Edit: Hello and welcome all newcomers! This blog post seems to have suddenly received a lot of attention from Pinterest and other blogs. Thank you for visiting! I saw several comments on Pinterest addressing the design and safety. This is not my design, so criticize all you like. I recommend following the link below to GardenFork.tv to get more information on the build. But if you're going to get critical I suggest you read instead of just looking at the pictures. For example, reading below the first picture will give you the original source of the design. I haven't had any problems with exploding bricks. These are not cement, they are clay, which are fired in a kiln and can withstand the heat. The perlite/cement base has also been a great insulator with no concern of spontaneous combustion or melting.
I've been wanting to make a wood fired pizza oven for a while, but haven't had the space to put it. Then I came across this "portable" design (GardenFork.tv) that can be taken down and put away or (relatively) easily relocated when needed.
The original design comes from the book Bread, Earth, & Fire by Stuart Silverstein. The author recommends making an insulated base with a mix of 6 parts perlite, 1 part Portland cement, and enough water to make a rough batter. It took 2-1/2 bags of perlite (2 yards each) to get a 2-1/2 inch base of the cement mix. The base weighs more than I thought it would, but it's still much lighter than straight concrete; about 100 lbs. Two people can easily carry it. It's also fairly brittle and "chalky," so care needs to be taken when laying the bricks.
There was a bit of a learning curve to figuring out how hot to get the fire and how to turn the pizza. But once I figured out that I need to just make it really freaking hot, the pizza cooks pretty fast. Less than 5 minutes total. This works out really well when there's a large crowd to feed. You can cook a pizza in the same time it takes to assemble the toppings. So one person can be building their pizza while one is cooking. No backlog of pizzas waiting to go in.
As for portability, well...you just take it apart and reassemble it somewhere else. Everything is dry stacked. No mortar. I plan to take this on a campout in a few weeks, so we'll see how well that goes...