difficulty with firing

I am new at firing my own stuff. I bought a used Skutt kiln (10 cubic feet fires to cone 8 with electronic controller) I initially fired it empty ( with shelves in) which is what the manufacturer suggests when the kiln is new or has been moved using the "med " cone 04 program (preset) All of the witness cones were uniformly and appropriately slumped. Since then I've fired 2 bisque loads (cone 6 stoneware) to 04 (supposedly) relying on the controller,however I did put cones in to be sure. The witness cone on the bottom shelf slumps appropriately, but each successive shelf up bends less and less with the topmost just leaning slightly. After the first load I thought that the kiln venting system (attached at the bottom sucks air in through holes drilled in the lid of the kiln) might be the problem so I made sure that there was a shelf at the very top of the kiln to prevent air being pulled in directly over the ware at the top of the kiln. I also programmed in my own firing schedule: !) 80/hr to 212F hold for 1 hour

2)180/hr to 1650 with no hold 3)200/hr to 1845 with no hold 4) 108/hr to 1945 with a 15 min hold (Whole thing takes about 14 hours) Could this be the problem? Any other suggestions? Thanks Evelyn
Reply to
Evelyn Bednarz
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We find this with some of our top loading kilns. The answer is to pack the bottom tightly and then pack progressively looser as you go up the kiln. When the kiln is hottest at the bottom doing it this way means that it has more to heat there than at the top, so by default it tends to even things up.

Steve Bath UK

In article , Evelyn Bednarz writes

Reply to
Steve Mills

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