Betsy Sharp on mon 21 jan 08
I=92m hoping to get some information to help me decide whether to bring =
my
small (about 3.7 cubic foot) electric kiln with me when we move to the
woods, off the grid=85
=20
We are planning to build a downdraft gas kiln, about 10 cubic feet =
interior,
which will use propane from our 500-gallon tank. We also have a 6000 =
watt
propane-fueled generator, which will be used for various shop tools and =
to
charge up the house batteries when there=92s not enough sun for the =
solar
panels.
=20
We could use the generator to run the small electric kiln for bisque
firings, which don=92t take very long. I make tiles from Cone 6 Dove
Porcelain, and I usually bisque them at about cone 05 or 06. We figure =
it
would take maybe 5 gallons of propane to do a bisque firing in the small
electric kiln, and we could use the generator for other tasks =
simultaneously
during the part of the firing where the kiln is not turned to =
=93high=94. So it
would only really monopolize the generator for 1 =BD to 2 hours. The =
generator
uses about 1 =BD gallons of propane per hour.
=20
So we=92re thinking of maybe taking the little kiln with us, to use just =
for
bisque firings. Or, we could sell it for $350.
=20
We certainly cannot use the generator for Cone 6 glaze firings; besides =
the
fact that I want to work with reduction glazes, hot firings would wear =
out
the generator.
=20
We haven=92t yet built the downdraft gas kiln. My husband has been =
studying
kiln design, and studying the kiln book we got which seems to be the =
main
source book of how to build gas kilns. The kiln we=92re going to build =
will
have 3 burners. It would appear that downdraft kilns are less useful or
efficient at low bisque temperatures, and that they are more set up to =
work
at higher temperatures; or at least, this is our impression.=20
What we don=92t yet know is how many gallons of propane the kiln we =
build will
use. Will it use more than 10 gallons of propane for a cone 05 or 06
firing?=20
=20
It=92s kind of a hassle to bring the little electric kiln out there when =
we
move, but if it makes sense financially we will do it.
=20
Any advice would be greatly welcome.
=20
Betsy Sharp
Currently in Seattle, soon to be on Waldron Island
David Hendley on tue 22 jan 08
I'm all for energy efficiency, reducing greenhouse gases,
and going off the grid, but I would not base my decision
of how to fire my pottery solely on cost or efficiency.
There are differences in firing with gas or electricity
that are more important than firing cost, and I would
choose which better fit my way of working.
As I wrote in my Clay Times column last year (The
Inconvenient Truth for Potters), electric resistance
heating is generally the least efficient way to heat
something, and this is how electric kilns work. In spite
of that, I was very happy when I got an electric kiln
and could quit bisque firing in my wood kiln. It was
a pain and waste of time to spend a whole day watching
the kiln, and no matter how careful I was, a few pots
would always be ruined by direct flame impingement.
I had the same problem, but not as bad, when, years
ago, I used to bisque fire in my natural gas kiln.
So..... part of the cost of firing in a fuel kiln is that
you are more likely to lose a few pots to kiln accidents.
That alone suggests that electric bisque firing is the
best choice. I mean, all you need to do is ruin one
$50 bowl and any fuel savings of going non-electric
are meaningless.
If Betsy is a professional potter, I would certainly
recommend that she move the electric kiln. It is
good to have the flexibility of choice. There
will undoubtedly be a time when she needs to get
some work finished in a hurry. A small electric is
a lifesaver then - no need to make enough to fill
the big kiln to get the load out.
David Hendley
Maydelle, Texas
david(at)farmpots(dot)com
http://www.farmpots.com
----- Original Message -----
I'm hoping to get some information to help me decide whether to bring my
small (about 3.7 cubic foot) electric kiln with me when we move to the
woods, off the grid.
We are planning to build a downdraft gas kiln, about 10 cubic feet interior,
which will use propane from our 500-gallon tank. We also have a 6000 watt
propane-fueled generator, which will be used for various shop tools and to
charge up the house batteries when there's not enough sun for the solar
panels.
