Wood Fired Pizza Oven Designs
Howdy,
I saw a number of posts I could have replied to but I thought it best to start a new post.
This relates to another earthen stove material.
Cob/adobe is not water stable. Portland cement does not breath and does not do well in high temperatures. Refractory cement is expensive and does not breath (I think). bricks are expensive.
There is another route which is not well understood by most DIY folk, but which has much potential. It draws from the ancient cements, the pozzolan cement of Rome and accelerated sodium silicate cements used by the Egyptians and also in modern times. The generalized chemistry that includes these is called geopolymerization.
The result is like ceramic, it breaths like terra cotta and is water/acid stable. But it can be cured with a fire inside the oven. Despite the root "polymer" in the name, there is no organic plastic funny business. Just, alkali (sodium hydroxide) and alumino-silicates (minerals). The DIY route of making this from fire ashes, local clays and lime is not well explored or documented.
Expensive? There is no centralized production available to citizens. But I am in the process of being able to make small batches, and even I could ship enough binder to build a BIG oven inside the US for under $100 (including materials, labor, shipping etc). Mix this with another $100 worth of cheap truckload type material to get your oven. If you have access to a ceramics kiln, then you could make it yourself for much less.
I am not offering anything for sale. I am just a student of the hard sciences pursuing an idea that sounds really excellent. And I am promoting my project to explore and publisize this technology, which will result in the compiled experiences of people from many backgrounds working on a variety of different applications.
Please follow up with me if you want to be informed of developments in this project, or if you want to participate/contribute. I cannot promise to post back here as the project unfolds.
Proposed Geopolymer Project
I am trying to raise money here: Making Geopolymer technology accessible — Kickstarter
thanks!
-Elliot
Firebricks, pavers, and a heavy metal table. All the materials needed for our oven.
Make sure the table is strong enough to hold the weight of the bricks and pavers, and can withstand the heat. Lay out the pavers first to create an insulating buffer.
This is the jig that will be used to form the archway.
On top of the pavers, lay down a tight-fitting pad of fire bricks. Keep them as even as possible–this will be the floor of the oven.
Build up the back wall, using half-sized bricks along the sides to keep everything fairly even.
With the back wall set, place a length of angle iron along what will become the side walls. The angle iron pieces are pre-drilled for threaded rod to extend across and keep the side walls fitting snug.
The side walls shouldn’t be too tall – you want to keep the internal heat contained in a low area. A standing brick is the right size. Continue these all the way forward on both sides, keeping the bricks as tight as possible.
With the side and back walls finished, it’s now possible to start sealing. A mix of fire clay and sand will keep in the smoke and some heat, but isn’t weather proof – this allows you to clean and disassemble the oven easily.
Apply the mix to the corners and all seams. Use a liberal amount of it to make sure no gaps form when it dries.
The archway is formed on top of the jig, starting from the back. Put the bricks on from both outside edges, moving inwards.
A small shard of broken brick helps maintain the spaces that occur by the curvature of the arch.
Before removing the jig, place another layer of bricks onto the sidewalls and lock them in place with angle iron, as done on bottom. Once done, the jig can be shimmied out to let the brick arch settle into place.
Three layers of bricks gives a fairly sizeable pizza area. You can see how they stack tightly.
Another piece of angle iron bridges the bricks on the side of the opening (large enough for a peel but not too large). Bricks on top leave a space for the chimney to vent from. Keep the chimney in front, to help pull the heat forward from the burning wood at the back of the oven.
Here is the front of the pizza with the bricked-in chimney and walls.
A healthy slathering of the sand/fireclay mix on the roof and chimney areas help seal everything from escaping heat and smoke.
The chimney and walls are now sealed.
Firing up! Start the fire small to let the heat build gradually, without blowing a ton of smoke out the top.
As the fire continues, soot collects on the interior of the dome. After the heat raises, the soot cooks off.
This design doesn’t have the same heat retention as a multi-thousand dollar commercial unit, so reaching the idea temperature can take 60-90 minutes or more. Once it’s hot enough, sweep the embers to the back and use a wet toweled stick to mop the bricks.
This is my pizza, about 2 minutes into cooking. The crust had a crispy exterior and a soft chewey interior, with the perfect char. Tastiest pizza I’ve ever made.
