Mike on thu 4 apr 02
hi potters----i need recommendations for labatories that do relatively
inexpensive glaze analysises. i have two nearly empty buckets of mixed
unknown glazes that are worth the trouble to duplicate. one a lovely
rich temoku amber that breaks to a kaki and the other i think is a
copper-titanium green that reminds me of green-blue titbetian
turquoise. or if anyone has such glazes and is willing to share or
trade please let me know.. thankyou------mike norman
Paul Lewing on fri 5 apr 02
on 4/4/02 7:24 PM, Mike at mikenorman@UNIQUE-SOFTWARE.COM wrote:
> i need recommendations for labatories that do relatively
> inexpensive glaze analysises. i have two nearly empty buckets of mixed
> unknown glazes that are worth the trouble to duplicate.
Mike, you're not going to want to hear this, but it's probably not possible.
At least not in the sense that I think you mean. I think what you want is a
lab that will give you the recipe for those glazes. That's not going to
happen. It might be possible to get an analysis of the oxides present,
which you might then be able to convert to a recipe. But chances are that a
testing lab will give you an analysis in percentage-by-weight values, not
flux-unity values, as potters are used to seeing. Again, you might be able
to convert that percentage analysis to a flux unity formula and then back to
a recipe. But if you choose to make that formula up into a recipe and mix
that using a different set of ingredients than the original batch was
comprised of, it still could be way different.
My advice would be to choose one of two other courses. First, you could
come as close to this recipe as you can using the recipes you and your
friends have, and learn to adapt them till it approximates the old ones.
This will be much cheaper, teach you more, and probably have a better chance
of success than any testing lab data.
Or you could face the fact that glazes come and go. There are always more
new ones, and there are always going to be those batches of glaze that, when
seen years later, evoke a sigh and the response, "Ah, that was a great
glaze- sure wish I knew what it was".
I'm an ardent user of scrap glazes, and I see lovely effects just disappear
with every few bucketsful. Oh, well. Just make more tests.
Paul Lewing, Seattle
Martin Howard on sat 6 apr 02
In the UK go to CERAM Queens Road, Penkhull, Stoke-on-Trent ST4 7LQ
Tel +44 (0) 1782 76444
fax +44 (0) 1782 412331
e-mail info@ceram.co.uk
www.ceram.co.uk
Ask for a XRF UNQUANT SEMIQUANTITATIVE ANALYSIS
Cost around 35 English pounds.
They will need a small amount of the dried material. Check the amount with
them first.
If there is any lead in it, then the cost is higher, because of the effect
lead has on their equipment. Another good reason to pot leadless!
Martin Howard
Webbs Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
01371 850 423
martin@webbscottage.co.uk
http://www.webbscottage.co.uk
Updated 3rd March 2002
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