Donna Kat on tue 22 jan 08
On Mon, 21 Jan 2008 23:08:35 -0800, Betsy Sharp
wrote:
>I=92m hoping to get some information to help me decide whether to bring my
>small (about 3.7 cubic foot) electric kiln with me when we move to the
>woods, off the grid=85
>
Have you considered doing single fire? I really liked what I have done
with it and it certainly would simplify life. I found it worked easily
with a number of glazes I used (on bone dry ware - leather hard was much
more difficult to get right). If you are interest, I have what
information I gathered that I can send you.
Donna
James and Sherron Bowen on wed 23 jan 08
That I would like to see. We have about 300 gallons of used crankcase oil
out here on the ranch and I was thinking of making a drip system to
supplement the LP burners, but if I could scrounge up some more brick I
could make hard brick salt kiln about that size. In fact I know where there
is an used cantenary arch salt kiln I can have if I demolish it and bring it
out here.
JB
----- Original Message -----
From: "Hank Murrow"
To:
Sent: Wednesday, January 23, 2008 10:16 AM
Subject: Re: Comparative efficiency of propane vs electric bisque firing
James and Sherron Bowen on wed 23 jan 08
Living off the grid would certainly make a potter more likely to want to do
single fire alright. I would also look into firing with waste oils, too.
Many years ago Dennis Parks wrote a book on single firing with waste oil.
It's readily available used and in libraries.
JB
----- Original Message -----
From: "Donna Kat"
To:
Sent: Tuesday, January 22, 2008 5:14 PM
Subject: Re: Comparative efficiency of propane vs electric bisque firing
Lee on wed 23 jan 08
I have been bisquing with recycled wood for the last 8 years.
If I were off the grid, that's the way I'd go.
If your woodkiln is designed to do so and you know how to
use it, you don't have to loose any pots. When we bisqued in my
teacher's noborigama and in 8 years of bisquing in my little wood
kiln, I have not lost any pots.
The main trick is to allow a long enough travel to the flame and
using large wood that doesn't burn quickly when you begin the firing.
Most single fire folks know how to do this.
--
Lee in Mashiko, Tochigi Japan
http://mashikopots.blogspot.com/
"Tea is nought but this: first you heat the water, then you make the
tea. Then you drink it properly. That is all you need to know."
--Sen No Rikyu
"Let the beauty we love be what we do." - Rumi
Hank Murrow on wed 23 jan 08
On Jan 23, 2008, at 8:06 AM, James and Sherron Bowen wrote:
> Living off the grid would certainly make a potter more likely to
> want to do
> single fire alright. I would also look into firing with waste oils,
> too.
> Many years ago Dennis Parks wrote a book on single firing with
> waste oil.
> It's readily available used and in libraries.
Dear James and Donna;
During my graduate work at the U of Oregon, I began to worry about
where I might set up, and what fuels might be available and/or
portable. So I developed a natural draft oil burner that could be
used with any waste oil or even new oil that I could carry in to
property in a pickup. The result was "An Oil Burner for a Natural
Draft Kiln", my graduate thesis. Natural draft to be able to work off
the electric grid, and oil because it was quite portable, and often
free with some enterprising scrounging.
During this period, I built 12 small kilns, most of them too
experimental to work with my burners. So, for my final kiln I made it
as solid and conservative as I knew how. The burners lit on the first
piece of burning paper and there was no smoke after the first minute
or so. I got to cone 10 in ten hours on ten gallons of stove oil.
Salted at the end, and had some fine wares from that 12 cuft kiln,
though I would not recommend it for bisquing. Once-fired salt or
soda.... YES!
I have pics that can be sent in an email. Robert in Cottage Grove OR
is trying a variation of the burner soon.
