First Firing in the Converted Gas Kiln

Pots in the kiln- some with homemade ash glaze made from red and yellow clays found on the property and hickory ashes from the fireplace. I dusted a few more ashes on them just to see what it would do by itself.

Kiln as it was set up for first firing. Always check propane connections for leaks with a bit of soapy water.

           With only a half a day drying time for the pieces I’d dipped in the ash glaze, I started the firing at 1 o’clock at very low flame, just enough to keep the torches from going out. About two hours later, I turned it up to a strong yellow flame and an hour on, to a loud blue flame. I heard no cracking or pinging from inside the kiln so everything seemed to be doing fine.

Warming up on low flame- 2 hrs

Turned up to halfway on the torches. The pipe elbow bottled up a lot of heat and probably restricted the flow despite the height of the chimney. Also, torches needed more room but backing them out made the flame erratic (I enlarged the holes for the next firing attempt).

After the 15lb tanks ran out, I increased the pressure on the 40lb one and tried to seal the second fire port with a brick. I turned it back again pretty quick...

          I had hoped to see cone 6 bending after four hours or at least five hours but the kiln seemed to level off and the small propane tanks kept running strong. Well, strong, they weren’t- the pressure change was so gradual that it wasn’t till I kicked one in the dark that the contents momentarily pressurized and suddenly the torches reminded me how loud they had been at first. I went ahead and shut off the right tank and unscrewed the line, substituting the new 40 lb. tank and relighting. All seemed to going well again and I alternated between reading in a chair by the kiln and carrying red bricks over to make a floor around the kiln to keep rain runoff away. Despite getting strong reduction flames out the chimney and later out every crevice in the lower 2/3s of the kiln, the cones all remained standing straight by 10pm (9 hours in) at which time I gave up and cut the valves to half and then off completely after 30 minutes. Total gas used was a little under 5 gallons from the 40lb. tank and 7 gallons between the two 15 lb. ones, so 12 gallons all told.

          I waited until the next afternoon to open the kiln and see how the pots had fared. The result was as expected; they were all well-bisqued but the ash glaze was just a dry flaky crust and the pure ash I’d dusted the rims with looked like burnt coffee grounds. The latter could be wiped off leaving a lightly brown stain.

         Well, that's the nature of experiments. Next- to figure out why it wasn't making it higher.