Tig Dupre on fri 24 oct 03
I broached this subject off-line and feel it might be of general interest to the group at large. How can I calculate the fit for a clay body when I don't know the composition?
I use commercial clays--porcelanic bodies--because I like the translucency and the white background. I don't have the facilities to mix my own, so I use boxed clay. The companies who make the clay are understandably reluctant to give out the recipes, and are only slightly less reluctant to give out the analysis of their clay body.
So, without doing extensive testing, how can I determine beforehand if my cone 6 Xavier Warm Jade will work on a B-Mix body? I know the glaze will look different, that's a given. But will it crawl, peel, bloat, spall, or run? Will it fit the body? How can I tell if I'm going to waste my time and money before I do the work?
Is there a reference I can go to? Any assistance will be most appreciated.
Tig
Curious in Port Orchard, WA
John Hesselberth on fri 24 oct 03
On Friday, October 24, 2003, at 10:54 AM, Tig Dupre wrote:
> So, without doing extensive testing, how can I determine beforehand if
> my cone 6 Xavier Warm Jade will work on a B-Mix body? I know the
> glaze will look different, that's a given. But will it crawl, peel,
> bloat, spall, or run? Will it fit the body? How can I tell if I'm
> going to waste my time and money before I do the work?
Hi Tig,
You probably can't. As useful as COE calculations are, they are a long
way from being able to help in all situations. For example Xavier's
Warm Jade Green is a matte glaze--at best COE calculations only give
directional information for matte glazes. It is a technique best used
with glossy, single phase glazes. Once you have experimentally
determined the COE range that fits your clay body, COEs can help you
find other glossy glazes that will fit that body.
The reason they are limited is that COE calculations are based on what
is often called the 'rule of mixtures' and that "rule" is a very
simplified approximation of how real materials behave. That is
particularly so when things like crystal formation enter the
picture--which happens with matte glazes. Another reason is that I'm
not aware of COE numbers being published for clay bodies. Most
commercial clay bodies have never seen the inside of a dilatometer. Now
for Tucker and Axner bodies (where Ron oversees them) and with glossy
glazes--well, maybe.
Regards,
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Mert & Holly Kilpatrick on fri 24 oct 03
Is it possible to get the chemical analyses of clay bodies? Another reason
that would be useful is when there is a big difference between how a glaze
looks/acts on a claybody that is not immediately explainable, such as two
buff clays. It would be educational to be able to compare the analyses of
the two different bodies, and over time, some patterns might emerge that
would allow the potter to have a better handle on why the glazes act as they
do.
I can understand that manufacturers won't give out their batch recipes, but
why not the analyses? Where I work, Mallinckrodt Baker, the chemical
analysis is a requirement of many of our customers for our products. Not
only do they want to know it, some of them audit us to see proof that the
specs are within control limits over time. But they have clout. Potters
don't!
----- Original Message -----
From: "Tig Dupre"
> I broached this subject off-line and feel it might be of general interest
to the group at large. How can I calculate the fit for a clay body when I
don't know the composition?
>
> I use commercial clays--porcelanic bodies--because I like the translucency
and the white background. I don't have the facilities to mix my own, so I
use boxed clay. The companies who make the clay are understandably
reluctant to give out the recipes, and are only slightly less reluctant to
give out the analysis of their clay body.
>
> So, without doing extensive testing, how can I determine beforehand if my
cone 6 Xavier Warm Jade will work on a B-Mix body? I know the glaze will
look different, that's a given. But will it crawl, peel, bloat, spall, or
run? Will it fit the body? How can I tell if I'm going to waste my time
and money before I do the work?
>
> Is there a reference I can go to? Any assistance will be most
appreciated.
Ron Roy on tue 28 oct 03
Calculation won't work for clay body expansion - but - in our book there is
a set of 5 glazes designed to give you the expansion of any cone 6 body -
it is the only way I know of except having the clay and the glaze measured
on a dilatometer.
By the way - every clay company must - by law - give an analysis of every
clay body they sell - and every material and every glaze - some refuse to
do it but they just need a couple of shoves.
