lrh on thu 26 sep 96
9/25/96
Help... At my request, a "former" friend of mine, on a trip west,
lugged back a full gallon of Mt. St. Helens ash after she blew
her top. I promised her a pot using the ash in the glaze, but
havent found a recipt that spacifically calls for "volcanic ash".
So that my friend can stop blowing her top, does anyone have a
suggestion about how to use this material in a glaze? (Any cone
will do, but 10 would be best).
Loran
lrh@DeltaFaucet@CCMGATE
art_selsor@vino.emcmt.edu on thu 26 sep 96
Pullman Washington had a conference after Mt St. Helen's blew. I picked
up several hundred pounds. At Pullman they distributed a sheet of
glaze recipes mostly ^10. Some were pretty nice. I can send them
if that is the temp. you are interested in.
Marcia in Montana
mjbmls@imt.net
Andrew S Lubow on thu 26 sep 96
Here's one from my notebook that's untested. I couldn't find the Lincoln
Clay in my area.
Lincoln Clay 30.3%
Custer Spar 25%
Dolmite 18.4%
Volcanic Ash 10%
Gerstly Borate 5.3%
Flint 4.7%
Bone Ash 3%
Opax 3.3%
Plus: Bentonite 1%
On Thu, 26 Sep 1996 08:03:48 EDT lrh writes:
>----------------------------Original
>message----------------------------
>
> 9/25/96
>
> Help... At my request, a "former" friend of mine, on a trip west,
> lugged back a full gallon of Mt. St. Helens ash after she blew
> her top. I promised her a pot using the ash in the glaze, but
> havent found a recipt that spacifically calls for "volcanic ash".
>
> So that my friend can stop blowing her top, does anyone have a
> suggestion about how to use this material in a glaze? (Any cone
> will do, but 10 would be best).
>
> Loran
> lrh@DeltaFaucet@CCMGATE
>
Mike McKim on thu 26 sep 96
At 08:03 AM 9/26/96 EDT, you wrote:
>----------------------------Original message----------------------------
>
> 9/25/96
>
> Help... At my request, a "former" friend of mine, on a trip west,
> lugged back a full gallon of Mt. St. Helens ash after she blew
> her top. I promised her a pot using the ash in the glaze, but
> havent found a recipt that spacifically calls for "volcanic ash".
>
> So that my friend can stop blowing her top, does anyone have a
> suggestion about how to use this material in a glaze? (Any cone
> will do, but 10 would be best).
>
> Loran
> lrh@DeltaFaucet@CCMGATE
>
Volcanic ash probably will not work as a glaze because chemically it is more
like clay than the sodium, potassium and calcium oxides in the traditional
organic material ash source. A simple test to perform to determine if it has
a high potassium or sodium oxide content is if it dissolves to any extent in
water.
Mike McKim on thu 26 sep 96
At 08:03 AM 9/26/96 EDT, you wrote:
>----------------------------Original message----------------------------
>
> 9/25/96
>
> Help... At my request, a "former" friend of mine, on a trip west,
> lugged back a full gallon of Mt. St. Helens ash after she blew
> her top. I promised her a pot using the ash in the glaze, but
> havent found a recipt that spacifically calls for "volcanic ash".
>
> So that my friend can stop blowing her top, does anyone have a
> suggestion about how to use this material in a glaze? (Any cone
> will do, but 10 would be best).
>
> Loran
> lrh@DeltaFaucet@CCMGATE
>
I found this information on the composition of typical volcanic
material,perhaps it will help.
Chemical composition of lavas remained almost
constant (around 65 wt. % SiO2; Miyahara et al., 1993; Nakada and Fujii,
1993; Chen et al.,
1993) during the activity. Lavas contain 20-30 vol. % of phenocrysts
(plagioclase, hornblende,
biotite, and quartz) (Miyahara et al., 1992; Nakada and Fujii, 1993). The
mineralogical data,
however, showed successive mixing of felsic magma with mafic or intermediate
magma before or
during extrusion.
The table below can be found at this web site.
http://volcano.und.nodak.edu/vwdocs/vwlessons/rocks.html
Table 2. Common minerals in volcanic rocks.
