I have always wanted to build a pizza oven, and I finally did. I have no prior experience in making pizza ovens or working with cement, so there was a lot of learning during this process.
I started by making a rough draft of pizza ovens shapes and designs and decided on the semi barrel shape.
Cement (A lot) : Regular for the base and counter, Portland for the oven mold
Stainless Steel Needles
Ceramic Insulating Fabric
5" Stainless Steel Pipe
Plastic Light Cover (or other flexible material)
Plastic Poly Sheet
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Step 1: Foundation
I chose a flat location, and made a 5' x 4' mold for the base of the oven out of plywood. I lined the bottom of the mold with hardboard, so the cement I poured would not bond with the patio. I filled the mold with about 2.5" of cement.
Step 2: Bricks and Base
Once the base had dried I got some bricks and arranged them in a pattern I liked, then fixed them in place. Each brick is 4" tall, and there are 7 layers so the height is around 28".
Step 3: Counter
I made a mold 5'3" x 4' x 2" for the counter to allow for 1.5" of overhang on either side. I placed the mold in my garage (as it has a nice flat surface), and lined the ground with a poly plastic sheet. The mold was filled about halfway up, then a metal grid was added for additional support, before filling the mold. The mold was allowed to dry for a week before being added on top of the brick structure.
Step 4: Making the Molds
I made a mold for the fire chamber with plywood and hardboard. There were 4 parts to the mold: Entry, Main Chamber, Front and, Back.
The entry mold was made out of plywood and plastic light covers. It was 11.5" long x 24" wide (20" opening plus 2" on either side to account for wall width). The width of the walls was 2". The plastic used to create the walls of the entry was 38" x 11.5" to create a height of 12" (semi-circular shape). Although I used the plastic light covers to make the curved roof of the entry, this material was very brittle and I would suggest using something else. I made an aluminum foil "doughnut" covered in clear tape to create a space where the chimney would go.
The main chamber mold was made out of plywood and hardboard. It was 33" long x 54" wide (50" plus 2" on either side to account for wall width). The width of the walls was 2". The hardboard piece used was 85" x 33" to create a barrel height of 27" (semi-circular shape).
The front mold was made after the main chamber mold had dried and based off of it. It was made to sit inside the main chamber. It had an opening the same size as the opening on the entry mold. It was made of a plywood base, with a hardboard curve.
The back mold was made after the main chamber mold had dried and based off of it. It was made to sit inside the main chamber. It was made of a plywood base, with a hardboard curve.
Step 5: Filling the Molds
All of the molds were filled with ~4:1 ratio of course perlite : portland cement and some stainless steel needles.
When packing the molds it is important the the cement mixture is tightly packed, and when filling the main chamber mold the mixture will need to be packed regularly as you go.
I let the molds dry for 2 weeks.
After dry I removed the cast pieces from the molds. After being removed from the molds all pieces were covered in a thin layer of portland cement.
Step 6: Firebrick Floor
I arranged the firebricks in a pattern I liked, and that I thought would allow a pizza peel to easily slide across. I marked the edge of the oven floor on the bricks, and used one brick to fill more than one edge gap where I could. The bricks were then cut and arranged in the pattern before being attached to the surface with an insulating cement.
Step 7: Oven Assembly
The 4 mold parts were assembled around the oven floor and attached together with refractory mortar.
Step 8: Insulating Fabric
A 2" ceramic insulating blanket was placed over the main chamber and back, then tightly wrapped in chicken wire.
Step 9: Chimney and Finishing Up
The Insulating fabric was then covered in portland cement. It took 3 layers to fully cover it, and then some finishing touches after that to make it nice and smooth. To attach the chimney, a stand was made to hold the chimney up in the entry. The chimney was placed onto the stand, and the gaps around the chimney were filled with refractory mortar to secure it in place.
Step 10: Test Fire
I started with a small curing fire lasting only around 10mins. Two days later I did a larger fire lasting around 30mins. I then did a fire lasting around 45mins.
Step 11: Pizza!
Char is flavor
Step 12: Failures
As stated at the start, I am a novice when it comes to working with cement, and as such there were several things that did not go too well along the way.
The original molds for the Front, Back and Main chamber ended up being redone.
The Main chamber mold piece cracked, due to inadequate concrete packing.
The Front mold piece did not fit, because the main chamber deformed a bit in the mold.
The back mold piece broke as it was knocked over.