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#1 Wind n Wing

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Posted 05 September 2012 - 11:40 AM

Morning all,

Just finished a firing with the new elements. Need to make a minor adjustment for the top shelf. Everything fired to cone 6 except the top shelf, know this because the oxidation I am using is a nice paperbag brown when mature. Top shelf ware has a carmel cast indicating its not up to cone.

This is a small Duncan kiln and holds up to four full shelves. I usually keep a 1" clearence between the tallest piece and the bottom of the next shelf up. This time the underfiring happened on the top shelf and there was only a 1/2" clearence between it and the platters. I am thinking that is what caused the difference in maturity.

All the elements are firilng just fine. Did an empty test run and everything looked good. Test run was Empty no furniture. Should have probably had the furniture in so I could place Witness cones just to be extra sure. Hindsight is 20/20Posted Image

Have another load in with plenty of clearence at the top shelf level with witness cones. Will know more tomorrow when I empty the kiln.

So a question comes to mind. I need just a bit more space if I am going to get the clearences I need. Could invest in the Advancer shelves, but forgot to water the money tree out back . Soooo--- Do I really need the bottom shelf which is raised on 1/2 supports or could I place a cone 6, 1/4" thick disk on the bottom and set a ware on it, with the shelf supports sitting directly on the kiln bottom? Kiln shelves are 5/8". Eliminating the shelf directly on the bottom and its supports would give me the extra space needed. Just dont want to damage the Kiln bottom.

Would appreciate any help on this.
Thanks,
RJ

#2 Chris Campbell

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Posted 05 September 2012 - 11:53 AM

A 10 -15 minute soak at peak temp could even out the whole load which could save on money for new shelves.
My bottom shelves are on 1/4" posts and I have no problems with air circulation.

Chris Campbell
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#3 Dinah

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Posted 05 September 2012 - 12:48 PM

Hi, best keep that btm shelf elevated. Not a good idea to put glazed ware on kiln floor. Much difficulty in grinding off any dripped glazes on kiln floor as you can well imagine. Stagger your shelving levels to allow heat work. Leave lots of room between pots. Some folks find a shelf over the final placement caps it off helping to retain heat work. And, as Chris mentioned, a soaking period will definitely help with the top layer. Be sure to post your results of latest firing!
Dinah
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#4 Wind n Wing

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Posted 05 September 2012 - 01:30 PM

A 10 -15 minute soak at peak temp could even out the whole load which could save on money for new shelves.
My bottom shelves are on 1/4" posts and I have no problems with air circulation.


Chris,

You will probably shake your head at this. But I don't have the foggest idea on how to soak at any temp let alone high. My kiln is old with new elements, uses a timer, cones w/ kiln sitter. Never did any product that needed soaking so never learned. Everything I have learned about pottery is by trial and error. Have been producing this product line for many years, sells well so the attitude if it aint broke dont fix it has regined supreme. I dont throw, my work is all slab. Birdfeeders, Birdbaths and Windchimes. Any further explanation or direction on soaking would be a great help.

Thanks,
RJ

#5 Wind n Wing

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Posted 05 September 2012 - 01:35 PM

Hi, best keep that btm shelf elevated. Not a good idea to put glazed ware on kiln floor. Much difficulty in grinding off any dripped glazes on kiln floor as you can well imagine. Stagger your shelving levels to allow heat work. Leave lots of room between pots. Some folks find a shelf over the final placement caps it off helping to retain heat work. And, as Chris mentioned, a soaking period will definitely help with the top layer. Be sure to post your results of latest firing!


Dinah,

I will refer you to my reply to Chris for additional info. Since I make open face birdfeeders/bath, (platter style) cant stagger shelves. I dont glaze my work. I use 7 different colors of clay and prefer the unglazed look when I hand marble the feeders/baths/leaves. So if I am not glazing do you see any other hitches to not using a elevated bottom shelf? Appreciate the suggestions.

Thanks,
RJ

#6 Chris Campbell

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Posted 05 September 2012 - 01:56 PM

Well, its been a while since I did it manually, so if anyone else has a better way jump on in.

You have to be there when the kiln sitter drops then there is a way to gently ease it back up again so the kiln thinks the cone is still there. Then you just start the kiln again on high for ten to fifteen minutes, then turn it off.

Chris Campbell
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#7 Wind n Wing

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Posted 05 September 2012 - 03:55 PM

Well, its been a while since I did it manually, so if anyone else has a better way jump on in.

You have to be there when the kiln sitter drops then there is a way to gently ease it back up again so the kiln thinks the cone is still there. Then you just start the kiln again on high for ten to fifteen minutes, then turn it off.


I will give it a try and will post on how the results came out.

Thanks,
RJ

#8 TJR

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Posted 05 September 2012 - 07:32 PM

Well, its been a while since I did it manually, so if anyone else has a better way jump on in.

You have to be there when the kiln sitter drops then there is a way to gently ease it back up again so the kiln thinks the cone is still there. Then you just start the kiln again on high for ten to fifteen minutes, then turn it off.


Chris, R.J;
If you look closely at your kiln sitter, you will see that there is a metal button in the middle of the sitter. It is more obvious when the sitter is down. As soon as you hear the click of the sitter shutting off, you ease the lever of the sitter back up, and gently push the button back in. Your kiln will turn back on. You should see that the red indicator light is on if you have one. Now you can ease the lever back down, while leaving the button pushed in. Make sure you stick around so as not to over fire your work.
This is way easier to show in person than to write in a blog. As Mark says, I am the guy who can talk you down from an airplane after the pilot has had a heart attack. Happy landings!
TJR.

#9 Wind n Wing

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Posted 06 September 2012 - 02:29 PM

Houston we have contactPosted Image. Just to let everyone know the firing was perfect. Soaking worked, witness cones bent and the pieces are paperbag brown. Couldnt ask for better. Well maybe an extra day to ship this order out but I will take what I have and dance. Not near anything breakable used my dance class money as a child for Bubble GumPosted Image.

Thanks everyone so much!!!!!!

RJ

#10 yedrow

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Posted 06 September 2012 - 09:37 PM

Another thing you may consider is how much surface area you have exposed to the elements. When I'm firing flatter stuff I try to keep at least two rows of elements radiating on any given layer of ware.

Joel.

#11 Wind n Wing

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Posted 07 September 2012 - 12:54 AM

Another thing you may consider is how much surface area you have exposed to the elements. When I'm firing flatter stuff I try to keep at least two rows of elements radiating on any given layer of ware.

Joel.


I'm with you on that, could have been a contributing factor to the problem. But things came out good this last firing.
Thanks
RJ

#12 Mark C.

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Posted 07 September 2012 - 01:41 AM

You said
Do I really need the bottom shelf which is raised on 1/2 supports or could I place a cone 6, 1/4" thick disk on the bottom and set a ware on it, with the shelf supports sitting directly on the kiln bottom? Kiln shelves are 5/8". Eliminating the shelf directly on the bottom and its supports would give me the extra space needed. Just dont want to damage the Kiln bottom.


I suggest a smaller than 1/2 supports for bottom shelve-1/8 or 1/4 will work fine.You can cut your own from stilts on a wet saw-smaller will save space.
If you fire this kiln a lot the advancers will save you money in the long run so start watering the money tree.
Mark
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