Danny Brumfield 6282 on tue 2 apr 96
I've done some low-fire single firing of artware. The only problem
I've encountered--aside from the fact that the green ware is
extremely fragile when handling to apply the glaze, which I brushed
on--is pinholes, apparently caused when the steam escapes the clay
body. So single firing may not be the best choice for tableware; but
for artware it's great. You just gloss over the pinholes with a very
thin wash of acrylic paint in a matching color and no one is the
wiser.
--
"Do you recognize my voice, Mandrake?"
LBlos72758@aol.com on thu 4 apr 96
About single firing. I single fire everything. Pinholes are a problem when
the glaze is slightly underfired. Also, I always use 1% binder (veegum). I
rarely see pinholes or crawling. I also fire slowly - 100 C per hour.
Linda
Ithaca, NY
Sam Cuttell on fri 5 apr 96
After reading more and more about single firing, I am getting very
interested and would like to try it. I would appreciate some answers to
some basic questions (sorry, I'm new to single fire). I currently am firing
to ^10 ox.
1. What changes do I need to make to present glazes to fit properly?
2. If changes are too difficult, can someone suggest glazes pls?
3. Obviously my tongs are out, how do I apply it? Dip? Pour?
4. How long does glaze need to dry on pot before firing? Presently,
I only let stuff dry a couple of hours before loading.
5. In lieu of doing an entire kiln load, can I fire side by side with
my regular stuff?.
6. And lastly, I guess a firing schedule would be a necessity (I use peeps
only, so I need hours, not temperatures - unless necessary, in which
case I will get my *"&%^ pyrometer fixed)
TIA for all your help!
sam - alias the cat lady
also looking for a used, de-airing pugmill
medelman@facstaff.wisc.edu on sat 6 apr 96
Reply to Sam Cuttell:
Sam, if you want to learn a great deal about single firing, check out
workshops available, and treat yourself to a week-end (or longer, if you can
afford) workshop led by Steven Hill. It is hard to answer all your
questions by e-mail, and Steve is someone who has worked out all the kinks,
is generous with his recipes, and will answer questions. He also exudes
warmth and fun. I noticed in the C.M. listings that he is holding workshops
all over the country this spring-summer.
I was fortunate enough to be at his workshop attended also by Dave Eitel and
Jan Beimborn in Cambridge, WI last Nov. I only rarely make functional pots
and throw, I don't dare single fire my labor-intensive work, and I went
simply because I love great functional work and needed some relief from some
nursing duties at home. It was a great week-end and a pleasure to watch him
work.
Bacia medelman@facstaff.wisc.edu
Gail Nichols on sun 7 apr 96
Sam,
Applying a raw glaze is like applying slip....you apply it at the leather
hard stage, and if the shrinkage rate of the glaze is inappropriate for your
clay body, the glaze will peel off as it dries. If your glaze already has a
high clay content, you might be able to use it as a raw glaze as it is. If
not, try adding some bentonite to increase the shrinkage rate. You will
need to do some tests to work this out. The glaze slop will probably have
to be thicker than it is with your current glaze, because the pots won't be
porous when you apply the glaze. Again, you will need to test. But if you
are familiar with working with slips, you should be able to adapt yourself
to raw glazes.
How long after the glaze application can you pack the kiln? The answer is:
as long as it takes for the pots to turn bone dry! It's the same as asking
how long after slip application can you do a bisque firing.
Yes, you can put bisqued ware into a raw firing. It won't damage the pots
to have a long slow glaze firing.
As far as a kiln schedule is concerned, think of it as doing a bisqe firing,
then continuing up to glaze maturation temperature. So do the first stage
the same as your current bisque. When you reach bisque temperature, just
keep going, using whatever schedule you use at this stage for your current
cone 10 oxidised firings. Be sure to put in a cone for bisque temperature,
along with ones for your glaze temperature. If you want to do a reduction
firing, make sure that the bisque stage is well oxidised to burn out
carbonaceous matter before starting reduction (to prevent bloating).
With raw firing, having a piece explode during the firing is much more
damaging than when this happens is a bisque, as you end up with shards and
dust embedded in your glazed surfaces. For this reason, you will probably
want to err on the side of caution, and perhaps take the bisque stage even
slower than your current bisques. Make sure your pots are dry before
firing, and start the firing with a slow warm-up, drying out period.
There is nothing inherently complicated about doing a raw firing. It is an
efficient way of working, and satisfying as well. Personally, I hate the
dry dead feel of bisqued ware, and raw firing avoids having to deal with
pots at this stage.
Good luck.
Gail Nichols
_______________________________
Gail Nichols
Sydney, Australia
gail@matra.com.au
http://www.matra.com.au/~gail/
peter pinnell on mon 8 apr 96
I don't believe anyones said this yet, but if you really want the story
on single firing, you need to go to THE SOURCE. Steven Hill has been
doing this for a couple of decades, and has really ironed out all the
bugs. He has had a couple of cover stories in Ceramics Monthly in which
he goes into the process in pretty good detail. I don't know the
dates:ask your friendly local librarian to look it up for you in Art Index.
Steven also does a terrific workshop. If you get a chance you might
attend one.
Pete Pinnell
tony nankervis on mon 8 apr 96
Sam
I believe I can answer your questions re Once-firing. I once-fired in a
wood kiln for several years. Pressed for time today - but if you don't get
any satisfactory answers, please write direct.
