Tony Hansen on sun 5 jan 97
After being corrected here about being down on single fire I had another
go at it in the last couple of weeks. Looks good. I guess the reason I
had trouble before was because I never knew how to properly 'gel' a
glaze for quick and thick application.
--
=================================================================
Tony Hansen, IMC - Publishers of INSIGHT/FORESIGHT/Magic of Fire
Get INSIGHT 5 beta at http://digitalfire.com/insight5.htm
Bill Amsterlaw on tue 7 jan 97
To Tony Hansen:
On 5 Jan 1997 Tony Hansen wrote:
>>
After being corrected here about being down on single fire I had another go at
it in the last couple of weeks. Looks good. I guess the reason I had trouble
before was because I never knew how to properly 'gel' a glaze for quick and
thick application.
<<
I would very much like to understand how to get consistently good results with
once-firing work glazed in the bone-dry state. Like you, I have been thinking
about ingredients that can make a glaze gel because of some advice I have
gotten from people with a lot of once-firing experience. What exactly do you
mean by "how to properly 'gel' a glaze for quick and thick application"?
Linda Blossom and others have advised me that successful raw glazing requires
an adequate amount of suspending agent or flocculant in the glaze. Various
substances have been recommended, including veegum, bentonite, ball clay,
methylcellulose gum, cornstarch, gum tragacanth (?), Irish moss (?), ammonia,
vinegar, epsom salts.
It seems to me there are two major problems associated with raw glazing: (1)
Poor adherence of the glaze to the clay which results in a tendency of the
glaze to detach, crack, and retract in the fire to produce crawling of the
glaze; and (2) Penetration of water from the glaze into the clay body causing
weakening of joints and loss of stiffness that can lead to collapse.
Intuitively, it seems to me that any glaze ingredient that has a strong
affinity for water might lessen the tendency of water to penetrate the clay
body and might also help attach the glaze to the clay body.
Have there been any rigorous studies of these phenomena? Has anyone measured
differences in the amount of water that penetrates bonedry clay when different
amounts of various suspending agents are used? Can a suspending agent have a
strong effect on water penetration and little effect on glaze adhesion (and
vice versa)? What is the best suspending agent or combination of agents to
use?
I have been advised to use glazes thin - but doesn't that mean you are
exposing pots to more water which can penetrate and weaken the clay? Would it
be better to use thicker glazes?
- Bill Amsterlaw (wamster@msn.com)
Plattsburgh, NY
Roeder on wed 8 jan 97
Hello all,
While I have not tried single firing at home in my electric kiln (yet...), I
took part in a hands on single firing workshop with Steven Hill last spring.
We made work all week long (this was a Monday-Sat. morning workshop), and
force dried it. We fired two salt firings and one cone 9/10 reduction
firing. All were single fire. We had only one pot develop a crack, and
that was because it was heavy-bottomed and a bit damp. Other than that...no
problems at all. Not one bit of crawling, pinholing, cracking, slumping, no
attachments came off. Tables full of wares. All skill levels. . We have
more problems in a "regular" load! Some were ugly, but well, ugly happens ;)
We used stoneware. We waxed the bottoms first.
We applied the glaze to bone dry work by pouring/ladling glaze into the
pots, and quickly pouring out the excess. We then held the pots and if
desired, poured or splashed more glaze on the outside. Then we took the
pots outside, where we had improvized several glaze spraying stations. We
sprayed the glaze on the outside of the pot, sometimes using four glazes or
more. We sprayed heavily until it was "wet looking" each time, for good
coverage.
The glaze was not much thicker than any other glaze I've used. I don't know
what you on the list mean by "gel" because it was just, well....glaze
consistancy.
You have to be careful not to knock a handle or spout against the side of
the glaze bucket. Don't pick up the pot by the lip. Handle carefully,
cause it may soften as glaze water is absorbed.
Then we fired them the same day....slowly, as in bisque technique, then
hotter and faster till done.
Really, I was very surprised at how easy it was. No big deal.
Worth a try.
Candice Roeder
in Michigan, brrrrrr
LINDA BLOSSOM on wed 8 jan 97
Dear Bill,
I do use glazes thicker when I can. When I spray I have to make them
thinner so I glaze and dry and glaze more if the piece is thin. I use a
binder - veegum. It also seems to make the glaze gel a bit, like gerstley
or bentonite does. Thickness depends upon the method of application and
the glaze's character due to its ingredients.
