stacey ballard on sat 26 jul 03
Hi all,
This may seem like a stupid question, but I saw some comments earlier and wanted to ask. Why do some people think low fired clay is inferior? I have been selling my work for about 7 years and have never had a problem. I make masks and vases ( I market my vases as art, not to hold water, if someone wants to put flowers in them, they put in a plastic liner) what's your thoughts on this? It's just always been more convenient for me to fire with low fire clay and glazes, plus I like the looks of the color of glazes I can use.
Thanks for your time,
Stacey Ballard
http://www.basicelements.biz
---------------------------------
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
Ababi on sun 27 jul 03
Nothing is inferior.=20
Just know where you are.
The wares will be more mature in ^6 much better in ^10.
The fact that you sell your wares of ^04 or 03 and I sell almost nothing
at ^6 do not give a hint of which cone is better. The fact that you sell
means either that you have nice wares or that your clients love your
wares.
Because your wares are flower's wares =96 I mean not for food - let me =
ask
it this way. Are you aware that low fire metallic glazes might harm your
health? (a lot of Manganese dioxide)
Do you know what Pewter means and how this glaze is made?
Do your clients know?
http://www.basicelements.biz/MetallicVases.html
=20
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
=20
=20
=20
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of stacey
ballard
Sent: Sunday, July 27, 2003 2:48 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: low fired clay is inferior?
=20
Hi all,
This may seem like a stupid question, but I saw some comments earlier
and wanted to ask. Why do some people think low fired clay is inferior?
I have been selling my work for about 7 years and have never had a
problem. I make masks and vases ( I market my vases as art, not to hold
water, if someone wants to put flowers in them, they put in a plastic
liner) what's your thoughts on this? It's just always been more
convenient for me to fire with low fire clay and glazes, plus I like the
looks of the color of glazes I can use.
=20
Thanks for your time,
Stacey Ballard
http://www.basicelements.biz
=20
=20
=20
Snail Scott on sun 27 jul 03
At 05:47 PM 7/26/03 -0700, you wrote:
>Hi all,
>This may seem like a stupid question, but I saw some comments earlier and
wanted to ask. Why do some people think low fired clay is inferior?
It's not inferior for everything, just for some things,
such as objects which need to be waterproof. For some
purposes, a porous, low-fired earthenware may actually be
preferable, and other types of clay would be inferior.
It all depends on the intended purpose of the work. Every
material has its appropriate uses, and no one material is
'the best' for every purpose.
-Snail
David Beumee on tue 29 jul 03
7/29/03 2:44:45 PM, Joe Coniglio wrote:
>No wonder so many in high fire stoneware jump to porcelain. The last 1/2
>dozen stoneware bodies I've worked with are pretty unimpressive and blah. So
>most folks go right for the blank canvas of porcelain and think no more of
>the stoneware dilema.
Don't forget the wonderful possibilities of iron slips to enrich stoneware surfaces.
David Beumee
>low fire vs high fire
>
>Porocity is a factor in low fire. Lowfire has served human kind rather well
>for thousands of years.
>
>Sure stonewares and porcelains are in their own classification. I'm in a ^10
>way and want to stay there as long as I can. I had low fire beginnings. The
>clays were a joy to work with and the results were still fairly lush. Low
>fire clays can be gorgious.
>
>I've been looking around for some dynamic stoneware bodies with some color
>and character to them reminiscent to the lively earthtones of earthenware.--
>recommend some to me if you want and source the supplier:
>jconiglio@ssaris.com.
>
>No wonder so many in high fire stoneware jump to porcelain. The last 1/2
>dozen stoneware bodies I've worked with are pretty unimpressive and blah. So
>most folks go right for the blank canvas of porcelain and think no more of
>the stoneware dilema. Porcelain with grog? Ain't that a scary thought!!
>Might have to be called white stoneware.