A useful book
AUTHOR: Parks, Dennis
TITLE: A potter's guide to raw glazing and oil firing
PUBLISHER: Scribner, c1980
Briefly:
can either glaze leather hard or bone dry - I have always preferred the
latter - but you need to be working with a clay that will cope with this
as a rule of thumb - most glazes that have 15-35% ball clay tend to raw
glaze OK - any less and an inclusion of 3-5% bentonite has worked for me. I
found that the thicker the glaze the more likely the piece was to crack.
Consequently I used thin glazes
for my clays, glazing that worked best was to plunge (dip) the whole piece
- inside and out at the same time. Spraying is probably safer - also a way
of getting a glaze on thickly with several applications.
leave pieces to dry at least 24 hrs - some suggest one week - it depends on
your willingness to fire slowly at the beginning of the firing - I packed
almost immediately.
OK to fire side by side with your bisqued ware - though under these
circumstances it may pay to dry the pieces out for the full week.
My firing schedule (without pyrometer) was (and I hasten to mention here
that this is a fairly speedy rise with raw ware - but it worked for me) - 4
hours to 200 deg C (hand in back of chimney couldn't touch bricks much
longer than a second) 2 hours to 400 deg C (paper in spy hole begins to
smoulder) 2 hours to 600 deg C (red Heat ) and then to top temp according
to taste. My experience as a wood firer was the longer the better - I now
fire for 5 days)
Longer reply than intended - If you require more info, please ask - Cheers
Tony Nankervis
Southern Cross University
Lismore NSW Australia
LBlos72758@aol.com on mon 8 apr 96
Dear Sam,
I thought I had met one glaze that I could not single fire. Then that glaze
worked beautifully in the last few firings. So, I guess I haven't met a
glaze yet that I could not use in a single fire method. I always add a
binder - veegum to my glaze. I do this when it is dry, about 1/2 per cent
and sieve once through a 80 mesh sieve. I fire at about 100 C per hour and
soak at the end to put down my cone. I have fired both glazed and previously
fired glazed ware in the same firing. I brush and spray glaze. I have
poured also. If you throw thin pieces, you will need to be careful with your
application. I had two friends describe how they dipped and poured and the
piece disintegrated in their bucket of glaze.
Linda
Ithaca, NY
LBlos72758@aol.com on tue 9 apr 96
I'd like to give a counter opinion on Gail's recommendation to glaze raw when
the piece is leather hard. It is perfectly possible to glaze a bone dry
piece. In fact, the few times I have glazed a leatherhard piece is when I
wanted to move the glazes around a bit, flowing them into each other.
Otherwise, I always glaze bone dry.
Linda
Ithaca, NY
dannon@ns1.koyote.com on wed 10 apr 96
>----------------------------Original message----------------------------
>I'd like to give a counter opinion on Gail's recommendation to glaze raw when
>the piece is leather hard. It is perfectly possible to glaze a bone dry
>piece. In fact, the few times I have glazed a leatherhard piece is when I
>wanted to move the glazes around a bit, flowing them into each other.
> Otherwise, I always glaze bone dry.
>
>Linda
>Ithaca, NY
>
>
Lucie Rie always brushed her glazes on to bone-dry work, once-fired everything.
JeaneanS@aol.com on fri 12 apr 96
Sam,
The posts referring you to Steven Hill should be pursued, but having attended
one of his workshops, I offer the following stopgap info gleaned from my
workshop notes:
Tony Nankervis' post gave many of the same basic "groundrules" as S. Hill...
Hill glazes bone dry ware, for a reason I found imminently practical: he is
not a prisoner to the (fleeting) leatherhard stage... The forms can wait
until he's ready. He also cautions to avoid making walls and rims too thin
and to burnish trimmed areas to seal them as much as possible.
I think it's also accurate to say that he believes his throwing technique
creates a wall which is sealed more tightly than usual, to stand up to the
weakening forces of the glaze slop: when refining his expanding, taut
pitcher shapes, he uses a wooden rib inside the vessel with it's edge
perpendicular to the wall, matched on the outside of the wall's curve with a
flexible metal rib held along the curve of the form(that is, held at right
angles to the wooden rib's position)... The wall is constantly being
compressed between these two ribs as the shape is refined.
Hill's comments about glazing technique included the observation that
"assembly-line" glazing should be avoided --- glaze one pot at a time,
completely. If you glaze several pots inside and then return to the first to
glaze the outside, the clay body will have softened too much for success.
Hill uses a combination of dipping and spraying, as his signature is a
complex surface with as many as seven or eight glazes used in partial,
overlapping (but _thin_) layers.
To allow burn off of gases, his firing schedule contains a long preheat under
220 deg.F for several hours and "coasting" during dull red heat --- as long
as all night, in his kiln.
He starts reducing (modest) at ^08 and fires in oxidation from ^9 to ^10 to
clear his glazes.
To go for an artificial re-fire after reaching ^10, he lets the temp slowly
decrease 200-300 deg. then fires back up slowly. He believes it reduces
blistering, brightens reds and other glazes.
Hope this helps, but don't be deterred from seeking out the gentleman
himself... It will be worth it.
Jeanean Slamen Houston, TX
sutter on thu 17 oct 96
Hi all!
