Mark Strayer on mon 16 aug 04
I could use some advice on using Spectrum Glazes in an electric kiln firing
to cone 6. I have been experincing a lot of bubbling in the glaze. I
thought it might be from under fired bisque so I changed from O4 to O3 in
the bisque fire...still getting bubbling. I've played with glaze
thickness...still bubbling. I've tried lightly mostening the bisque before
glazing and still bubbling occurs. I have added a 1 hour soak at the end
of the fire and I still have bubbling.I have been firing other glazes in
the same load and don't seem to have the problem on those pieces. I'm
wondering now if that I might be overfiring? Would I have better sucess at
Cone 5 instead of 6? Thoughts?
Thanks for any help in advance.
Mark
Northstar Pottery
Lamar, MO
John Hesselberth on mon 16 aug 04
On Monday, August 16, 2004, at 01:39 PM, Mark Strayer wrote:
> I could use some advice on using Spectrum Glazes in an electric kiln
> firing
> to cone 6. I have been experincing a lot of bubbling in the glaze.
Hi Mark,
One of the biggest problems with commercial glazes is that you don't
know what is in them. Therefore when you have a problem you haven't a
clue how to go about fixing it. The folks at Spectrum are very helpful
and I would address your question directly to them. If anyone can help
they can.
Regards,
John
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Carole Fox on tue 17 aug 04
Mark - you don't say which Spectrum glazes you have tried. However, I have
used all of the following on cone 04 bisque, and have fired pieces at both
cone 5 & cone 6: 1121 (Satin White), 1129 (Texture Oasis); 1140 (Texture
Kiwi Fruit); 1145 Texture Autumn); and 1173 (Texture Hot Chowder). On my
pieces, all give better color and a more satiny surface at cone 5 than at
cone 6. They all got very glossy at cone 6. The only one that pitted was
1129 at cone 6. I did not have any problems with blistering.
Cynthia Bracker on tue 17 aug 04
Do you use witness cones? If so, do they indicate that your bisque
firing is actually an 03 and glaze is actually 6? If you have a kiln
sitter, it may be out of adjustment and causing the cone to bend early.
If you have a computer, you may have a thermocouple that is not reading
correctly or something. It definitely seems you have tried all the
standard adjustments. I think someone else also asked which glaze(s)
specifically. I'd also like to add what clay body to the question
list. Our mid-range buff colored stoneware body used to have some
problems with glaze fit and such until we "tweaked" it a little with
silica. I think John Hesselberth also suggested calling Spectrum and
talking to them which is a great idea. Richard is very nice and his son
is now also in the business (although Ken Adamson recently left which is
very unfortunate. He was great!) You might also call the supplier
where you bought the clay and glaze to see if they've heard any other
problems specific to their bodies. I didn't find you in our database,
so I'm guessing you're getting your supplies either in Nixa or St.
Louis. Either way you're in good hands. I'm sure they will be happy to
try and help you out. And they'll appreciate the notice. Some bodies
just have problems with certain glazes and if the supplier has this
information, they can pass it on for the benefit of future customers.
Cindy Bracker
Bracker's Good Earth Clays, Inc.
Mark Strayer wrote:
>I could use some advice on using Spectrum Glazes in an electric kiln firing
>to cone 6. I have been experincing a lot of bubbling in the glaze. I
>thought it might be from under fired bisque so I changed from O4 to O3 in
>the bisque fire...still getting bubbling. I've played with glaze
>thickness...still bubbling. I've tried lightly mostening the bisque before
>glazing and still bubbling occurs. I have added a 1 hour soak at the end
>of the fire and I still have bubbling.I have been firing other glazes in
>the same load and don't seem to have the problem on those pieces. I'm
>wondering now if that I might be overfiring? Would I have better sucess at
>Cone 5 instead of 6? Thoughts?
>
>Thanks for any help in advance.
>
>Mark
>Northstar Pottery
>Lamar, MO
>
>______________________________________________________________________________
>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.
>
>
>
>
Mark Strayer on tue 17 aug 04
Hi Cindy,
I am actually using your buff. I've been up to Lawerence several times
to buy glaze and clay. I am experimenting with different clay bodys. I'm=
using yours, Nixa and Laguna. I need to use witness cones...I haven't be=
cuause
I'm using a Skutt Kiln sitter and I thought I wouldn't have too. Can yo=
u
suggest what type of cones I should get. I've only fired my kiln about
a dozen times that include both bisque and glaze fires. Most all my defe=
cts
are occuring with the Specturm glazes. I appreciate your help and time.