>
>There are a lot of lovely slip cast earthenware bowls and plates out there
>with good glazes that resist porocity and are "plenty hard"
>
>Low fire $$ tip:
>Want some good profits? Go to the garden supply center and buy at $2-3 each
>those terra cotta pots and saucer planters made in italy and germany and take
>them home and glaze the outside or interior as well, with your low fire color
>glaze pallet. I've seen them fetch $24 each and you've saved a lot of work.
>Or as a potter who has access the the kiln---just try these for fun one day
>and place a few in your low fire kiln---you'll find they'll sell and might
>(along side) augment your sales.
>
>Nothing wrong with this! Use your glaze pallets, your choices and asthetics.
>You'll find them classic and pretty and they will sell!!
>
>______________________________________________________________________________
>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.
>
Wanda Holmes on tue 29 jul 03
I have fired the local commercial earthenware clay (Longhorn Red) to
cone 01 - by most standards low fire - and it is well vitrified and
harder to break than my stoneware tests. I would urge each and every
one of us to test and not operate on assumptions. I would not hesitate
to use this clay, fired at 01, for unglazed outdoor tile installations.
Wanda
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Snail Scott
Sent: Sunday, July 27, 2003 11:30 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: low fired clay is inferior?
At 05:47 PM 7/26/03 -0700, you wrote:
>Hi all,
>This may seem like a stupid question, but I saw some comments earlier a
wanted to ask. Why do some people think low fired clay is inferior?
It's not inferior for everything, just for some things,
such as objects which need to be waterproof. For some
purposes, a porous, low-fired earthenware may actually be
preferable, and other types of clay would be inferior.
It all depends on the intended purpose of the work. Every
material has its appropriate uses, and no one material is
'the best' for every purpose.
-Snail
________________________________________________________________________
______
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.
Joe Coniglio on tue 29 jul 03
low fire vs high fire
Porocity is a factor in low fire. Lowfire has served human kind rather well
for thousands of years.
Sure stonewares and porcelains are in their own classification. I'm in a ^10
way and want to stay there as long as I can. I had low fire beginnings. The
clays were a joy to work with and the results were still fairly lush. Low
fire clays can be gorgious.
I've been looking around for some dynamic stoneware bodies with some color
and character to them reminiscent to the lively earthtones of earthenware.--
recommend some to me if you want and source the supplier:
jconiglio@ssaris.com.
No wonder so many in high fire stoneware jump to porcelain. The last 1/2
dozen stoneware bodies I've worked with are pretty unimpressive and blah. So
most folks go right for the blank canvas of porcelain and think no more of
the stoneware dilema. Porcelain with grog? Ain't that a scary thought!!
Might have to be called white stoneware.
There are a lot of lovely slip cast earthenware bowls and plates out there
with good glazes that resist porocity and are "plenty hard"
Low fire $$ tip:
Want some good profits? Go to the garden supply center and buy at $2-3 each
those terra cotta pots and saucer planters made in italy and germany and take
them home and glaze the outside or interior as well, with your low fire color
glaze pallet. I've seen them fetch $24 each and you've saved a lot of work.
Or as a potter who has access the the kiln---just try these for fun one day
and place a few in your low fire kiln---you'll find they'll sell and might
(along side) augment your sales.
Nothing wrong with this! Use your glaze pallets, your choices and asthetics.
You'll find them classic and pretty and they will sell!!
Burness Speakman on wed 30 jul 03
Ditto my local clay. But the shrinkage is amazing.
Ababi on wed 30 jul 03
When I started ceramics I had an old and bad kiln - bad because of time
and perhaps bad handling of people that used it before me.
It hardly fired to 1020C
Yet I had beautiful glazes, beautiful beginner's glazes.
Beautiful terra cotta bodies.
Nothing inferior.
On the other had it is a wrong justification to say (write) that because
it has been used since the dawn of history it is that good. In the dawn
of history they could not fire higher than low fire and I will surprise
you they have never heard about low fire in an electric kiln!
When we choose or by force - economical or any other to use low fire we
shall make the best out of it.
When I fire ^6 ox I try to go beyond its limits. Sometimes I arrive to
the wall that tells me "Go back this is not your zone!" So I tell you
"Low fire potters" Know your limits and try to break them! Just do not
break the coils!
