Good Morning,
Dale,

Sigh.Please try to grasp the idea.
This is my last post on this.Okay.

See.
page 282.
Illustrated Dictionary of Practical Pottery by Fournier.
Especially of the last paragraph.

Also you might want to take a general read-up on
your Hamer.

I was only trying to keep the pot information sensible,
not turn this into a show of brain power.
Apologies to All.
Khaimraj
West Indies


-----Original Message-----
From: dalecochoy
To: Khaimraj Seepersad ;

Date: 25 May 2004 17:42
Subject: [IBC] Fw: [IBC] Ceramic Pots


----- Original Message -----
From: "Khaimraj Seepersad" Subject: [IBC] Fw: [IBC] Ceramic Pots


Dale,
I simply gave you the limits as defined by Pottery
Science,since I have noted that once these statements
pass across the IBC,they will be treated as fact.

Freeze/Thaw is thermal shock.

No, thermal shock is the shock your clay gets when heated to fast in the
kiln ( can shatter) and a similar thing happens when cooled to quickly as
in
the methods of making Raku. Clays are specially designed for these types of
shock. This doesn't really have anything to do with vitrified clay ( or
should I say "Not vitrified" clay) absorbing water and shattering when it
freezes ( as was, I believe, the concern of the original poster?)

Check your body mixes for Stoneware and Porcelain,
you will find the answer there.

uh...OK.


The answers become relevant when you spend $$ for
a pot and it breaks when you don't look after it.

To much glass in the body and what happens when you
knock it,does it shatter like a bottle or chip like a flower
pot?

Well, not quit sure how to answer. I've never seen a bonsai pot "shatter
like a bottle" from too much "Glass) in the clay? and they all pretty much
chip if "whacked" but high fired stoneware is more durable to chipping than
a "flower pot"


I would say if you guys give such precise information on
trees or fertiliser or insecticides,the pots should be afforded
the same.

uh...OK...again
Dale



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----- Original Message -----
From: "Khaimraj Seepersad"
Subject: [IBC] Fw: [IBC] Ceramic Pots 1


Good Morning,
Dale,

Sigh.Please try to grasp the idea.
This is my last post on this.Okay.

Okay....I'm ready to GRASP!!!....


Also you might want to take a general read-up on
your Hamer.

I'll think about a "General Read-up"


I was only trying to keep the pot information sensible,
not turn this into a show of brain power.

I'm glad we side-stepped that one!

Dale.


-----Original Message-----
From: dalecochoy
To: Khaimraj Seepersad ;

Date: 25 May 2004 17:42
Subject: [IBC] Fw: [IBC] Ceramic Pots


----- Original Message -----
From: "Khaimraj Seepersad" Subject: [IBC] Fw: [IBC] Ceramic Pots


Dale,
I simply gave you the limits as defined by Pottery
Science,since I have noted that once these statements
pass across the IBC,they will be treated as fact.

Freeze/Thaw is thermal shock.

No, thermal shock is the shock your clay gets when heated to fast in the
kiln ( can shatter) and a similar thing happens when cooled to quickly as
in
the methods of making Raku. Clays are specially designed for these types
of
shock. This doesn't really have anything to do with vitrified clay ( or
should I say "Not vitrified" clay) absorbing water and shattering when
it
freezes ( as was, I believe, the concern of the original poster?)

Check your body mixes for Stoneware and Porcelain,
you will find the answer there.

uh...OK.


The answers become relevant when you spend $$ for
a pot and it breaks when you don't look after it.

To much glass in the body and what happens when you
knock it,does it shatter like a bottle or chip like a flower
pot?

Well, not quit sure how to answer. I've never seen a bonsai pot "shatter
like a bottle" from too much "Glass) in the clay? and they all pretty
much
chip if "whacked" but high fired stoneware is more durable to chipping
than
a "flower pot"


I would say if you guys give such precise information on
trees or fertiliser or insecticides,the pots should be afforded
the same.

uh...OK...again
Dale

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Good Day to all,

Ms.Iris,

just in case in my last e-mail I stepped on your toes,
please accept my most humble apologies.

With regards to bodies.

Stoneware [traditional]
Vitrification is between 3 to 5 %[or what ever is on the
packaging of the clay powder.]

If exceeded,past the %[seen above],the body will
have too much glass.It will then be more susceptible to
Thermal shock[the stress created within a ceramic object
by temperature change.Thermal shock is responsible
for the occurrence of cracks and is an OVERALL term,
pg.320 The Potter's Dictionary-Hamer 3rd edition.]

So freeze/thaw as experienced in winter or sun on a cold
pot or possible expansion of water in soil and so on
[which is what I meant and hoped would be understood
because there is a great deal of Japanese information dealing
with winter care.]Could after slow time damage a pot.
Especially since most pots already have fine cracks present
in the body after firing.

