Richard Aerni on tue 1 apr 97
stevemills wrote:
>
> We are phasing out the use of rutile in a lot of our products and are not
> advising its use to our customers who want a consistant colour over time.
> It has proved to be a very inconsistant material with variations in
> concentration, colour production etc
>
Good noon day all,
I wanted to put forth a question to the group about rutile. I use quite
a bit of it in my glazes, for everything from rutile/chrome pinks to
cobalt greens to just spritzing up all the other colors in my
single-fired ash glazed pieces. I'd been using a rutile which I'd bought
almost ten years ago from Columbus Clay Co, in Ohio--had bought several
hundred pounds worth cuz it worked well and I wanted some quality control
in this most uncontrollable mineral. So now, time has come to get more
and I called Columbus Clay, told them my story, and ordered a couple
hundred pounds more. It comes, looks totally different, and turns all my
glazes really nasty. I've been ordering rutiles from all kinds of
ceramic supply houses, and testing to try to get something amenable to my
taste and expectations. So far no real luck.
I've been trying to research where in the world rutile comes from, and
who are the main suppliers, in hopes of tracking down my good stuff.
Seems that there used to be a big mine over in Sierra Leone which shut
down in 1995 due to political problems. There is a good possibility that
is where my old supply came from. Where it comes from now I'm not sure,
but I've got calls into TAM Ceramics in Niagara Falls, and Chem Alloy,
near Philadelphia, which I've been told are two of the major national
suppliers. My old (and sadly outdated) college mineralogy texts talk
about beach sands from Australia being the main source.
So I'm wondering if anyone else is having problems, and whether anyone
else has any info to share on rutile and its sources. I realize I
painted myself into a corner with my reliance on an unreliable material,
but that happens sometimes. Now I'm trying to find a way out without
having to change the look of my work entirely.
Any info would be gratefully received.
Richard Aerni
Bloomfield, NY rcaerni@servtech.com
COOPJ@aol.com on wed 2 apr 97
Hi Richard,
I haven't heard of any Rutile problems . I think Laguna used to get theirs
from TAM.
You may want to consider synthesising with Titanium and Iron oxide which are
the main oxides in Rutile.
Jim Cooper
Sylvia See on thu 3 apr 97
Hi Richard;
Since everyone in the whole world has gone to the NCECA thought I'd take
the opportunity to ask you for some advice about your glazes in the Dec94
issue of Ceramics Monthly. To start with I love your work and your glazes
are wonderful. So of course I wanted to try them. Problems: I use electric
kiln, in town, ash supply doubtful, so I decided to see what would happen
if I substituted volcanic ash for the wood ash. I did and although my
glazes are not yours, they were very hard with an orange peel effect if
sprayed on the pots. The basic ash glaze with vol.ash has been a standard
glaze for me for the past 3 years. However, alone it gives a cream color
which I am not too crazy about and with the mason stains I have tried, they
give almost an earth color. I would suspect something in the ash is
affecting the mason color. However over the top of the obsidian glaze, it
is wonderful. The leather, over the obsidian was not to bad, but terrible
under the base or alone, which I blamed on the electric firing and vol ash.
Never would have thought about the rutile, but now am wondering.
I also do alot of Raku and sawdust primitive firing in the summer as long
as my neighbors remain friendly. So far so good, but have new ones moving
in next to me this summer and things could change in a hurry. Very iffy
project in town. I have two sources of sawdust, one from a furniture
manufacturer which is very fine with assorted woods, and a shake factory,
very course green shaving sawdust, probably mostly pine, fir, and spruce. I
use two old electric kiln to sawdust fire in and I use vermiculate, red
salt and blue salt around the pots in the sawdust. I fill the kilns to the
top with pots and sawdust and it slowly burns down in about 3 days. That is
so far is my only source of ash.