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
John Hesselberth on wed 30 jul 03
On Tuesday, July 29, 2003, at 04:44 PM, Joe Coniglio wrote:
> Porocity is a factor in low fire. Lowfire has served human kind
> rather well
> for thousands of years.
Yes it has, but it has only been in the last 25-30 years that microwave
ovens have been around. At least in the U.S. and Canada, microwaves are
now in essentially every kitchen. Earthenware has its pros and its
cons, but microwaves have generated one huge con which tips the balance
on the scales quite a bit. Unless an earthenware pot is completely
coated in a durable glaze that fits, it will absorb water with use.
Especially during dishwashing. Microwaves ovens love to heat water and
earthenware dishes will often be so hot they will burn fingers when you
try to remove them from a microwave. There have also been cases of
earthenware pots exploding in microwave ovens.
So please, if you make functional pottery from earthenware be extremely
careful about how you glaze it and make sure you use a durable glaze
that fits the clay body very well with absolutely no crazing. This, of
course, can also be a problem with poorly vitrified stoneware (e.g.
using a cone 10 body at cone 5 or 6) but at least it is not inherent in
the system.
Regards,
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Norman van der Sluys on wed 30 jul 03
As someone who cooks and uses a microwave oven dailyI must protest that
the incompatiblity of lowfire ware with that wonderful convienience is
not such a "huge con."
Must everything in our kitchen or china cabinet be microwave and
dishwasher safe? My metal pots and pans never go inside the microwave
and my high-carbon steel Chinese cleaver never goes in the dishwasher.
The same is true for a number of utensiles and dishes I use regularly.
Unglazed terra cotta has a proud place in a cooks arsenal.
Many on the list have proclaimed that the only logical market for
handmade pottery is the (excuse the term -) elite. And by "elite" one
is to infer wealthy. Well, perhaps there is an elite in terms of
knowledge (or, perhaps, common sense.) Perhaps as well, one could aim
one's sights on this elite market.
It all boils down to knowing your product's virtues and shortcomings,
and potting accordingly. Porosity is a characteristic of many lowfire
clays, and that can be very desireable in some circumstances.
High-fired porcelain would be a poor choice for a water filter. Does
that make it inferior to terra cotta?
Norman van der Sluys (who does not "do" lowfire :>) )
Jackpottery!
by the shore of Lake Michigan,
...where I recently made a trip to the local Wal-Mart to buy ink
cartridges for my printer. Should I spend $65 for a set of cartridges,
or buy the printer for $35 that includes the same cartridges in the
package?
Hmmmm.
John Hesselberth wrote:
>
> ... it has only been in the last 25-30 years that microwave
> ovens have been around. At least in the U.S. and Canada, microwaves are
> now in essentially every kitchen. Earthenware has its pros and its
> cons, but microwaves have generated one huge con which tips the balance
> on the scales quite a bit. Unless an earthenware pot is completely
> coated in a durable glaze that fits, it will absorb water with use.
> Especially during dishwashing. Microwaves ovens love to heat water and
> earthenware dishes will often be so hot they will burn fingers when you
> try to remove them from a microwave. There have also been cases of
> earthenware pots exploding in microwave ovens.
>
psci_kw on wed 30 jul 03
That's a no-brainer! Buy the cheap printer just for the cartridge. Buy two!
Then go to inkfarm.com or MrInkjet.com (or some place similar)
and buy their version of the refill kit.
Then take the cartridge out, and donate the printers
to your local school for the tax deduction
...which effectively gives you double the price back of the refill kit!
The school gets much needed (new) technology,
you come out of it with plenty of ink, and looking like a pottin'
philanthropist!
You're happy, the school is happy, the gubment
is satisfied (they ain't never happy!)... what's not to like?
Wayne in Key West
who did that just last month with 7 of those "printer-to-go" deals at
WallyWorld.
