clennell on tue 6 dec 05
Susan Towell wrote:
> Getting to my next question- At about
> 2000 degrees, there is a considerable amount of flame coming out the
> chimney-is this normal? I realize the heat has to go somewhere, but if I
> push the damper in anymore, the reduction is too heavy, and the temp. will
> actually drop. Also. I fired today and it was -20, perhaps this is
> another reason why it is not firing off as quickly. We had a similar
> problem at Sheridan with the Bailey kilns and it would take us forever to
> fire off-we didn't really care though cause we weren't paying for fuel. I
> guess its that delicate balance of maintaining a good reduction while
> acheiving an equally goo rise in temp. Otherwise the kiln has been
> wonderful and I am happy with the results. I appreciate your time and I
> hope someone can give me some feedback. Thanks, Susan
Hey dahling, how's it going? You're doing the ole boy proud here. glad
you're up and running. Stay with those quiet ones. the north can't take
those tropical colours.
Sounds like you've got too much gas. I fire ours at 2 1/2 inches W/C which
is about 1/3 throttle. I think you are propane, so the guage will read
differently. This is really a common problem with students- more is more.
Everyone thinks turning up the gas will make it go faster- not so.There
should be some flame where your chimney ends and meets the hood. Since I
don't have the hood, I left two little passive damper holes so I could see
some flame. A small flame about 2-3 inches out the bottom peep is about
right.
Send me a pic of some pots will ya. Your crit with me will never end, so
beware I'm watching you.
Cheers,
Tony
P.S Yo to your mum and dad.
Tony and Sheila Clennell
Sour Cherry Pottery
4545 King Street
Beamsville, Ontario
CANADA L0R 1B1
http://www.sourcherrypottery.com
Susan Towell on wed 7 dec 05
Tony, where do you have your damper set at? My kiln is natural gas, and I
fired at max 2.5 inches wci. I will send you some pics of my work. I
agree about keeping it simple, I just love plain. I tried some highly
decorated stuff-awful, never again. Thanks for the info. and let me know
about the damper setting.
Susan
clennell on wed 7 dec 05
Sour Cherry Pottery
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Susan: I did a little experiment for you with the firing that is now in
progress. I usually start redction at 012 bending by having the gas a 2"WC
and the damper at 2" open. As I have an oxpyprobe and want to nail the
carbon trapping i aim for a good 7 on the probe which is strong reduction.
Today I turned the gas up to 2 1/2 " WC and the probe reduction reading went
down to around 5 which is quite a bit less reduction. As the firing
progresses the reduction decreases so i turn the gas up a bit to 2 1/2 and
slowly start bringing the damper out to end the firing around damper open 2
1/2 ".
If the kiln stalls just inch and I mean that figureativly the damper just by
increments of the width of an armpit hair till the digital pyrometer starts
to show climb again.
Bon feu!
Tony
Tony and Sheila Clennell
Sour Cherry Pottery
4545 King Street
Beamsville, Ontario
CANADA L0R 1B1
http://www.sourcherrypottery.com
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