RR
>I broached this subject off-line and feel it might be of general interest
>to the group at large. How can I calculate the fit for a clay body when I
>don't know the composition?
>
>I use commercial clays--porcelanic bodies--because I like the translucency
>and the white background. I don't have the facilities to mix my own, so I
>use boxed clay. The companies who make the clay are understandably
>reluctant to give out the recipes, and are only slightly less reluctant to
>give out the analysis of their clay body.
>
>So, without doing extensive testing, how can I determine beforehand if my
>cone 6 Xavier Warm Jade will work on a B-Mix body? I know the glaze will
>look different, that's a given. But will it crawl, peel, bloat, spall, or
>run? Will it fit the body? How can I tell if I'm going to waste my time
>and money before I do the work?
>
>Is there a reference I can go to? Any assistance will be most appreciated.
>
>Tig
>Curious in Port Orchard, WA
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Holly Kilpatrick on tue 28 oct 03
Ron Roy wrote:
By the way - every clay company must - by law - give an analysis of every
clay body they sell - and every material and every glaze - some refuse to
do it but they just need a couple of shoves.
RR
Ron,
Is that just in Canada? I checked the Standard Clay MSDS's and they do not give an analysis -- as we have said before on Clayart, the MSDS info is largely worthless, along the lines of clay is dusty. Anyway, I called Standard and asked if it is possible to obtain an analysis of their bodies and the woman I spoke with said No, they are only required to provide the MSDS and they don't provide an analysis. Is that contrary to what you think is required in the US? Does Tucker's provide a chemical analysis of their clay bodies?
Thanks, Holly
Louis Katz on tue 28 oct 03
This isn't true to my knowledge in the US. As I understand it we can't
even get analysis of newer frits.
Louis
> By the way - every clay company must - by law - give an analysis of
> every
> clay body they sell - and every material and every glaze - some refuse
> to
> do it but they just need a couple of shoves.
Catherine White on tue 28 oct 03
I bought Tom Coleman's Desert Sand and was told that it's his personal =
recipe, therefore not available. I did get it from his book. Also, they =
said their generic Clear Gloss ^10 recipe was unknown to them.=20
Catherine in Yuma, Arizona
Last night the weatherman warned that there'd be a chilly low of =
72=BA.
Brrrrrrrrrr........
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> By the way - every clay company must - by law - give an analysis of =
every
> clay body they sell - and every material and every glaze - some refuse =
to
> do it but they just need a couple of shoves.
>=20
> RR
Linda Ziesmer on tue 28 oct 03
Per RR:
By the way - every clay company must - by law - give an analysis of every
clay body they sell - and every material and every glaze - some refuse to
do it but they just need a couple of shoves.
______________
Ron, since you're talking law, we'll do the shoving! Would you define the
elements of that "analysis"? Just what do they have to tell us about the
clay body? Thanks,
Linda
Tony Hansen on wed 29 oct 03
I look after the bodies at Plainsman Clays and there
is a detailed data sheet with analysis on each one,
we have had this since around 1996. I have never seen
data sheets by any other manufacturer with the detail
that these ones have. Here is an example:
http://digitalfire.com/plainsman/data/m340.htm
At our new
ceramicmaterials.info website body manufacturers
will be able to enter a body recipe and it will
generate a data sheet, hoping to have this working
by spring.
-------8<--------
Ron Roy wrote:
By the way - every clay company must - by law - give an analysis of every
clay body they sell - and every material and every glaze - some refuse to
do it but they just need a couple of shoves.
RR
Ron,
Is that just in Canada? I checked the Standard Clay MSDS\'s and they do not give an analysis -- as we have said before on Clayart, the MSDS info is largely worthless, along the lines of clay is dusty. Anyway, I called Standard and asked if it is possible to obtain an analysis of their bodies and the woman I spoke with said No, they are only required to provide the MSDS and they don\'t provide an analysis. Is that contrary to what you think is required in the US? Does Tucker\'s provide a chemical analysis of their clay bodies?