Linda Blossom
2366 Slaterville Rd.
Ithaca, NY 14850
blossom@lightlink.com
http://www.artscape.com
607-539-7912
Tony Hansen on thu 9 jan 97
> What exactly do you
> mean by "how to properly 'gel' a glaze for quick and thick application"?
My theory on glazes is forget about textbook glazes and get one good base that w
and understand every ingredient, why its there and why it is in the amount it is
it to make any glaze you want.
Then you have control. I use a base that gels well. If I immerse my hand in the
slurry and pull it out not one drip falls off. No curtains or runs in the glaze.
There are many ways to do this. I don't like to use additives if possible.
Check the web page at:
http://digitalfire.com/magic/articles/slurry.htm
I have been glazing thin green mugs with dipping tongs and can achieve a thick l
of glaze similar to what I would get on bisque. However, you must be sure the wa
is really dry before firing.
--
=================================================================
Tony Hansen, IMC - Publishers of INSIGHT/FORESIGHT/Magic of Fire
Get INSIGHT 5 beta at http://digitalfire.com/insight5.htm
Craig Martell on thu 9 jan 97
Hi Bill: Epsom Salts are sometimes used to "set" a glaze, which means to
make the glaze thicker without the removal of water. "Setting", also greatly
aids in the suspension of everyting in the glaze slop. Epsom Salts form a
mild solution of sulfuric acid that changes the electrostatic charge of the
clay particles in the glaze. Normally, the clay platelets lie in a flat
state on top of each other. The sulfuric acid solution makes the platelets
orient themselves at right angles to each other, thus forming a thicker more
suspended glaze slop. The way to add the Salts, is to make a saturated
solution in water, and add it a few drops at a time until you reach the
desired "set" for your glaze. John Glick uses Epsom Salts to thicken his
slips for trailing. He just adds a few drops to his more fluid mixtures that
he uses for painting and gets a instant "pudding" ready to be trailed on. If
you try epsom salts, be careful not to use too much. If you get the glaze
too thick, you have to add fresh "unset" glaze to thin it down, not just more
water.
Best Regards, Craig Martell-Oregon
Cummings Pottery on fri 10 jan 97
I have always single fired salt, can't imagine wasting time bisquing. I
like to decorate a pot when it is still wet. I just like the look and feel
of wet clay. Bisqued pots are dry, and kind of give me the heebie-jeebies.
I would apply an albany slip type band on the pot just after trimming, and
maybe slip trail another color over that, or make a comb design, or do brush
work. Then I would let the pots dry, and do minimal glazing. Just a high
rutile/iron type glaze on the inside and rim. I like runny, sparkley
surprises. I never waxed, just wadded up lids. Because I handled the pots
quick and gentle, I rarely had problems with breakage. And I wasn't glazing
every little bit, down to the foot.
Wad pots on shelves in kiln, candle overnight, then bring up slowly
the next day. Late that night, throw the salt in, run around hyper and
excited by the flames & fumes and roar of the kiln. Maybe do a little dance
for the kiln goddess.
Two days later, after melting a few flashlights, unload and marvel
at the beauty of the salt and the flames. Because in this firing, it is the
salt that does the glazing. And they come out looking wet and shiny again,
with sparkles of rutile, just like I like them.
Pat - who misses her salt kiln..........sigh
----------------------------Original message----------------------------
Hello all,
While I have not tried single firing at home in my electric kiln (yet...), I
took part in a hands on single firing workshop with Steven Hill last spring.
We made work all week long (this was a Monday-Sat. morning workshop), and
force dried it. We fired two salt firings and one cone 9/10 reduction
firing. All were single fire. We had only one pot develop a crack, and
that was because it was heavy-bottomed and a bit damp. Other than that...no
problems at all. Not one bit of crawling, pinholing, cracking, slumping, no
attachments came off. Tables full of wares. All skill levels. . We have
more problems in a "regular" load! Some were ugly, but well, ugly happens ;)
We used stoneware. We waxed the bottoms first.
We applied the glaze to bone dry work by pouring/ladling glaze into the
pots, and quickly pouring out the excess. We then held the pots and if
desired, poured or splashed more glaze on the outside. Then we took the
pots outside, where we had improvized several glaze spraying stations. We
sprayed the glaze on the outside of the pot, sometimes using four glazes or
more. We sprayed heavily until it was "wet looking" each time, for good
coverage.