I can still hear the squeals of delight from the teachers :>)
> ...where I recently made a trip to the local Wal-Mart to buy ink
> cartridges for my printer. Should I spend $65 for a set of cartridges,
> or buy the printer for $35 that includes the same cartridges in the
> package?
> Hmmmm.
Ron Roy on thu 31 jul 03
That would have been me - but I don't think I used the word inferior - but
I do think that is true - and certainly in the sense of functional ware.
First of all - because mulite does not begin to form till stoneware
temperatures - the ware is more susceptible to chipping. This is because
the mulite crystals form an interlocking bond within the clay body - makes
stonewares stronger - no doubt about that - it's part of the definition -
earthenware has no mulite (unless added as a part of the body composition -
stoneware has it naturally.
Second - earthenware bodies are not mature enough to be water proof. Too
much flux is needed to melt them properly so the maturing range is so small
it is impractical to use. This leads to leaking and the rehydration of the
body through contact with water - and causes eventual crazing even if the
glaze is formulated to not normally craze.
Water in the body makes any ware unfit for microwave use - and can be a
problem in an ordinary oven.
Earthen ware glazes are hard to make durable - takes to much flux to melt
alumina and silica - which are key to durability.
Not that all stoneware and porcelain are immune from the same problems -
but at least they can be solved easier.
It is not a very good argument - that low fire is cheaper by the way - all
those frits you need to use come at a high price.
It also seems to me that you can do anything at cone 6 you can do at
earthenware temperatures.
If inferior means - inferior ware - well yes I did mean that.
RR
>Hi all,
>This may seem like a stupid question, but I saw some comments earlier
>and wanted to ask. Why do some people think low fired clay is inferior?
>I have been selling my work for about 7 years and have never had a
>problem. I make masks and vases ( I market my vases as art, not to hold
>water, if someone wants to put flowers in them, they put in a plastic
>liner) what's your thoughts on this? It's just always been more
>convenient for me to fire with low fire clay and glazes, plus I like the
>looks of the color of glazes I can use.
>
>Thanks for your time,
>Stacey Ballard
>http://www.basicelements.biz
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Eric B on thu 31 jul 03
what about "white" low-fire clay? in this thread i've seen low-fire clay
(and its weaknesses) used synonimously with earthenware. but i have been
experimenting with a whitish low-fire clay called "M-210" that i bought at a pottery
supply house. i haven't tested the finished ware for water-holding integrity,
but they look and feel much less porous than earthenware.
does anyone have experience with this clay? i made some coffee mugs with it,
and glazed them with "food safe" glazes. i realize that due to the mullite
absence, etc., they may not be as physically strong, but other than that do
they suffer -- as functional ware -- from the same weaknesses as earthenware?
thanks.
eric
SpunMud
Cindi Anderson on thu 31 jul 03
Run a porosity test and find out. I'm sure many would love to hear your
results. Here is the procedure.
Take a piece of clay and fire it to temperature. Weigh it. Put it in boiling
water for 5 minutes, and leave in the water as it cools. When cold, remove
the piece and dry it off with a sponge. Weigh it again. The difference in
weight divided by the original weight times 100 is the % porosity.
Cindi
Ron Roy on fri 1 aug 03
Hi Norman,
The big problem is - they (the customers) don't know the pro and cons -
imagine oil and fat absorbed into a porous body - then used to store food
in for instance - this salad tastes like fish!
If we could inform them in a way that the message travels with the ware -
then it would not be such a potential problem.
If we want hand made pottery to be more popular then we must consider how
the customer will react when using our pots. If they have a "bad"
experience we are shootng our collective selves in the foot.
It is not only lowfire ware - it can happen at all temperatures.
One of my points was - at stoneware temperatures you at least have a chance
of addressing the absorbency problems and a much better chance of solving
those other concerns that come with functional ware.
By the way - porcelain would work just fine for a water filter - if fired
low enough so the flow rate was right.
A better argument would be for low fired flame ware - no glaze - and still
- it would have a lifetime and at the end - there would be, at least, a
mess to clean up.
