RubySuMoon on wed 21 jan 98
Hi All --
One of my students asked me a question I couldn't answer, but I know somebody
can!
Would a Bonsai container made from a ^10 stoneware (Black Mountain) and fired
to ^5 crack if subjected to outside freezing temperatures for any period of
time?
(For that matter, would a ^5 body fired to ^5 crack if frozen?)
Thanks for the expertise!
Su
Potting in Piedmont, CA
Cindy on thu 22 jan 98
Su,
It may crack if the body has absorbed a sufficient amount of water, but I
kind of doubt it. Deeper containers can crack if they are holding wet soil
which freezes, but this shouldn't be a problem with the shallow bonsai
containers I've seen.
Cindy in Custer, SD
Robert Katz on thu 22 jan 98
Any glass container ( translated = glaze ) has the potential to crack in
freezing tempretures with the expansion of moisture ( as in absorbed in the
clay or held in the soil ).
Vicki Katz
Katz Creek Pottery
Sugar Land, TX
At 04:18 PM 1/21/98 EST, you wrote:
>----------------------------Original message----------------------------
>Hi All --
>
>One of my students asked me a question I couldn't answer, but I know somebody
>can!
>
>Would a Bonsai container made from a ^10 stoneware (Black Mountain) and fired
>to ^5 crack if subjected to outside freezing temperatures for any period of
>time?
>
>(For that matter, would a ^5 body fired to ^5 crack if frozen?)
>
>Thanks for the expertise!
>
>Su
>Potting in Piedmont, CA
>
Vince Pitelka on thu 22 jan 98
>Would a Bonsai container made from a ^10 stoneware (Black Mountain) and fired
>to ^5 crack if subjected to outside freezing temperatures for any period of
>time?
Su -
If the soil is dry there will be no problem, but if it contains a lot of
water when the freezing occurs, than the pot will crack no matter what the
clay or the firing temperature. No normal ceramic pot can withstand the
force of freezing water contained within. Regarding moisture within the
clay itself, there is a chance that this clay would be perfect. It all
depends on the degree of porosity. Too little, and water which still seeps
into the vitrified clay cannot escape. Too much and the excessive water
freezing within the weaker porous clay causes the body to disintegrate.
There are formulas for figuring whether or not a claybody is ideal for
long-term exterior use. The firing temperature is not particularly
important. The critical thing is absorption. Thus a terracotta sculpture
body fired to ^1 might be ideal, or a ^10 stoneware body fired to ^5 might
be perfect. Val Cushing's handbook contains a good description of the
testing process.
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Kris Bliss on fri 23 jan 98
>----------------------------Original message----------------------------
>Hi All --
>
>One of my students asked me a question I couldn't answer, but I know somebody
>can!
>
>Would a Bonsai container made from a ^10 stoneware (Black Mountain) and fired
>to ^5 crack if subjected to outside freezing temperatures for any period of
>time?
>
>(For that matter, would a ^5 body fired to ^5 crack if frozen?)
>
>Thanks for the expertise!
>
>Su
>Potting in Piedmont, CA
>
my experience has been that you can freeze most any
fired clay.....
BUT if said container contains Bonsai tree in moist
or wet potting medium, it is more likely to crack. If the container
is such that the freezing water cannot expand,,, it's pretty
much guarenteed.
kbliss@customcpu.com
13781 Arne Erickson Cir.
Anchorage, Alaska 99515
Lili Krakowski on fri 23 jan 98
Aha! Trick question time! You are dealing with TWO problems not one. The
pot if vitrified should not crack. In other words take an empty, dry,
vitrified pot, stick it outside, let it freeze. It should not crack. If
the clay is not vitrified (and some commrcial clays, although fired to c.
10 still absorb water) it may crack. You'd have to check. I expect it
would relate to how much water is in it. BUT REMEMBER: the earth in your
planter will be WET AND IT WILL EXPAND IN FREEZING. Many a pot has been
blamed for cracking when in fact the earth inside it expanded andd cracked
the poor pot. .
On Wed, 21 Jan 1998, RubySuMoon wrote:
> ----------------------------Original message----------------------------
> Hi All --
>
> One of my students asked me a question I couldn't answer, but I know somebody
> can!
>
> Would a Bonsai container made from a ^10 stoneware (Black Mountain) and fired
> to ^5 crack if subjected to outside freezing temperatures for any period of
> time?
>
> (For that matter, would a ^5 body fired to ^5 crack if frozen?)
>
> Thanks for the expertise!
>
> Su
> Potting in Piedmont, CA
>
Lili Krakowski
John H. Rodgers on fri 23 jan 98
-- [ From: John H. Rodgers * EMC.Ver #2.5.02 ] --
I have been following this thread a bit and here's my $.02 worth.
