iandol on tue 23 jan 01
Dear Martin,
This does seem incongruous when more people are resorting to computer =
glaze programs to find out about their own products and ensure safety =
and compatibility with current consumer protection regulations.
One might assume that "high alkali" means sodium. Sodium means crazing.
It is almost an axiom that to get maximum profits many companies are =
known to incorporate the cheapest and most readily available materials. =
Potassium and Lithium would drive the price up.
The quick solution is not to encourage them by being a customer.
Best regards,
Ivor.=20
Martin Howard on wed 24 jan 01
Ivor, the firm concerned has now agreed to send us all the full details of
their frits.
It seems that a too enthusiastic employer did not realise the difference
between frits and glazes.
But at the back of all this is the fear within the industry of being sued if
something sold is not up to specification. You lot in the States have upped
the anti as far as this concerned. We in Europe are catching on quickly and
the number of lawyers is increasing.
The vendors of the RMs for frits are subject to the vagaries of mining
companies, different seams, odd changes in law in their own country. There
are so many possible reasons, quite logical, for the current supply to not
be EXACTLY what the frit analysis says it should be.
I for one, promised this particular firm not to take any legal action
against them should the frit be a little different from the figures they
eventually list and I then put into the computer list of RMs.
But, as a quaker, I do not go to law in any case. Far better to sort it out
in a reasonable way, but firmly. That brings results more often than not.
One day these firms will catch up with us computer potters. But give them a
little time.
Martin Howard
Webb's Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
England
martin@webbscottage.co.uk
Have you seen http://www.thefriend.org
Download The Friend, the weekly Quaker Newspaper,
3 days before it is published.
That's Quick for Quakers.
Khaimraj Seepersad on fri 26 jan 01
Good Day to All ,
Martin ,
it may never be possible to accurately say what is in a frit .
If you check the archives , there was a discussion on Fluorine ,
in glazes .
I wrote to the Porcelain Enamel Institute asking about the loss
of Fluorine in the manufacturing of an enamel . The response
from an Enamel manufacturer was that between 40 to 60 %
of what was put in vaporised and was lost .
I then wondered what happened when firing the frit ?
I would imagine Na20 and B203 have similar track records and
do remember something about Flue tests in , I believe , Parmelee
where readings were taken on what was going out , while glazes
were being fired .
When I make one of my frits , I usually , put a note next to the
calculated Na20 , B203 figures and say - should be ???
For my sanity it is easier to just use one frit as a glaze and float it
with up to 5 % bentonite . [ yes , I know I should use a blend of two
or three frits - lazy potter ] .
Often if the fritted glaze can handle it , I just add on 5 % Si02 to
make up for the loss of the glass former B203 - no problems yet.
Now , if I could only figure out why - Li20 has a low expansion figure
in Pottery Glaze Calculation and a High Expansion Figure in Enamels.
Na20 = 10 and Li20 = 12 ??????? [ Mayer and Havas 1910 . 1911 -
according to Maskall and White - ]
Khaimraj
-----Original Message-----
From: Martin Howard
To: CLAYART@LSV.CERAMICS.ORG
Date: 25 January 2001 12:01
Subject: Re: PATENTS and SECRECY Frit content
>Ivor, the firm concerned has now agreed to send us all the full details of
>their frits.
>It seems that a too enthusiastic employer did not realise the difference
>between frits and glazes.
>
>But at the back of all this is the fear within the industry of being sued
if
>something sold is not up to specification. You lot in the States have upped
>the anti as far as this concerned. We in Europe are catching on quickly and
>the number of lawyers is increasing.
>
>The vendors of the RMs for frits are subject to the vagaries of mining
>companies, different seams, odd changes in law in their own country. There
>are so many possible reasons, quite logical, for the current supply to not
>be EXACTLY what the frit analysis says it should be.
>
>I for one, promised this particular firm not to take any legal action
>against them should the frit be a little different from the figures they
>eventually list and I then put into the computer list of RMs.
>
>But, as a quaker, I do not go to law in any case. Far better to sort it out
>in a reasonable way, but firmly. That brings results more often than not.
>
>One day these firms will catch up with us computer potters. But give them a
>little time.
>
>Martin Howard
>Webb's Cottage Pottery
>Woolpits Road, Great Saling
>BRAINTREE, Essex CM7 5DZ
>England
>martin@webbscottage.co.uk
>Have you seen http://www.thefriend.org
>Download The Friend, the weekly Quaker Newspaper,
>3 days before it is published.
>That's Quick for Quakers.
>
>___________________________________________________________________________
___
>Send postings to clayart@lsv.ceramics.org
>
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>settings from http://www.ceramics.org/clayart/
>
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melpots@pclink.com.
>
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