Silicon Carbide Baking Surface
I first proposed using silicon carbide (SiC) as a baking surface material back in December 2006 (http://www.pizzamaking.com/forum/index.php/topic,4215.msg35417.html#msg35417
). Since then there have been a few more mentions of it, but nobody really picked up the ball and ran with it (to my knowledge), so recently, after finding a supplier that offered a decent compromise between the properties I was looking for and price, I purchased a silicon carbide shelf to use in my unmodified electric home wall oven.
To use such a material for baking in a basic electric home oven, the material has to be placed in close proximity to a source of radiant heat so that the top and bottom of the pizza bake at the same time. This is accomplished in the setup I have by situating the top surface of the SiC shelf 6 cm from the bottom of the top heating elements. In other words, I have a 6 cm clearance for the pizza. To maximize efficiency, I use only the broil setting, which for my oven is actually consuming less energy than the bake setting. That's why my broiler is not that great but the oven can reach over 600°F when baking. Modern electric ovens should be able to surpass what my oven can turn out, but the pizzas are going to finish fast on the SiC surface in any case.
The bake times I have reported thus far (90 s, 120 s, and a burnt 113 s) pretty much tell the story about how much faster SiC conducts heat than a typical baking stone. The pizza that burnt in 113 seconds (picture attached) was part of an experiment to increase the baking surface temperature to above 700°F just to add a little extra energy to play with. This is also pretty easy to accomplish in most ovens by leaving the oven door open so that the thermostat doesn't turn the broiler off. It's completely unnecessary, but I did it to drive the point home about super fast baking in a basic home oven. Based on my calculations, I should have pulled the pizza out in 82 seconds for a perfect bake.
Generically, SiC (nitride bonded in this case) has a thermal conductivity approximately 30 times greater than that of a typical baking stone. Of course that doesn't mean baking is 30 times faster, as the pizza will have something to say about how fast it will receive the transferring energy. It does mean baking can be made as fast as you want, and faster. It also means preheat times are faster. It only takes about 15 minutes to reach 550°F in my oven, and a few minutes more with the oven door open gets it to over 700°F. The physical properties, price, and location of purchase for my SiC shelf are:
Dimensions: 16" x 16" x 0.625"
Weight: 6.464 kg
In addition to the picture of the burnt pizza, which I don't intend to duplicate, I will post more pictures as I continue to use the SiC shelf. Also included in this post is a picture of the actual SiC shelf I'm using. The thermal properties of SiC notwithstanding, it is a beautiful material.