Michael Wendt on fri 20 apr 07
Eric,
Something is wrong with the design.
I run old style Olympic Kilns burners
and the bring our 12 cf updraft to
cone 10 from cold on the following
schedule:
Load before 10 am
Start at 10 am
Pass red heat slowly at
12- 12:30 pm
Once above red heat,
turn burners on full and
adjust the damper for
neutral flame ( just an
occasional flicker of flame)
Turn off at 5- 5:30 pm w/cones
flat cone 10 on the bottom
shelf.
Cone 9 is always down on the
top and cone 11 is down in
the midline.
Can you supply dimensions of the
kiln (including ports and flue sizes
and burner ratings?
It is possible you have a design
correction to make.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, ID 83501
USA
208-746-3724
http://www.wendtpottery.com
wendtpot@lewiston.com
Eric wrote:
Hi All,
I just thought I'd throw this out there to see
what everybody thinks.
My firing is going on now and I'm afraid I
will be running out of
gas shortly.
The kiln is about 12 cu ft including the soft
brick firebox, the
electric kiln carcass main section and a fiber top. I
am running 2
Ward 750 burners.
I'm at ^07. I started at 6 am and it is now 6
pm. and have had
the burners first at 1# pressure then 2#, 2.5 and 3#,
(propane). I
have backed off to 2.5 to save gas and closed the
burner a bit. (in
fact I just backed off to about 1# ) bottom is much
hotter, it almost
looks like ^6 is bending and the top registers ^07.
What do you think?
Frustrated, (this is the second round
for a bunch of these pots)
Eric
Eric Suchman on sat 21 apr 07
Hi All,
I just thought I'd throw this out there to see what everybody thinks.
My firing is going on now and I'm afraid I will be running out of
gas shortly.
The kiln is about 12 cu ft including the soft brick firebox, the
electric kiln carcass main section and a fiber top. I am running 2
Ward 750 burners.
I'm at ^07. I started at 6 am and it is now 6 pm. and have had
the burners first at 1# pressure then 2#, 2.5 and 3#, (propane). I
have backed off to 2.5 to save gas and closed the burner a bit. (in
fact I just backed off to about 1# ) bottom is much hotter, it almost
looks like ^6 is bending and the top registers ^07.
What do you think?
Frustrated, (this is the second round for a bunch of these pots)
Eric
William & Susan Schran User on sun 22 apr 07
On 4/21/07 9:14 PM, "Eric Suchman" wrote:
> I'm at ^07. I started at 6 am and it is now 6 pm. and have had
> the burners first at 1# pressure then 2#, 2.5 and 3#, (propane). I
> have backed off to 2.5 to save gas and closed the burner a bit. (in
> fact I just backed off to about 1# ) bottom is much hotter, it almost
> looks like ^6 is bending and the top registers ^07.
> What do you think?
Eric,
I this a downdraft or updraft design?
If an updraft, take a quick look at my web site (below my signature) and
there is a link for what I have done (with much help form some Clayart
folks) with an Olympic updraft that may provide some insights. I've been
able to achieve almost even temperature top to bottom with this hateful
beast.
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
WJ Seidl on sun 22 apr 07
Eric:
1) If your kiln is ^6 at the bottom (where I presume, the burners are)
and ^07 at the top,you have packed it much too tightly.
Your packing is not allowing air and heat movement throughout.
Loosen it up, leave some room, and make sure your shelves do not go
closer than one inch or so to the walls. Allow the heat to circulate up
and through, and then back down. You are trying to create a
circulation. A kiln isn't a pizza oven. If you add major heat at the
bottom, it does not always flow to the top.
2) Do you have a "target brick" at the opposite side of the kiln from
your burners? If cut as a wedge shape, with the small edge
facing the burner, it will then divert the flame path "upward". Not
near the burners, on the other side of the kiln, but with the burners
pointing toward it/them.
3) If your damper is open, close it almost completely. It might be
letting too much heat flow through.
If that was indeed the case, you will watch the heat "rocket" up from
that point. You can then adjust it as needed.
12 hours for 12 cu ft to cone 6 is way too long.
Best,
Wayne Seidl
Eric Suchman wrote:
> Hi All,
> I just thought I'd throw this out there to see what everybody
> thinks.
> My firing is going on now and I'm afraid I will be running out of
> gas shortly.
> The kiln is about 12 cu ft including the soft brick firebox, the
> electric kiln carcass main section and a fiber top. I am running 2
> Ward 750 burners.
> I'm at ^07. I started at 6 am and it is now 6 pm. and have had
> the burners first at 1# pressure then 2#, 2.5 and 3#, (propane). I
> have backed off to 2.5 to save gas and closed the burner a bit. (in
> fact I just backed off to about 1# ) bottom is much hotter, it almost
> looks like ^6 is bending and the top registers ^07.
> What do you think?
> Frustrated, (this is the second round for a bunch of
> these pots)
> Eric
>
> ______________________________________________________________________________
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Lynne and Bruce Girrell on sun 22 apr 07
Cone 6 at the bottom and 07 at the top?
The only thing that would cause that, to my knowledge, is that you choked
the kiln by stacking (or placing shelves) too close to the walls.
Did you use the shelves that were for the electric? That would be way, way
too tight for a fuel kiln.
Bruce Girrell
_________________________________________________________________
Exercise your brain! Try Flexicon.
http://games.msn.com/en/flexicon/default.htm?icid=flexicon_hmemailtaglineapril07
Paul Vernier on mon 23 apr 07
Eric,
With an updraft kiln not scientific, but it works. Closing the damper pushes
the heat down. Opening the damper pulls the heat up. Maybe you are trying to
hard for reduction.
Little adjustments and don't push it. Next time keep the pressure below 2
psi and the damper adjusted so there is no back pressure out your peeps.
Open it farther that you would think it should be and see if the temperature
at the top comes up. Lot's of other things you can do. But usually it is the
simple things that have the greatest impact. Don't over Mother your kiln.
Within bounds it should reach temperature in a small kiln quite rapidly.
The best tool you can get to help understand a kiln is a pyrometer with two
thermocouple inputs. That way you can monitor the settings and temp top to
bottom and reach temperature long before running out of gas and patience.
Also, search the archives. There is a lot of good information on firing,
stacking and setup for this style kiln posted by myself and others.
Good Luck.
Paul
Lee Love on tue 24 apr 07
What does the flame look like out the top of the exit flue?
Something that occurred to me is that if you have too much fuel
pressure, you could get a hot bottom because of secondary air coming
in around the burner port, but push the combustion to the outside of
the kiln because of a lack of oxygen in the kiln. Sometimes, more
fuel means less heat.
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://potters.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
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