If I remember my chemistry and physics correctly, water as it cools reaches
it maximum density at 4 degrees C. As it cools further it begins to expand,
and at some point it reaches it maximum expansion as a solid. I don't
remember for certain, but I beleive the maximum expansion is at 0 degrees.
There is an expansion ratio, but I have long ago forgotten it. This
expansion in a ceramic/glass/cast iron/steel/copper/plastic/etc.vessel, will
crack or split the material of the container, unless the contailer material
is of elastic material.
Just remember, below 4 degrees C, even though it is still liquid, the water
is starting to put pressure against the walls of the vessel.
John Rodgers
Wet in Alabama
-------- REPLY, Original message follows --------
Date: Thursday, 22-Jan-98 07:50 AM
From: Vince Pitelka \ Internet: (vpitelka@dekalb.net)
To: CLAYART LIST \ Internet: (clayart@lsv.uky.edu)
Subject: Re: If It Freezes Will It Crack?
----------------------------Original message----------------------------
>Would a Bonsai container made from a ^10 stoneware (Black Mountain) and
fired
>to ^5 crack if subjected to outside freezing temperatures for any period of
>time?
Su -
If the soil is dry there will be no problem, but if it contains a lot of
water when the freezing occurs, than the pot will crack no matter what the
clay or the firing temperature. No normal ceramic pot can withstand the
force of freezing water contained within. Regarding moisture within the
clay itself, there is a chance that this clay would be perfect. It all
depends on the degree of porosity. Too little, and water which still seeps
into the vitrified clay cannot escape. Too much and the excessive water
freezing within the weaker porous clay causes the body to disintegrate.
There are formulas for figuring whether or not a claybody is ideal for long-
term exterior use. The firing temperature is not particularly important.
The critical thing is absorption. Thus a terracotta sculpture body fired to
^1 might be ideal, or a ^10 stoneware body fired to ^5 might be perfect.
Val Cushing's handbook contains a good description of the testing process. -
Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
-------- REPLY, End of original message --------
Danny Bird on sat 24 jan 98
Have you ever looked close at an ice cube, one that was frozen in an ice
cube tray? You will notice that they rise up in center as they freeze
(and expand). The top surface is convex.
I believe moist soil in a bonsai container would behave the same way.
The practice of pruning a bonsai tree includes root pruning as well as
pruning foliage and branches. This requires that the soil and root ball
be easily removed from the container. To achieve this, the walls of most
bonsai containers I've seen have sides that flare out slightly. Like
this: \____/
IMHO. Assuming the pot is made sufficiently thick and fired to a fair
state of maturation (strong), I think the expanding volume of moist soil
would tend to rise up slightly out of the container before it forced
the sides of the pot to crack.
Birdboy
pedresel@3-cities.com on sun 25 jan 98
The Jack Huggins article on weather resistant pots in the June 1997 Studio
Potter suggests that pots with the traditional straight flaring out sides
allow freezing soil to expand upward while rounded pots may break because
the soil doesn't have room to expand. He also says that drainage is very
important and that you want low (no necessarily no) porosity. After all one
of the big reasons for terra cotta planters is that they are somewhat
porous. Since many bonsai pots seem to be flat and open, you may not have a
problem if you put a little thought into the shape.
-- Evan in W. Richland WA USA in the damp and gray and drizzly desert
At 07:44 AM 1-23-98 EST, you wrote:
>----------------------------Original message----------------------------
>Aha! Trick question time! You are dealing with TWO problems not one. The
>pot if vitrified should not crack. In other words take an empty, dry,
>vitrified pot, stick it outside, let it freeze. It should not crack. If
>the clay is not vitrified (and some commrcial clays, although fired to c.
>10 still absorb water) it may crack. You'd have to check. I expect it
>would relate to how much water is in it. BUT REMEMBER: the earth in your
>planter will be WET AND IT WILL EXPAND IN FREEZING. Many a pot has been
>blamed for cracking when in fact the earth inside it expanded andd cracked
>the poor pot. .
>
>
>
>
>On Wed, 21 Jan 1998, RubySuMoon wrote:
>
>> ----------------------------Original message----------------------------
>> Hi All --
>>
>> One of my students asked me a question I couldn't answer, but I know somebody
>> can!
>>
>> Would a Bonsai container made from a ^10 stoneware (Black Mountain) and fired
>> to ^5 crack if subjected to outside freezing temperatures for any period of
>> time?
>>
>> (For that matter, would a ^5 body fired to ^5 crack if frozen?)
>>
>> Thanks for the expertise!
>>
>> Su
>> Potting in Piedmont, CA
>>
>
>Lili Krakowski
>
>
| |
|