Thanks, Holly
-------
You can update your personal and affiliation info on our website:
http://digitalfire.com/services/register.php?password=pertatup
===============
Tony Hansen, http://digitalfire.com
Personal Contact Page: http://digitalfire.com/services/contact.php?pwd=pertatup
Calculation/Database Software for Ceramic Industry
Alex Solla on wed 29 oct 03
WOW. Tony I had no idea. This is mighty nice. Seriously nice. Alright... let's see the other clay manufacturers ante up on this one. Tucker's should be able to do the same pretty easily. C'mon! This would really save me a lot of trial and error time in terms of my crazing remedies etc. It would have also saved me HOURS of testing when I was messing around with new stains and getting crap results. Talc in claybody can sure mess things up. Helps with vitrification, but boy does it play havoc with purples and reds! Live and learn.
Thanks Tony for laying it all out there, clear as day.
Mighty nice.
Alexander Solla
Cold Springs Studio
4088 Cold Springs Road
Trumansburg, NY 14886
Tony Hansen wrote:
I look after the bodies at Plainsman Clays and there
is a detailed data sheet with analysis on each one,
we have had this since around 1996. I have never seen
data sheets by any other manufacturer with the detail
that these ones have. Here is an example:
http://digitalfire.com/plainsman/data/m340.htm
At our new
ceramicmaterials.info website body manufacturers
will be able to enter a body recipe and it will
generate a data sheet, hoping to have this working
by spring.
-------8<--------
Ron Roy wrote:
By the way - every clay company must - by law - give an analysis of every
clay body they sell - and every material and every glaze - some refuse to
do it but they just need a couple of shoves.
RR
Ron,
Is that just in Canada? I checked the Standard Clay MSDS\'s and they do not give an analysis -- as we have said before on Clayart, the MSDS info is largely worthless, along the lines of clay is dusty. Anyway, I called Standard and asked if it is possible to obtain an analysis of their bodies and the woman I spoke with said No, they are only required to provide the MSDS and they don\'t provide an analysis. Is that contrary to what you think is required in the US? Does Tucker\'s provide a chemical analysis of their clay bodies?
Thanks, Holly
-------
You can update your personal and affiliation info on our website:
http://digitalfire.com/services/register.php?password=pertatup
===============
Tony Hansen, http://digitalfire.com
Personal Contact Page: http://digitalfire.com/services/contact.php?pwd=pertatup
Calculation/Database Software for Ceramic Industry
______________________________________________________________________________
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!?
Exclusive Video Premiere - Britney Spears
Mert & Holly Kilpatrick on wed 29 oct 03
I agree with Alex, this is fantastic information. But we don't have
Plainsman Clays here in Pennsylvania! But we can get Tucker's. I looked on
Tucker's website, but don't see any analyses. We haven't heard back from
Ron on this thread, he must be busy. I am hoping to hear that they also
supply the chemical analysis.
Holly
East Bangor, PA
----- Original Message -----
From: "Alex Solla"
Sent: Wednesday, October 29, 2003 4:13 PM
Subject: Re: Clay Body/Glaze fit, by Design
> WOW. Tony I had no idea. This is mighty nice. Seriously nice. Alright...
let's see the other clay manufacturers ante up on this one. >
> Tony Hansen wrote:
> I look after the bodies at Plainsman Clays and there
> is a detailed data sheet with analysis on each one,
> we have had this since around 1996. I have never seen
> data sheets by any other manufacturer with the detail
> that these ones have. Here is an example:
>
> http://digitalfire.com/plainsman/data/m340.htm
>
> At our new
> ceramicmaterials.info website body manufacturers
> will be able to enter a body recipe and it will
> generate a data sheet, hoping to have this working
> by spring.
>
Ron Roy on thu 30 oct 03
Sorry to be so late with this - got way behind - again.
I've done some research on the subject so that took some time as well.
First of all I look after the clays at Tuckers - and they publish the
analyses of all the clays they make - and all the glazes - it is the law
here in Canada.
A phone call to Tuckers will get you the MSDS sheets you need - it is the law.
MSDS are useful in that they must warn about any toxicity - manganese for
instance - and any carcinogens, flammability, corrosiveness etc. The saying
" what you don't know won't hurt you" does not seem at all appropriate any
more.
