Paul Borian on mon 2 nov 09
as far as not getting reduction at the bottom - are the pots down there
really coming out different than the ones in other parts of the kiln? i
often do not get flames out the bottom spy hole but it does not make a
difference in the finished product - they look the same down there as
anywhere else.
Paul
---------- Forwarded message ----------
From: mudduck
Date: Nov 1, 2009 4:11pm
Subject: Reduction-fuel saving
To: Clayart@lsv.ceramics.org
CC:
> I built and have been trying to learn to fire a gas kiln for about a year
> now. The kiln is built to Nils Lou's style of MFT, but it has an arch.
> It's is 45 wide X 45 deep and 50 from the car floor to the arch. The exit
> flue approx. 36 sq. inch, one full brick and double venturi with the
> fiber lined metal chimney. Burners are 2 Ransom B-4 high pressure on
> propane purchased from Mark Ward.
> It takes me 11 hrs to fire to cone 10 using 42 gallons of fuel. I would
> really like to learn to fire the kiln a little faster and more efficient
> on the propane.
> I get poor reduction on the bottom shelf, which sits on a brick laid on
> its side. So my first shelf is just above the flue opening. I hear of
> people having 4"flame coming from the bottom peep. As yet I haven't been
> able to get any flame from the bottom peep. The most I've pushed the
> damper in is 2 inches open. If I push the damper in any more the kiln
> seems to make a woofing sound and seems to stall or have very little
> temp. rise. As some have said I don't want to blow this thing up. And
> being self taught on firing I don't know what to change to get the
> reduction on the bottom shelf and save more fuel. I have an oxy probe
> inserted in the center of the door. During reduction I'm reading from .78
> to .80. Reduction is good to heavy in the rest of the kiln just not on
> the bottom shelf.
> The kiln fires even from top to bottom as far as the temp. goes, a little
> hotter in the back than front.
> I've tried to include as much info that I can think of, hope I included
> enough.
> I'd like to talk to someone about this. I talk much better than I type!!
> Gene
> mudduck@mudduckpottery.net
> www.mudduckpottery.net
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