Mark
>-- Original Message --
>Date: Tue, 17 Aug 2004 13:37:31 -0500
>Reply-To: Clayart
>From: Cynthia Bracker
>Subject: Re: Spectrum Glaze @Cone 6
>To: CLAYART@LSV.CERAMICS.ORG
>
>
>Do you use witness cones? If so, do they indicate that your bisque
>firing is actually an 03 and glaze is actually 6? If you have a kiln
>sitter, it may be out of adjustment and causing the cone to bend early.
>If you have a computer, you may have a thermocouple that is not reading
>correctly or something. It definitely seems you have tried all the
>standard adjustments. I think someone else also asked which glaze(s)
>specifically. I'd also like to add what clay body to the question
>list. Our mid-range buff colored stoneware body used to have some
>problems with glaze fit and such until we "tweaked" it a little with
>silica. I think John Hesselberth also suggested calling Spectrum and
>talking to them which is a great idea. Richard is very nice and his son=
>is now also in the business (although Ken Adamson recently left which is=
>very unfortunate. He was great!) You might also call the supplier
>where you bought the clay and glaze to see if they've heard any other
>problems specific to their bodies. I didn't find you in our database,
>so I'm guessing you're getting your supplies either in Nixa or St.
>Louis. Either way you're in good hands. I'm sure they will be happy to=
>try and help you out. And they'll appreciate the notice. Some bodies
>just have problems with certain glazes and if the supplier has this
>information, they can pass it on for the benefit of future customers.
>Cindy Bracker
>Bracker's Good Earth Clays, Inc.
>
>Mark Strayer wrote:
>
>>I could use some advice on using Spectrum Glazes in an electric kiln fi=
ring
>>to cone 6. I have been experincing a lot of bubbling in the glaze. I
>>thought it might be from under fired bisque so I changed from O4 to O3
in
>>the bisque fire...still getting bubbling. I've played with glaze
>>thickness...still bubbling. I've tried lightly mostening the bisque be=
fore
>>glazing and still bubbling occurs. I have added a 1 hour soak at the
end
>>of the fire and I still have bubbling.I have been firing other glazes
in
>>the same load and don't seem to have the problem on those pieces. I'm
>>wondering now if that I might be overfiring? Would I have better sucess=
>at
>>Cone 5 instead of 6? Thoughts?
>>
>>Thanks for any help in advance.
>>
>>Mark
>>Northstar Pottery
>>Lamar, MO
>>
>>_______________________________________________________________________=
_______
>>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@pcl=
ink.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@pcli=
nk.com.
Cynthia Bracker on wed 18 aug 04
The first thing I would do is check the kiln sitter. You should have a
firing gauge (about the size of a quarter with a hole in the middle and
two notches on the side) If you don't have it or can't find it, you can
buy one for about $2.00 or so. (While I'm on the topic, a trick my dad
used to tell people to do is to unbend a paperclip half-way and hang the
firing gauge on one side of the loop and put the other loop around the
hingepin of your kiln. That way, it's always right where you need it!)
To check the accuracy / make the adjustment to the sitter: 1. lift the
drop plate up and push the claw down over it (as if you were going to be
putting a cone in the sitter in preparation to fire) 2. Place the firing
gauge where you would put a cone. The Top of the gauge should be
marked, but it is impossible to make it fit if you have the bottom up,
so don't worry that you'll do it backwards or anything. The rod goes
through the hole in the middle and the two slots/notches on the side are
for the cone supports. Once that is in place, the drop plate should
have a "hair trigger" Theoretically, if you "thunk" the side of the
kiln sitter, the plate should fall. (I say "theoretically" because my
kiln tech here hates me telling people to hit their kiln. We've had
many hours of debate about that. So now I use it more to illustrate the
tension rather than to advocate hitting your kiln) 3. If it needs
adjustment, there will be a screw on the front of the drop plate.
Loosen that and the plate part will slide up and down. Move it to the
proper position and retighten the screw. That's all there is to it!