The glaze was not much thicker than any other glaze I've used. I don't know
what you on the list mean by "gel" because it was just, well....glaze
consistancy.
You have to be careful not to knock a handle or spout against the side of
the glaze bucket. Don't pick up the pot by the lip. Handle carefully,
cause it may soften as glaze water is absorbed.
Then we fired them the same day....slowly, as in bisque technique, then
hotter and faster till done.
Really, I was very surprised at how easy it was. No big deal.
Worth a try.
Candice Roeder
in Michigan, brrrrrr
Bill Amsterlaw on mon 13 jan 97
Date: Thu, 9 Jan 1997 11:24:40 EST
From: Tony Hansen
Subject: Re: Single Fire
>>
I use a [glaze] base that gels well. If I immerse my hand in the slurry and
pull it out, not one drip falls off. No curtains or runs in the glaze.
Check the web page at:
http://digitalfire.com/magic/articles/slurry.htm
<<
Yes! I looked at your web page and also Magic of Fire II. I think I see
exactly what you mean. I thinned down a bucket of my glaze with water and
then added some vinegar and watched it fatten up and develop an ability to
stick in an unbroken sheet to a nonporous surface. I then tried glazing some
bone-dry greenware ... and got flawless adhesion with no drips. I saw for the
first time the ideal way a glaze should behave. I am very grateful.
>> I have been glazing thin green mugs with dipping tongs and can achieve a
thick layer of glaze similar to what I would get on bisque. <<
Handling thin greenware with tongs!? Every time I try this, the points of the
tongs break right through the fragile clay. Do you just use a very light
touch ... or do you have a special technique for handling greenware with
tongs?
- Bill Amsterlaw (wamster@msn.com)
Plattsburgh, NY
Tony Hansen on mon 13 jan 97
Bill:
I am able to glaze greenware (mugs,etc.) without the dipping tongs
going through because I use Plainsman native clays. These bodies
are made from incredible pottery clays mined in Alberta, Saskatchewan,
Idaho and Montana. The bodies are 100% stoneware clays (no spar,
flint, etc) and they have a green strength 2 or 3 times as high as
many bodies made from industrial minerals force-fit to pottery bodies.
--
=================================================================
Tony Hansen, IMC - Publishers of INSIGHT/FORESIGHT/Magic of Fire
Bill Amsterlaw on wed 15 jan 97
On Mon, 13 Jan 1997 Tony Hansen wrote:
>>
I am able to glaze greenware (mugs,etc.) without the dipping tongs going
through because I use Plainsman native clays. These bodies are made from
incredible pottery clays mined in Alberta, Saskatchewan, Idaho and Montana.
The bodies are 100% stoneware clays (no spar, flint, etc) and they have a
green strength 2 or 3 times as high as many bodies made from industrial
minerals force-fit to pottery bodies.
<<
If this is true, claybodies comprised entirely of clay with no non-clay
additives would be a superior material for once-firing.
Some questions:
1. How do you measure the green strength of a clay body?
2. Can you present one or more recipes that illustrate that clays of similar
working characteristics and fired characteristics could have markedly
different green strength measurements?
3. What sources other than Plainsman produce such claybodies? Wouldn't it be
possible to formulate claybodies with good green strength from clays mined in
locations other than the one's you mentioned? What is a good source for
recipes and information on 100%-clay commercial claybodies?
4. When you say that these claybodies are "100% stoneware clays" with no
non-clay additives, does this mean that they contain no grog or calcined clay?
If not, doesn't this result in claybodies that like to collapse and which
shrink a lot tend to develop s-cracks easily?
- Bill Amsterlaw (wamster@msn.com)
Plattsburgh, NY
Tony Hansen on thu 16 jan 97
>> I am able to glaze greenware (mugs,etc.) without the dipping tongs going
>> through because I use Plainsman native clays. Still have trouble getting the
> If this is true, claybodies comprised entirely of clay with no non-clay
> additives would be a superior material for once-firing.
> 1. How do you measure the green strength of a clay body?I have a machine and p
strength variation on 10 samples.
> 2. Can you present one or more recipes that illustrate that clays of similar
> working characteristics and fired characteristics could have markedly
> different green strength measurements?The clay particles glue the dried mass t
the strength. Plainsman has raw materials that a already balanced, just right
for pottery without any additions. Bodies blending from these are very strong.