________________________________________________________________________
Light-colored minerals (formula) Dark-colored minerals (formula)
________________________________________________________________________
Feldspar: Olivine (Mg,Fe)2SiO4
Plagioclase (Ca,Na)AlSi3O8 Pyroxene:
Orthoclase KAlSiO8 Hypersthene Mg,Fe)SiO3
Anorthoclase (K,Na)AlSi3O8 Pigeonite (Mg,Fe)SiO3
Quartz SiO2 Augite
Ca(Mg,Fe)Si2O6(Al,Fe)2O3
Nepheline NaAlSiO4 Biotite K(Mg,Fe)3AlSi3O10(OH)2
Magnetite Fe3O4
Hematite Fe2O3
________________________________________________________________________
Mike
June Perry on fri 27 sep 96
Dear Andrew:
Lincoln is a plastic fireclay that is available on the west coast. You would
probably be fine substituting whatever fireclays are available in your area.
Regards,
June
Tom Gray on fri 27 sep 96
lrh wrote:
>
> ----------------------------Original message----------------------------
>
> 9/25/96
>
> Help... At my request, a "former" friend of mine, on a trip west,
> lugged back a full gallon of Mt. St. Helens ash after she blew
> her top. I promised her a pot using the ash in the glaze, but
> havent found a recipt that spacifically calls for "volcanic ash".
>
> So that my friend can stop blowing her top, does anyone have a
> suggestion about how to use this material in a glaze? (Any cone
> will do, but 10 would be best).
>
> Loran
> lrh@DeltaFaucet@CCMGATE
Try this glaze out of an old ceramics monthly.
Volcanic ash---40
epk------------30
dolomite-------30
fires to cone 10. I have used this glaze in the past-has a very narrow
firing range-but nice color and texture when you nail it. Similar to
mamo white.
Tom Gray
Seagrove, NC
http://www.cclay.com
WHampton@aol.com on fri 27 sep 96
Hi,
The following is a Mt. St. Helens ash glaze from the Seattle area.
Mt St Helens Almond
Makes 1 gal - ^6 ox
Custar Spar 800g
Zinc Oxide 172g
Whiting 298g
EPK 236g
Flint 94g
Rutile 160g
St. Helens Ash 400g
----------
Mt. St. Helens Blue
^6 ox. Makes 3 gal.
Custar Spar 1988g
Flint 268.6g
Whiting 706.8g
EPK 580.8g
Zinc Oxide 410.4g
Dolomite 22.2g
Colmanite 44.4g
St. Helens Ash 1000g
Total 5000 g
Cobalt Oxide 5g
--------
Tamaras Blue
^6 ox Makes 1 gal.
Custar Spar 780g
Silica 180g
EPK 140g
Whiting 340g
Zinc Oxide 160g
St. Helens Ash 400g
Cobalt Oxide 30g
Good luck!
Wendy from Bainbridge Island WA
Marcia Selsor on fri 27 sep 96
These are from Robin Reynolds and Michael McDowell, Bellingham WA.
distributed in 1980 or so in Pullman WA. where Garth Clark, Bill Daley,
Rudy Autio gave a panel discussion, and an aside topic was volcanic ash.
All are for ^10-11
#1 Mt St Helen's Base
99% Ash
1% Bentonite
#2 Matte Black
91% Ash
3% Manganese Dioxide
3% Red Iron Oxide
1% Cobalt Oxide
2% Bentonite
#3 Cinnamon
87% Ash
12% Ultrox
1% Bentonite
#4 Oil Spot Gloss (I fired this with my oil burners, it was beautiful)
89% Ash
8.7% Zinc
1.3% Titanium
1% Bentonite
#5 Ochre Matte
85.5% Adh
12.5
12.5DELETE this mistake
#5 Ochre Matte
85.5% Ash
12.5% Titanium
2% Bentonite
#6 Dark Red Semi-matte
92% Ash
6% Red Iron Oxide
2 % Bentonite (I'd call this one a "plum" color)
#7 Rust Semi-matte
92% Ash
4% Rutile
2% Tin Oxide
2% Bentonite
#8 Green Gloss w/ Gold Specks
*6% Ash
start over
86% Ash
10% Zinc
0.3% Titanium
2% Bentonite
#9 Gold Brown Gloss
456.7 grams Ash
6.65 grams Zinc Oxide
26.65 grams Titanium
10.00 grams Bentonite
Sorry for the typo's. I can't erase on my Vax account email. Had to
do this from my office where my glaze notebooks were.
