Bert Gibson on thu 19 jun 03
I just finished my first glaze firing. I used the glazes from John and =
Roy's book and have some questions. The witness cones showed cone 6 =
touching and cone 7 bent. I used the firing schedule as shown on the web =
page for thier book, which had 2185F as the temperature to reach and a =
20 minute hold. Around the rim and sometimes inside the cylinder the =
results were close or encouraging, but I did not have any comparable =
results to the book on the outside of the cylinder. I suspect I may have =
gotten the glaze to thin on the outside, however I never got the glaze =
thin enough in the bucket to meet the "fingernail" test. I used three =
different clays for each glaze and I had 18 glazes and did 5 of those =
glazes twice for a total of 69 cylinders. So I am seeking advice or =
suggestions on what to correct other than maybe a thicker glaze =
application. Any input would be appreciated.
Thanks,
Bert Gibson
John Hesselberth on fri 20 jun 03
Hi Bert,
It does sound like you had the glazes on a little too thin. One good
way to test for the right thickness on a test tile is to dip the whole
thing for, say, the count of 5. Let that dry a bit and then redip the
upper 2/3. Let dry again and dip only the upper 1/3. It is always best
to have the thickest test (3 dips) at the top in case the glaze runs.
I also sounds like you are firing a bit too hot. Every person will have
the adjust the firing schedule we proposed a bit to match their own
thermocouples and computer controller to the cones. I would recommend
you lower the peak temperature about 10-15 deg F for your next trial.
Lastly you might try slowing the cooling even more. In the book we
proposed 150 deg F / hr from peak temperature down to 1500 deg F. I now
use a slightly modified schedule which works a little better for me. I
drop quickly from peak temp (after the soak) down to 1900 deg F -- say
500 deg F/hr or even faster. Then I slow down to 125 deg F/hr down to
1500. That seems to give me slightly better mattes and more depth to
the glazes.
Good luck,
John
On Thursday, June 19, 2003, at 11:37 PM, Bert Gibson wrote:
> I just finished my first glaze firing. I used the glazes from John and
> Roy's book and have some questions. The witness cones showed cone 6
> touching and cone 7 bent. I used the firing schedule as shown on the
> web page for thier book, which had 2185F as the temperature to reach
> and a 20 minute hold. Around the rim and sometimes inside the cylinder
> the results were close or encouraging, but I did not have any
> comparable results to the book on the outside of the cylinder. I
> suspect I may have gotten the glaze to thin on the outside, however I
> never got the glaze thin enough in the bucket to meet the "fingernail"
> test. I used three different clays for each glaze and I had 18 glazes
> and did 5 of those glazes twice for a total of 69 cylinders. So I am
> seeking advice or suggestions on what to correct other than maybe a
> thicker glaze application. Any input would be appreciated.
>
> Thanks,
>
> Bert Gibson
>
> _______________________________________________________________________
> _______
> 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.
>
>
http://www.frogpondpottery.com
http://www.masteringglazes.com
Amy Brenner on fri 20 jun 03
I keep seeing references to this glaze book, but don't know what book you are
talking about. What is it please? Amy
Bert Gibson on fri 20 jun 03
Thanks for responding John. I've really learned alot from the book
and have been using it as a guide to learn how to mix and apply glazes
on my own. I would like to clarify the 3 part application procedure.
If I applied the way you describe, would that mean that the top part
of the test tile that got 3 "dips" would have been in the glaze for
about a count of 15 total? The community college teacher had us
dip in and out as quick as we could so that is how I did it. The glaze
was probably the thickness of a piece of paper. That would explain alot
about my results.
Thanks again. This gives me a direction instead of feeling my way in the
dark. I was actually wondering if I needed to go a few degrees higher
before I read your post. Without you, Roy, and Clayart I would be totally
frustrated. With all of you, I am only partially frustrated.:) I am setting
out
to prove to myself, fellow students, and teacher what can be achieved with
a little care, craftsmanship, and attention to detail instead of the
haphazard
way they all go about things. Hope I can open thier eyes.
Will report next week on the second round of tests, probably with a second
round of questions.
Bert Gibson
----- Original Message -----
From: "John Hesselberth"
To:
Sent: Friday, June 20, 2003 1:44 PM
Subject: Re: J&R Glaze results question
> Hi Bert,
>
> It does sound like you had the glazes on a little too thin. One good
> way to test for the right thickness on a test tile is to dip the whole
> thing for, say, the count of 5. Let that dry a bit and then redip the
> upper 2/3. Let dry again and dip only the upper 1/3. It is always best
> to have the thickest test (3 dips) at the top in case the glaze runs.