Cheers, Hank
www.murrow.biz/hank
Hank Murrow on wed 23 jan 08
On Jan 23, 2008, at 8:06 AM, James and Sherron Bowen wrote:
> Living off the grid would certainly make a potter more likely to
> want to do
> single fire alright. I would also look into firing with waste oils,
> too.
> Many years ago Dennis Parks wrote a book on single firing with
> waste oil.
> It's readily available used and in libraries.
Dear James and Donna;
During my graduate work at the U of Oregon, I began to worry about
where I might set up, and what fuels might be available and/or
portable. So I developed a natural draft oil burner that could be
used with any waste oil or even new oil that I could carry in to
property in a pickup. The result was "An Oil Burner for a Natural
Draft Kiln", my graduate thesis. Natural draft to be able to work off
the electric grid, and oil because it was quite portable, and often
free with some enterprising scrounging.
During this period, I built 12 small kilns, most of them too
experimental to work with my burners. So, for my final kiln I made it
as solid and conservative as I knew how. The burners lit on the first
piece of burning paper and there was no smoke after the first minute
or so. I got to cone 10 in ten hours on ten gallons of stove oil.
Salted at the end, and had some fine wares from that 12 cuft kiln,
though I would not recommend it for bisquing. Once-fired salt or
soda.... YES!
I have pics that can be sent in an email, or posted to someone's site
if one is available. Robert( nativeclay@GMAIL.COM ) in Cottage
Grove OR is trying a variation of the burner soon.
Cheers, Hank
www.murrow.biz/hank
Hank Murrow on fri 25 jan 08
On Jan 25, 2008, at 3:00 PM, Donna Kat wrote:
> I would really appreciate having those pictures.
Did you receive them, Donna?
Cheers, Hank
Donna Kat on fri 25 jan 08
On Wed, 23 Jan 2008 09:16:24 -0800, Hank Murrow wrote:
>Dear James and Donna;
>
>During my graduate work at the U of Oregon, I began to worry about
>where I might set up, and what fuels might be available and/or
>portable. So I developed a natural draft oil burner that could be
>used with any waste oil or even new oil that I could carry in to
>property in a pickup. The result was "An Oil Burner for a Natural
>Draft Kiln", my graduate thesis. Natural draft to be able to work off
>the electric grid, and oil because it was quite portable, and often
>free with some enterprising scrounging.
>
>During this period, I built 12 small kilns, most of them too
>experimental to work with my burners. So, for my final kiln I made it
>as solid and conservative as I knew how. The burners lit on the first
>piece of burning paper and there was no smoke after the first minute
>or so. I got to cone 10 in ten hours on ten gallons of stove oil.
>Salted at the end, and had some fine wares from that 12 cuft kiln,
>though I would not recommend it for bisquing. Once-fired salt or
>soda.... YES!
>
>I have pics that can be sent in an email. Robert in Cottage Grove OR
>is trying a variation of the burner soon.
>
>Cheers, Hank
>
>www.murrow.biz/hank
>
I would really appreciate having those pictures. Thank you for offering!
Donna
Would it be legitimate to post the pictures on
http://groups.google.com/group/WoodKiln ?
Donna Kat on mon 28 jan 08
On Fri, 25 Jan 2008 19:14:02 -0800, Hank Murrow wrote:
>On Jan 25, 2008, at 3:00 PM, Donna Kat wrote:
>
>> I would really appreciate having those pictures.
>
>Did you receive them, Donna?
>
>Cheers, Hank
>
Just to let the list know - I received the pictures and information, they
are great! (it was my bad - thought I sent a message and I obviously
didn't). I am passionate about recycling and not throwing things away so
being able to use the electric kiln shells I have is very exciting.
I have 3, I'm on Long Island - so if anyone else wants to play with this
let me know. Sadly the University is so overly cautious that my plans on
using them for the crafts studio as a workshop project or just a party has
fallen through.
Thank you Hank. Much appreciated. Donna
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