I do all the numbers - simply have them in my calculation program and can
see the % analysis.
I have also been reading Monona's book - the section on MSDS (material
safety data sheets) and it does not seem to be required down there - to
list the analysis - but here is what Monona says about that "the percentage
of each ingredient in products that are mixtures is optional, but
responsible manufactures supply them."
Interesting item on the news tonight - seems some people - Europe some
where - are beginning to get interested in which chemicals we are all
exposed to are harmful - the chemical manufactures are saying none of
course and don't want anybody investigating.
RR
>By the way - every clay company must - by law - give an analysis of every
>clay body they sell - and every material and every glaze - some refuse to
>do it but they just need a couple of shoves.
>RR
>
>Ron,
>Is that just in Canada? I checked the Standard Clay MSDS's and they do
>not give an analysis -- as we have said before on Clayart, the MSDS info
>is largely worthless, along the lines of clay is dusty. Anyway, I called
>Standard and asked if it is possible to obtain an analysis of their bodies
>and the woman I spoke with said No, they are only required to provide the
>MSDS and they don't provide an analysis. Is that contrary to what you
>think is required in the US? Does Tucker's provide a chemical analysis of
>their clay bodies?
>
>Thanks, Holly
>
>______________________________________________________________________________
>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
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Tony Hansen on thu 30 oct 03
Actually we started in the 70s publishing complete
body information at Plainsman on paper sheets.
We moved them to the internet in 1996.
Also, I believe that the chemistry of a body is not
nearly as important knowing its physical properties
(unless you are comparing two very similar bodies).
If a body has 70% silica, for example,
how much of that exists as silica sand?
as feldspar? as kaolin? as talc? All these materials
contribute silicon dioxide and some or none may
actually melt. But these silica contributing materials
impart profoundly different properties to the body.
Thus two bodies of similar chemistry can be completely
different in firing. So I guess the questions is:
How valuable is knowing the chemistry of a body
unless you are smart enough to rationalize it in terms
of the recipe and what you know about that type
of body? I guess it is valuable in comparing similar
types of bodies.
At Plainsman in the late 70s we had graphs of fired
shrinkage and porosity at about 6 temperatures for
each body and a graph for sieve anlaysis. We also
had fired strength, dry strength, dry shrinkage,
pyroplastic deformation all published on data sheets.
We have 25 years of product testing data in our
computer using my FORESIGHT software with a couple
hundred thousand measurements. We have developed
specifications for all the bodies and can compare
body to body and body to specification. We have
storage racks with probably around 30,000 shrinkage
porosity test bars alone all location indexed in
the computer. And the glazes tests. Other tests.
Yikes.
------8<----------
Looks like the KIWI\'s Have first here. I used a clay from New Zealand in
the 1970\'s
from Nelson ( GB 2) , and they supplied analysis of all their clays.
John
Tony Hansen wrote:
>I look after the bodies at Plainsman Clays and there
>is a detailed data sheet with analysis on each one,
>we have had this since around 1996. I have never seen
>data sheets by any other manufacturer with the detail
>that these ones have. Here is an example:
>
>http://digitalfire.com/plainsman/data/m340.htm
>
>At our new
>ceramicmaterials.info website body manufacturers
>will be able to enter a body recipe and it will
>generate a data sheet, hoping to have this working
>by spring.
>
>-------8<--------
>Ron Roy wrote:
>
>By the way - every clay company must - by law - give an analysis of every
>clay body they sell - and every material and every glaze - some refuse to
>do it but they just need a couple of shoves.
>RR
>
>Ron,
>Is that just in Canada? I checked the Standard Clay MSDS\'s and they do not give an analysis -- as we have said before on Clayart, the MSDS info is largely worthless, along the lines of clay is dusty. Anyway, I called Standard and asked if it is possible to obtain an analysis of their bodies and the woman I spoke with said No, they are only required to provide the MSDS and they don\'t provide an analysis. Is that contrary to what you think is required in the US? Does Tucker\'s provide a chemical analysis of their clay bodies?