Raku bodies resist this damage because of the particles
within the body blocking the crack from physically passing.

I don't know,and wasn't talking about the absorption of water
into the stoneware body and then freezing.

On Porcelain.

In porcelain the body is homogenous;it does not contain
variously-sized particles of sand,grog etc.
[ The Potter's Dictionary -Hamer pg.312 ]

Stoneware isn't homogenous,but this article deals more with
glazes and but I think the above is enough to explain the difference
in response between the two clay types.

I have no way of know how porcelain pots handle cold.

All that said.

Today's clay bodies are often designed and books now
carry these categories.

Soft Stoneware
Hard stoneware
Stoneware type
Hard Porcelain
Soft Porcelain
Vitreous
Low fired Vitreous
Low fired Translucent
Ultra low fired Vitreous
Ultra Low fired Translucent
Bone China
Boron Phosphate Bone China
Low fired Bone China
Ultra Low fired Bone China
Earthenware
High fired Earthenware
Low fired Earthenware
add on Vitreous/translucent to
the above as well as Ultra low.

and so it goes.
Temperature range is 750 to 1400 deg.c
and so on.

As to finishes on the body.
Anything goes.

You can have,
Stain coloured bodies,dark or light.
Slip coloured bodies
Smoke/reduction/carbon coloured bodies
Glazed coatings
Enamel coatings
Hard resin coatings
and so on.

I am sorry,I did want to throw all of this at the group.

Glazed on the inside problems-
I think that breathe bit comes from high fired
but still say 8% porous earthenware ,with probably heavier
soils.
[Not everyone is too bothered by the salts deposited
on the outside of the pot.]

This is probably still popular with those using more
traditional soils.[The Yi Xing pots are supposed to
be the best here for these soil types.]

I have a few plants in porcelain pots that are exterior
glazed,but I use freely draining mixes.I believe the
plants would have died in heavier [perhaps clay based]
soils.
So I would say the comment is true if using heavy soils,
but not so for freely draining soils.

If your still reading,I will let the newcomers know that I
have been in pottery for about 25 years.I dig,clean and
process my own clay bodies.I specialise in Low fired
vitreous bodies [ 980 deg.c and lower.],Egyptian Paste
[980 deg.c orton 08 small cone ] making my own glazes
and enamels from oxides/carbonates and ground glass
cullet.I have a ball mill.

I do not sell my objects,just give them away as gifts.
So I do not make a living through pottery and am not
a professional,just a serious hobby.
Khaimraj
West Indies/Caribbean.

*Patrizia I haven't forgotten.










-----Original Message-----
From:
To:
Date: 26 May 2004 17:32
Subject: [IBC] Ceramic Pots


Actually, I am pretty sure I've seen some pots which were slip-glazed & some
which were self-colored.

Iris, You've been reading! The term is "vitrification." I've read this "no
glaze inside or bottom so pot can "breathe" thing three times in bonsai
magazines last year!
Perhaps you alone can rest the urban legend! :)

Along with the legends about irregular shaped gravel and humidity trays, no
doubt.
I have about three or so pots which are glazed on the inside. The bonsai do
not care in the least.
I didn't necessarily read this stuff recently. I majored in arts & crafts 55
years ago, including four years of ceramics. Khaimraj has a great deal of up
to date information on the subject.
Iris

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+++++ Questions? Help? e-mail +++++

Khaimraj,

Thanks for this effort - it is helpful as text to grasp
the picture for newcomers curious and inexperienced with the
"pot" appreciation part of bonsai/penjing.

I'm glad to hear you stay at it. I still spend a lot of time
with potter friends and don't miss a firing, but as for the
clay throwing my hands took me out of that except for the
occasional small raku. It is great that we have some very
fine potters in IBC.
------

With regards to bodies:

Stoneware [traditional]
Vitrification is between 3 to 5 %[or what ever is on the
packaging of the clay powder.]

If exceeded,past the %[seen above],the body will
have too much glass.It will then be more susceptible to
Thermal shock[the stress created within a ceramic object
by temperature change.Thermal shock is responsible
for the occurrence of cracks and is an OVERALL term,
pg.320 The Potter's Dictionary-Hamer 3rd edition.]

So freeze/thaw as experienced in winter or sun on a cold
pot or possible expansion of water in soil and so on
[which is what I meant and hoped would be understood
because there is a great deal of Japanese information
dealing
with winter care.]Could after slow time damage a pot.
Especially since most pots already have fine cracks present
in the body after firing.

Raku bodies resist this damage because of the particles
within the body blocking the crack from physically passing.

I don't know,and wasn't talking about the absorption of
water
into the stoneware body and then freezing.

