MJ on wed 18 may 11
Thanks Randall and David - this was my fear. I still cannot see the crack
and I cannot feel it either, but tomorrow I will take a 2 by 4 to it and se=
e
what happens. In any event, it will wind up in the trash but I hope I can
expose the crack first - just out of curiosity.
Cheers, MJ
On Wed, May 18, 2011 at 7:15 PM, David Hendley wrote:
> If all your bowls produce a ring when rapped except one that makes a thud=
,
> that odd bowl probably has a cooling crack. These cracks can be very
> difficult to see. I have had this problem with my bowls that have unglaze=
d
> exteriors. If the glaze fit is not good, a radial cooling crack (the top
> half
> of the bowl separates from the bottom half) can develop. The problem is
> magnified with large bowls and/or if the wall thickness is too thin.
>
> Every time I unload a bowl from the glaze kiln, I give it a good knock,
> knock and listen to the sound. A thud or muted sound indicates a crack.
> I have sometimes looked for 10 minutes trying to find the crack and
> sometimes never find it, but I know it is there. Sometimes the crack can
> be found by gently feeling the glaze rather then looking. For proof I can
> smartly hit the bottom of the bowl with a smooth heavy object, such as
> a piece of a 2 X 4. The bowl will usually separate into two pieces. Of
> course I have been working to eliminate this problem, but through
> the years I have lost several dozen bowls to this phenomenon, so am
> well familiar with it.
>
> David Hendley
> david@farmpots.com
> http://www.farmpots.com
> http://www.thewahooligans.com
>
>
>
>
>
>
> ----- Original Message -----
>
>> Hello - I just did a glaze firing over the weekend. I noticed that two
>> mid-size bowls that were on the same shelf with the same base glaze (but
>> different layered glazes) have completely different sounds. Both bowls
>> are
>> b-mix and are roughly the same shape and size. One does have a lip that
>> is
>> turned out more. Both about the same thickness. The one with the lip
>> turned out has a real thud sound if I hit the rim, while the other one h=
as
>> somewhat of a ping. Another bowl in the same firing is a different shap=
e
>> (more of a bowl and less of an "open" bowl) and is probably thrown a bit
>> thinner and it has much more of a ping. There are no visible cracks or
>> glaze defects in the bowl that is giving me the thud.
>>
>
> In general - what can one deduce from the sound (or lack of sound) of
>> pinging a bowl?
>>
>>
>
David Hendley on wed 18 may 11
If all your bowls produce a ring when rapped except one that makes a thud,
that odd bowl probably has a cooling crack. These cracks can be very
difficult to see. I have had this problem with my bowls that have unglazed
exteriors. If the glaze fit is not good, a radial cooling crack (the top
half
of the bowl separates from the bottom half) can develop. The problem is
magnified with large bowls and/or if the wall thickness is too thin.
Every time I unload a bowl from the glaze kiln, I give it a good knock,
knock and listen to the sound. A thud or muted sound indicates a crack.
I have sometimes looked for 10 minutes trying to find the crack and
sometimes never find it, but I know it is there. Sometimes the crack can
be found by gently feeling the glaze rather then looking. For proof I can
smartly hit the bottom of the bowl with a smooth heavy object, such as
a piece of a 2 X 4. The bowl will usually separate into two pieces. Of
course I have been working to eliminate this problem, but through
the years I have lost several dozen bowls to this phenomenon, so am
well familiar with it.
David Hendley
david@farmpots.com
http://www.farmpots.com
http://www.thewahooligans.com
----- Original Message -----
> Hello - I just did a glaze firing over the weekend. I noticed that two
> mid-size bowls that were on the same shelf with the same base glaze (but
> different layered glazes) have completely different sounds. Both bowls
> are
> b-mix and are roughly the same shape and size. One does have a lip that
> is
> turned out more. Both about the same thickness. The one with the lip
> turned out has a real thud sound if I hit the rim, while the other one ha=
s
> somewhat of a ping. Another bowl in the same firing is a different shape
> (more of a bowl and less of an "open" bowl) and is probably thrown a bit
> thinner and it has much more of a ping. There are no visible cracks or
> glaze defects in the bowl that is giving me the thud.
> In general - what can one deduce from the sound (or lack of sound) of
> pinging a bowl?
>
Randall Moody on wed 18 may 11
On Wed, May 18, 2011 at 1:43 PM, MJ wrote:
> The one with the lip
> turned out has a real thud sound if I hit the rim, while the other one ha=
s
> somewhat of a ping. Another bowl in the same firing is a different shape
> (more of a bowl and less of an "open" bowl) and is probably thrown a bit
> thinner and it has much more of a ping. There are no visible cracks or
> glaze defects in the bowl that is giving me the thud.