I still havent fired my brand new skutt 818 "automagic" kiln yet...I'd
like to know more about single firing. I have looked around the book
stores and there just isnt alot out there on the subject. I love the
work of Lucie Rie, and wonder if anyone out there can help me with this.
I have never fired in anything other than the Geil gas kiln- back in
Henderson, NV. I had a teacher there who highly discouraged any other
kind of firing. Now I live in Anchorage, AK and want to expand my
knowledge-if you will.
ds
ps...we just had 3 feet of snow fall this week and believe me it is
gorgeous....some kind of wonderful in Autumn!
Janet H Walker on fri 18 oct 96
(Hi. Tried to send this privately but the mailer couldn't find the
necessary host. Sorry to the rest of you.)
Electric kiln firing is Just Fine. (Ref the recent posts by people
who survived & ignored the gas kiln snobbism!) I have a Skutt 1027
with a controller. Works fine. To start to learn to love electric,
get hold of Richard Zakin's Electric Kiln Ceramics, 2nd edition.
Library might have it? Be sure you are on the mailing list for the
Potter's Shop bookstore in Needham MA because they have a huge
selection of books (including all the Zakin ones) at discount prices.
As far as developing colors for ^6 electric firing, ignore all the
snobs who tell you that only reduction firing can give you vivid
colors and exciting surfaces. Get hold of Robin Hopper's Ceramics
Spectrum, which is the best book I've read yet on glaze development,
and go to it. Don't wait. (He treats single firing in close to a
single page, basically saying that you might start with glazes that
contain 20% clay or more, make them up quite thick but don't apply
them too thickly. (I know, sounds contradictory but that's what
it says!))
Just start messing around. It's YOUR kiln and no one is going to
grade you on how you use it!!
Best,
Jan Walker
Fun & Functional Arts
Cambridge MA USA
--MAA25188.845654793/europe.std.com--
David Hooker on fri 18 oct 96
Sutter-
I am glad you have gotten away from a teacher who discourages
"other" types of firing! I've done a lot of single firing with good
success. You probably won't find many books about single firing (although I
think there is a chapter about it in "Self-Reliant Potter"), but there have
been numerous articles about single-firing in Ceramics Monthly.
Basically, it's pretty simple- but there is a catch. It takes a lot
of experimenting to get started. Don't think of anything you are about to
glaze green as "precious," at least not for a while. You will destroy some
pots along the way.
Most of what I read suggested glazing while the pots were
leather-hard with glazes that are about 50% clay. The theory being that
your less likely to crack the pot from "water shock" and that the glaze
will shrink along with the clay body. I found this didn't work for me as
well as using bone dry pots and glazing quickly. I know, it sounds crazy.
If you are only glazing one side of the pot, you might want to spray down
the other side with water- that way the outside and inside will
expand/contract together.
ok, so this is the experimenting part. It took me 4-5 different
clay bodies before I found ones that could handle dry glazing. You will
probably have some crack on you as they are drying- and you'll probably be
able to see the cracks before the firing- LOOK CLOSELY.
I also don't follow the 50% clay in the glaze rule. Some glazes
with 25% clay in them worked fine. I use a lot of shinos and ash glazes.
As for th firing, I just fire slowly, like a bisque, until I get
past bisque temperature (say, cone 08), then continue firing like a normal
glaze firing.
That's it. Good luck.
David JP Hooker
Snail Scott on tue 20 nov 01
At 10:32 PM 11/19/01 -0600, Cathi wrote:
>First, can someone explain the pros and cons of single firing, and when it
>is appropriate?
Cathi-
There's lots of discussion in the archives; try searching
'once-fire' or 'single-fire', and variations on those.
Briefly:
Single-fire is cheaper, and you spend less time firing.
It's great for slip-glazes. No bisque storage needed.
You only have to load the kiln once. And for unglazed
work, why fire twice?
But, each firing is longer than either a bisque firing
or a glaze firing separately. Some glazes respond badly
to single-fire. And, some clays don't cope well with
glazing while green...thin forms are especially
vulnerable.
And, I have a few non-standard reasons of my own:
I do some modifications to large multi-part forms that
can't be done in greenware for strength reasons, but are
harder to do after vitrification, so I bisque these even
if they won't be glazed later. I also bisque if I am
planning a series of pieces, and I want to apply their
surface treatments at the same time. My studio is too
small and cramped to store fragile greenware, but bisque
can be stacked like cordwood in any corner of the kiln
yard.
I used to single-fire quite often when I was in school,
because of the competing demands for kiln space. I do
it less now, mainly for the reasons above.
-Snail
Russel Fouts on wed 21 nov 01
Tony,
>> Otherwise, I single fire because I don't have to waste on a bisque and I
like the clay glaze interface (how they knit) and the surface aesthetic
this
union produces. <<
This was one of the things I loved about single firing when we did it
when I was in school. You can glaze a leather hard pot and then decorate
by scratching or "swiping" through the glaze like you would a slip. Nice
way to work.
Raw glazing and oil firing... I get nostalgic.
Russel
--
Russel Fouts
Mes Potes & Mes Pots
Brussels, Belgium
Tel: +32 2 223 02 75
Mobile: +32 476 55 38 75
Http://www.mypots.com
http://www.Japan-Net.ne.jp/~iwcat
"There is a theory which states that
if ever anyone discovers exactly what
the universe is for and why it's here,
it will instantly disappear and be
replaced by something even more bizzarly
inexplicable."