On Porcelain.

In porcelain the body is homogenous;it does not contain
variously-sized particles of sand,grog etc.
[ The Potter's Dictionary -Hamer pg.312 ]

Stoneware isn't homogenous,but this article deals more with
glazes and but I think the above is enough to explain the
difference
in response between the two clay types.

I have no way of know how porcelain pots handle cold.

All that said.

Today's clay bodies are often designed and books now
carry these categories.

Soft Stoneware
Hard stoneware
Stoneware type
Hard Porcelain
Soft Porcelain
Vitreous
Low fired Vitreous
Low fired Translucent
Ultra low fired Vitreous
Ultra Low fired Translucent
Bone China
Boron Phosphate Bone China
Low fired Bone China
Ultra Low fired Bone China
Earthenware
High fired Earthenware
Low fired Earthenware
add on Vitreous/translucent to
the above as well as Ultra low.

and so it goes.
Temperature range is 750 to 1400 deg.c
and so on.

As to finishes on the body.
Anything goes.

You can have,
Stain coloured bodies,dark or light.
Slip coloured bodies
Smoke/reduction/carbon coloured bodies
Glazed coatings
Enamel coatings
Hard resin coatings
and so on.

I am sorry,I did want to throw all of this at the group.

Glazed on the inside problems-
I think that breathe bit comes from high fired
but still say 8% porous earthenware ,with probably heavier
soils.
[Not everyone is too bothered by the salts deposited
on the outside of the pot.]

This is probably still popular with those using more
traditional soils.[The Yi Xing pots are supposed to
be the best here for these soil types.]

I have a few plants in porcelain pots that are exterior
glazed,but I use freely draining mixes.I believe the
plants would have died in heavier [perhaps clay based]
soils.
So I would say the comment is true if using heavy soils,
but not so for freely draining soils.

If your still reading,I will let the newcomers know that I
have been in pottery for about 25 years.I dig,clean and
process my own clay bodies.I specialise in Low fired
vitreous bodies [ 980 deg.c and lower.],Egyptian Paste
[980 deg.c orton 08 small cone ] making my own glazes
and enamels from oxides/carbonates and ground glass
cullet.I have a ball mill.

I do not sell my objects,just give them away as gifts.
So I do not make a living through pottery and am not
a professional,just a serious hobby.
Khaimraj
West Indies/Caribbean.

************************************************** ******************************
++++Sponsored, in part, by John Quinn++++
************************************************** ******************************
-- The IBC HOME PAGE & FAQ: http://www.internetbonsaiclub.org/ --
+++++ Questions? Help? e-mail +++++

Ms.Iris,
just in case in my last e-mail I stepped on your toes,
please accept my most humble apologies.

My feet are of clay, with totally impervious toes. Not to worry. I suppose I
was oversimplifying again. I think for the average amateur bonsai grower, the
important thing to remember is that junky pots are more likely to crack than
good ones, especially if they are exposed to freezing. And a good soil mix
which drains properly is more important than the exact type of pot. I have put
trees in the ground for the winter, here in Zone 5, in "unglazed" brown pots,
and they were fine. The pots were fine. I would not put a tree in the ground
for the winter in an expensive pot, a pot glazed on the inside, or a porcelain
pot. If the tree needs to be outside for the winter, in most cases you can slip
the plant out of the pot & put it in the ground, and pot it up again in the
spring. If you're not sure, you can usually store the tree in the garage or a
similar location.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

----- Original Message -----
From: "Khaimraj Seepersad"
To:
Sent: Thursday, May 27, 2004 4:34 PM
Subject: [IBC] Ceramic Pots 1

KHAIMRAJ,
( I'M GOING TO TYPE IN CAPITALS TO KEEP MY ANSWERS SEPERATE FROM YOUR BOOK
FACT QUOTES SO, PEOPLE DON"T SEND ME 15 NOTES ABOUT "YELLING" :))
I BELIEVE YOU ARE CONFUSING THE ORIGINAL POSTERS CONCERNS WITH WHAT YOU ARE
READING IN YOUR TEXT. BASICALLY THE "THERMAL SHOCK" YOU ARE READING ABOUT
IS "NOT" WHAT THE DISCUSSION WAS ABOUT, CONCERNING CLAY BODIES ABSORBING
MOISTURE THEN CRACKING IN WINTER DUE TO FREEZING CAPTURED MOISTURE IN THE
POROUS CLAY BODY.

If exceeded,past the %[seen above],the body will
have too much glass.It will then be more susceptible to

Thermal shock[the stress created within a ceramic object
by temperature change.Thermal shock is responsible
for the occurrence of cracks and is an OVERALL term,
pg.320 The Potter's Dictionary-Hamer 3rd edition.]

