search  current discussion  categories  kilns & firing - misc 

continuing dual fuel kiln story

updated tue 3 apr 07

 

Chris trabka on sat 31 mar 07


Robin,

You may want to search the achives or google "glaze forward". This is a
project by Diana Pancioli to produce the look of cone 10 reduction glazes
at cone 6.

Chris

Robin Wolf on sat 31 mar 07


Hello All;

=20

Thought that I would just touch base and pick some more brains while I =
was
at it!

=20

My last posting was about my conversion of my electric kiln to dual fuel =
=96
coated the bricks with ITC 100, the new coils with 213, and a final =
coating
of 296a on top of everything as a final seal after the coils were =
installed=96
then I put a layer of 2=94 ceramic fiber between the bricks and skin of =
my old
Cress B27h =96 Absolutely loved it! . I started this project by =
replacing
all 6 elements with new Euclid=92s, scrubbed them with Clorox water, =
rinsed
them well, dried them, them dipped them in a thin coat (like paint) of
ITC213. I had problems with little black flecks coming off of the coils =
in
both bisque or reduction firing, but vacuumed the coils before every =
use,
and kept at it. Fired 4 glaze loads to cone 10, each firing taking a =
bit
longer. First firing was 5 hours, last was 10 hours

=20

Two weeks ago today, I fired a full load of ^10 reduction. I started =
the
kiln on electric up until cone 06 went down, turned on my little propane
burner that was coming in the floor of the kiln (1 =BD=94 hole in the =
floor and
same size hole in the lid), left the electric on with the propane going
until I reached ^10. I even have a Bosch Oxygen sensor and a multimeter
that I was using to monitor the exhaust gases to make sure that I was
getting good reduction. I had studied and read all I could on the dual
fuel kiln, and I think I was on the right track. My other glaze firings
came out great; I was very thrilled with what I was getting. This load =
had
the most smoke =96 least oxygen of any of the previous loads, so I was
dreaming of oxblood and OU (University of Oklahoma) crimson gracing my
pottery shelves =96 FINALLY! But, no such fulfillment. Cone 9 was not =
moving
yet when the top element stopped glowing, and shortly thereafter every =
other
element went out, one after the other. Needless to say, I never made =
cone
10. All 6 elements broke (burned?) through at some point during that =
final
firing. When I saw that all 6 element were gone and my temperature was
dropping, I just turned off the gas and closed her down tight.

=20

The load is a mass of grays and blacks, with the carbon still trapped in =
the
glazes. I had one jug that had a ^8 to ^10 desert sand glaze on it that
turned out great, every other glaze was a full ^10. I think (hope) that =
the
colors will come on when I re-fire this load to a full ^10.=20

=20

I have 2 questions =96 first off, was I hallucinating that the dual fuel
should be accomplished with electricity on and propane on at the same =
time?
Or did I fail at the ITC213 step of this project? I thought that the =
213
protected the coils from the reduction atmosphere when they were =
heating?
Were the black flecks the coating coming off of the coils? Any insight =
into
this?

=20

Second question =96 now what? When I take inventory of my WORKING =
assets, I
can say I have a very good 7cu ft kiln body, shelves and stilts. =
Because of
the $$ invested in ITC and adding the ceramic fiber to it, I would like =
to
keep using the kiln itself. But I am not sure about replacing the =
elements
again for almost $300 for the 6 elements. I have even struggled with =
the
thought of going to ^6 and back to electric firing completely, but I =
have
also just invested in getting my first round of ^10 reduction glazes =
put
together. I have 8 different glazes, all between =BD and 1 full gallon =
of
each that I have compounded & tested. With all of my previous steps =
headed
toward ^10 reduction, I think that I ought to keep going down this road
since I really do like the look and feel of the art that I am creating.
Going to straight gas seems a logical thought that would insure me the
ability to do ^10 reduction.

=20

My work is getting better, and I feel comfortable in making decisions =
that
will allow me to grow my firing capabilities in the future. Either =
finding
at least 1 more 7 cu ft kiln body to rehab like the other, or build a =
small
(12 cu ft?) Minnesota Flat Top would be great. I have considered =
investing
in a GOOD burner or burner system that I could use on the old Cress, and
then be able to use it on a small Minnesota Flat Top later on down the =
line.
Is there a burner or burner system that I could use on either my old =
Cress
body and a MFT, or does anyone have any suggestions? I have looked at =
the
Profire 500 burner from Axner that Nils is part of, but I wasn=92t sure =
if
that was too big for the 7 cu ft box or what the minimum sized kiln =
would be
for it.

=20

Or, just do the easy thing and order a new 12-18 cu ft gas kiln? Talk =
about
chunks of $$, but the lack of worry and the headaches and possible =
horror
stories associated with building one may out weigh the cost.

=20

Sorry to ramble on at such lengths, but I feel like I am at a major
intersection of my pottery dream, and I trust that Clayarters understand =
and
will share their own insights and advice to help me find my right path =
on
this clay journey.

=20

=20

Robin Wolf

Kingfisher, OK=20

robinwolf@pldi.net

William & Susan Schran User on sun 1 apr 07


On 3/31/07 8:23 PM, "Lee Love" wrote:

> Gas/electric kilns are common in Japan. But the elements are
> very heavy bar elments and not coil type. Take a look at the photos
> below:
>
> http://claycraft.blogspot.com/2005/05/elements-and-not-thin-coils-like-home.ht
> ml

Lee,
Thanks for posting the images.

Could you do a bit more investigation and find out about the elements?

What gauge are the element wire?

How often would one need to change them if one did reduction in the kiln?

How much do replacement elements cost?

Do these kilns fire to ^10?

Bet it's just as much a pain to replace these elements as the ones in this
country.


Thanks,

--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com

Lee Love on sun 1 apr 07


Hi Robin,

Gas/electric kilns are common in Japan. But the elements are
very heavy bar elments and not coil type. Take a look at the photos
below:

http://claycraft.blogspot.com/2005/05/elements-and-not-thin-coils-like-home.html

http://claycraft.blogspot.com/2005/05/this-is-little-gas-burner-that.html

http://claycraft.blogspot.com/2005/05/not-cheap-but-you-can-fire-it.html


--
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

Jeremy McLeod on mon 2 apr 07


On Sat, 31 Mar 2007 22:55:36 -0500, Chris trabka wrote:

>Robin,
>
>You may want to search the achives or google "glaze forward". This is a
>project by Diana Pancioli to produce the look of cone 10 reduction glazes
>at cone 6.
>
>Chris
>

A Google Search on: Diana Pancioli "glaze forward"
yielded several links including this one to a page of
CM articles, one of which is her article, "Glaze Forward"

http://www.ceramicsmonthly.org/selectarticles.asp

Jeremy McLeod

Marcia Selsor on mon 2 apr 07


Robin
I have several times posted my old ^6 reduction recipes in the archives.
Also there are several of my ^6 glazes published in the new Oriental
Glaze book by Micahael Bailey


Marcia Selsor
http://marciaselsor.com

Lee Love on mon 2 apr 07


On 4/1/07, William & Susan Schran User wrote:
> On 3/31/07 8:23 PM, "Lee Love" wrote:

> Could you do a bit more investigation and find out about the elements?

Probably not. Am incredibly busy right now. Spring Tokichi
(pottery fair) is coming up and I have to make work for Mpls before it
starts.

Did you look at the thickness of the elements? These are
much more durable than our coil elements. They are similar to what
you find on electric ranges.

--
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