Kristin on fri 27 dec 02
Happy holidays, everyone!
Thanks to the help of many a wonderful folk here, I
attempted the first glaze firing of my kiln. The kiln
was mostly empty, but with 20 test tubes dipped in the
first glazes that I have ever mixed.
Exciting!
Well, it was for me at least. I unfortunately
over-fired the kiln. I attempted a soak when the 6
cone was at a perfect angle, but somehow during that
soak time, when the pyrometer showed that the temp was
falling, the cones continued to bend, and I ended up
at a ^7. Oh well. I'll figure this out next time.
But if you'd like to take a gander at my tubes, I
threw them up on a Web page here:
http://www.tamarac.net/alby/test_tubes
It's possible that the mess-ups in the glazes could be
from my inadequacies as a mixer-upper of glazes, but I
think it's probably from the over-firing.
Anyway all, I had so much fun with this endeavor, I
had to share the results. Please have a safe and happy
holiday season! – Kristin
p.s. These are all shown on “Domestic Porcelain” from
Great Lakes Clay.
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Ms Noel on fri 27 dec 02
Kristin,
Great job!
Thanks for sharing. I think we can all share in your excitement and recall
some of our first ventures. Keep us informed!
Noel
Canton, GA
----- Original Message -----
From: "Kristin"
To:
Sent: Friday, December 27, 2002 9:50 AM
Subject: images of RR and JH's glazes fired to ^7
> Happy holidays, everyone!
>
> Thanks to the help of many a wonderful folk here, I
> attempted the first glaze firing of my kiln. The kiln
> was mostly empty, but with 20 test tubes dipped in the
> first glazes that I have ever mixed.
>
> Exciting!
>
> Well, it was for me at least. I unfortunately
> over-fired the kiln. I attempted a soak when the 6
> cone was at a perfect angle, but somehow during that
> soak time, when the pyrometer showed that the temp was
> falling, the cones continued to bend, and I ended up
> at a ^7. Oh well. I'll figure this out next time.
>
> But if you'd like to take a gander at my tubes, I
> threw them up on a Web page here:
> http://www.tamarac.net/alby/test_tubes
>
> It's possible that the mess-ups in the glazes could be
> from my inadequacies as a mixer-upper of glazes, but I
> think it's probably from the over-firing.
>
> Anyway all, I had so much fun with this endeavor, I
> had to share the results. Please have a safe and happy
> holiday season! - Kristin
>
> p.s. These are all shown on "Domestic Porcelain" from
> Great Lakes Clay.
>
>
> __________________________________________________
> Do you Yahoo!?
> Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
> http://mailplus.yahoo.com
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>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
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>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Christena Schafale on fri 27 dec 02
Kristin,
Congratulations on your first firing. I remember that exciting moment from
a few years ago, myself.
You've learned something about heat work -- cones respond to both time and
temperature, so if you soak at a temperature close to your top temp, the
cones will continue to bend, as you observed. I wasn't sure, looking at
your website, what cones you used. 5, 6, 7? or 6, 7, 8? It looked to me
like the middle cone was "just right", so if that was your 7 cone, then you
are correct that you fired to cone 7.
Some of the results you observed may have to do with how quickly the kiln
cooled, rather than with the overfiring. John and Ron's glaze results in
the book are mostly based on a slow-cool firing schedule. It's tough to
achieve slow cooling in a mostly empty kiln, since you don't have as much
thermal mass to slow things down. You would need to "fire down" --
continue adding enough heat to slow down the cooling process -- for
several hours after your cone dropped, in order to achieve the same results
as John/Ron display.
Another thing to be aware of is that glaze appearance will vary
tremendously with thickness of application. In my experience, test tiles
always seem to look more like the glaze will be when thinly
applied. Frequently, it looks very different on a real pot, where the
walls may be thicker and thus you get more glaze deposited when you
dip. Don't rush to mix up huge batches of anything until you have tried
the glazes on real pots. (Been there, done that, still have huge buckets
of scrap glazes to prove it.) If you like how something turned out on your
test tiles, mix up a 2000 gram batch, which should be plenty to dip some
mugs, soup bowls, or other smallish pots. Once you are satisfied with
that, then you can go for the big batches.