RR
>It all boils down to knowing your product's virtues and shortcomings,
>and potting accordingly. Porosity is a characteristic of many lowfire
>clays, and that can be very desireable in some circumstances.
>High-fired porcelain would be a poor choice for a water filter. Does
>that make it inferior to terra cotta?
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on sat 2 aug 03
Hi Eric - same problem with the white clay - perhaps even more so because
the iron and trace elements in the red clay helps them to vitrify a bit
more.
Some low fire white ware bodies have generous amounts of talc - this helps
solve two of the problems associated with this type of body.
Such bodies do not absorb water and therefor so not suffer from delayed
crazing due to rehydration of the clay - however - it does not solve the
problem of water in the body heating up when microwaved.
High talc low fired bodies develop enstatite - which shows up as a slight
inversion in the same area (200C) as cristobalite does - and helps keep
glazes in compression.
RR
>what about "white" low-fire clay? in this thread i've seen low-fire clay
>(and its weaknesses) used synonimously with earthenware. but i have been
>experimenting with a whitish low-fire clay called "M-210" that i bought at
>a pottery
>supply house. i haven't tested the finished ware for water-holding integrity,
>but they look and feel much less porous than earthenware.
>
>does anyone have experience with this clay? i made some coffee mugs with it,
>and glazed them with "food safe" glazes. i realize that due to the mullite
>absence, etc., they may not be as physically strong, but other than that do
>they suffer -- as functional ware -- from the same weaknesses as earthenware?
>
>thanks.
>
>eric
>SpunMud
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on sat 2 aug 03
I use a different test for absorbency.
Make bars 1" wide by 6" long by 1/2" high. Fired weight will be around 150
grams. Fire to glaze temp - if once firing treat as thick clay - dry em
well and slow fire up to 100C
Weigh as soon as the bars come out of the kiln - before the clay has a
chance to absorb any moisture from the air. Boil for two hours. Run under
cold water till cold - pat dry and weigh again.
Subtract dry weight from wet - divide that by the dry weight times 100 = %
absorption (same as below.)
RR
>Run a porosity test and find out. I'm sure many would love to hear your
>results. Here is the procedure.
>
>Take a piece of clay and fire it to temperature. Weigh it. Put it in boiling
>water for 5 minutes, and leave in the water as it cools. When cold, remove
>the piece and dry it off with a sponge. Weigh it again. The difference in
>weight divided by the original weight times 100 is the % porosity.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Cindi Anderson on mon 4 aug 03
"Low fire" does suffer from a terminology problem I think. Most people
think of "low fire" as the typical Cone 04/06. At those temps I have never
heard of a vitrified body. But if you go to Cone 1 then there are clays
that are accepted as vitrified. But many people still call this temperature
range low fire. Maybe Cone 1 is more properly called "mid fire".
It is similar to the "Cone 6 porcelain not really being a porcelain"
argument we had last month.
By the way, what is the absorption % of your clay fired at 01? That is a
little lower temp than what I have typically heard you need to get
vitrification.
Cindi
----- Original Message -----
From: "Wanda Holmes"
> I have fired the local commercial earthenware clay (Longhorn Red) to
> cone 01 - by most standards low fire - and it is well vitrified and
> harder to break than my stoneware tests.
Elzbieta Sekula on mon 4 aug 03
What cone equivalent do you figure the ancient pots that have managed to
survive down to our time were fired? I don't mean to sound sarcastic with my
question. I just wonder if they had any idea of high or low fire clays and glazes?
I know some ancient civilizations are known to have performed brain surgery
and have their patients survive, so maybe they did.
Elzbieta
Wanda Holmes on tue 5 aug 03
Cindi, the results of my tests were:
Claybody Cone Shrinkage Stength Porosity
Longhorn Red C01 13-15% 19.50 0.7%
Longhorn Red C1 13-15% 23.10 0.2%
I prefer the color of the fired body at C01 and the porosity is low
enough for me at that point. At cone 01, the body still has a nice
terra cotta red color; at cone 1 is going brown.