The Pullman Conference was a nice little event. It featured the
American Potter Exhibition that Garth Clark curated (16 years ago)
I took two vehicles of students and we sewpt up ash in a
parking lot on the Coure 'd lane Indian reservation (they were
pleased to see it go) Still have several boxes of ash.
Our ash was fairly light and refined. Literally "air floated"
for several hundred miles. In central Montana we only had a trace of ash
but very fine.
Best wishes
Marcia in Montana
PJLewing@aol.com on fri 27 sep 96
Loran,
Here's more than you ever wanted to know about Mt. St. Helens ash. Like
every other Washington potter, I have buckets of the stuff, and have worked
with it at both ^10 reduction and ^5 oxidation.
First of all, there is no formula for "volcanoc ash". What spews out of a
volcano as powder is whatever mineral happens to be beneath that volcanic
vent at the time it erupts. So the ash from one volcano is not necessarily
the same as another's ash. And different eruptions from the same vent can be
different. Then it makes a difference where the material was collected.
Lighter, finer particles will travel farther on the wind than heavy coarse
particles. Totally aside from chemical composition, this can make a
difference in a glaze. The May 18, 1980 eruption of Mt. St. Helens put out
stuff the size of golf balls near the mountain, and stuff the size of cake
flour in Missoula, Montana.
What is usually sold in ceramic supply houses as volcanic ash is from Mt.
Etna.
According to the September 1980 issue of Science Magazine, the mineral spewed
out by MSH was dacite. They list chemical composition from 9 locations
around eastern Washington and western Montana. I have used ash from both
Ellensburg and Spokane, and they are noticably different, but I'll give you
their average formula just for simplicity. It's what I've used to calculate
glazes with Insight.
CaO 4.89%; MgO 2.19%; K2O 1.45%; Na2O 4.52%; Fe2O3 4.76%; MnO .08%;
TiO2 .68%; P2O5 .37%; Al2O3 16.73%; SiO2 64.33%.
Insight calculates this to be, as a unity formula:
CaO .38; MgO .24; K2O .07; Na2O .32; Fe2O3 .13; MnO .00; TiO .04; P2O5
..01; Al2O3 .71; SiO2 4.66.
Al/Si Ratio is 6.53, Expansion is 7.02, Weight is 535.11.
There are also traces of 23 other elements, most notably S (up to 1400 ppm),
Cl, Sr, and Zr.
So what the hell does that mean? It means that you've got a ^10 glaze here,
but way too much alumina and silica for a ^6 glaze.
You can try mixing this stuff up with water like any other glaze, but it will
settle hard in seconds. You need to add some bentonite or other suspenders,
and then it will fire to ^10 to a speckly black/brown/rust glossy surface.
It might work better as an addition to another glaze, in which it will act
like ilmenite, only with more variety.
At ^6, it's a little more problematic, since what you really want to add for
workability is clay, and that's exactly what it doesn't need chemically. The
best base I've come up with so far is this:
Mt St H Ash 68
Frit 3134 23
Bone Ash 4.5
EPK 4.5
Bentonite 3
This will be a pale greenish grey clear with lots of varied speckles in it,
not particularly attractive, but a nice surface, and good fit. It makes a
better base with additions of zircopax (a paler version of the base), tin
(nice orange blushes), or titanium (nice crystals). Then you can try
coloring it.
If none of this works, give the stuff to a glassblower. It works great for
them.
And now a report on the mountain herself. Permanent snowfields, the
beginnings of new glaciers, have started to form on the upper slopes, and a
new cinder cone is forming inside the crater. It's about 1500 feet high now.
She still rumbles and puffs steam occasionally, but Rainier, 30 miles or so
to the north, is more active. In the blast zone, ferns and lupine started
the first year, and there are good-sized Douglas fir trees now. In the Goat
Rocks Wilderness, the first high ridge east of MSH, there was 6-8 inches of
ash laid on the meadows. Lupine was one of the first things to recolonize,
and it got a few years head start. Now there's so much lupine at Snowgrass
Flats the smell will make you dizzy. You can still see traces of ash in
eastern Washington, as far east as the tree line over by Spokane, and you can
still see where the ash sifted down the draws in the Columbia River gorge at
Vantage.
Good luck with the ash.
Paul Lewing, Seattle
http://digitalfire.com/magic/lewing.htm
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