> 3. What sources other than Plainsman produce such claybodies?No where that I k
> Wouldn't it be
> possible to formulate claybodies with good green strength from clays mined in
> locations other than the one's you mentioned?I don't know of any such material
Plainsman mines 2000 tons of each kind, ages it for 3 or 4 years, then blends in
1000-3000 boxes quantities and puts the raw mix through a continuous plant. No
batching. Bodies made from things like OM4 ball, kaolin, flint, spar are blends
'extreme' materials, none of which on its own is useful. Variations in these
ingedients has a much more profound effect on the body then when balanced materi
are used.
> 4. When you say that these claybodies are "100% stoneware clays" with no
> non-clay additives, does this mean that they contain no grog or calcined clay?
> If not, doesn't this result in claybodies that like to collapse and which
> shrink a lot tend to develop s-cracks easily?Nope. The bodies do tend to have
mineral bodies, but their extra strength counteracts cracking. Admittedly they m
dry quite as well, thousands of customers across North America seem to find them
OK.
You should see the iron and buff stoneware these materials make. Awesome.
I tested a truck load of OM4 ball clay this week again. 12% porosity at cone 11.
Last year it was almost zero porosity at cone 8. This is a completely different
material. This is a widely used clay in many commercial bodies. Kaolins, fire
clays vary even more. These materials are frustrating so Plainsman native clays
are quite refreshing. We are in shock when we see a clay vary 1/10 as much as th
--
=================================================================
Tony Hansen, Plainsman Clays
Margaret Arial on fri 24 jan 97
TONY, I havenot been with Clayart long but I havenot seen any claybody
receipes where can I get some with "MODERN" MATERIALS. I have been using
clays no longer available like Jordan,Calvert, Pine Lake Fire Clay and O.M.#4
, and Albany Slip and now I am about running out and must practically start
over. Please help. I fire frequently between cone 4 &6 both propane gas and
electric (i use the same glazes for both). i also fire porcelain to 9-10 in a
sprung arch 45 cuft blower burner fired.
Ron Roy on sat 25 jan 97
>----------------------------Original message----------------------------
>TONY, I havenot been with Clayart long but I havenot seen any claybody
>receipes where can I get some with "MODERN" MATERIALS. I have been using
>clays no longer available like Jordan,Calvert, Pine Lake Fire Clay and O.M.#4
>, and Albany Slip and now I am about running out and must practically start
>over. Please help. I fire frequently between cone 4 &6 both propane gas and
>electric (i use the same glazes for both). i also fire porcelain to 9-10 in a
>sprung arch 45 cuft blower burner fired.
Hi Margaret,
This isn't TONY but I do this sort of change on a regular basis. Send me
the old recipe, tell me where you are, and we will get it sorted out.
Better include a list of ball clays you can get and some that have some
iron in them.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
Bob Hanlin on mon 3 feb 97
Val Cushing's Handbook contains a substitution table for these........
At 06:52 AM 1/24/97 EST, you wrote:
>----------------------------Original message----------------------------
>TONY, I havenot been with Clayart long but I havenot seen any claybody
>receipes where can I get some with "MODERN" MATERIALS. I have been using
>clays no longer available like Jordan,Calvert, Pine Lake Fire Clay and O.M.#4
>, and Albany Slip and now I am about running out and must practically start
>over. Please help. I fire frequently between cone 4 &6 both propane gas and
>electric (i use the same glazes for both). i also fire porcelain to 9-10 in a
>sprung arch 45 cuft blower burner fired.
>
>
Bob Hanlin
Oklahoma City, OK
bhanlin@ionet.net
Margaret Arial on tue 4 feb 97
What is the name of Val Cushings handbook and where is it available?Has
anyone published a book on claybodies in the mid range cone 4-6 in this
country with available ingredients?
Reid Flock on fri 27 nov 98
Hello mudslingers!
I have a quick jot for you.
When is it possible (or safe) to complete a single firing ? Is it possible
to fire a cone 6-8 cream stoneware once?
Questionable chemic,
Reid
John Fazzino on sat 28 nov 98
In a message dated 11/27/98 10:38:03 AM, Reid.Flock@digital.com writes:
<
I have a quick jot for you.