"There is another theory which states
that this has already happened!"
Douglas Adams' The Hitch Hiker's Guide to the Galaxy
PBORIAN on tue 27 nov 01
I AM LOOKING FOR ANY ON LINE INFO ABOUT SINGLE FIRING TECHNIQUES, SUCH AS
WEB SITES OR ANY OTHER SOURCE WITHOUT HAVING TO PURCHASE BOOKS OR ATTEND
WORKSHOPS. ANY FEEDBACK WOULD BE GREATLY APPRECIATED. THANKS,
PAUL BORIAN
dayton j grant on thu 29 nov 01
If you throw leather hard clay you can cut peices off of the hump (still
spinning) pour glaze in and out (of the inside) dip them in glaze
(outside) and set them in a warm kiln to candle, repeat until the kiln is
full ,close the door ,finish candling(depending on thickness of ware
being fired)and fire ,thats how they did it in the old days ,it seems
like a lot of the best (and most obvious) techniques were ,phased out
all at once for $ome unknown reason ,throwing leather hard clay is the
most efficient way to handle clay on the wheel and I predict that it will
make a recovery as the most widely used wheel method over the next few
years .
d.g.
Maid O'Mud on thu 29 nov 01
Subject: Re: single firing
dayton j grant said:
> If you throw leather hard clay you can cut peices off of the hump
OUCH - do you really mean throw *leather hard*????
Sounds extremely painful. Easier to throw soft "baby-poo" clay and bisque
later. Easier on _my_ body fer shure.
sam - holding her wrists and wincing at the thought.
iandol on fri 30 nov 01
Dear dayton j grant,
You say <hump (still spinning) pour glaze in and out (of the inside)>>
If I were to throw leather hard clay I would do myself a serious injury. =
Perhaps that is what happened to the person in a post above. Leather =
hard clay that I have come in contact has lost most of its plastic =
nature, the property which makes it possible for me to throw the stuff.
If you are throwing, say a twenty pound pug to work from the hump, how =
much force do you need to achieve the process. Possibly you could =
explain this technique for the enlightenment of the rest of the crew.
Best regards,
Ivor Lewis
Tommy Humphries on sat 1 dec 01
This is how who did it in the old days? I have never heard of this leather
hard throwing technique. I have thrown some stiff clay in my time, but to
try to throw true leather hard would seem to me to be foolish, since the
clay would be prone to cracking when flexed, not to mention the wear and
tear on the skin and joints.
If you employ this method, perhaps that is the reason you have had so many
injuries...something to think about.
Tommy
----- Original Message -----
From: "dayton j grant"
To:
Sent: Thursday, November 29, 2001 7:14 AM
Subject: Re: single firing
> If you throw leather hard clay ,thats how they did it in the old
days ,it seems
> like a lot of the best (and most obvious) techniques were ,phased out
> all at once for $ome unknown reason ,throwing leather hard clay is the
> most efficient way to handle clay on the wheel and I predict that it will
> make a recovery as the most widely used wheel method over the next few
> years .
> d.g.
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
iandol on sun 2 dec 01
Would love to accept your offer Dayton but we are on VHS PAL.
I am wondering how you define "Leather Hard Clay". For me, it means a
stiff sheet which will cut with a knife but will not bend without
cracking or splitting. In this, I am in agreement with Fournier and
Hamer. Although Leather Hard Clay has lost it's ability to be deformed
plastically, it retains sufficient moisture to be burnished or to be
incised, planed, carved and even decorated with slip. It will, as the
leather sole of my shoe will, bend and flex. But is would not deform
to allow me to press my thumb into it to create a cavity in a turning
pug without fracturing possibly both.
So, how do you define "Leather Hard".
Enlighten me!
Best regards,
Ivor Lewis. Redhill, South Australia.
-----Original Message-----
From: dayton j grant
To: iandol@tell.net.au
Date: Saturday, 1 December 2001 4:12
Subject: Re: single firing
>hey Ivor , throwing leather hard clay is possible with normal hand
>strengh and does not cause injury(if youre careful) , the most
difficult
>aspects of this method are the preparation of the leather hard clay
and
>the steadiness of the hands in motion, which can be easily learned by
a
>serious student,I may be making instructional videos of this method
that
>would commercially available soon,I have a two hour sample video
>available now for 10 dollars but if you are unable to pay I will send
you
>one anyway if you are interested .
>Dayton
>
Debi Wichman on mon 30 jun 03
Bill Campbell wrote in early June:
"I have been single firing for many years. I start the kiln slowly. I =
fire to
200F and hold for an hour. Then I let it go to temperature at 270F/Hr. =
to its
maturing temperature, and the reduction stuff.
On my crystalline glazes I put in another hold for an hour at 1050F to =
make
sure that I get rid of any carbon that could be unburned in the body. I =
do that
so that I do not have any blisters showing up from localized reduction =
from
any dirt that could be left in the body.