>
> I also sounds like you are firing a bit too hot. Every person will have
> the adjust the firing schedule we proposed a bit to match their own
> thermocouples and computer controller to the cones. I would recommend
> you lower the peak temperature about 10-15 deg F for your next trial.
>
> Lastly you might try slowing the cooling even more. In the book we
> proposed 150 deg F / hr from peak temperature down to 1500 deg F. I now
> use a slightly modified schedule which works a little better for me. I
> drop quickly from peak temp (after the soak) down to 1900 deg F -- say
> 500 deg F/hr or even faster. Then I slow down to 125 deg F/hr down to
> 1500. That seems to give me slightly better mattes and more depth to
> the glazes.
>
> Good luck,
>
> John
>
> On Thursday, June 19, 2003, at 11:37 PM, Bert Gibson wrote:
>
> > I just finished my first glaze firing. I used the glazes from John and
> > Roy's book and have some questions. The witness cones showed cone 6
> > touching and cone 7 bent. I used the firing schedule as shown on the
> > web page for thier book, which had 2185F as the temperature to reach
> > and a 20 minute hold. Around the rim and sometimes inside the cylinder
> > the results were close or encouraging, but I did not have any
> > comparable results to the book on the outside of the cylinder. I
> > suspect I may have gotten the glaze to thin on the outside, however I
> > never got the glaze thin enough in the bucket to meet the "fingernail"
> > test. I used three different clays for each glaze and I had 18 glazes
> > and did 5 of those glazes twice for a total of 69 cylinders. So I am
> > seeking advice or suggestions on what to correct other than maybe a
> > thicker glaze application. Any input would be appreciated.
> >
> > Thanks,
> >
> > Bert Gibson
> >
> > _______________________________________________________________________
> > _______
> > 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.
> >
> >
> 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.
Ababi on sat 21 jun 03
Mastering cone six glazes
By John Hesslberth and Ron Roy
http://www.masteringglazes.com/
visit also John's site ( be careful not to step on a frog and you will find there a lot of
information.
http://www.frogpondpottery.com/
I use only one recipe from the book (Gloss Liner) but it is my guideline of what to do
and how to do when I want a foodsafe glaze. Since reading the book I check every new
claybody for porosity before making the first ware. I check every glaze that might have
any contact with food , even as a decorative glaze and try to improve its residence.
Because English is not my mother tough I am carful while using the terms Ron and
John are using : Durably and stability. I shall say I am more eager to have my glazes
higher rigidness for there lifetime troubles.
It is an excellent book.
The authors giving there recipes.
There is a unique way to make them.
Potter are trying. Some fail some succeed. They asked as not to pass them in the
net.
This is the reason you see names not recipe.
It is worse buying!
Ababi Sharon
Glaze addict
Kibbutz Shoval Israel
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910/
http://www.matrix2000.co.nz/Matrix%20Demo/Ababi.htm
---------- Original Message ----------
>I keep seeing references to this glaze book, but don't know what book you are
>talking about. What is it please? Amy
John Hesselberth on sat 21 jun 03
On Friday, June 20, 2003, at 07:07 PM, Bert Gibson wrote:
> If I applied the way you describe, would that mean that the top part
> of the test tile that got 3 "dips" would have been in the glaze for
> about a count of 15 total? The community college teacher had us
> dip in and out as quick as we could so that is how I did it. The glaze
> was probably the thickness of a piece of paper. That would explain alot
> about my results.
Hi Bert,
Here is a little more info than I gave you in my off-list message.
Getting the right thickness of glaze is highly dependent on the
absorbency of your bisque and the thickness of your glaze slop. It
takes a bit of experimentation to get it right. Most people describe
the 'right' thickness to be more like postcards than paper. Some like
even thicker applications. I like to mix my glazes thin enough to allow
a 5 second dip--I think that gives me better uniformity both on a
single pot and pot to pot. Others aim for 3 seconds--it really doesn't
matter as long as you get the results you want and can do so
consistently--but it does take some experimentation and experience. In
time, you will learn to look at the glaze slop as you stir it and know
how long you have to dip in order to get what you want. You will also
be able to tell by looking at a dipped pot whether or not it is what
you want.
And yes, what I proposed for your test would result in a total count of
15 for the 3-layer section. That will almost certainly be too thick
unless your glaze slop is quite thin or your bisque is relatively
non-porous. But I like to practice good artillery techniques--always
bracket the target, then zero in.
Regards,
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Ron Roy on sun 22 jun 03
Hi Bert,
I wrote all this before I read your description of how you dipped - in and
out as fast as possible - no wonder it is too thin. Teachers have to
overcompensate with beginners because they tend to dip too slow. Perhaps
all students should have to clean and wash a bunch of shelves before they
get their glaze license.