The second thing I would do is get some witness cones. If you've never
used them before, buy self supporting cones. (They're more expensive,
but you don't have to make your own cone plaques. Cone plaques, if made
improperly, can cause witness cones to give a false reading) General
accepted principle is the three cone method: Guide cone, Fire cone and
Guard Cone. If you're aiming for a Cone 5 firing, your guide cone would
be a 4, Fire cone a 5 and guard cone a 6. You want at least 1 set per
shelf, possibly more depending on the size of your kiln.
Third, test the glazes on all the bodies you are using. If the problem
is consistent across the bodies, it's probably the glaze. If it only
happens on one or two, it's probably a body-glaze fit problem. Also,
call us (toll-free (888) 822-1982) and Jerry at L&R (if the problems
occur on the bodies you got there) with which glazes specifically are
causing the problem, so we can make notes of that for future reference.
I'd also like to get more details about the problem one on one and see
if we can get it solved.
Fourth, I e-mailed your original post to Spectrum. Following is their
reply:
"Hi Cindy, Richard's away in Africa right now so I'm checking his emails
for him (this is jacob just so you know). The glaze definitely shouldn't
boil at cone 6. most of our testing is for cone 5 and most of the 1100
series work best at cone 5 but they do hold up at six. I would expect
the reactive glazes to run quite a bit at cone 6 but they shouldn't be
boiling. If mark is using a reactive glaze in that series I would
recommend firing to cone 5 but it still shouldn't boil at six. My only
other suggestion is to take it to six and let it soak at five. if the
glaze is boiling at six then it will just keep boiling, that will work
for gas from the bisque but if the problem is the glaze itself then a
soak at peak temperature will make it worse.If you can find out what the
specific glaze is or get them to call us that would help. also, the
batch number which is printed on the bottom right of every label
(hopefully). Let me know what happens and thanks for letting us know."
I hope this gives you a place to start and I hope to hear from you soon!
Cindy
Mark Strayer wrote:
>Hi Cindy,
>I am actually using your buff. I've been up to Lawerence several times
>to buy glaze and clay. I am experimenting with different clay bodys. I'm
>using yours, Nixa and Laguna. I need to use witness cones...I haven't becuause
>I'm using a Skutt Kiln sitter and I thought I wouldn't have too. Can you
>suggest what type of cones I should get. I've only fired my kiln about
>a dozen times that include both bisque and glaze fires. Most all my defects
>are occuring with the Specturm glazes. I appreciate your help and time.
>Mark
>
>
>>-- Original Message --
>>Date: Tue, 17 Aug 2004 13:37:31 -0500
>>Reply-To: Clayart
>>From: Cynthia Bracker
>>Subject: Re: Spectrum Glaze @Cone 6
>>To: CLAYART@LSV.CERAMICS.ORG
>>
>>
>>Do you use witness cones? If so, do they indicate that your bisque
>>firing is actually an 03 and glaze is actually 6? If you have a kiln
>>sitter, it may be out of adjustment and causing the cone to bend early.
>>If you have a computer, you may have a thermocouple that is not reading
>>correctly or something. It definitely seems you have tried all the
>>standard adjustments. I think someone else also asked which glaze(s)
>>specifically. I'd also like to add what clay body to the question
>>list. Our mid-range buff colored stoneware body used to have some
>>problems with glaze fit and such until we "tweaked" it a little with
>>silica. I think John Hesselberth also suggested calling Spectrum and
>>talking to them which is a great idea. Richard is very nice and his son
>>is now also in the business (although Ken Adamson recently left which is
>>very unfortunate. He was great!) You might also call the supplier
>>where you bought the clay and glaze to see if they've heard any other
>>problems specific to their bodies. I didn't find you in our database,
>>so I'm guessing you're getting your supplies either in Nixa or St.
>>Louis. Either way you're in good hands. I'm sure they will be happy to
>>try and help you out. And they'll appreciate the notice. Some bodies
>>just have problems with certain glazes and if the supplier has this
>>information, they can pass it on for the benefit of future customers.
>>Cindy Bracker
>>Bracker's Good Earth Clays, Inc.