>
>Thanks, Holly
>
>-------
>You can update your personal and affiliation info on our website:
>http://digitalfire.com/services/register.php?password=pertatup
>===============
>Tony Hansen, http://digitalfire.com
>Personal Contact Page: http://digitalfire.com/services/contact.php?pwd=pertatup
>Calculation/Database Software for Ceramic Industry
>
>______________________________________________________________________________
>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.
>
>
>
--
John Dellow \"the flower pot man\"
Home Page http://www.welcome.to/jkdellow
http://digitalfire.com/education/people/dellow/
-------
You can update your personal and affiliation info on our website:
http://digitalfire.com/services/register.php?password=dugbedec
===============
Tony Hansen, http://digitalfire.com
Personal Contact Page: http://digitalfire.com/services/contact.php?pwd=dugbedec
Calculation/Database Software for Ceramic Industry
David Beumee on thu 30 oct 03
> I look after the bodies at Plainsman Clays and there
> is a detailed data sheet with analysis on each one,
> we have had this since around 1996. I have never seen
> data sheets by any other manufacturer with the detail
> that these ones have. Here is an example:
Well done Tony. Lots of good info on M340. Keep up the good work.
David Beumee
Earth Alchemy Pottery
Lafayette, CO
> I look after the bodies at Plainsman Clays and there
> is a detailed data sheet with analysis on each one,
> we have had this since around 1996. I have never seen
> data sheets by any other manufacturer with the detail
> that these ones have. Here is an example:
>
> http://digitalfire.com/plainsman/data/m340.htm
>
> At our new
> ceramicmaterials.info website body manufacturers
> will be able to enter a body recipe and it will
> generate a data sheet, hoping to have this working
> by spring.
>
> -------8<--------
> Ron Roy wrote:
>
> By the way - every clay company must - by law - give an analysis of every
> clay body they sell - and every material and every glaze - some refuse to
> do it but they just need a couple of shoves.
> RR
>
> Ron,
> Is that just in Canada? I checked the Standard Clay MSDS\'s and they do not
> give an analysis -- as we have said before on Clayart, the MSDS info is largely
> worthless, along the lines of clay is dusty. Anyway, I called Standard and
> asked if it is possible to obtain an analysis of their bodies and the woman I
> spoke with said No, they are only required to provide the MSDS and they don\'t
> provide an analysis. Is that contrary to what you think is required in the US?
> Does Tucker\'s provide a chemical analysis of their clay bodies?
>
> Thanks, Holly
>
> -------
> You can update your personal and affiliation info on our website:
> http://digitalfire.com/services/register.php?password=pertatup
> ===============
> Tony Hansen, http://digitalfire.com
> Personal Contact Page: http://digitalfire.com/services/contact.php?pwd=pertatup
> Calculation/Database Software for Ceramic Industry
>
> ______________________________________________________________________________
> 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 fri 31 oct 03
Hi Linda,
As it turns out - US companies don't have to give the analysis - but that
does not mean you can't ask for it - it an easy job to supply the analysis
if they use calculation software.
It is a simple list of the oxides in any mixture - adding up tp 100 like -
SiO2 - 72.0
Al2O3 - 23.0
Fe2O3 - 2.0
TiO2 - 1.2
CaO - 0.5
MgO - 0.3
K2O - 1.0
If it's an actual raw caly analysis - like from a mine it will kave a Loss
on Ignition amount included in the amounts that total 100.
There is no reason for any company to not give out that kind of information
- as Tony says - much depends on the working properties of the clays used
in a body - the chemical composition is only a small part of the story.
RR
>Per RR:
>By the way - every clay company must - by law - give an analysis of every
>clay body they sell - and every material and every glaze - some refuse to
>do it but they just need a couple of shoves.
>______________
>Ron, since you're talking law, we'll do the shoving! Would you define the
>elements of that "analysis"? Just what do they have to tell us about the
>clay body? Thanks,
>Linda
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on fri 31 oct 03
Hi Alexander,
Yes - the analysis would show any MgO - there is always some by the way -
if there is more than a little it can come from Talc or Dolomite.