>
>
The thud usually means that there is a crack somewhere in the piece.
--
Randall in Atlanta
http://wrandallmoody.com
Lis Allison on wed 18 may 11
I don't know what the sounds might mean, but if you are trying to see if
something has a crack, wetting it will make any crack show up.
Lis
--
Elisabeth Allison
Pine Ridge Studio
website: www.pine-ridge.ca
Pottery blog: www.studio-on-the-ridge.blogspot.com
Garden blog: www.garden-on-the-ridge.blogspot.com
MJ on wed 18 may 11
Hello - I just did a glaze firing over the weekend. I noticed that two
mid-size bowls that were on the same shelf with the same base glaze (but
different layered glazes) have completely different sounds. Both bowls are
b-mix and are roughly the same shape and size. One does have a lip that is
turned out more. Both about the same thickness. The one with the lip
turned out has a real thud sound if I hit the rim, while the other one has
somewhat of a ping. Another bowl in the same firing is a different shape
(more of a bowl and less of an "open" bowl) and is probably thrown a bit
thinner and it has much more of a ping. There are no visible cracks or
glaze defects in the bowl that is giving me the thud.
I just tried to google information on sounds of bowls but did not find any
information. Most of the bowls I have done with b-mix have a mild/slight
ring similar to the non-thud bowl.
Does the thud mean that there is a crack in the bowl somewhere and I am jus=
t
not seeing it? Could it be symptomatic of a bad glaze fit that will
ultimately show up? What kind of sound should I be getting from bowls made
out of b-mix? How about bowls made out of stoneware? Does it mean that on=
e
is more vitrified than the other?
In general - what can one deduce from the sound (or lack of sound) of
pinging a bowl?
As usual, any and all help is appreciated. Cheers, MJ
MJ on thu 19 may 11
Thanks again for the responses. Another question - is it only bowls? I
don't know that I have routinely tried to ping other items such as vases or
cups. Bowls definitely have their own sound I think - but I wonder if more
closed form also should ping.
Cheers, MJ
2011/5/19 Ric Swenson
> MJ,
>
> I have used my master's degree ring from Univ of Puget Sound in 1976 to
> SOUND every piece I make....after so many years...it is quite thin where =
I
> have used it to test pieces from the kiln.
>
> Each clay might sound a little diferent...thin porcelain will sound more
> like bell....stoneware not quite so resonate. A dull thud means there i=
s a
> dunt (crack) somewhere...difficult to see usually.
>
>
> Sometimes when glazes craze (crackle) the small cracks in the glaze
> prevent sound transmission and give a less resonate ring. Soak a piece i=
n
> water and it might sound different from a dry piece too.
>
> Vitrification level (the level of glass-like properties) determines the
> sound.
>
>
> JDZ (JingDeZhen, China) has a ceramic orchestra...all instuments made of
> porcelain...quite resonate and pleasing.
>
>
>
> At Bennington Potters Inc. we checked each of our 10,000 pieces
> produced per week with the white grinding stone we used by the person doi=
ng
> the grading....if it didn't sound right...it went in the trash. Even
> terracotta, without glaze, will sound a bit like a bell...but not the sam=
e
> as thin porcelain.
>
>
>
> Just my 2 rmb...15 cents?
>
>
> Ric
>
>
>
>
>
>
>
> > Date: Wed, 18 May 2011 10:43:53 -0700
> > From: mjcarizona@GMAIL.COM
> > Subject: bowl sounds
> > To: Clayart@LSV.CERAMICS.ORG
>
> >
> > Hello - I just did a glaze firing over the weekend. I noticed that two
> > mid-size bowls that were on the same shelf with the same base glaze (bu=
t
> > different layered glazes) have completely different sounds. Both bowls
> are
> > b-mix and are roughly the same shape and size. One does have a lip that
> is
> > turned out more. Both about the same thickness. The one with the lip
> > turned out has a real thud sound if I hit the rim, while the other one
> has
> > somewhat of a ping. Another bowl in the same firing is a different shap=
e
> > (more of a bowl and less of an "open" bowl) and is probably thrown a bi=
t
> > thinner and it has much more of a ping. There are no visible cracks or
> > glaze defects in the bowl that is giving me the thud.
> >
> > I just tried to google information on sounds of bowls but did not find
> any
> > information. Most of the bowls I have done with b-mix have a mild/sligh=
t
> > ring similar to the non-thud bowl.
> >
> > Does the thud mean that there is a crack in the bowl somewhere and I am
> just
> > not seeing it? Could it be symptomatic of a bad glaze fit that will
> > ultimately show up? What kind of sound should I be getting from bowls
> made
> > out of b-mix? How about bowls made out of stoneware? Does it mean that
> one
> > is more vitrified than the other?