Bill Campbell "
I tried the above single-firing method this weekend (even though I was a =
bit afraid I may have a mess in the kiln to clean up) - and am happy to =
say that not a single pot exploded. I wanted to pass this along to =
other newbies who may want to try it. It was a quick way to try out =
some test pots and glaze combinations - and considering it is getting =
warm and muggy here in Tennessee where I only have the weekend to work =
on pottery, it was nice to skip the longer bisque firing. =20
Thanks to Bill for the original post, I intend to do more =
experimentation with this method!
Debi
Jenny Lewis on tue 28 oct 03
Hi Ababi
That book by Fran Tristram is really good, and got me all inspired to find
out about single firing. When I went to Art in Clay at Hatfield in early
August, Fran was one of the exhibitors and I stopped for a chat. She said she was
trying to organise a workshop on raw glazing and single firing so I promptly
added my name to her list, and found myself in Nottingham at the end of August
for a long weekend of total enjoyment.
Fran is absolutely delightful, and while we muddy people were slaving away
over buckets of glaze, her husband Rod Bailey (he's an artist and also brilliant
cook) was rustling up some terrific meals, and producing regular supplies of
coffee and tea.
There were 6 of us, and we each took a few pots of our own to glaze and fire
in her large gas kiln. We spent the Saturday talking about the glazes, and
sloshing them all over our masterpieces - well, some people were being a bit
more refined about the glazing process, but I quite enjoy sloshing all over in
the hopes that something interesting happens. She then went over the firing
timing, temperatures, etc., the pots were warmed up overnight at a low temp
(sorry, I should have made copious notes...) and then on Sunday we kept watching
the temperature, the cones etc, while Fran did some throwing demos and we asked
all sorts of questions about throwing and glazing. She does some really good
oval and square oven dishes on the wheel, and we each asked her to try out
something that we wanted to know about specifically.
It was a really good weekend, and I am quite sold on the idea of single
firing, for which the two main advantages are - saving of time/money, and not
having to load and unload twice - once is enough!
Jenny
Snail Scott on wed 8 jun 11
On Jun 8, 2011, at 11:35 AM, Rose Heim wrote:
> I would like to fire medium sized sculptural pieces, unglazed, in a=3D20
> single firing. I am using cone 10 b-mix and would like to single fire =3D
it to=3D20
> cone 5 or 6 in an electric kiln. I want to maintain the whiteness of =3D
the=3D20
> surface. I am looking for advice as to how to program my kiln to do=3D20
> that.=3D20
> Can I use the slow bisque option and enter cone 5? Or, should I create=3D=
20=3D
> an entirely manual program - and what should it be? So far, I have =3D
only=3D20
> used the automatic programs, so it's safe to assume that I know=3D20
> nothing.
First: what is 'medium-sized'? Not just how tall or wide...
how _thick_ are they?
If you are only firing the ^10 body to ^5 you probably=3D20
won't have warping issues, as you would if taking this=3D20
fairly pyroplastic body to vitrification as something like=3D20
'medium-sized' sculpture. It won't be vitrified-looking,=3D20
of course, if you do this. It will look a bit like white=3D20
earthenware, lacking the slight gloss and depth of=3D20
vitrified B-Mix, and it will be weaker than the matured=3D20
clay body would be . There are valid reasons for doing=3D20
this, such as the aforementioned non-warping, but=3D20
drawbacks as well. In addition to the issues mentioned=3D20
above, glazes can tend to craze on unvitrified bodies.=3D20
I am assuming that you aren't glazing these pieces? I=3D20
also am curious why you chose B-Mix, which throws=3D20
well but wouldn't be the ideal choice for anything
bigger than maybe 10"-12" tall. The main attribute of=3D20
B-mix for most people, the near-porcelainous surface=3D20
appearance, will be lacking unless fired to vitrification.=3D20
If you like this body mainly for its working texture, it can=3D20
make sense, though I personally find B-mix too plastic=3D20
for easy handbuilding beyond a rather small scale.
=3D20
(Note: I am assuming you are handbuilding. If you are=3D20
mainly throwing your sculpture, your choice of B-mix=3D20
makes more sense to me. But I digress...)
Assuming you are doing all this for well-considered=3D20
reasons, the critical issue remains thickness. B-Mix=3D20
is a tight body, with little porosity in its green state.=3D20
Bodies like this must be candled more carefully than=3D20
normal (gritty, open) sculpture bodies, and the=3D20
thicker the clay, the longer you must candle to be=3D20
sure of driving off all the moisture. Candling is cheap,=3D20
so I would do a crazy-long preheat just to be on the=3D20
safe side. If these are, say, 1/4" thick, I'd candle for=3D20
four or five hours. If they are 1/2" thick, double that=3D20
at least. Electricity for candling isn't much, and you=3D20
don't want to risk losing the work in case there is a=3D20
thicker spot than you think there is. The more complex=3D20
and convoluted the form, the greater the possibility=3D20
of unanticipated thick spots, though a lot depends on=3D20
your particular working methods.
The standard candling interval built in to the pre-
programmed firing schedules is, in my mind, mainly=3D20
suitable for very thin work in dry climates. Anything=3D20
thicker than slip-casting needs extra candling, and=3D20
the thicker or tighter the clay, the more it needs. When=3D20
using a pre-set program, I always add a pre-heat cycle.
You could do a manual program, but I find that the=3D20
built-in ones are usually sufficient unless the work is=3D20
very, very thick (like a brick) or had other special issues=3D20
(like glazes in need of specific firing schedules). It's=3D20
good to learn how to create a firing program, and it's=3D20
not difficult, but I doubt you'll need it for this.
