Posted 12 October 2010 - 03:56 AM
There are several things you didn’t mention-- did this happen in your previous firings or is this the first time this has occurred? If so, what have you done differently? Is your kiln a zoned kiln? Check your manual. And do you have the correct size kiln shelves recommended by Paragon? It sounds like the heat is being trapped in the bottom of the kiln. Improper stacking can be a cause for the uneven firing. To help resolve this try using half shelves that when put together they are at least one and a half inches smaller than the interior diameter of your kiln to allow the heat to move up and allow for a gap between the two shelves when they are stacked at the same level. Stagger some of the shelves and try not to cover up the gap so heat can rise. Also this is very important be sure you leave a 1” space between the kiln floor and the first shelf. Do not cover up your elements with the shelves. Make every attempt to keep shelves between the elements. Be sure your peephole plugs are in place except for the top one. It allows heat and fumes to escape. Keep a log of every firing by date, time and program. List which pots are in the kiln on each shelf and be sure to note the clays, glazes and underglazes in your log, so that you can repeat your successful firings. Be sure to place the correct cones at the correct angle if not using self-supporting cones. Remember junior, senior, and self supporting cones all have different firing temperatures and firing speeds. Be sure to test new clays and glazes before you commit to firing your fully decorated load. *Most importantly read your kiln manual for trouble shooting.*
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