> >
> > In general - what can one deduce from the sound (or lack of sound) of
> > pinging a bowl?
> >
> > As usual, any and all help is appreciated. Cheers, MJ
>
Ric Swenson on thu 19 may 11
MJ,
I have used my master's degree ring from Univ of Puget Sound in 1976 to SOU=
ND every piece I make....after so many years...it is quite thin where I hav=
e used it to test pieces from the kiln.
Each clay might sound a little diferent...thin porcelain will sound more l=
ike bell....stoneware not quite so resonate. A dull thud means there is a=
dunt (crack) somewhere...difficult to see usually.
Sometimes when glazes craze (crackle) the small cracks in the glaze preven=
t sound transmission and give a less resonate ring. Soak a piece in water =
and it might sound different from a dry piece too.
Vitrification level (the level of glass-like properties) determines the sou=
nd.
JDZ (JingDeZhen, China) has a ceramic orchestra...all instuments made of p=
orcelain...quite resonate and pleasing.
At Bennington Potters Inc. we checked each of our 10,000 pieces produced pe=
r week with the white grinding stone we used by the person doing the gradin=
g....if it didn't sound right...it went in the trash. Even terracotta, wit=
hout glaze, will sound a bit like a bell...but not the same as thin porcela=
in.
Just my 2 rmb...15 cents?
Ric
> Date: Wed, 18 May 2011 10:43:53 -0700
> From: mjcarizona@GMAIL.COM
> Subject: bowl sounds
> To: Clayart@LSV.CERAMICS.ORG
>
> Hello - I just did a glaze firing over the weekend. I noticed that two
> mid-size bowls that were on the same shelf with the same base glaze (but
> different layered glazes) have completely different sounds. Both bowls ar=
e
> b-mix and are roughly the same shape and size. One does have a lip that i=
s
> turned out more. Both about the same thickness. The one with the lip
> turned out has a real thud sound if I hit the rim, while the other one ha=
s
> somewhat of a ping. Another bowl in the same firing is a different shape
> (more of a bowl and less of an "open" bowl) and is probably thrown a bit
> thinner and it has much more of a ping. There are no visible cracks or
> glaze defects in the bowl that is giving me the thud.
>
> I just tried to google information on sounds of bowls but did not find an=
y
> information. Most of the bowls I have done with b-mix have a mild/slight
> ring similar to the non-thud bowl.
>
> Does the thud mean that there is a crack in the bowl somewhere and I am j=
ust
> not seeing it? Could it be symptomatic of a bad glaze fit that will
> ultimately show up? What kind of sound should I be getting from bowls mad=
e
> out of b-mix? How about bowls made out of stoneware? Does it mean that on=
e
> is more vitrified than the other?
>
> In general - what can one deduce from the sound (or lack of sound) of
> pinging a bowl?
>
> As usual, any and all help is appreciated. Cheers, MJ
Steve Mills on thu 19 may 11
My "Rule of Thumb" is; if it "rings/pings" it's good. If it produces a dull=
s=3D
ound it stays "home" and is either put to work or becomes hardcore, dependi=
n=3D
g on size and visibility of the fault.=3D20
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my Ipod touch
On 18 May 2011, at 18:43, MJ wrote:
> Hello - I just did a glaze firing over the weekend. I noticed that two
> mid-size bowls that were on the same shelf with the same base glaze (but
> different layered glazes) have completely different sounds. Both bowls a=
r=3D
e
> b-mix and are roughly the same shape and size. One does have a lip that =
i=3D
s
> turned out more. Both about the same thickness. The one with the lip
> turned out has a real thud sound if I hit the rim, while the other one ha=
s=3D
> somewhat of a ping. Another bowl in the same firing is a different shape
> (more of a bowl and less of an "open" bowl) and is probably thrown a bit
> thinner and it has much more of a ping. There are no visible cracks or
> glaze defects in the bowl that is giving me the thud.
>=3D20
> I just tried to google information on sounds of bowls but did not find an=
y=3D
> information. Most of the bowls I have done with b-mix have a mild/slight
> ring similar to the non-thud bowl.
>=3D20
> Does the thud mean that there is a crack in the bowl somewhere and I am j=
u=3D
st
> not seeing it? Could it be symptomatic of a bad glaze fit that will
> ultimately show up? What kind of sound should I be getting from bowls ma=
d=3D
e
> out of b-mix? How about bowls made out of stoneware? Does it mean that =
o=3D
ne
> is more vitrified than the other?
>=3D20
> In general - what can one deduce from the sound (or lack of sound) of
> pinging a bowl?
