Maputo Ceramic Stove - 2 samples fired differently
Crispin Pemberton-Pigott, New Dawn Engineering, Swaziland, August 18, 2006

Dear Clay Stove Makers

I am forwarding a photo of two Maputo Ceramic Stoves (MCS) without a grate. One was fired by a thumb-suck method and the other was fired in an oven with a temperature controller.

One of the things I have found is that there is more confidence in the ceramic industry than knowledge.

The two stoves are exactly the same, made from PK11 which is a high feldspar clay, the greater portion being black plastic clay.

You will notice that the darker of the two has a shiny appearance. This is from the melting of the minerals. Looking closely you can see small pock-marks which is where the powdered charcoal burned out (about 10% by weight).

The lighter one is powdery when touched, much lower tone when struck and significantly weaker. The only difference between the two is the firing temperature.