[Clayart] phosphorus

Michelle Joseph michellejoseph256 at hotmail.com
Wed Aug 7 00:35:48 EDT 2019

Hi Carol,

Thank you so much for the update...
still working on this iron red down fire.

Ran a full load at the end of the spring 2019 semester using your protocol...
the results were mixed.

These are my conclusions:

  *   Though the kiln was kept in oxidation through the whole firing the reds were somewhat muddied; do not believe a fuel firing will ever produce the heavy oxidation of an electric firing.
  *   Got a fair amount of crystals, enough to give the work a "look-good-feel"; meaning the glaze did not look like a Kohler toilet bowl... a good thing, but not the targeted quality.
  *   I was getting good to very good results in my glaze exploration when I fired everything in saggars; but received a lot of grief over their use. After this firing, I am convinced that their use is a needed addition to what I am looking for, with the exception of a very controlled electric firing [and that is only an assumption].
  *   They [BSU] has invested in a new multi-million dollar art building and must have invested a huge amount in new equipment, e.g., $175,000 for an OSHA approved burn out kiln for the sculpture department for lost wax casting. The point being, the new electric kilns should fire to ∆10 without faulting out. We tried twice to get the Skutts to fire using your protocol and both times they threw an error message. Will be trying again this fall.
  *   Until the firings are on mark, it is best to continue using the well known "Tomato Red" formula. This is so complex, having multiple variables may not be a good thing.

As a side note:

I will be headed to Table Mountain in Southern Oregon shortly to pick up some raw Nepheline Syenite. Hopefully it will provide a "back bone" for my glaze research into natural glazes. The feldspar [flux] is the one mineral that is so hard to locate; hopefully it will provide what is needed.

I have tried several different volcanic ashes, with inconsistent results. The best was a one off firing of some volcanic ash from that massive deposit just north of Lake Havasu City in Arizona; it was a beautiful blue-green celadon [nothing added]. Have tried multiple times to repeat the results, but it was not to be. It may be that with the new kilns and saggars, better results may be possible.

I want more than natural glazes based on wood ash; my professor, though supportive, was not very encouraging... she thinks it might not be possible create glazes based completely on found minerals... we will see. I will let you know how it turns out.

David [Michelle] Joseph

From: Clayart <clayart-bounces at lists.clayartworld.com> on behalf of carol at knighten.org <carol at knighten.org>
Sent: Tuesday, August 6, 2019 11:36 AM
To: clayart at lists.clayartworld.com <clayart at lists.clayartworld.com>
Subject: [Clayart] phosphorus


The same glaze with and without phosphorus:



    Carol Marians
    (541) 296-4528
  carol at knighten.org

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