>=3D20
> As usual, any and all help is appreciated. Cheers, MJ
ivor and olive lewis on thu 19 may 11
Dear MJ mjcarizona@GMAIL.COM
You do not mention your firing temperature but I presume since you mention
stoneware that you are firing below cone 6.
I would suggest that bowls that ring or ping are to some degree vitrified.
Those that do not ring but give a dull tone when struck are not vitrified.
If there is little or no tone you may have a dunted pot.
Regards,
Ivor Lewis,
REDHILL,
South Australia
pdp1 on thu 19 may 11
Alcohol - or Alcohol in which one has dissolved an Aniline Dye - would
probably work well to find subtle cracks...filling the Vessel carefully wit=
h
it,
and, then, watching the outside
Alcohol can migrate through cracks or fissures too fine to see, and, which
Water may not...or would not do so as quickly.
----- Original Message -----
From: "Lis Allison"
>I don't know what the sounds might mean, but if you are trying to see if
> something has a crack, wetting it will make any crack show up.
>
> Lis
> --
> Elisabeth Allison
> Pine Ridge Studio
> website: www.pine-ridge.ca
> Pottery blog: www.studio-on-the-ridge.blogspot.com
> Garden blog: www.garden-on-the-ridge.blogspot.com
Ron Roy on thu 19 may 11
Hi MJ,
Probably crazing - you may need a magnifying glass to see the crazing
or rub on some ink.
If you want to send me the recipes for the glazes you used I can tell
you which glaze or glazes are most likely to craze.
RR
Quoting MJ :
> Hello - I just did a glaze firing over the weekend. I noticed that two
> mid-size bowls that were on the same shelf with the same base glaze (but
> different layered glazes) have completely different sounds. Both bowls a=
re
> b-mix and are roughly the same shape and size. One does have a lip that =
is
> turned out more. Both about the same thickness. The one with the lip
> turned out has a real thud sound if I hit the rim, while the other one ha=
s
> somewhat of a ping. Another bowl in the same firing is a different shape
> (more of a bowl and less of an "open" bowl) and is probably thrown a bit
> thinner and it has much more of a ping. There are no visible cracks or
> glaze defects in the bowl that is giving me the thud.
>
> I just tried to google information on sounds of bowls but did not find an=
y
> information. Most of the bowls I have done with b-mix have a mild/slight
> ring similar to the non-thud bowl.
>
> Does the thud mean that there is a crack in the bowl somewhere and I am j=
ust
> not seeing it? Could it be symptomatic of a bad glaze fit that will
> ultimately show up? What kind of sound should I be getting from bowls ma=
de
> out of b-mix? How about bowls made out of stoneware? Does it mean that =
one
> is more vitrified than the other?
>
> In general - what can one deduce from the sound (or lack of sound) of
> pinging a bowl?
>
> As usual, any and all help is appreciated. Cheers, MJ
>
Mike Gordon on thu 19 may 11
I had a small bowl that never had a ring, but it was an old Albany clay
glaze, with a majority of the glaze being clay. It has been used
regularly for over 20 yrs. No cracks. Could high clay in the glaze
account for no ring? Mike Gordon
Lee on thu 19 may 11
On Thu, May 19, 2011 at 12:30 PM, Mike Gordon wrote=
=3D
:
> I had a small bowl that never had a ring, but it was an old Albany clay
> glaze, with a majority of the glaze being clay. It has been used
> regularly for over 20 yrs. No cracks. Could high clay in the glaze
> account for no ring? Mike Gordon
>
Low vitrification would.
--
Lee Love in Minneapolis
http://mingeisota.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he land
of eternal youth is behind the house, a beautiful land fluent within
itself." -- John O'Donohue
Randall Moody on thu 19 may 11
On Thu, May 19, 2011 at 1:30 PM, Mike Gordon wrote:
> I had a small bowl that never had a ring, but it was an old Albany clay
> glaze, with a majority of the glaze being clay. It has been used
> regularly for over 20 yrs. No cracks. Could high clay in the glaze
> account for no ring? Mike Gordon
>
My guess is that it wasn't fired to vitrification. I have also had cups
that don't ring after putting them through the dishwasher. I think that the=
y
pick up a little water through the foot.
--
Randall in Atlanta
http://wrandallmoody.com
Shaw Pottery on fri 20 may 11
Ping or no ping, no need to throw it away. If it accomplishes the
purpose for which it was made, use it yourself. Our home and
cupboards have many items we wouldn't put on the display to sell, but
are perfectly fine to use.
However, if you _must_ crash a pot, use the shards in the bottom of a
planting pot. They work just fine for that!
Rita
--
353 Jullien Drive
Orcutt, CA 93455
(805) 937-9995
http://shawpottery.com/
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