Good luck, and happy firing!
Chris
At 06:50 AM 12/27/02 -0800, you wrote:
>Happy holidays, everyone!
>
>Thanks to the help of many a wonderful folk here, I
>attempted the first glaze firing of my kiln. The kiln
>was mostly empty, but with 20 test tubes dipped in the
>first glazes that I have ever mixed.
>
>Exciting!
>
>Well, it was for me at least. I unfortunately
>over-fired the kiln. I attempted a soak when the 6
>cone was at a perfect angle, but somehow during that
>soak time, when the pyrometer showed that the temp was
>falling, the cones continued to bend, and I ended up
>at a ^7. Oh well. I'll figure this out next time.
>
>But if you'd like to take a gander at my tubes, I
>threw them up on a Web page here:
>http://www.tamarac.net/alby/test_tubes
>
>It's possible that the mess-ups in the glazes could be
>from my inadequacies as a mixer-upper of glazes, but I
>think it's probably from the over-firing.
>
Light One Candle Pottery
209 N Woodrow St
Fuquay-Varina, NC 27526
(919) 567-1098
candle@intrex.net
www.lightonecandle.com
Snail Scott on fri 27 dec 02
At 06:50 AM 12/27/02 -0800, you wrote:
>Well, it was for me at least. I unfortunately
>over-fired the kiln. I attempted a soak when the 6
>cone was at a perfect angle, but somehow during that
>soak time, when the pyrometer showed that the temp was
>falling, the cones continued to bend, and I ended up
>at a ^7. Oh well. I'll figure this out next time.
Heat-work is still occurring even when the temperature=20
is lower than the maximum. It's happening at a reduced=20
rate compared with a higher temperature, but it's=20
still happening.=20
I generally start a soak for ^6 at the point when the=20
^5 is almost flat, or the ^6 is just barely starting to=20
bend. Then I let it soak until the ^6 is at the perfect=20
point. (I prefer a 90=BA bend, not fully down, for my=20
stuff.) Then I turn everything to 'low' for a slow cool=20
if my glazes are supposed to be matt, or I just turn it=20
off for glossy glazes. The 'perfect' final cone reading=20
is the time to stop the soaking, not to start it.=20
Sounds like you're on the right track, though. Glaze=20
tests seldom come out right the first time, but those=20
tests gives you the information you need to tweak them=20
for better results the next time, and the time after=20
that...
-Snail
John Hesselberth on fri 27 dec 02
Hi Kristen,
Thanks for posting your test tiles. Actually your results look quite
good for a first attempt. You really nailed Raspberry right on the
money. You ought to feel pretty happy about them. A couple comments that
might help.
First I think your Spearmint color is a problem with your rutile,
although it could be something else. Unfortunately I don't know enough
yet to advise on exactly what rutile to buy, but try some from another
supplier or, if your supplier carries another grade, try that. Then
keep track of the results so we can gradually build up some information
on which rutiles give that cool green and which don't.
I think you may be applying the glazes a little on the thin side. Try
double dipping the upper half of some of your samples next time and see
if you like the results better. Might even do it in thirds--one dip on
the bottom third, two on the middle and 3 at top. A thicker coat will
help licorice be blacker too. Always put the multiple dips toward the
top--if they run they are less likely to get all the way down to your
shelf.
It looks like you did overfire a little, but I also am wondering about
your cooling rate. Could it be that raw sienna was in a part of the kiln
that overfired and then also cooled faster. The one other thing that
does support overfiring is how far down your rim-dipped samples drooled.
It now appears to me that you can spend too much time in the temperature
range of 1900-2150 (on the way up or down) and this may have caused some
of your "overfiring".