When is it possible (or safe) to complete a single firing ? Is it possible
to fire a cone 6-8 cream stoneware once?
Questionable chemic,
Reid
>>
Hi Reid. I've had good results once firing to cone ten with a very open
stoneware. This is with glazes. Just must be careful to go very slowly as
first.
John Fazzino
Hill family on sun 29 nov 98
Reid.
It is possible to single fire most any clay. A good resource book on the
subject is Single Firing, The pros and cons by Fran Tristram. Published by
A.C. Black Ltd. in the U.K. and by Gentle Breeze publishing in the U.S.
Check it out.
Dan Hill
Hill Pottery, Wilno Ontario, Canada.
----------
> From: Reid Flock
> To: CLAYART@LSV.UKY.EDU
> Subject: Single fire
> Date: Friday, November 27, 1998 10:37 AM
>
> ----------------------------Original message----------------------------
> Hello mudslingers!
>
>
> I have a quick jot for you.
>
> When is it possible (or safe) to complete a single firing ? Is it
possible
> to fire a cone 6-8 cream stoneware once?
>
>
> Questionable chemic,
>
> Reid
Joy Holdread on thu 10 dec 98
When is it possible (or safe) to complete a single firing ? Is it possible
> to fire a cone 6-8 cream stoneware once?
Years ago I worked for production potters who single fired. They used glazes
that single fired with very simple glazing techniques oxides painted on &
single dipped glaze. They fired simple forms mostly thrown some with simple
handles. I've single fired unglazed works no problem. Test test test That's
your pleasure.
Joy in Tucson
Lori Pierce on fri 11 dec 98
Hi Joy...I had no trouble single firing my stoneware body in a highfire
kiln...I adjusted all glazes by changing the clay content from EPK to ball
clay, used an hydrometer and learned to dip my pots in the glaze bucket
quickly, deliberately and efficiently. I preferred to glaze my pots when
bone dry, and only trial and error will show you the way. The book, A
potters Guide to Raw Glazing and Oil Firing by Dennis Parks might be helpful
as well as Michael Cardew's Pioneer Pottery. ( if there is no clay to speak
of in the glaze, add a bit of bentonite.) There are potters that glaze their
pots on the wheel head, using a brush, but I did not do well with that
technique. Good luck, Lori Pierce Lorinfl@hotmail.com
-----Original Message-----
From: Joy Holdread
To: CLAYART@LSV.UKY.EDU
Date: Thursday, December 10, 1998 2:22 PM
Subject: Re: Single fire
>----------------------------Original message----------------------------
>
> When is it possible (or safe) to complete a single firing ? Is it
possible
>> to fire a cone 6-8 cream stoneware once?
>
>
>Years ago I worked for production potters who single fired. They used
glazes
>that single fired with very simple glazing techniques oxides painted on &
>single dipped glaze. They fired simple forms mostly thrown some with
simple
>handles. I've single fired unglazed works no problem. Test test test
That's
>your pleasure.
>Joy in Tucson
Lori Pierce on sat 12 dec 98
I forgot to answer Joy's first question.Always fire your pots to maturity in=
a
single or any glaze firing. Fire very slowly at first as you would in any
careful bisque firing, then just go on thru the usual glaze firing.I never =
tried
to rush it, but speed was not a factor. for all I know one can whip right
through it without sacrificing anything...but I know the first way works. =
Lori
Pierce
Klyf Brown on mon 5 may 03
Hi Judith
The liner glaze is also in Ron & John's book listed as glossy clear liner
glaze on pp 97. I added 8% zircopax, 1% CMC and 1% bentonite to
make a single fire white liner glaze. This glaze works well thick or thin,
underfired, cone 5 or overfired. It is not runny. It works well sprayed,
but I had problems with it poured or dipped over greenware.
I used the other Ron & John recipes as listed with the exception of
CMC and bentonite additions.
I have done some colour testing on the white liner, but not ready to
release those results yet, more experimenting needs to be done first.
Klyf Brown in New Mexico, usa
>Hi fellow potter person. I've been off of Clayart for a while and
missed
>the discussion leading up to your single fire success post. Can you
give me
>or tell me where to find the recipe for the liner glaze you were so
happy
>with? I have Ron and John's book and have used several of the
glazes.
>Waterfall brown is a good one and the Licorace (sp?) is a great
black. Glad
>your single fire experience was such a good one. Regards. Judith
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