>>
>>Mark Strayer wrote:
>>
>>
>>
>>>I could use some advice on using Spectrum Glazes in an electric kiln firing
>>>to cone 6. I have been experincing a lot of bubbling in the glaze. I
>>>thought it might be from under fired bisque so I changed from O4 to O3
>>>
>>>
>in
>
>
>>>the bisque fire...still getting bubbling. I've played with glaze
>>>thickness...still bubbling. I've tried lightly mostening the bisque before
>>>glazing and still bubbling occurs. I have added a 1 hour soak at the
>>>
>>>
>end
>
>
>>>of the fire and I still have bubbling.I have been firing other glazes
>>>
>>>
>in
>
>
>>>the same load and don't seem to have the problem on those pieces. I'm
>>>wondering now if that I might be overfiring? Would I have better sucess
>>>
>>>
>>at
>>
>>
>>>Cone 5 instead of 6? Thoughts?
>>>
>>>Thanks for any help in advance.
>>>
>>>Mark
>>>Northstar Pottery
>>>Lamar, MO
>>>
>>>______________________________________________________________________________
>>>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.
>>>
>>>
>>>
>>>
>>>
>>>
>>______________________________________________________________________________
>>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.
>>
>>
>
>______________________________________________________________________________
>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.
>
>
>
>
Mark Strayer on thu 19 aug 04
Hi Cynthia,
WOW! I really appreciate the efforts you have made to help me. I was won=
dering
if you were going to be in the store on Saturday? If so, perhaps I could
pay you a visit in person and disucss and show you some of my pieces with=
the bubbling?
Mark
>-- Original Message --
>Date: Wed, 18 Aug 2004 09:34:24 -0500
>Reply-To: Clayart
>From: Cynthia Bracker
>Subject: Re: Spectrum Glaze @Cone 6
>To: CLAYART@LSV.CERAMICS.ORG
>
>
>The first thing I would do is check the kiln sitter. You should have a
>firing gauge (about the size of a quarter with a hole in the middle and
>two notches on the side) If you don't have it or can't find it, you can=
>buy one for about $2.00 or so. (While I'm on the topic, a trick my dad
>used to tell people to do is to unbend a paperclip half-way and hang the=
>firing gauge on one side of the loop and put the other loop around the
>hingepin of your kiln. That way, it's always right where you need it!)
>To check the accuracy / make the adjustment to the sitter: 1. lift the
>drop plate up and push the claw down over it (as if you were going to be=
>putting a cone in the sitter in preparation to fire) 2. Place the firing=
>gauge where you would put a cone. The Top of the gauge should be
>marked, but it is impossible to make it fit if you have the bottom up,
>so don't worry that you'll do it backwards or anything. The rod goes
>through the hole in the middle and the two slots/notches on the side are=
>for the cone supports. Once that is in place, the drop plate should
>have a "hair trigger" Theoretically, if you "thunk" the side of the
>kiln sitter, the plate should fall. (I say "theoretically" because my
>kiln tech here hates me telling people to hit their kiln. We've had
>many hours of debate about that. So now I use it more to illustrate the=
>tension rather than to advocate hitting your kiln) 3. If it needs
>adjustment, there will be a screw on the front of the drop plate.
>Loosen that and the plate part will slide up and down. Move it to the
>proper position and retighten the screw. That's all there is to it!
>The second thing I would do is get some witness cones. If you've never
>used them before, buy self supporting cones. (They're more expensive,
>but you don't have to make your own cone plaques. Cone plaques, if made=
>improperly, can cause witness cones to give a false reading) General
>accepted principle is the three cone method: Guide cone, Fire cone and
>Guard Cone. If you're aiming for a Cone 5 firing, your guide cone would=
>be a 4, Fire cone a 5 and guard cone a 6. You want at least 1 set per
>shelf, possibly more depending on the size of your kiln.
>Third, test the glazes on all the bodies you are using. If the problem
>is consistent across the bodies, it's probably the glaze. If it only
>happens on one or two, it's probably a body-glaze fit problem. Also,
>call us (toll-free (888) 822-1982) and Jerry at L&R (if the problems
>occur on the bodies you got there) with which glazes specifically are
>causing the problem, so we can make notes of that for future reference.
>I'd also like to get more details about the problem one on one and see
>if we can get it solved.
