Pizza Kiln!

7/14/2017

Sometime in the last year, Simon built a small woodfired pizza oven out in his backyard. After a few uses it became apparent that the design was flawed because they were having trouble building and retaining heat. Simon went back to the drawing board, redesigned the oven, and assigned me the task of demoing the old and rebuilding the new. I was stoked to take on this project because of the similarity to building a wood kiln for pottery. I was sure to gleen lots of knowledge and experience in that direction.

The main differences in this design are a taller entry door and interior arch, and the addition of four stoke ports, two in front, two in back. The stoke ports will provide better air circulation and a space for wood to burn out of the way of the cooking surface, and the larger interior space should allow for a more efficient heat distribution.

I took some process shots that I wanted to share along with a little insight into the process. If you have any questions, please feel free to ask!

I began by marking out the dimensions of the first layer and drawing the lines for each row of brick.

Complete first layer. I used scrap softbrick for everything except the two rows of full hardbrick which will become the bottom of the stoking aisles.

Complete second and third layers. Here you can see the stoking aisles. I used larger 6 x 9 hardbricks for the cooking surface. These layers are entirely hardbrick. Notice how seams are always crossed for stability. Always being very careful to make sure the bricks are level and not wobbling. Add a little clay under corners to fix wobbles. I also used a grinder to smooth out the cooking surface and take down any lips.

Simon's friend Justyn is building a woodfired pizza oven as well so he and his daughter came over for a few hours one day to help out and learn a bit. His daughter, Alicyn helps us trace the catenary arch form created by hanging a chain from the width of the door, down to a mark for the height.

Forms.

Complete form suspended in place, ready to support the first arch.

First arch complete with high-temp mortar.

We created the main arch form by tracing the doorway arch. The first row of the large arch will rest halfway over the door arch.

Complete main arch. No mortar was used here, just coils of clay. Then I stuffed clay into all of the cracks, allowed to dry, then removed the form. You can also barely see where I left a roughly 5 x 6 opening toward the front of the arch for the chimney.

A peek inside.

Next, a layer of refractory fiber wrapped tightly in chicken wire to help the mortar adhere. This was my least favorite part of the process. Chicken wire sucks to work with. After this picture was taken I went back in and put more wire across the bottom in between and beneath the ports. Mortar will not stick to brick alone.
I also notched out the chimney hole from two 4.5 x 9 soft bricks. They look like this [] from above. And put scraps underneath to level them out.