Question: Do you think the ash from this primitive firing would be useable
as an ash glaze in an electric kiln? I have hesitated so far, as I am
concerned about the possiblity of salt in the ash fuming my bricks and
elements in my electric kiln. I thought I'd like to see what happens with a
little sifted wood ash sifted on top of the ash variation I'm currently
using (Vol. ash sub). I'd like to get the orange peel effect with the shiny
wood ash and runs at the top of the pieces. I've thought about just firing
a couple of loads of sawdust alone just to get the ash, but thought there
still would be salt in the firebicks of the kiln, don't know for sure. The
walls are not like they were glazed or coated, so it is hard to tell. I
can't think of another way to fire the sawdust in town without a ton of
smoke. The kilns burn so slowly, there is just a trickle of smoke and I
throw wet blankets over the kiln, which cuts the smoke even more. To die
for your setup. Ahh well, not to be stopped. All problems solved, one way
or tuther.
I will be following your thread on the rutile problem. Something I never
thought about. I just knew some recipes I liked and some were the pits. I
did however do some playing with crystalline glazes, substituting strontium
for barium, and less fluidity, so they may be used on fuctional pieces. I
didn't get the traditional crystals of crystalline glazes but I did get
some really neat hairs fur patterns on a wonderful silky smooth finish.
Really wonderful on the inside of bowls. I did a lot of tests with
different recipes, and substitutions using the same recipes with both
rutile and titanium. I did like the titanium tests alot better than the
rutile but never made the connection that the rutile may not be behaving as
it should. I just operated on a like this don't like that basis.
Sorry for the length of this post, but have wanted to ask this for weeks
now. The poor ol sun is trying hard to shine, and the Raku pots are
waiting. Back to working on my castles while we wait and wait and wait.
Sylvia See Claresholm, Alberta sylviac@telusplanet.net
I really like my bifocals
My dentures fit me fine
My hearing aid works perfect
But Lord I miss my mind!!!!
Barbara Webb on mon 7 apr 97
Sylvia,
Since you were using ash glazes, I thought I should share my little
secret. I live in Georgia so I rarely build a fire in the fireplace and
have no other place to get wood ash. There are Bar-b-que restaurants on
every corner and they cook on wood. They are more than happy to give the
ash away or point you towards their dumping sight. I have no idea what
kind of wood they use or how much pork grease affects the glaze, but my
glazes look pretty good, and an added benefit is that the whole valley
smells good when I fire!
Barbara Webb
barbara@fujikura.com
Marietta, GA USA
SLPBM@cc.usu.edu on mon 7 apr 97
Richard-
When I find a precocious material like rutile or gerstley borate or Albany,
I always try to get a good analysis from the supplier. It also helps if I can
find out who they purchased it from (what mine and where??)
In addition, I also try to find workable subs long before really running out.
IN the case of Rutile, try iron and titanium combinations. Should take much
and you may find it really does something "better" for your glazes.
Good luck and let us know.
Alex Solla
in Utah
slpbm@cc.usu.edu
Richard Aerni on thu 17 apr 97
Hi Jim,
I was just at a workshop in Wooster Ohio with 220 other potters, and
brought up the subject. Seems a lot of folks are noticing changes in
their glazes that depend on rutile to various effects, including Dick
Lehman, who developed one of the glazes I was using. His is doing the
same nasty things mine is. It's not that the rutile is bad, so much as
it is just different, and it's going to take some work to recalibrate my
glazes.
I'll keep you informed about my progress or lack thereof.
Thanks for the idea about the titanium and iron--it was something I was
going to try.
Richard
COOPJ@aol.com wrote:
>
> ----------------------------Original message----------------------------
> Hi Richard,
>
> I haven't heard of any Rutile problems . I think Laguna used to get theirs
> from TAM.
> You may want to consider synthesising with Titanium and Iron oxide which are
> the main oxides in Rutile.
>
> Jim Cooper
Richard Aerni on fri 18 apr 97
Hi Sylvia,
Sorry to have been so long in replying--I was felled by az long nasty
flu, and then upon recovering, had to leave town and workshop. Just now
getting back into a routine, and back to soem testing.
