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soft firebrick wall thickness in l&l and others

updated mon 14 jan 02

 

vince pitelka on sat 12 jan 02


> I certainly think the more robust "Jupiter" line with 3"
> walls will perform better, and the next electric will be one of them,
> but I would bet going with a 4 1/2" wall & lid would be even greater.
> Yeah, it would cost more, but it would be worth it!

I'm with Bill on this. We use our L&L J230s only for bisque and low-fire.
It is way too much of a strain on them to push them much higher, because of
the heat loss. 3 1/2" of insulation is a big improvement, but why not a
full brick's width - 4 1/2"? Sure the kiln would cost more, but those who
want the most efficient kiln would gladly pay the price.
Best wishes -
- Vince

Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/

Ceramic Design Group on sun 13 jan 02


> 3 1/2" of insulation is a big improvement, but why not a
> full brick's width - 4 1/2"? Sure the kiln would cost more, but those who
> want the most efficient kiln would gladly pay the price.
>

Check out the new line of Paragon Viking Kilns. 3.5" IFB and .5" mineral
block behind the IFB. The heating and cooling profiles of these are quite
different than their earlier kilns. We are very pleased with our new Viking
kiln.

I would think that potters who fire regularly to cone 10 in an electric kiln
should perhaps move towards the front loading industrial versions of the
multi-sided stainless steel jacketed ones that are so prevalent in studios.

Yes they do cost more but they are designed specifically for high fire work
and feature robust frames, the correct insulation and elements for elevated
temperatures, and hosts of other features.

It would seem prudent thinking that if one's livelihood is based on cone 10
ware fired in an electric kiln, that an investment in the correct kiln would
pay for itself rather quickly.

As a sidebar, we have been designing cone 5-6 plastic white-ware bodies,
using domestic ingredients for a few clients to move away from poorly
formulated boxed clay. We have finished the freeze/part of testing and the
results are perfect, for our particular situation. The next series of
testing will be for fully mature stoneware bodies at this temperature as
well as for cone 10 in both white and dark colors. All this work is in
preparation for our new industrial clay mixing system that will arrive
shortly. But the point is that I just received a copy of "Glazes Cone 6" and
shortly, many on the list will receive Ron and John's pivotal text for cone
6 glazes, "Mastering Cone 6 Glazes." With these excellent texts, there
should be very little whining on the list about being able to produce
beautiful surfaces at cone 6. Coupling this information with a decent
prepared clay at that temperature, most of the commercially available kilns
from the major manufacturers have been all designed with mercury relays and
heavier duty elements and even some extra insulation that can easily handle
cone 6 work. It all comes together!

So the question is if you now have a workable clay body that meets the
criteria, balanced glazes derived from your testing that uses the new texts
as a baseline for exploration, and a workable kiln all for cone 6, why is it
necessary to beat your head up against the wall firing electric kilns to
cone 10?

Respectfully,

Jonathan

Jonathan Kaplan, president
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
info@ceramicdesigngroup.net

Plant Location:
1280 13th Street Unit 13
Steamboat Springs CO 80487
(please use this address for all deliveries via UPS, comman carrier, Fed Ex,
etc.)

"Custom design and manufacturing for the ceramic arts, giftware and pottery
industries. Molds, models, and tooling for slip casting, jiggering and
hydraulic pressing. Consultation on clay and glaze formulation, production
systems,firing, and kilns.

John Hesselberth on sun 13 jan 02


on 1/13/02 11:21 AM, Ceramic Design Group at info@CERAMICDESIGNGROUP.NET
wrote:

> So the question is if you now have a workable clay body that meets the
> criteria, balanced glazes derived from your testing that uses the new texts
> as a baseline for exploration, and a workable kiln all for cone 6, why is it
> necessary to beat your head up against the wall firing electric kilns to
> cone 10?

Amen, Jonathon. But you still would benefit from a well-insulated kiln at
Cone 6. If for no other reason so you don't have to fire down to get the
best out of your glazes. Somehow it seems a little immoral to have to fire
down, yet you do have to to get good, durable mattes with the typical 2 1/2
- 3 inch walls on today's common electric kilns.

Regards,

John

P.S. To Stephen Lewicki. I live only 20 miles from your shop. In fact you
personally sold me my L&L about 3 years ago. If you want to see some
examples of what glazes you can get with slow cooling I'd be happy to come
by and show you--or at your NCCA booth in a couple months. Let me know.

web sites: http://www.masteringglazes.com and http://www.frogpondpottery.com
EMail: john@frogpondpottery.com

"It is, perhaps, still necessary to say that the very best glazes cannot
conceal badly shaped pots..." David Green, Pottery Glazes