Recently I have found a slightly better firing cycle--at least for
me--than we have in the book. It is the same up to peak temperature.
Then start your 15-20 minute soak when cone 6 is about 2 o'clock. At the
end of the soak, turn the kiln off and let it drop quickly to about 1900
deg F. Then put the brakes on--turn the kiln back on--and let it slow
cool at 125-150 deg F per hour down to 14-1500 deg F. Then turn it off.
You might even slow down to 100 deg per hour if you are still getting
glazes that are too glossy after your next try.
Good luck.
Regards,
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Kristin on fri 27 dec 02
Hi Chris -
Thanks for checking out my little test tubes!
I commented in your e-mail below . . .
--- Christena Schafale wrote:
> Kristin,
>
> Congratulations on your first firing. I remember
> that exciting moment from
> a few years ago, myself.
I'm having a hard time firing up the folks at work
about my little test tubes. The think it's pretty
nerdy. So glad to have Clayart folks to share them
with.
> You've learned something about heat work -- cones
> respond to both time and
> temperature, so if you soak at a temperature close
> to your top temp, the
> cones will continue to bend, as you observed. I
> wasn't sure, looking at
> your website, what cones you used. 5, 6, 7? or 6,
> 7, 8? It looked to me
> like the middle cone was "just right", so if that
> was your 7 cone, then you
> are correct that you fired to cone 7.
Those cones are 5, 6, and 7. I read somewhere that
with these free-standing cones, the tip being at 9
o'clock or so is equal to the tip touching on a
regular cone. By that, I have a solid cone 7 going.
But who knows where I read that or if it's correct?
> Some of the results you observed may have to do with
> how quickly the kiln
> cooled, rather than with the overfiring. John and
> Ron's glaze results in
> the book are mostly based on a slow-cool firing
> schedule. It's tough to
> achieve slow cooling in a mostly empty kiln, since
> you don't have as much
> thermal mass to slow things down. You would need to
> "fire down" --
> continue adding enough heat to slow down the cooling
> process -- for
> several hours after your cone dropped, in order to
> achieve the same results
> as John/Ron display.
I cooled pretty slowly -- about 100* C per hour until
about 800*, at which point I turned it off. Ya, it
wasn't so simple to do this. It required going out
there and turning the dials down a tiny bit every 1/2
hour or so. I was up really late that night!
> Another thing to be aware of is that glaze
> appearance will vary
> tremendously with thickness of application. In my
> experience, test tiles
> always seem to look more like the glaze will be when
> thinly
> applied. Frequently, it looks very different on a
> real pot, where the
> walls may be thicker and thus you get more glaze
> deposited when you
> dip.
Each tube was held in the glaze for 5 full seconds to
the line you can see, then, after the first dip dried,
the top 3/4 inch or so dipped for another 2-3 seconds.
This is generally how I glaze a pot, but of course I
hadn't thought that a pot would probably be thicker
than this test tube, etc. The glazes on these tubes
all melted and sort of collected in little glassy
rings along the bottom, but never ran one bit. I
figured that meant it was over-firing.
> Don't rush to mix up huge batches of anything
> until you have tried
> the glazes on real pots. (Been there, done that,
> still have huge buckets
> of scrap glazes to prove it.) If you like how
> something turned out on your
> test tiles, mix up a 2000 gram batch, which should
> be plenty to dip some
> mugs, soup bowls, or other smallish pots. Once you
> are satisfied with
> that, then you can go for the big batches.
This makes so much sense, and I hadn't thought about
it at all. Small batches. Small batches. I'll remind
myself again . . . small batches, Kristin.
> Good luck, and happy firing!
>
> Chris
Thanks so much for the great advice and for sharing in
my joy. This stuff is just too much fun. - Kristin
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Alisa Liskin Clausen on fri 27 dec 02
Dear Kristin,
Your photos are worth all my words when I try to accurately describe my
results. Great job. I believe R and J's glazes are very successful for
most, including myself. I substitute the frits for all of the recipes with
my local frit and have consistently results. I second what John says about
application of the Licorice. I double dip that glaze to get a real black.
