Adventures in Pottery, Pt. 3
Whether it was the insulation on the kiln, or my lack of fuel, I needed to start over with firing. I researched small kilns in an effort to build something that I could feasibly use in a back yard of my apartment setting.
Then I found the work of LiMing Zhang.
He is a potter and kiln builder who makes small scale kilns. After looking at much of his work, I decided to attempt to emulate his process.
I start by making more clay through a dry processing method and built a vessel to be a kiln. I had doubts that it would be effective because his kilns cracked even though their walls were much thicker than the one I created but I figured it was worth a shot.
The making to using a clay kiln is that it needs to be fired before firing. So, I took this and all of the pots to a place where I could pit fire. I decided to pit fire the pots as well in case the kiln did not survive.
The pit fire was a success. I successfully created ceramic. As I anticipated the kiln fell apart. I believe the clay had a lot of sand in it which led to a particularly destructive quartz inversion (the silica crystals realign which can cause cracks and fissures if it does not happen evenly through the whole body). Some of the pots also suffered cracking but I believe this was an issue of the uneven heat more than the quartz inversion since I processed the potting clay more thoroughly.
From this I learned that whatever kiln I build needs to have thicker walls and be made of a more reliable material. I also researched ways to prevent cracking in the pots and learned that grog (ground up ceramic) can be used as a stabilizing additive that minimizes cracking while firing. In the original pottery technique video, I saw this added but did not understand the significance. They pit fired successfully and I think the grog was a key factor.
This was a great experiment and I feel I know how to make more pots successfully in the future. I am excited to take this further. Next step for the current pots is to clean them, seal the cracks, make legs, and put some plants in them!