Zoe Paddy Johnson on tue 9 sep 03
I have completed my second rock glaze. The first glaze, made from crumbled
Sandia Granite and ash, made a pale olive green transparent glaze, with
some crawling problems. It looks sort of like snot. The second glaze,
made from kiln popped obsidian and wood ash, made a darker green
transparent glaze, with less crawling problems. It looks like a lot like
snot. I have managed to almost wear out my $40 harbor freight rock
tumbler, so this is not cheap glaze, but the process has been fun. I have
also had fun heating cups of rocks up in the kiln to "calcine" them, which
seems to make most rocks more friable, but also causes interesting color
and texture changes. In the process I have learned the following:
1. Snot green is not necessarily an attractive color.
2. I need to be more scientific about the process.
3. When making ash in the barbecue from maple twigs, don't leave the
cooling ash out for the goose to investigate, unless one, wants a totally
black goose (the goose was not injured, he is just very dirty).
4. The cheap rock tumbler from harbor freight is not necessarily a good
deal, and at best one should wait until they are on sale for $19 just
before Christmas (advice from a salesman) .
5. The closure system for barrels on the harbor freight tumbler is superior
to the system on thumler's tumblers if you are a woman with small hands.
To that end, I have a different tumbler, and am grinding up 3 mixtures
currently. This will be blended much more carefully. They are:
1. Fault gouge from the San Andres Fault near Indio, mostly decomposed
granite with heavy iron staining
2. Beach sand from Santa Barbara and red marbles.
3. Petrified wood carefully selected from the gravel in a parking lot.
I am planning on doing blends with the rest of the wood ash, and/or using
different ingredients to balance the glazes. Sheesh, this glaze is hard
stuff to learn.
Some questions: Is the snot green due to the ash? or iron in the rock? Can
I add oxides to color it?
ZoeJ
Ababi on wed 10 sep 03
I believe the green is because of the iron in the rock.
Why not say waxy like? This way I will not for my Kleenex while reading
your letter!
If it is not a secret recipe, please add it we can estimate the analysis
and help you repair the glaze.
I want to offer you a low cost book that can assist you.
A Potter's Geology: Clay and Glazes From Natural Materials By Row
http://digitalfire.com/books/517.php
Keep digging - you might find gold!
Ababi Sharon
Glaze addict
Kibbutz Shoval Israel
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910
http://www.matrix2000.co.nz/Matrix%20Demo/Ababi.htm
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Zoe Paddy
Johnson
Sent: Tuesday, September 09, 2003 6:03 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Rock Glaze Experiments
I have completed my second rock glaze.
| |
|
