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Glazing Cone 6 Pottery


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Hi there! I am new to the forum and new to pottery, and I have just completed my first pots in my first firing. I just bought a used Skutt is-1027 in great shape, and fired my first (small) batch. I placed an 06 cone in the kiln sitter and followed the manufacturers recommendations for firing the kiln. 2 hours on low, two hours on medium, and then high until cone is reached. I think I must have placed the cone incorrectly, or the sitter gauge was out of adjustment, because 3 hours in to my bisque ramp schedule at high temperature, it was still firing. I shut down the kiln and let it cool until the next day. When I opened the lid, the cone had been vaporized by the high heat (it's a cone 10 kiln). I think it goes without saying that I overtired the pottery. But I wanted to glaze it and see how it came out and the resulting cone 6 that I fired the kiln to only took about 4 hours to complete. The glaze turned out nothing like it was pictured to turn out. I used coyote blue purple, and the resulting glaze firing was light blue and white. Nothing like it is supposed to look. Is this because I was glazing vitrified pottery?

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Yes it is almost impossible to glaze vitrified pieces properly.  But you need to fix the sitter first.  You didn't mention how you shut off the glaze firing.  The sitter is suppose to be a safety device.   Did you use witness cones to shut off the glaze firing?  You could google Dawson kiln sitter and get information about the sitter and how to adjust it, plus repair parts.

David

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I had a problem with a kiln setter once that involved part of the setup of the kiln. There were removable rings, and the setter sat across two rings. Once when unloading, I removed the top ring to reach pots in first layer easier. Some way or other I bumped the ring that had top screws into setter. This caused the cut off bar to not drop when the cone bent. So the kiln fired longer than ^6. However, as I was in the building doing sets for the school play, when I walked into the dark kiln room to double check, I saw the white orange band of color on the wall(top of kiln gap-common). Since I fire down the home kiln by color heat, I knew immediately I was near to cone 8. Shut the kiln off said a little prayer, and went home.  Next day, the load was a little dark on the top layers, a little bloat on a very few pieces, but next layer down was fine, as was the bottom. Whew.

 

So double check that the drop off bar that the setter rod releases on the outside of the kiln is free to move and does.

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The two metal brackets that the cone rests on can come out. They could be cleaned with a wire brush attachment on your bench grinder. Or you can buy new ones they are cheap. you can also buy a guide template to adjust the setting of your sitter.

Do you know a potter or teacher in your area who can show you? Not complicated, but I am a two finger typer and this would take a lot of words. Better to show.

TJR.

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Hi there! I am new to the forum and new to pottery, and I have just completed my first pots in my first firing. I just bought a used Skutt is-1027 in great shape, and fired my first (small) batch. I placed an 06 cone in the kiln sitter and followed the manufacturers recommendations for firing the kiln. 2 hours on low, two hours on medium, and then high until cone is reached. I think I must have placed the cone incorrectly, or the sitter gauge was out of adjustment, because 3 hours in to my bisque ramp schedule at high temperature, it was still firing. I shut down the kiln and let it cool until the next day. When I opened the lid, the cone had been vaporized by the high heat (it's a cone 10 kiln). I think it goes without saying that I overtired the pottery. But I wanted to glaze it and see how it came out and the resulting cone 6 that I fired the kiln to only took about 4 hours to complete. The glaze turned out nothing like it was pictured to turn out. I used coyote blue purple, and the resulting glaze firing was light blue and white. Nothing like it is supposed to look. Is this because I was glazing vitrified pottery?

 

There's a big difference between cone 06 and cone 6. (albeit that's probably not the problem here).

 

Cone chart at link below:-

 

http://www.ceramicstoday.com/cones.htm

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I was once given a used kiln that would over fire. The kiln sitter would never trip the shut off. After giving it a once over it was quite obvious the problem. The bar that drops down to bend the cone in the kiln sitter had been eroded over time til it was not as thick or heavy as it once was...it actually looks more like a tapering needle than the bar you usually see. After the bar was replaced the kiln fired nicely. So check the bar and make sure it is not damaged or eroded.

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Thanks so much to everyone for their replies. There is a metal tab on the kill switch that, if adjusted too high, won't trip the kiln no matter what cone is in there. I do have the small adjusting disc and have adjusted it properly. The glaze firing to cone 6 went flawlessly, and the kiln turned off as it should. With the amount of pieces I had in the kiln, I'm sure it got up to at least cone 7 on the bisque fire. When I applied the glaze it just sat on the surface and didn't dry. I used a blow dryer after about an hour to dry the rest of the glaze for the final firing. I'm pretty confident that I did the second fire correctly and future firings will be much better. I was just curious about coating vitrified pottery with glaze and how it effects the general outcome of the firing. This glaze didn't look anything like it was supposed to look. I'm sure it's because none (or very little) of the glaze penetrated the vitrified clay body. I'm going to fire again in a couple of weeks and see how that goes. Thanks again everyone for your responses. They were really helpful. Trial and error!

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I was just curious about coating vitrified pottery with glaze and how it effects the general outcome of the firing. This glaze didn't look anything like it was supposed to look. I'm sure it's because none (or very little) of the glaze penetrated the vitrified clay body. I'm going to fire again in a couple of weeks and see how that goes. Thanks again everyone for your responses. They were really helpful. Trial and error!

 

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