=3D20
If you are single-firing, you are right to choose one of=3D20
the bisque cycles, since until it is well past red heat, it=3D20
IS a bisque firing. The same need to slowly drive off=3D20
moisture, and burn off offending substances applies=3D20
whether you only go partway then do a separate final=3D20
firing, or simply continue on to maturity. Unless your=3D20
work is more than 1/2" thick, I'd pick the slowest standard=3D20
bisque program, and still add the extra preheat. Candling=3D20
is cheap insurance.=3D20
(So are witness cones. Have you checked the accuracy=3D20
of the kiln's built-in pyrometer lately?) =3D20
The only thing that I would change if you make your=3D20
own firing program is to simply speed up the cycle=3D20
above 1000F, as the bisque programs are usually a=3D20
little slower than the glaze programs in all stages of=3D20
firing. They needn't be, once the clay is past 900F or=3D20
so. No hazard to firing faster at that point; I have never=3D20
met a standard-model electric kiln that could go too fast=3D20
for the clay once it's above the normal bisque range of=3D20
temperatures. Gas kilns... that's another story. Electrics,=3D20
though, unless it's a tiny kiln with serious juice, just can't=3D20
crank that fast.
-Snail
Rose Heim on wed 8 jun 11
I would like to fire medium sized sculptural pieces, unglazed, in a=3D20
single firing. I am using cone 10 b-mix and would like to single fire it =
=3D
to=3D20
cone 5 or 6 in an electric kiln. I want to maintain the whiteness of the=3D=
20=3D
surface. I am looking for advice as to how to program my kiln to do=3D20
that.=3D20
Can I use the slow bisque option and enter cone 5? Or, should I create=3D20=
=3D
an entirely manual program - and what should it be? So far, I have only=3D2=
0=3D
used the automatic programs, so it's safe to assume that I know=3D20
nothing.
Thanks for any suggestions. Rose
DJ Brewer on thu 9 jun 11
Why don't you do it in 2 firings. For sculptural work it really needs
to go slooooooooooooooooooooooooooooooooow. Don't use the programmed
slow firing -- its not near slow enough. When I fire thick pieces, I
program it manually, with about 7 ramps. I start at 30 degrees an hour
to 170 and hold it for 6 to 12 hours depending on the thickness of the
piece. The reason I program it to 170 is to err on the side of caution
-- I don't want the piece accidentally going over 212 just in case the
thermocoupler's reading may not be spot-on accurate.
Then I usually go up about 200 degrees an hour to 950, then around 75 or
100 degrees an hour to 1250, then on to cone 08 for a bisque.
Sometimes the firing can take 30 hours. If your pieces are a half inch
thick or thicker, you'll definitely want to take that long.
I personally would not risk a single firing with thick work. But other
people here are far more experienced than I, and may have other advice
that is more accurate.
good luck
DJ
On 6/9/2011 9:06 PM, Ron Roy wrote:
> Hi Rose,
>
> Will there be any thick clay - like over 1/2 inch thick?
>
> RR
>
>
> Quoting Rose Heim :
>
>> I would like to fire medium sized sculptural pieces, unglazed, in a
>> single firing. I am using cone 10 b-mix and would like to single fire
>> it to
>> cone 5 or 6 in an electric kiln. I want to maintain the whiteness of the
>> surface. I am looking for advice as to how to program my kiln to do
>> that.
>> Can I use the slow bisque option and enter cone 5? Or, should I create
>> an entirely manual program - and what should it be? So far, I have only
>> used the automatic programs, so it's safe to assume that I know
>> nothing.
>> Thanks for any suggestions. Rose
>>
>
Ron Roy on thu 9 jun 11
Hi Rose,
Will there be any thick clay - like over 1/2 inch thick?
RR
Quoting Rose Heim :
> I would like to fire medium sized sculptural pieces, unglazed, in a
> single firing. I am using cone 10 b-mix and would like to single fire it =
to
> cone 5 or 6 in an electric kiln. I want to maintain the whiteness of the
> surface. I am looking for advice as to how to program my kiln to do
> that.
> Can I use the slow bisque option and enter cone 5? Or, should I create
> an entirely manual program - and what should it be? So far, I have only
> used the automatic programs, so it's safe to assume that I know
> nothing.
> Thanks for any suggestions. Rose
>
Michael Flaherty on fri 10 jun 11
i'd do just as you suggested (slow bisque to cone 5) with one addition: d=
=3D
o a=3D20
preheat for 12 hours. unless your work is extremely thick (2"+) i can't =
=3D
imagine=3D20
there being a big problem. the preheat is probably under the option butt=
=3D
on,=3D20
but do read your manual to make sure you're doing it properly.
Rlucas on tue 20 sep 11
I am totally thrown by this term. I have heard about it but most of the
explanations are foreign to me.
Does it really work? Do I simply dip my mug, dry green ware, into regular
glaze that I would use for
bisque? It seems it would "melt" down and fall apart.
How long do you have to wait before firing?
Can it be done in an electric kiln? I have a Skutt KM 1027 computer
controlled. What type of setting
would I use? Slow, fast, etc. Any hold time? Do I make any changes to my
regular firing regimen?
