Joseph Herbert on wed 14 mar 01
Lanier Meaders, a Georgia (US state) folk potter used 50% body clay, 40%
wood ashes, and 10% ground glass. Mr. Meaders fired a 'hogback' kiln with
wood over a period of 10 hours or longer if large pieces, like 5 gal. churns
were in the kiln.
The temperature of firing is uncertain but, if things are really primitive
there, a series of draw rings can help you monitor the progress of the
firing. As someone has undoubtedly mentioned, a draw ring is a ring of the
made of the body clay and glazed. The ring is retrieved from the kiln during
the firing so it may be necessary to alter the kiln to allow this activity.
Several of these rings are set standing in a row and pulled out with a metal
hook at intervals as the kiln heat climbs. When the glaze on the most
recently pulled ring seems fully melted and the clay is sufficiently
vitrified, the firing can stop and the kiln can be cooled.
Your only real salvation in the situation is good accurate record keeping:
of glaze trials, of firings, of materials sources, of clay locations, of
clay processing methods, of glazing methods. Write down everything that is
done and the result of that effort. Reviewing the records leads you to your
goal. Scattered efforts are frustrating and costly of time and sweat.
Try to find a consistent clay to mine in quantity, several years worth, if
possible. Develop a process to refine the clay that is as simple as
possible while still effective. Develop one base glaze from available
materials that fits the clay body and is safe for functional ware. Record
all firings as to fuel used, atmospheric conditions, temperatures reached
(by color if necessary), results of draw ring trials during firing,
observations of the fired ware as it is found in the various parts of the
kiln. Record every thing!!
Records will shorten your time to success and, when you have found it, you
will be able to do it again.
Joe
David Hendley on wed 14 mar 01
Dear Joseph and Louis, I use glass in my glazes all the time.
A few years ago I did a tri-axial blend of glass cullet, white
clay, and wood ashes from the kiln. I call it the 'free glaze
series', as the cost of the ingredients is zero.
At cone 10, I can make any glaze from a dry matt, to a
textured semi-gloss, to a shiny clear using just these
materials. Now, these glazes are not perfect. The shiny
clear, for instance, crazes badly because of the high sodium
content of the cullet. In a 'pioneer pottery' situation, however,
you could certainly make serviceable glazes with just these
ingredients.
To make glass cullet, I lay bottles in the firebox coals of my
kiln in the early stage of the firing. They have to be heated
slowly or they will break. When they start to slump, which
happens at a surprisingly low temperature, I retrieve them
with a long steel rod inserted in the opening and drop them in
a bucket of water. This shatters the glass to a coarse sand
size and makes it easier to mill down to 80 mesh powder.
I use a ball mill, but I think it could reasonably be done by
hand on a small scale.
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: Joseph Herbert
To:
Sent: Wednesday, March 14, 2001 12:20 AM
Subject: glass based glaze
| Lanier Meaders, a Georgia (US state) folk potter used 50% body clay, 40%
| wood ashes, and 10% ground glass. Mr. Meaders fired a 'hogback' kiln with
| wood over a period of 10 hours or longer if large pieces, like 5 gal.
churns
| were in the kiln.
|
| The temperature of firing is uncertain but, if things are really primitive
| there, a series of draw rings can help you monitor the progress of the
| firing. As someone has undoubtedly mentioned, a draw ring is a ring of
the
| made of the body clay and glazed. The ring is retrieved from the kiln
during
| the firing so it may be necessary to alter the kiln to allow this
activity.
| Several of these rings are set standing in a row and pulled out with a
metal
| hook at intervals as the kiln heat climbs. When the glaze on the most
| recently pulled ring seems fully melted and the clay is sufficiently
| vitrified, the firing can stop and the kiln can be cooled.
|
| Your only real salvation in the situation is good accurate record keeping:
| of glaze trials, of firings, of materials sources, of clay locations, of
| clay processing methods, of glazing methods. Write down everything that
is
| done and the result of that effort. Reviewing the records leads you to
your
| goal. Scattered efforts are frustrating and costly of time and sweat.
|
| Try to find a consistent clay to mine in quantity, several years worth, if
| possible. Develop a process to refine the clay that is as simple as
| possible while still effective. Develop one base glaze from available
| materials that fits the clay body and is safe for functional ware. Record
| all firings as to fuel used, atmospheric conditions, temperatures reached
| (by color if necessary), results of draw ring trials during firing,
| observations of the fired ware as it is found in the various parts of the
| kiln. Record every thing!!
|
| Records will shorten your time to success and, when you have found it, you
| will be able to do it again.
|
| Joe
|
Jim V Brooks on thu 15 mar 01
David.. please tell us more about using glass cullet.... Jim in Denton.
| |
|