Otherwise
it is brown where thinner. In general, I use the glazes on the thick side
because
they have more movement in the surface, but stay put. The Raspberry has
also been a little tricky in application. I find that I need to let this
glaze
soak as long as possible before using and then need to get a even and
slightly thick application. When I do this, I get a covering, even glaze
that is
the same color as your tile.
It is very exciting even after many, many tests with both good and bad
results.
I also like your test tubes. I will make some for my next tests with the
wide
ribbon die for my extruder. Congratulation on a good job.
regards from Alisa in Denmark
Susan Cline on fri 27 dec 02
I recently completed my very first firing of my new kiln as well. I was so
excited, and very pleased by some of my results. Interestingly and
disappointingly, my Spearmint and Raw Sienna came out looking almost exactly
like Kristen's. This was in a kiln with a computer controller -- I programmed
it to follow the sample in "Mastering Cone 6 Glazes." I placed cones 5-6-7 on
each of 3 shelves and they fell, I think, exactly as they should have, with 5
all the way down and droopy, 6 touching, and 7 about half-way.
My Licorice was "delicious" with an interesting gold break over texture (I
wrote "think Temmoku" next to it.)
Also tried some samples pulled from some Ian Currie test tiles as I had just
taken his 2-day workshop, one of which was based on the Licorice set. Yum, but
somewhat runny.
This is a fascinating, though sometimes frustrating, process for us relative
beginners -- I am loving every minute.
My thanks to the masters who have so generously given us the tools and shared
their information and advice.
On Fri, 27 Dec 2002 14:47:57 -0500 John Hesselberth
wrote:
> Hi Kristen,
>
> Thanks for posting your test tiles. Actually
> your results look quite
> good for a first attempt. You really nailed
> Raspberry right on the
> money. You ought to feel pretty happy about
> them. A couple comments that
> might help.
>
> First I think your Spearmint color is a problem
> with your rutile,
> although it could be something else.
> Unfortunately I don't know enough
> yet to advise on exactly what rutile to buy,
> but try some from another
> supplier or, if your supplier carries another
> grade, try that. Then
> keep track of the results so we can gradually
> build up some information
> on which rutiles give that cool green and which
> don't.
>
> I think you may be applying the glazes a little
> on the thin side. Try
> double dipping the upper half of some of your
> samples next time and see
> if you like the results better. Might even do
> it in thirds--one dip on
> the bottom third, two on the middle and 3 at
> top. A thicker coat will
> help licorice be blacker too. Always put the
> multiple dips toward the
> top--if they run they are less likely to get
> all the way down to your
> shelf.
>
> It looks like you did overfire a little, but I
> also am wondering about
> your cooling rate. Could it be that raw sienna
> was in a part of the kiln
> that overfired and then also cooled faster. The
> one other thing that
> does support overfiring is how far down your
> rim-dipped samples drooled.
> It now appears to me that you can spend too
> much time in the temperature
> range of 1900-2150 (on the way up or down) and
> this may have caused some
> of your "overfiring".
>
> Recently I have found a slightly better firing
> cycle--at least for
> me--than we have in the book. It is the same
> up to peak temperature.
> Then start your 15-20 minute soak when cone 6
> is about 2 o'clock. At the
> end of the soak, turn the kiln off and let it
> drop quickly to about 1900
> deg F. Then put the brakes on--turn the kiln
> back on--and let it slow
> cool at 125-150 deg F per hour down to 14-1500
> deg F. Then turn it off.
> You might even slow down to 100 deg per hour if
> you are still getting
> glazes that are too glossy after your next try.
>
> Good luck.
>
> Regards,
>
> John
>
> http://www.frogpondpottery.com
> http://www.masteringglazes.com
>
>
______________________________________________________________________________
> 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.
>
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