It is useful information - the Candaian version of the MSDS sheet also
demand information on odors - so you can tell if there is a smell
asscociated with the material - useful safely imformation.
Tuckers does include an analysis on the MSDS by the way - I know cause I'm
the one who works it out.
RR
>WOW. Tony I had no idea. This is mighty nice. Seriously nice. Alright...
>let's see the other clay manufacturers ante up on this one. Tucker's
>should be able to do the same pretty easily. C'mon! This would really save
>me a lot of trial and error time in terms of my crazing remedies etc. It
>would have also saved me HOURS of testing when I was messing around with
>new stains and getting crap results. Talc in claybody can sure mess things
>up. Helps with vitrification, but boy does it play havoc with purples and
>reds! Live and learn.
>
>Thanks Tony for laying it all out there, clear as day.
>Mighty nice.
>
>Alexander Solla
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
David Hewitt on fri 31 oct 03
Ron,
In message , Ron Roy writes
>First of all I look after the clays at Tuckers - and they publish the
>analyses of all the clays they make - and all the glazes - it is the law
>here in Canada.
I think that the Tucker's data sheets are excellent and I have tried to
encourage UK potters to press for UK suppliers to give similar
information.
When you say it is the law in Canada, does this also prescribe the
degree of information that is supplied? For example, when recently
asking for data on colouring oxides the information came back in the
following form:-
Iron oxide black
Fe2O3 >70.00%
Iron oxide natural
Fe2O3 >75.00%
SiO2 <13.00%
Al2O3 <3.00%
MnO <1.00%
Cobalt oxide
Co 72.00%
Cu 0.01%
Fe 0.01%
Mn 0.01%
Zn 0.01%
Ni 0.02%
These are just examples which leave you wondering what the balance might
be.
Is this what you would get in Canada?
>
>
>Ron Roy
>RR#4
>15084 Little Lake Road
>Brighton, Ontario
>Canada
>K0K 1H0
>Phone: 613-475-9544
>Fax: 613-475-3513
--
David Hewitt
David Hewitt Pottery
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ.
Tel:- +44 (0) 1633 420647
Fax:- +44 (0) 870 1617274
Web:- http://www.dhpot.demon.co.uk
Ron Roy on sun 2 nov 03
Hi David,
Good to hear from you!
I guess the obvious answer is - not if they are done by me.
I am not surprised - most suppliers are not exactly on the ball when it
comes to this sort of thing. Seems there was no reason to be technically
aware up until recently.
The situation is appalling from where I stand and it does not seem to be
getting much better with any degree of speed.
The problem - as far as I can see it - there are not many around who they
can hire to do the work for them and they obviously see the task as
meddling in their business - so no compelling reason to do it right.
Potters - most of them - are not going to spot this sort of thing anyway -
never mind make a fuss.
Then there is the even bigger problem of having to admit you don't know
what you are talking about - after all those years of pretending that you
do.
I'm not sure about the degree of information - most probably are just as
happy to fill in with whatever they can find that looks right - does any
body check it out? I don't think so - unless something goes wrong. I wonder
if they ever think of that eventuality.
RR
>In message , Ron Roy writes
>
>>First of all I look after the clays at Tuckers - and they publish the
>>analyses of all the clays they make - and all the glazes - it is the law
>>here in Canada.
>I think that the Tucker's data sheets are excellent and I have tried to
>encourage UK potters to press for UK suppliers to give similar
>information.
>When you say it is the law in Canada, does this also prescribe the
>degree of information that is supplied? For example, when recently
>asking for data on colouring oxides the information came back in the
>following form:-
>
>Iron oxide black
> Fe2O3 >70.00%
>
>Iron oxide natural
> Fe2O3 >75.00%
> SiO2 <13.00%
> Al2O3 <3.00%
> MnO <1.00%
>
>Cobalt oxide
> Co 72.00%
> Cu 0.01%
> Fe 0.01%
> Mn 0.01%
> Zn 0.01%
> Ni 0.02%
>
>These are just examples which leave you wondering what the balance might
>be.
>
>Is this what you would get in Canada?
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
| |
|
