We held our most recent Filter Friday yesterday. We created one large filter and build and fired a small wood kiln to fire two mini filters. Our intention was to build a small kiln that we could fire in a short amount of time for use with demonstrations, workshops, and other educational events. We started using tightly rolled newspapers as the fuel and then switched to wood. The firing lasted a little less than three hours and the filters almost reached a low bisque temperature. The pyrometer reading was 1300 degrees F which is about 700 degrees C; not quite hot enough for all organic matter to have burned out (based on this firing and temperature chart), and therefore, not quite the bisque temperature we wanted. A longer firing should help get us there. We are looking forward to building and firing the next one.

Here are some images of the kiln, the firing, and the filters. We used soft bricks given to us by Joy Pottery in Bryan, Texas. Joy Pottery dismantled their gas kiln (the kiln where we fired the previous mini filters and large filters) and is in the process of building a new kiln shed for their new gas kiln. We will use the bricks for the mini filter wood kiln and a larger kiln either here for our local kiln or as part of our project in the Colonias.

The mini filters seem to filter water at the proper filtration rate of about two liters per hour, although their surface in some places becomes a bit soft.