Leanne Juliana on thu 23 mar 06
Dear Clayarters,
Last night my professor showed the graduate students a tile that had been done for a pool commission. Aparently, the artist had used a commercial tile, and a commercial low fire glaze, but had not fired the glaze to temperature and so after a winter the glaze began to flake off. $60,000 and a lawsuit later, she might be having us redo the project for her. Be that as it may, my professor mentioned there were companies who could test glazes and clays for fit, as well as durability, and food safety. He named Allcloud? (add in a heavy Turkish accent) but couldn't tell me any more about it, like address or website.
So.... My question is two fold. One, does anyone have any contact information about any of these companies? I hope to move towards functional potter, and of course don't want to be a.sued, or b. the cause of unpleasantness because my glazes aren't safe. Two, what's best to use in this kind of situation. High fire the tile and then after vitrification, low fire the glaze, low and low, high and high?
Thanks,
~L
Dave Finkelnburg on thu 23 mar 06
Leanne,
Your question shows you obviously recognize what
you need to know! :-)
Testing of ceramics is based on how the fired
ceramic performs in service. Tests for how tile
endures freeze-thaw cycles, for chemical durability,
for fit, for strength, etc, ignore how the piece was
made
Most of the paths you mention can lead to durable
ceramics if the right combination of materials,
mixing, forming and firing are followed. The weakness
of high bisque, low glaze firing is it is possible to
get a nicely melted glaze that isn't bonded well to
the body. Such an approach needs to be tested to
confirm a very good bond has, in fact, formed. It can
be done. Virtually all hotel china is made this way,
and the result is very durable!
Low temperature tile permits use of certain
materials and saves energy and time in the firing
cycle, but may require use of certain materials like
low-melting glaze ingredients or frits which are not
cheap. So firing temperature becomes an economic
trade-off. Of course, the body ultimately limits how
high either first or second firing can be. Of course,
you did leave out single-firing, which is commonly
used for commercial tile manufacture.
--- Leanne Juliana wrote:
> Dear Clayarters,
>
> Last night my professor showed the graduate students
> a tile that had been done for a pool commission.
> Aparently, the artist had used a commercial tile,
> and a commercial low fire glaze, but had not fired
> the glaze to temperature and so after a winter the
> glaze began to flake off. $60,000 and a lawsuit
> later, she might be having us redo the project for
> her. Be that as it may, my professor mentioned there
> were companies who could test glazes and clays for
> fit, as well as durability, and food safety. He
> named Allcloud? (add in a heavy Turkish accent) but
> couldn't tell me any more about it, like address or
> website.
>
> So.... My question is two fold. One, does anyone
> have any contact information about any of these
> companies? I hope to move towards functional
> potter, and of course don't want to be a.sued, or b.
> the cause of unpleasantness because my glazes aren't
> safe. Two, what's best to use in this kind of
> situation. High fire the tile and then after
> vitrification, low fire the glaze, low and low, high
> and high?
>
> Thanks,
> ~L
>
>
______________________________________________________________________________
> 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.
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Dave Finkelnburg on thu 23 mar 06
Leanne,
I sent an incomplete post to the list. Here's a
couple more thoughts. There's a group that sets
standards for tile testing.
http://www.tileusa.com/test_main.htm
This is the Tile Council of North America site.
They offer testing services.
Good luck!
Dave Finkelnburg
--- Leanne Juliana <> wrote:
my professor mentioned there
> were companies who could test glazes and clays for
> fit, as well as durability, and food safety. > does
anyone
> have any contact information about any of these
> companies?
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Linda Ferzoco on thu 23 mar 06
Hi Dave,
Ya got me going! This site led me to think about ANSI
standards and I found this:
http://webstore.ansi.org/ansidocstore/find.asp?
where one can enter a word, like 'ceramics' or
'whiteware' and find the industry standards for some
of the things we make.
Mind you, I'm not saying we have to meet such
standards and I'm wondering what industries are
covered. Perhaps whiteware used in hospitals and
restaurants have to meet some of these standards, such
as the ones about crazing, etc.
Any legal-begles out there who know?
John and Ron, did you look at any of these standards
when compiling your book?
Cheers, Linda
--- Dave Finkelnburg wrote:
> Leanne,
> I sent an incomplete post to the list. Here's a
> couple more thoughts. There's a group that sets
> standards for tile testing.
> http://www.tileusa.com/test_main.htm
John Hesselberth on fri 24 mar 06
On Mar 23, 2006, at 9:01 PM, Linda Ferzoco wrote:
> John and Ron, did you look at any of these standards
> when compiling your book?
Hi Linda,
Yes, some of them. Most of them are really ASTM standards that ANSI
adopted or helped participate in developing. We reference a few of
the relevant ones in the book. Some of the tests we suggest for
studio potters are "Can-do-at-home versions" of the ASTM standards.
That is one reason some here on Clayart and elsewhere recommend the
book to their friends who fire at other temperatures. It is about the
only place where questions like that are addressed at all in the
studio potter literature.
Crazing is something the whiteware industry takes seriously--much
more seriously than studio potters do. Commercial dinnerware is
tested in a variety of ways, although one of the more important (in
my opinion) they seem to ignore--metal marking. I have seen a lot of
commercial dinnerware that is just awful in metal marking. They also
have a very rigorous test for stability in dishwashing. I have been
told, but never have been able to confirm, that some county health
departments will shut down a restaurant that has crazed dinnerware.
There are thousands upon thousands of county health department
inspectors out there with differing views on what is important. And
they rule in their area.
Regards,
John
Ivor and Olive Lewis on sat 25 mar 06
Dear Leanne Juliana,
Tile making is one of the largest sectors of Industrial Ceramic =
Production manufacturing quantities amounting to millions of square =
metres per year.
I am sure if you research Tile Production you will find there are =
national quality standards. Adhering to these may solve you anticipated =
dilemma. A good place to start would be in the records of the American =
Ceramic Society.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
=20
| |
|