Can anyone just stay do this, this and this like in a list. Without lots o=
f
comments so I can follow
easier.
At the cost of electricity it would be worth trying but I don't want to rui=
n
my kiln.
Thanks anyone
Verna
Pagosa Springs, Colorado
Lili Krakowski on tue 20 sep 11
As so well said by others, single firing is a great option--when it is =3D
usable.
Unpleasantnessses to my hands--repeated carpal tunnel surgeries, =3D
arthritis--have made glazing by pouring quite difficult. I rarely =3D
spray--generally brush.
And have found that glazing a pot, raw, on the wheel, is a nice way of =3D
doing it. Trim, Glaze. Voila.
Of course not applicable in all situations...but when it is feasible, =3D
lovely.
There is a wonderful book called "Single Firing" by Fran Tristram. One =3D
in the Ceramics Handbooks series (A & C Black)--which series I consider =3D
an absolute total marvelous godsend to potters. And the ISBN is =3D
0-9650786-1-2
Lili Krakowski
Be of good courage
Lili Krakowski on tue 20 sep 11
As so well said by others, single firing is a great option--when it is =3D
usable.
Unpleasantnessses to my hands--repeated carpal tunnel surgeries, =3D
arthritis--have made glazing by pouring quite difficult. I rarely =3D
spray--generally brush.
And have found that glazing a pot, raw, on the wheel, is a nice way of =3D
doing it. Trim, Glaze. Voila.
And I have found that replacing some of the clay in the glaze by =3D
Bentonite works very well for raw glazing. Carl Judson says that a =3D
glaze for raw glazing should have 40-50% ball clay. Failing that 8-13% =3D
Bentonite, replacing even all kaolin.Bill Criz says 12% Ball Clay, =3D
and.or Bentonite for total of 24--even replacing spar by Bentonite.
CM suggests a modes 3% Bentonite.
I go by trial and error. (Duh!)
Of course not applicable in all situations...but when feasible, lovely.
There is a wonderful book called "Single Firing" by Fran Tristram. One =3D
in the Ceramics Handbooks series (A & C Black)--which series I consider =3D
an absolute total marvelous godsend to potters. And the ISBN is =3D
0-9650786-1-2
Lili Krakowski
Be of good courage
John Hesselberth on wed 21 sep 11
On Sep 21, 2011, at 4:11 PM, Url Krueger wrote:
> My belief at the moment is that single firing requires
> more attention to detail.
Hi Earl,
I think you put your finger on it with that statement. There is no =3D
question that single firing can be done successfully. But it depends on =3D
your willingness to pay careful attention to detail. If, for example, =3D
your yield of first grade pots coming out of a firing drops from 98 or =3D
99 % to, say, 90%, you have just lost more than you have gained. When =3D
you consider the time and cost of that lost 8 or 9% of your work, it =3D
isn't worth it. That is why most potters who try single firing give it =3D
up after a few bad experiences. Those who are willing to be be extremely =
=3D
careful and learn how to manage single firing can do fine with it.=3D20
Most potters do not. I'm one of those. After trying it for a while it =3D
seemed to take some of the joy out of potting for me. It became too much =
=3D
like fine woodworking where extreme care at every step of the process =3D
was necessary--that's why I turned away from woodworking many years =3D
ago--making good joints was just no fun for me.
Regards,
John
Snail Scott on wed 21 sep 11
On Sep 20, 2011, at 10:48 PM, Rlucas wrote:
> Does it really work? Do I simply dip my mug, dry green ware, into =3D
regular
> glaze that I would use for
> bisque? It seems it would "melt" down and fall apart...
Some clay bodies handle it better than others. Also,
Dipping is not a big issue with beefier forms with=3D20
consistent thickness, but can be an issue with very=3D20
thin work and delicate bits. =3D20
Dry greenware is far less absorbent than bisque, For=3D20
this reason as well as those mentioned above, many=3D20
people prefer to brush or spray the glaze for single-fired=3D20
work. When dipping is preferred anyway, one solution=3D20
is to use a thicker glaze, or one deflocculated to contain=3D20
less water. This reduces the absorption into the clay=3D20
while also permitting the necessary thickness of the=3D20
glaze to build up.=3D20
> How long do you have to wait before firing?
How long do you have to wait before semi-damp=3D20
greenware is normally fired? 'Til it's dry. That doesn't=3D20
change. You can fire sooner, of course if you like to=3D20
candle longer in lieu of waiting, just like with any not-
quite-dry clay. How fast it dries depends on how much=3D20
water was absorbed, how dry your studio is, and all=3D20
the same stuff you normally consider. The standard test -=3D20
'does it feel cool to the touch' - actually works better for=3D20
this, since the moisture is penetrated from the outside,=3D20
and deep hidden moisture in thick spots isn't a factor.
> Can it be done in an electric kiln? I have a Skutt KM 1027 computer
> controlled. What type of setting
> would I use? Slow, fast, etc. Any hold time? Do I make any changes =3D
to my
> regular firing regimen?