>Fourth, I e-mailed your original post to Spectrum. Following is their
>reply:
>"Hi Cindy, Richard's away in Africa right now so I'm checking his emails=
>for him (this is jacob just so you know). The glaze definitely shouldn't=
>boil at cone 6. most of our testing is for cone 5 and most of the 1100
>series work best at cone 5 but they do hold up at six. I would expect
>the reactive glazes to run quite a bit at cone 6 but they shouldn't be
>boiling. If mark is using a reactive glaze in that series I would
>recommend firing to cone 5 but it still shouldn't boil at six. My only
>other suggestion is to take it to six and let it soak at five. if the
>glaze is boiling at six then it will just keep boiling, that will work
>for gas from the bisque but if the problem is the glaze itself then a
>soak at peak temperature will make it worse.If you can find out what the=
>specific glaze is or get them to call us that would help. also, the
>batch number which is printed on the bottom right of every label
>(hopefully). Let me know what happens and thanks for letting us know."
>I hope this gives you a place to start and I hope to hear from you soon!=
>Cindy
>
>Mark Strayer wrote:
>
>>Hi Cindy,
>>I am actually using your buff. I've been up to Lawerence several times=
>>to buy glaze and clay. I am experimenting with different clay bodys.
I'm
>>using yours, Nixa and Laguna. I need to use witness cones...I haven't
becuause
>>I'm using a Skutt Kiln sitter and I thought I wouldn't have too. Can
you
>>suggest what type of cones I should get. I've only fired my kiln about=
>>a dozen times that include both bisque and glaze fires. Most all my de=
fects
>>are occuring with the Specturm glazes. I appreciate your help and time=
.
>>Mark
>>
>>
>>>-- Original Message --
>>>Date: Tue, 17 Aug 2004 13:37:31 -0500
>>>Reply-To: Clayart
>>>From: Cynthia Bracker
>>>Subject: Re: Spectrum Glaze @Cone 6
>>>To: CLAYART@LSV.CERAMICS.ORG
>>>
>>>
>>>Do you use witness cones? If so, do they indicate that your bisque
>>>firing is actually an 03 and glaze is actually 6? If you have a kiln
>>>sitter, it may be out of adjustment and causing the cone to bend early=
.
>>>If you have a computer, you may have a thermocouple that is not readin=
g
>>>correctly or something. It definitely seems you have tried all the
>>>standard adjustments. I think someone else also asked which glaze(s)
>>>specifically. I'd also like to add what clay body to the question
>>>list. Our mid-range buff colored stoneware body used to have some
>>>problems with glaze fit and such until we "tweaked" it a little with
>>>silica. I think John Hesselberth also suggested calling Spectrum and
>>>talking to them which is a great idea. Richard is very nice and his
son
>>>is now also in the business (although Ken Adamson recently left which
is
>>>very unfortunate. He was great!) You might also call the supplier
>>>where you bought the clay and glaze to see if they've heard any other
>>>problems specific to their bodies. I didn't find you in our database,=
>>>so I'm guessing you're getting your supplies either in Nixa or St.
>>>Louis. Either way you're in good hands. I'm sure they will be happy
to
>>>try and help you out. And they'll appreciate the notice. Some bodies=
>>>just have problems with certain glazes and if the supplier has this
>>>information, they can pass it on for the benefit of future customers.
>>>Cindy Bracker
>>>Bracker's Good Earth Clays, Inc.
>>>
>>>Mark Strayer wrote:
>>>
>>>
>>>
>>>>I could use some advice on using Spectrum Glazes in an electric kiln
firing
>>>>to cone 6. I have been experincing a lot of bubbling in the glaze.
I
>>>>thought it might be from under fired bisque so I changed from O4 to
O3
>>>>
>>>>
>>in
>>
>>
>>>>the bisque fire...still getting bubbling. I've played with glaze
>>>>thickness...still bubbling. I've tried lightly mostening the bisque
before
>>>>glazing and still bubbling occurs. I have added a 1 hour soak at the=
>>>>
>>>>
>>end
>>
>>
>>>>of the fire and I still have bubbling.I have been firing other glazes=
>>>>
>>>>
>>in
>>
>>
>>>>the same load and don't seem to have the problem on those pieces. I'=
m
>>>>wondering now if that I might be overfiring? Would I have better suce=
ss
>>>>
>>>>
>>>at
>>>
>>>
>>>>Cone 5 instead of 6? Thoughts?
>>>>
>>>>Thanks for any help in advance.
>>>>
>>>>Mark
>>>>Northstar Pottery
>>>>Lamar, MO
>>>>
>>>>_____________________________________________________________________=
_________
>>>>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@p=
clink.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@pc=
link.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@pcl=
ink.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@pcli=
nk.com.
| |
|