> Since everyone in the whole world has gone to the NCECA thought I'd ta
> the opportunity to ask you for some advice about your glazes in the Dec94
> issue of Ceramics Monthly. To start with I love your work and your glazes
> are wonderful. So of course I wanted to try them. Problems: I use electric
> kiln, in town, ash supply doubtful, so I decided to see what would happen
> if I substituted volcanic ash for the wood ash. I did and although my
> glazes are not yours, they were very hard with an orange peel effect if
> sprayed on the pots. The basic ash glaze with vol.ash has been a standard
> glaze for me for the past 3 years. However, alone it gives a cream color
> which I am not too crazy about and with the mason stains I have tried, they
> give almost an earth color. I would suspect something in the ash is
> affecting the mason color.
I don't add mason stains to the ash glazes, generally I try to just add
oxides. Not sure really why that is so, perhaps it just seems more
"natural". Some of the mason stains may react adversely to glazes rich
in calcium (wood ash), and also some are very refractory. You may want
to consult your stain chart to see if any of these things are so.
However over the top of the obsidian glaze, it
> is wonderful. The leather, over the obsidian was not to bad, but terrible
> under the base or alone, which I blamed on the electric firing and vol ash.
Yes, I would guess that the leather would not look good in oxidation. It
is a glaze that I use only in the part of the kiln which reduces
heaviest. In a more neutral area it appears very harsh and unpalatable.
Also, in the reduction kiln, I often overspray the leather with a rutile
bearing ash glaze, which gives the leather a nice warm blush. This I
think wouldn't work so well in oxidation.
You might try adding additions of copper carb and cobalt carb to the
basic wood ash glaze in order to give them some color. Also, if the
volcanic ash (I've never tried it) is too refractory, you might want to
add some more whiting or wollastonite to the glaze, as it's the calcium
which makes it all run.
> Never would have thought about the rutile, but now am wondering.
> I also do alot of Raku and sawdust primitive firing in the summer as l
> as my neighbors remain friendly. So far so good, but have new ones moving
> in next to me this summer and things could change in a hurry. Very iffy
> project in town. I have two sources of sawdust, one from a furniture
> manufacturer which is very fine with assorted woods, and a shake factory,
> very course green shaving sawdust, probably mostly pine, fir, and spruce. I
> use two old electric kiln to sawdust fire in and I use vermiculate, red
> salt and blue salt around the pots in the sawdust. I fill the kilns to the
> top with pots and sawdust and it slowly burns down in about 3 days. That is
> so far is my only source of ash.
> Question: Do you think the ash from this primitive firing would be use
> as an ash glaze in an electric kiln? I have hesitated so far, as I am
> concerned about the possiblity of salt in the ash fuming my bricks and
> elements in my electric kiln. I thought I'd like to see what happens with a
> little sifted wood ash sifted on top of the ash variation I'm currently
> using (Vol. ash sub). I'd like to get the orange peel effect with the shiny
> wood ash and runs at the top of the pieces. I've thought about just firing
> a couple of loads of sawdust alone just to get the ash, but thought there
> still would be salt in the firebicks of the kiln, don't know for sure. The
> walls are not like they were glazed or coated, so it is hard to tell. I
> can't think of another way to fire the sawdust in town without a ton of
> smoke. The kilns burn so slowly, there is just a trickle of smoke and I
> throw wet blankets over the kiln, which cuts the smoke even more. To die
> for your setup. Ahh well, not to be stopped. All problems solved, one way
> or tuther.
I try to stay away from using ash from softwoods. I use only hardwood
ash. The soft stuff tends to blister for me. It might be interesting to
try the salted ash--lots of people salt their ash glazed work and it
looks good. Don't know about the elements. Perhaps you could check
around and see if any of your neighbors or friends burn wood for heat or
in their fireplaces. I collect from some people around me and some of
the ash works and some doesn't. Just a thought.
> I will be following your thread on the rutile problem. Something I nev
> thought about. I just knew some recipes I liked and some were the pits.
I'll keep you informed if I make any progress--though this promises to be
a slow series of tests...
Thanks again for the nice note.
Best wishes,
Richard
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