The type of kiln doesn't matter! And you fire just like=3D20
an ordinary bisque firing, with the same concerns,=3D20
until red heat. You can fire to your normal bisque=3D20
temp, but since you aren't concerned about the=3D20
hardness or absorption of the bisque, your only issue=3D20
is to burn out the water and organics. If your clay is=3D20
really loaded with stuff that needs burnout, spend=3D20
longer in the low range, but with most clays, you=3D20
can ramp up at normal 'glaze firing' speed as soon=3D20
as you reach red heat, and follow all your normal=3D20
glaze firing procedures.=3D20
If you want to use one of those automatic kiln settings,=3D20
look in your manual to see how fast the top ramp of=3D20
your normal bisque is, compared with the speed of=3D20
your usual glaze firing setting. If it's similar, just tell the=3D20
kiln to do your usual bisque run, except set the cone=3D20
to your glaze maturation temp. If it's significantly slower,=3D20
or otherwise different, I'd use the manual program,=3D20
putting in your normal bisque settings up to maybe=3D20
1000F, then your normal glaze-firing ramp from that=3D20
point upward, including whatever holds, etc, you prefer.
Just copy the settings from the manual. You may find=3D20
that one of your built-in bisque programs is just fine.=3D20
Just because the button on the controller calls it a=3D20
bisque, doesn't make it so. It's just a program with a=3D20
gradual low-temp ramp, nothing more.
> Can anyone just stay do this, this and this like in a list. Without =3D
lots of
> comments so I can follow
> easier...
Easier? Well, if you don't want to fine-tune the process,=3D20
just put your stuff in the kiln, hit 'fast bisque', enter the=3D20
cone of your normal glaze firings, and hit the 'start' button.
Come back when it's done and unload.
> At the cost of electricity it would be worth trying but I don't want =3D
to ruin
> my kiln...
Why would it ruin your kiln? It's just a firing, like any=3D20
other firing. It merely starts like a bisque and ends like=3D20
a glaze firing. That's all. All the stuff your kiln is doing=3D20
anyway.
Remember that although it uses less power to single-
fire than to do two separate firings, the single-firing will=3D20
be longer and more expensive than either your normal=3D20
glaze or bisque firings by themselves, because the low=3D20
ramp speed for bisque has to replace the faster speed=3D20
of a glaze firing of already-bisqued work during the=3D20
lower temps of the firing.
-Snail=3D
Michael Wendt on wed 21 sep 11
Step 1: make the walls very uniform
(thin areas can be a problem)
Sep 2. Let dry completely if you plan to use glaze normally
meant for bisque ware.
Step 3. Remove a few cups of water prior to stirring
the glaze so it is a little thicker ( green clay won't absorb
as much water as bisque without disintegrating)
Step 4. I dip the outside first. Let dry a day, then quickly
pour the inside and drain.
Step 5. Fire the early part of the firing like a bisque, then
finish the same as a regular glaze load.
There is a learning curve... some clay bodies (like the one I use) that tak=
e
once firing very well. Do lots of testing
before committing all your work to this
Regards,
Michael Wendt
----- Original Message -----
From: "Rlucas"
To:
Sent: Tuesday, September 20, 2011 8:48 PM
Subject: Single firing
>I am totally thrown by this term. I have heard about it but most of the
> explanations are foreign to me.
>
> Does it really work? Do I simply dip my mug, dry green ware, into regula=
r
> glaze that I would use for
> bisque? It seems it would "melt" down and fall apart.
>
> How long do you have to wait before firing?
>
> Can it be done in an electric kiln? I have a Skutt KM 1027 computer
> controlled. What type of setting
> would I use? Slow, fast, etc. Any hold time? Do I make any changes to
> my
> regular firing regimen?
>
> Can anyone just stay do this, this and this like in a list. Without lots
> of
> comments so I can follow
> easier.
>
> At the cost of electricity it would be worth trying but I don't want to
> ruin
> my kiln.
>
> Thanks anyone
>
> Verna
> Pagosa Springs, Colorado
Url Krueger on wed 21 sep 11
There seems to be much interest but yet concern
about single firing so I thought I would relate my
experiences.
When I first started out in pottery I hand built forms
using the coil method. Once the pots had dried out
I brushed on commercial glazes and let them dry
again. Then I put them in the kiln and fired much
the same as you would a bisque firing except that
I fired to a full cone 6 instead of stopping at cone 04.
Worked great.
After a while I purchased a wheel and began mixing
my own glazes. I also started bisquing as it seemed
like the thing to do. Also, I did have one raw pot that
I had spent considerable time on collapse on me from
the water absorbed from the glaze.
This also worked great.
Lately I have been experimenting again with raw
glazing with my own glazes and am working
through some problems. About half of the bone
dry pots I have attempted this with have
developed blisters in the clay.
My belief at the moment is that single firing requires
more attention to detail. You may have to only glaze
the inside or the outside of the pot and then let it dry
before glazing the other side. You have to pay more
attention to the amount of water in your glaze. This
means checking the density as well as perhaps adjusting
the flocculation. You may need to try other clay bodies.
The energy savings associated with single firing is
definitely appealing to me but even more so is the
time savings. As my pottery time is limited I don't
like having to wait the extra two days while the bisque
load heats up and cools down before I can glaze.
Often for me this translates into a week's delay.
I'm still learning and would like to get the finished
pot feedback sooner while the overall concept is
still fresh in my mind.
However the bisqued pots are sturdier and can take
a little more banging around while decorating.
Anyway, these are my experiences. Take what you
will from them.
Earl...
Oregon, USA
| |
|
