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updraft kiln firing help needed

updated sat 19 feb 00

 

Dave Finkelnburg on thu 17 feb 00

Below is a message from a potter who is not on the list. The gist of his
problem is he has fired his kiln for 11 years and is now having problems
with the temperature not being even. If you have any suggestions for him,
I'm sure he would appreciate hearing from you directly. I will forward any
on-list comments to him. Thanks for your help!
-----Original Message-----
From: Nicholas O'Keeffe
To: dfinkeln@cyberhighway.net
Date: Tuesday, February 15, 2000 11:23 AM
Subject: kiln problems


>Hi Dave,
> Thank you for responding to my friend's pleas for help (Jack &
>Peggy - ouellett@auracom.com - Sunday Feb. 13th. - subject: updraft kiln).
>I am his buddy - Nicholas O'Keeffe. I live in Newfoundland, Canada and
have
>been potting for 11 years.
> First let me describe my kiln. Its an Olympic Gas Kiln 2331G
(out
>of Atlanta, GA - now out of business so I can't go to them for help).
>Firing chamber size: width 23" depth 31" 5 burners.
>BTU/Burner 50,000 Total BTU/HR 250,000. Its a basic updraft gas kiln
with
>an 8"high metal stand which, according to the manufacturer, is necessary
>for proper burner position and adequate cooling beneath the kiln. Under
the
>kiln is a circular tube which receives the gas and which contains tiny
holes
>and when ignited producess a multitude of pilot lights. From this circular
>tube the five burners ignite. Each burner has an airadjuster plate which
is
>between the burner orfice and the burner. The kiln opens at the top with
>hinges on one side. There is a metal hood entirely over the kiln situated
>6" above the kiln when opened fully. The chimney is 10" wide and 5' high.
>There is a circular port opening on the top of the kiln - this opening is
7"
>in width. In accordance with the manufacturer I allow 3" space between the
>kiln bottom and the bottom shelf and 1" all around between the shelfs and
>the inner wall of the kiln. There is a baffle shelf 12" wide which is
>recommended to be 1 and 1/2"below the top port. Now I have been firing
>this kiln successfully for the last 11 years - to cone 04. Last summer I
>took my kiln apart to clean the circular metal tube, in particular, the
>openings for the pilot lights since some of these holes were blocked and I
>was finding lighting my kiln not smooth. To do this I used a wire brush
and
>used a tip cleaner to open some of the tiny holes. Since that operation I
>have been having problems. This is my problem: Suddenly the center part
>of my kiln is firing 2 to 3 comes higher than the top and bottom which
>remain similar to each other. During the firing, what I am aware of is
that
>the flame is being sucked up the kiln and out the port hole much more than
>before. For example I am having a flame at the port hole half way through
>the firing whereas before it was only at the end of the firing this would
>happen. My procedure in firing has been to close off 80% of the port for
>the first 600% (degrees) and open to 30% for the next !000% and open fully
>for the last 3/400%. I am tempted in my next test firing to place the
>baffle shelf closer to the top port say 1" instead of 1 and 1/2" and see if
>that will reduce the draft and produce a more even firing. But I don't
>know.
> I'm desperate
>right now and I'm in a location where NO ONE fires updraft gas kilns. So
>any help you or/and you associates can offer will be much appreciated. If
>you wish me to call you and talk on the telephone after you have looked
over
>this e-mail (the longest in my life) and talked to others please say so
when
>you e-mail me giving me a day and time that's good for you. I need 24
hours
>notice to get to a telephone (and a computer). Keeping my fingers crossed.
>Nicholas.
>
>http://members.aol.com/diosg/pottery.htm

David Woodin on fri 18 feb 00

Olympic is not out of business. Phone 770-967-4009 or 800-241-4400