The strength index is of my own devising (due to the tools I have at my
disposal). I have a torque wrench fixed to an arbor press and the
numbers you see listed are the average amount of torque need to break an
unglazed 1" by 4" bar. I generally test 4 to 6 bars for the average and
retest if I get widely varying data points. The bar rests on the arms
of the arbor press (like a bridge between them) and the point of the
press comes down on the center of the suspended bar. I just press down
until the tile breaks and note the torque required. It is only useful
as a comparison to other tiles measured this way, and here are some of
my comparisons:
Glazed talavera - 3.75 strength index ( a constant reminder to me not to
go overboard - this tile is beloved and has been used extensively
indoors and out around here for centuries despite the fact that it is
weak and crazes like the dickens.)
Presealed saltillo - 14.00 strength index
Glazed Walker Zanger Alhambra field tile - 12.50 strength index (rated
for
kitchen counters)
Unglazed Clayworld Special Stoneware II - cone 8 - 18.30 strength index
Bee Mix 5 - cone 5 - 24.60 strength index
Glazed Walker Zanger Newport field tile - 27.50 strength index
Wanda
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Cindi
Anderson
Sent: Monday, August 04, 2003 4:36 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: low fired clay is inferior?
"Low fire" does suffer from a terminology problem I think. Most people
think of "low fire" as the typical Cone 04/06. At those temps I have
never
heard of a vitrified body. But if you go to Cone 1 then there are clays
that are accepted as vitrified. But many people still call this
temperature
range low fire. Maybe Cone 1 is more properly called "mid fire".
It is similar to the "Cone 6 porcelain not really being a porcelain"
argument we had last month.
By the way, what is the absorption % of your clay fired at 01? That is
a
little lower temp than what I have typically heard you need to get
vitrification.
Cindi
----- Original Message -----
From: "Wanda Holmes"
> I have fired the local commercial earthenware clay (Longhorn Red) to
> cone 01 - by most standards low fire - and it is well vitrified and
> harder to break than my stoneware tests.
________________________________________________________________________
______
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.
Ron Roy on wed 6 aug 03
Hi Wanda,
Thanks for posting this information to the list - usable stuff.
Glaze fit has an important effect on MOR - if the glaze is crazed the tile
(or pot) is weakened. If the glaze is under compression (glaze winds up
bigger than the clay) it can add a lot of strength to the ware - but too
much leads to shivering.
I'm sure there has been a lot of research in this area - not with potters
clay though.
RR
>Claybody Cone Shrinkage Stength Porosity
>Longhorn Red C01 13-15% 19.50 0.7%
>Longhorn Red C1 13-15% 23.10 0.2%
>
>I prefer the color of the fired body at C01 and the porosity is low
>enough for me at that point. At cone 01, the body still has a nice
>terra cotta red color; at cone 1 is going brown.
>
>The strength index is of my own devising (due to the tools I have at my
>disposal). I have a torque wrench fixed to an arbor press and the
>numbers you see listed are the average amount of torque need to break an
>unglazed 1" by 4" bar. I generally test 4 to 6 bars for the average and
>retest if I get widely varying data points. The bar rests on the arms
>of the arbor press (like a bridge between them) and the point of the
>press comes down on the center of the suspended bar. I just press down
>until the tile breaks and note the torque required. It is only useful
>as a comparison to other tiles measured this way, and here are some of
>my comparisons:
>
>Glazed talavera - 3.75 strength index ( a constant reminder to me not to
>go overboard - this tile is beloved and has been used extensively
>indoors and out around here for centuries despite the fact that it is
>weak and crazes like the dickens.)
>
>Presealed saltillo - 14.00 strength index
>
>Glazed Walker Zanger Alhambra field tile - 12.50 strength index (rated
>for
>kitchen counters)
>
>Unglazed Clayworld Special Stoneware II - cone 8 - 18.30 strength index
>
>Bee Mix 5 - cone 5 - 24.60 strength index
>
>Glazed Walker Zanger Newport field tile - 27.50 strength index
>
>Wanda
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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