[Clayart] Thanks and Sumi's kiln works fine now
wetherby.ss at gmail.com
Mon Oct 3 00:11:11 EDT 2016
Several years ago my friend Colleen Black Dunigan and I were learning to
fire a small downdraft kiln at our coop studio. We used Nils Lou's kiln
firing book as our textbook but still had a few problems we couldn't
resolve. We wrote to Nils asking his advice, which he kindly supplied by
return email. He told us to turn on the kiln full blast rather than
starting on low. It worked for us. Never blew up anything and fired in 8
hours rather than 14 hours. Shut down at cone 10+ and relighted at 1900
degrees for about an hour (I can't remember how long for sure). Everyone
was happy when their pieces came out of the kiln.
On Sat, Oct 1, 2016 at 9:50 PM, William Schran <wschran at cox.net> wrote:
> May I ask a favor?
> Will you please try firing the kiln with no preheating?
> Use the same settings you used with this last firing except just start it
> cold and go for it.
> The kiln I fired at school, turned on 1 wci to start, damper a #3 (I drew
> pencil lines every 1/4²).
> After two hours kiln was at 1000F, NEVER had ANY problems with student
> work exploding or anything else.
> Then increased gas pressure to 2 wci, at 1600F pushed in damper to #2 3/4
> mark, started reduction.
> Another hour increased gas to 2 3/4 wci at that was it.
> At 2000F, pulled damper back to #3 mark.
> Cone 6 over in 7 - 8 hours.
> Perfect copper reds, celadons and shinos.
> Did the same thing at Mel¹s, just kicked the kilns on and let them go.
> Last time I preheated a kiln was back in 1973Š.
> Bill Schran
> wschran at cox.net
> On 10/1/16, 6:15 PM, "Clayart on behalf of sumi"
> <clayart-bounces at lists.clayartworld.com on behalf of sumi at herwheel.com>
> >Just wanted to thank everybody who responded to me and tell you that my
> >latest firing was just about right. 6.5 hours to cone 7, with an
> >overnight preheat. Temperature and reduction pretty much even
> >throughout. Pretty much the only changes I made were I took away the
> >bag wall and moved the bottom shelf back towards the back wall. And I
> >took out the extra bricks I had put underneath the load to baffle the
> >flames. I'm sure I can tweak it a bit and make it more perfect but now I
> >know what I might want to do.
> >Bill Schran, I can't thank you enough for telling me that if you pull
> >the damper out the heat goes to the bottom. I'm so glad you caught that
> >in my first post. Now my kiln fires right side up. Turning down the gas
> >pressure or pulling out the damper both do exactly the opposite of what
> >they used to do!
> >The next step, Mel, is to try preheating with 1/2" instead of 1" of
> >pressure to save fuel and protect the bricks.
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