misses has been diagnosed with wheat, egg, and diary allergies. so................not sure at this point. I am trying to win the arguement for conversion to a forge - I've a hankering to pound out some sharp n pointy things.

jon ball (author)  jon ball3 months ago

sorry, i meant Dairy ....not diary.

saosport6 months ago

Does anyone know how one of these would hold up in the Midwest? I live in WI and thought it would be great but I am not sure how it would hold up in winter.

ilhadad1 year ago
What is clay slip? Where can you get this material?
jon ball (author)  ilhadad9 months ago

Sorry about the delay. Yup, just mix clay with water. Runny or thick, it is up to you.

theegghead9 months ago

clay slip is just clay mixed with water

This looks great! I am working on starting a bakery, and have been wondering about doing something like this for some more special breads, in addition to stuff baked in a regular oven. Wood in my area is kind of sparse, so I might take on your challenge of making a gas powered version.
I am wondering (you might have an answer), are these kinds of ovens more energy efficient than modern kitchen ovens or industrial ovens?
I'll let you know if I ever get to making my own one.
surfdude2 years ago
Great job an nice instructable.
drewgrey3 years ago
Good job, Did you say half a 5 gallon bucket of wood to bring it to temp. Thats amazing. Mine takes alot more than that. I have a laser thermometer that says that I have an average cooking temp of 750 or so. Do you have a metal peel yet?
jon ball (author)  drewgrey3 years ago
Ya sure. We bought one from our local Grocery Outlet. It was a tad bit wide so I had to shave it up a bit.

Tell me about your laser thermometer. I've not seen one of those. We would like to be able to tell just how hot the oven gets. "white" "red" "orange" works pretty well when temping metal, but not so much for the inside of a dark oven.

Remember that for our heat we burn the wood to coals and then soak the oven with the door on for a couple of hours. That really saturates the base and the oven with heat which is then reflected back into the cooking chamber. Patience is a virtue here. If we have a long day ahead of us we will renew the coals and keep a few pushed to the back of the oven. It does take more wood then. Usually we use scrap fir or cedar to start it going and the heating fire is from maple or alder. We are curious how this would work with charcoal briquettes right out of the bag. I suppose that this could be rigged to use gas as well. Curious.
We got our laser thermometer from sears but harbor frieght has them cheap also.It gives a reading off whatever its pointed at. We got it for brewing beer but have found it entertaining for other stuff ( like testing my cladding compound for heat retention and insulation).
We start our fire at least 2 hours before showtime and continue burning while we cook. Since we have an interior diameter of 36" there is room for the fire at the back and pizza in front. After every few pizzas we pull the fire to the front to clean the cooking area, or after a cheese and topping malfunction. A great benifit of having a fire while cooking is that the pizza wants to be cooked from both sides at the same time. Perfect crust and slightly tan cheese!
IMG_9796.jpgIMG_1871.JPG
Lovely work.
I have lots of questions.
Can you please add a photo of your door?
Is there a chimney, or does all the smoke come out the front?
Where does the fresh air come from to feed the fire?
What method do you use to remove fire and ash before cooking?
Thanks.
jon ball (author)  Ricardo Furioso3 years ago
No chimney. All smoke come out of the front. The wood is burned with the door off. When only coals are left, the door is placed. After a period of time (the "soak" period) the door is removed. we bent a piece of metal, attached it to a stick, and use it to scrape out the coals into a steel bucket. A rag wrapped end of another stick is soaked in water and used to "mop" out all (most) of the charcoal.

I am getting ready to post another series of pics. we've torn off the exterior layer, mixed in about 40% more sand, have placed the new exterior layer back on, are letting it cure to the right consistency for wacking (preshaping) then final shaping. We are going to add on an arched entry made of clay which has been fired in the kiln. This will give us a place and the support for a front located chimney.

I'll post pics of the hardware then as well.
jbchurchill3 years ago
Nice! Very inspiring!
tim_n3 years ago
You wanted pics, I post pics :)

Mine is more rustic, I've not added the final finishing clay level. The odd rustic look is made by the insulation - that's clay slip mixed with sawdust. Seemed to do the trick anyway - only started getting really hot after we'd been using it about 4hrs. First pic as the pizza was in, 2nd pic as I removed the first ever cooked pizza.
pizzaoven.JPGpizzas.JPG
tim_n tim_n3 years ago
If you want to see my pics you can goto www.waark.com and see the steps I used.
brazell3 years ago
Great job!!!! It looks beautiful! Can you take a pic of the door?
jon ball (author)  brazell3 years ago
As you can see the door is rough. The next one will fit better. Still, after a year, it works great! All of the screws are short so that they do not go all the way through. The handles stay cool.
mis 001.jpgmis 003.jpg
DriX jon ball3 years ago
Your door is made of wood???
Mine is made of 1/2'' iron and bends a little over time because of the extreme heat.
brazell DriX3 years ago
No, the door has a tile backer, but I did not understand what he meant, so I asked for a picture. You just have to read the whole thing and it is on step 13. See below. Also, I am not trying to be snippy/snarky/sarcastic, hope it doesn't seem that way.

