Friday, June 07, 2013

Not bad tor a toy kiln

These little Olympic gas kilns (mine is 4cubic feet, which was fine for test tiles), are a bit of a challenge when you have enough bisques pots  from your old 36 Cubic foot kiln that need firing and this pipsqueak of a kiln is the only firing option.

Everything that could go wrong yesterday did; but 38 years of experience got this little baby fired high enough for my blue celadon liner glaze which has a Cone 8 to cone 11 or even higher range. Even when it's not reduced as well as the serving bowl in front, the liner resembles a  light shino or cream glaze.

Everything was prepped well for the firing - my gorilla sprayer motor and back up were charged, except, it wouldn't work. No big problem since it can be hand pumped. It took 15 hrs of playing with burners, and pressure to get this kiln to fire to cone 8 and cone 9. I had drilled out the orifices for natural gas, but the problem is that my household pressure isn't enough. Olympic says it should be 7 lbs and around here it's only 6, but I thought a long enough firing should give me results I'd be happy with, if not the optimum. After all - what other choice did I have at this point.

Once I started spraying, it was going as well as could be expected, firing a kiln that long ion the south facing side of the house in 93 degree weather with no cover. Just as I was finishing the second round of spraying, the tip of the sprayer fell off and into the kiln. The melted tip certainly made an interesting and colorful mess. The only good part about this under insulated, uneven firing toy kiln is that it was cool enough to empty, less than ten hours after I shut it down.

I couldn't see my cones until the very end when I just used the color of the kiln and my level of exhaustion to call it quits, and put it into soak mode and clean the atmosphere. Oh, I forgot to mention, that my thermocouples were giving me crazy readings the entire firing, so knew I just had to go use the color in the kiln as my guide. It was an interesting day. Sometimes you just have to laugh.

Before I fire it again, I'm going to see if the gas company will up my pressure. For now, I'm off to Lowes hardware to buy a replacement brass tip and new o ring.  This firing was like childbirth, so I will need another week or two to forget the pain before I fire the next load. Meantime I need to mix up more liner and accent glazes and get those other pots finished and wadded.


  1. That's a lot of work for a handfulof pots but they do look nice.Love the liner in the big bowl.

  2. Thanks. It's all the same liner Dennis, just showing the different levels of reduction of my blue green celadon. The bottom of this kiln just didn't reduce much, if at all, so the same glaze comes out a cream color, or much paler blue green.

  3. Christine, I inadvertently deleted your message, so I copied and pasted it here. Didn't want you to think I wouldn't post it. Love the line about selling story rights. That gave me a lovely morning chuckle.
    "Well, the pots look wonderful, I wonder if you can sell the story rights to the movies!

    As to the toy kiln, I do all my firing in an electric one that size or maybe a little smaller but it's what I could afford ($350 w/ shelves and furniture used) when I came back into the trade. It limits the size of the individual pieces and it seems as though I fire all the time, but I don't have to wait/work to fill and fire a larger kiln when someone wants 4 matching mugs--the turn around can be pretty fast. In my next incarnation I'd like a gas kiln again, even if only 2x that size.

    I admire all your glaze testing, too, as I am still using commer$ial glazes this round as I do not have room and resources to set up a glaze pantry and test area."

  4. Reading this post makes me feel like I'm totally missing out. I have only fired in oxidation. I would love to buy a gas kiln and learn about reduction, salt and soda. It would certainly be a learning journey.

    Your new babies look beautiful :)

  5. Thanks Cindy. I started 38 years ago with cone 6 electric too. There's a lot more interesting glazes and work coming out now in cone 6, particularly with multiple glazes which can give a depth that a lot of the old cone 6 work didn't have forty years ago.
    Love your bright lime, green glaze. Is copper the only colorant? I'd love to know the colorants so I could make it for cone 04.
    You could find an old non working,decent sized electric kiln and convert it to gas. Check out Simon Leach's old videos on You tube where he actually took a non working electric kiln and actually turned it into a down draft by making an inner chimney with a flu at the bottom. It was pretty neat. I've seen other converted to updrafts but his was the first one I've seen made into a down draft.

    1. I have seen Simon's gas kiln video. I'm going to invest some time in reading and learning more about gas kilns and firing.
      "Brave Green" is only 3% copper carb.

  6. I thought it might be more than 3% or maybe copper with a touch of chrome, since it's so bright. Love the color.