THE "THERMAL SHOCK" YOU DESCRIBE HERE ( PARAGRAPH ABOVE) IS FROM FIRING "TOO
FAST" ( OR COOLING TOO FAST) NOT FROM FREEZING THE CLAY BODY.

So freeze/thaw as experienced in winter or sun on a cold
pot or possible expansion of water in soil and so on
[which is what I meant and hoped would be understood
because there is a great deal of Japanese information dealing
with winter care.]Could after slow time damage a pot.
Especially since most pots already have fine cracks present
in the body after firing.

Raku bodies resist this damage because of the particles
within the body blocking the crack from physically passing.

BUT,RAKU BODIES ARE VERY POOR RISKS FOR BONSAI POTS IN COLD TEMP AREAS
BECAUSE OF THE CLAY TYPE USED TO AVOID THERMAL SHOCK....IT IS OPEN AND VERY
POROUS, THEREFORE MOISTURE IN THE BODY CAUSES POTS TO CRACK WHEN FROZEN,
BUTTHIS CLAY IS EXCELLENT IN 'THERMAL SHOCK" PROBLEM AVOIDANCE. THAT
IS WHY IT CAN BE TAKEN RED HOT FROM A KILN AND THROWN INTO STRAW R PAPERS OR
EVEN WATER. .


I don't know,and wasn't talking about the absorption of water
into the stoneware body and then freezing.

THIS IS WHAT THE ORIGINAL POSTER WAS CONCERNED ABOUT. SINCE YOU DON'T GET
HARD FREEZES, AND DON'T KNOW ABOUT THIS YOU SHOULDN'T SPEAK TO IT. THAT IS
EXACTLY WHAT YOU WERE TALKING ABOUT WHEN YOU MENTIONED THAT TOO MUCH
MISINFORMATION IS PASSED THROUGH IBC. YOU KNOW, WHEN YOU TOLD ME TO TRY TO
'GRASP THE IDEA" and TO DO A 'GENERAL STUDY UP"



On Porcelain.

In porcelain the body is homogenous;it does not contain
variously-sized particles of sand,grog etc.
[ The Potter's Dictionary -Hamer pg.312 ]

Stoneware isn't homogenous,but this article deals more with
glazes and but I think the above is enough to explain the difference
in response between the two clay types.


I have no way of know how porcelain pots handle cold.

AGAIN, THIS WAS THE ORIGINAL POSTERS CONCERN!



Glazed on the inside problems-
I think that breathe bit comes from high fired
but still say 8% porous earthenware ,with probably heavier
soils.

[Not everyone is too bothered by the salts deposited
on the outside of the pot.]

WELL YES THEY ARE, MOST WOULDN'T WANT THIS, BUT, THE POINT WAS THAT HIGHLY
POROUS BODIES ( WHICH WILL ALLOW THIS TO HAPPEN) WILL ALSO BE THE ONES TO
ABSORB WATER IN THE COLD AND FREEZE AND SHATTER. THIS WAS THE ORIGINAL
POSTERS CONCERN. MANY CHEAP POTS HAVE THIS EXACT PROBLEM


ALTHOUGH YOU HAVE BEEN IN CERAMICS FOR YEARS YOU ARE STILL MISUNDERSTANDING
THE RELATIONSHIP OF THE TERM "THERMAL SHOCK" IN REGARDS TO MANUFACTURING AND
DIRECT USE OF THE POTS. THERMAL SHOCK IS WHAT CAUSES A CLAY BODY TO SHATTER
IF HEATED TO FAST ( OR COOLED TO FAST). THIS IS WHY POTS ARE BISQUED VERY
SLOW AND HIGH FIRED WITH CAUTION BUT NOT AS SLOW AS BISQUE ( BECAUSE MOST
WATER HAS BEEN DRIVEN OUT IN BISQUEING) . IF YOU HEAT TOO FAST....THERMAL
SHOCK WILL DAMAGE THEM. ONCE A POT IS COMPLETED THE WINTER FREEZING EFFECT
IS "NOT" FROM THERMAL SHOCK, IT IS FROM POOR VITRIFICATION ALLOWING
MOISTURE INTO THE CLAY THUS CAUSING SHATTERING/CHIPPING/CHUNKING/ETC. DURING
WINTER MONTHS ( WHICH I DON'T BELIEVE YOU ARE HAVING LIKE WE DO). FURTHER,
THIS POORLY VITRIFIED CLAY ( OR CRAPPY CHEAP CLAY BODY) WHICH IS HIGHLY
POROUS WILL ALLOW WATER TO SEEP THROUGH THE CLAY AND ,AFTER DRYING ON THE
SURFACE, LEAVE MINERAL DEPOSITS.

Regards,
Dale

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