13...."A door made from 2x6’s was cut to shape. 1x6’s were cut to go over the face of the door and to extend 1” beyond the door in order to act as a flange to keep the door from falling in. An extra chunk of tile-backer was cut to shape and screwed onto the inside surface of the door for a heat shield. A pair of handles left over from a previous project completed the door."

DriX brazell3 years ago
Thanks, english isn't my first language so somethimes i don't understand something (i didn't knew the meaning of "tile-backer").

Now it's clear. But i'm concerned about that door, it might catch on fire.. Mine turns orange-red sometimes..

Here they are quite common, we call them "hornos de barro" ("mud oven").

But we don't make it that way, we use mud mixed with: dry grass, horse/cow poop, glass dust, and other little secret engredients. And it's VERY important to bake it very very very well. And you have to let the mix seat a couple days so it ferments a little.
We also use mud bricks for the structure.
And is mandatory to put a chimney with some sort of valve if possible.

They reach sick temperatures, if you put a piece of wood inside, it will start to burn just in contact with the inside hot air.

I'm not trying to criticize your work, I really like your oven, I just want to give some advice because I know the subject ;)
jon ball (author)  DriX3 years ago
I didn't take it poorly. Ours gets very hot. We used a wood stove thermometer and the heat was off of the scale. So, it's over 1600 farenheit. I'd be careful of the glass dust due to the risk of silica poisoning - silicosis.

As I mentioned someplace else here, we are going to remove the outer clay layer, mix in more binder material, recover it, and add a small chamber in front with a chimney.

I'll update this with the new pics as we progress.
jon ball (author)  jon ball3 years ago
I forgot to mention that we soak the door in water prior to firing.
jon ball (author)  DriX3 years ago
Yup. The Hardi Backer keeps it from burning. The chard part is because I have a slight gap there. The handles and exterior wood only get warm. The handles would get hot if I would have put the handle screws all the way through the door. But they are recessed a bit into the 2x6 - the Hardi Backer doesn't even touch them. I would think that an iron door would get too hot. Too hot to handle. (sorry, that reminded me of a song from one of my fav early 80's bands UFO)
Thank you for posting that. I just wanted to get an idea of what you were talking about. I have tons of rocks from the creek below the house. I saw one of the commentators below say that they made one years ago from one like that and in ancient times they did as well, I may have to do some research on that technique since I have different local materials here in Alabama. Thanks so much for sharing!!! I love the taste from a wood fire oven and like the idea of not having to use that much wood.
What a wonderful job and willing to share the details with us here. I love just looking at it let alone it being useful! Something I always wondered and wanted to do also. Maybe someday soon...ahhhh..
splazem3 years ago
Cool! Looks amazing!
mandersen3 years ago
is it possible to design it to have a wood storage area under the oven? That would be convenient if it could be done.
neffk3 years ago
I have a 36" hemispherical WFO and it takes a lot more wood---a paper grocery bag full---to get it up to temp for pizzas. And that's real wood, not sticks and twiggs.
jon ball (author)  neffk3 years ago
We had intended to go with a 36" as well but decided that would could enjoy it and use it more if it was smaller.
neffk jon ball3 years ago
A good choice, I think. And nicely executed.
germeten3 years ago
Artfully done, but couldn't the lower foundation have been used as the
firebox, with the upper portion for cooking, baking etc.? It seems like a
lot of work and a burly foundation, just to have a relatively smaller
cooking area from which you need to add and remove coals
jon ball (author)  germeten3 years ago
We considered doing just that but decided to keep it simple. The massive foundation layer truly acts as thermal mass that radiates the heat back into the oven over time. Plus, we never have to bend over. The oven gets very hot. Though the exterior layer only gets warm to the touch.
The cinder blocks used on the outside of the foundation wouldn't stand up to the heat, so a layer on insulation and an inner liner would need to be between the firebox and the cinder block.
ctrimble13 years ago
This looks fantastic! you both did an awesome job- !!!
I don't see a chimney.

No chimney?
traditional southwest style adobe ovens don't seem to have a chimney either. You burn wood with the door open until the retained heat is high enough and then brush out the ashes, add the food and seal the door.
jon ball (author)  kill-a-watt3 years ago
This one works great! The next incarnation will work better. Our foundation and foundation height really helps, as a heat sink and as a convenient height from which to work.
gfc623 years ago
Did you lay the blocks set in mortar or did you just dry lay them without any mortar or other adhesive?
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