It's hard to believe - if the glaze is that thickness in the bucket - some
skin showing through the glaze - just around your finger nail - after
dipping in a dry finger.
What temperature are you firing your bisque to.
I assume you are using cones for both the bisque and glaze firing?
I suggest you try dipping a test tile as John has suggested - two actually.
Wait till they dry a bit and scratch through one (all three layers) so you
can actually see the thickness of the dry glaze. Now fire the duplicate
tile. Now you have a visual reference and before you start glazing you can
dip a piece of bisque in your glaze and see if it needs to be thinned or
thickened - or is just right.
If it's too thin wait a day and take some of the water out - more than you
think you need to. Stir and add water till it gives the right coating
according to your tiles.
Let us know how the next load looks.
RR
>I just finished my first glaze firing. I used the glazes from John and
>Roy's book and have some questions. The witness cones showed cone 6
>touching and cone 7 bent. I used the firing schedule as shown on the web
>page for thier book, which had 2185F as the temperature to reach and a 20
>minute hold. Around the rim and sometimes inside the cylinder the results
>were close or encouraging, but I did not have any comparable results to
>the book on the outside of the cylinder. I suspect I may have gotten the
>glaze to thin on the outside, however I never got the glaze thin enough in
>the bucket to meet the "fingernail" test. I used three different clays for
>each glaze and I had 18 glazes and did 5 of those glazes twice for a total
>of 69 cylinders. So I am seeking advice or suggestions on what to correct
>other than maybe a thicker glaze application. Any input would be
>appreciated.
>
>Thanks,
>
>Bert Gibson
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Bert Gibson on mon 23 jun 03
Thank you Roy for responding and for your book. This was my
first attempt to mix glazes, but I feel I've learned alot from the
experience. With only your book to guide me, I was able to mix
and fire all the glazes on my own and at least have some similar
results around the rim of my pots as your book. Now that I know
the difference in the approach from what I was taught in class
and John's observation that I might have to lower the peak
temperature a bit, I feel confident that my results in this next
round of tests will be much better. I will let you know the results.
I bisqued to cone 04 but did not use witness cones, I will use
them this next time though. Thanks again.
Bert Gibson
----- Original Message -----
From: "Ron Roy"
To:
Sent: Sunday, June 22, 2003 7:46 PM
Subject: Re: J&R Glaze results question
> Hi Bert,
>
> I wrote all this before I read your description of how you dipped - in and
> out as fast as possible - no wonder it is too thin. Teachers have to
> overcompensate with beginners because they tend to dip too slow. Perhaps
> all students should have to clean and wash a bunch of shelves before they
> get their glaze license.
>
> It's hard to believe - if the glaze is that thickness in the bucket - some
> skin showing through the glaze - just around your finger nail - after
> dipping in a dry finger.
>
> What temperature are you firing your bisque to.
>
> I assume you are using cones for both the bisque and glaze firing?
>
> I suggest you try dipping a test tile as John has suggested - two
actually.
> Wait till they dry a bit and scratch through one (all three layers) so you
> can actually see the thickness of the dry glaze. Now fire the duplicate
> tile. Now you have a visual reference and before you start glazing you can
> dip a piece of bisque in your glaze and see if it needs to be thinned or
> thickened - or is just right.
>
> If it's too thin wait a day and take some of the water out - more than you
> think you need to. Stir and add water till it gives the right coating
> according to your tiles.
>
> Let us know how the next load looks.
>
> RR
>
>
>
>
> >I just finished my first glaze firing. I used the glazes from John and
> >Roy's book and have some questions. The witness cones showed cone 6
> >touching and cone 7 bent. I used the firing schedule as shown on the web
> >page for thier book, which had 2185F as the temperature to reach and a 20
> >minute hold. Around the rim and sometimes inside the cylinder the results
> >were close or encouraging, but I did not have any comparable results to
> >the book on the outside of the cylinder. I suspect I may have gotten the
> >glaze to thin on the outside, however I never got the glaze thin enough
in
> >the bucket to meet the "fingernail" test. I used three different clays
for
> >each glaze and I had 18 glazes and did 5 of those glazes twice for a
total
> >of 69 cylinders. So I am seeking advice or suggestions on what to correct
> >other than maybe a thicker glaze application. Any input would be
> >appreciated.
> >
> >Thanks,
> >
> >Bert Gibson
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
> Phone: 613-475-9544
> Fax: 613-475-3513
>
>
____________________________________________________________________________
__
> 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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