[Clayart] discussion topics
gerholdclay at gmail.com
Thu Jan 9 04:53:39 EST 2020
Holding a firing at max temp is effectively just firing at a higher cone. Nothing wrong with doing it. Any time you are working on developing a new glaze you should fire at different cones and with or without holds or down firing till you find out what suits your aesthetic.
Just did a test where the piece was elevated on a clay disc and deliberately fired to run the glazes. End result a vase that is sitting on glaze feet about a half inch above the table. Just wonderful. Going to fire a kiln load to see if this can have a reasonable success rate.
> On Jan 8, 2020, at 5:35 PM, mel jacobson <melpots at mail.com> wrote:
> my new adult student has been working on cone 6, mel6 and our glazes.
> she had a firing and a commercial rutile blue glaze ran right off
> the pot onto her kiln shelf. obviously she was puzzled, she also
> has some crazy pin holing in that glaze.
> in discussing the problem she mentioned to me that she has
> programmed a hold at cone 6 for something over 30 minutes.
> i told her not to hold at temp. no need. that is old wives tales
> and in a program kiln who knows if the temp does not rise during the hold.
> hit the mark, turn off the kiln. down fire should be at 1900F. and, who
> knows if you need down firing? (we all know what carol is doing with
> high iron glazes...and most of you know that i fired hare's fur at cone 12
> with a down fire. in many cases i turned pots into bright metallic gold.)
> but, i was firing all my hare's fur, partridge feather and oil spot glazes
> in oxy atmosphere, or only slightly neutral. no reduction. high iron clay, and
> high iron glazes. they look like they come from a fuel, reduction kiln...as in
> look like..but not. that is the key to hare's fur. fired in saggers in a wood
> fired, very hot kiln. no kiln shelves at all. 400 pots fired in a chamber.
> the pots were snug in a neutral atmosphere, in a really wild wood fired reduction
> kiln. i have never seen puke green in my firings. clean atmosphere in the kiln.
> (many of us saw puke green in that old temmoku recipe of the late 60's. and remember
> folks turned the world full of smoke from over reduction..we all did it. not now.
> over reduction is a scourge.)
> i am convinced that there is a reaction with that high rutile content
> glaze sort of boiling at the clay surface. high iron clay, high iron
> glaze. (and i think some titanium) they may not be compatible, or make the bubbles and pin holes part
> of the aesthetic. make the so called flaw a new signature glaze.
> we did that with colleen and the boiling shino. now we do not get the
> boil...it is back to lovely orange and black basic shino. it may be as
> simple as a dead mouse rotten in the shino. who knew? i think it was too
> much table salt.
> i would love to have others join in on this topic...especially about holding
> at temp...i would like to ban it. only bad things happen.
> that is one reason i always fire a new glaze to one cone hotter. i want to see
> what happens.
> i fired two bowls with mel6 and our five equal amounts of glaze materials to cone
> 12 last month. they looked great...they still had a ring...but, man, that is pushin
> to the limit. how does one know, unless you try to test to limit?
> (thanks paul, you know how to push limits too...and we appreciate it. and, if we
> can make our dear woofey jump...that is fun. by the way folks, i have known david
> woof since he was a baby wolf. you cannot find a kinder better person to sit and have
> a beer with. like paul, he loves controversy like air itself. they make clayart rich.)
> website: www.melpots.com
More information about the Clayart