Dan Fogelberg on tue 20 dec 05
I tried posting this awhile back, but must have made a mistake, so attempt #=
2:
Item 1: I've been following the debate about art and pottery, and have restr=
ained myself so far. But
the post about the public piece in Minnesota consisting of the rapidly weath=
ering word "hope"
engraved in a stone slab was just too funny. What a wonderful visual metapho=
r! If I had to endure
those Minnesota winters, I'd lose all hope, too=85 (full disclosure: though =
I was born in Chicago, I'm
a longtime Colorado resident who expects the sun to be shining every morning=
. Two days of
clouds, and I get depressed.)
Item 2, and actual reason for post: regarding the use of stannous chloride f=
or fuming:
To answer a recent question by Rick:
I=92ve been doing the stannous fuming for about five years, and keep learni=
ng with every firing. I
use the granular form, though the last batch I got was clumped and requires =
some grinding in a
mortar and pestle. I learned the fuming (or vapor glazing) technique from th=
e master, Biz Littell,
and when I first watched him at a workshop he just sprinkled the stuff into =
the kiln. That works,
but even at 700-800 degrees F, it works fast. Your =91light the fuse and get=
out=92 technique had
better be quick, because you=92ll hear the sizzling of the melting chemical =
as soon as you toss it in,
and those rising fumes are bad for you.
Also, it=92s all too easy to get granules flying around the kiln and into yo=
ur elements. My experience
is that when I burn out elements, there is always a chunk of foreign matter =
sitting on the coil at
the point where it burned out. Being totally anal about vacuuming after ever=
y firing will save on
element replacement. I really don=92t know, but it seems like the oxidation =
layer built up on the
elements during bisque and glaze firings may protect from the vapors themsel=
ves. I=92m certainly
not an expert on what affects element life, so others may have some info on =
this that would help
us both.
I=92ve developed a variation on the =93sprinkle and run=94 technique that gi=
ves me a bit more time and
control. I make little bundles using Kleenex and masking tape: tissue cut ab=
out 2=94 square, double
thickness, rolled around a half teaspoon or so of the granules and taped. To=
tal amount needed
will depend on interior size of kiln, size and position of pieces, etc. You=
can do the vapor glazing
on the cool down from your glaze firing, but I prefer to unload the kiln and=
restack just a few
pieces for fuming. (Be careful when handling pieces=97I use a special clean =
pair of gloves to avoid
fingerprinting the surface.) Depending on the effect you want, for instance,=
shallow bowls or wall
pieces that have to be glaze-fired flat on a shelf may fume better when prop=
ped on edge. The way
you position the works will have an impact on how the vapors circulate aroun=
d them. For taller
pieces I also place little platforms at different levels so that my chemical=
s aren=92t all sitting at the
base of the pieces. Color variations seem to be a function of temperature, p=
roximity to the
chemicals, position both within the kiln and relative to other pieces, thick=
ness and shape of the
pieces and the whim of the kiln gods. Especially the latter.
So: I reheat the kiln to about 1000 degrees F, don my protective gear and op=
en the kiln. I drop the
bundles in, attempting to distribute them in proximitiy to the important are=
as of the pots. Of
course, it=92s hot, you=92re not able to place them perfectly with big glove=
s on, they roll or bounce and
you=92re trying to get finished before the tissue starts burning through and=
the pots cool too much
or your sleeve catches on fire. It=92s a real dance. If you don=92t get prox=
imity of pot and chemical, not
enough color. If you get too close, ugly scum instead of color. (One reason =
I don=92t generally pitch
loose granules in is the possibility of getting the chemical directly on the=
piece. Still, I=92ve done
some pieces where I put the chemicals directly on a matt glaze and got some =
interesting effects.
Hey, this is art: there aren=92t any rules=85)
Don=92t get discouraged if you don=92t get spectacular results the first tim=
e. There are lots of
variables, just like copper matt raku, and it=92s taken me years to feel I w=
as starting to get the hang
of this technique. Of course, I just may be a slow learner and you=92ll hit =
the jackpot the first time.
By the way, I=92ve used several clay bodies, but find the thermal shock resi=
stance of a kyanite raku
body has worked best for me. I do some serious altering of the pieces after =
they come off the
wheel, and don=92t need another way to crack and lose a piece. To get an ide=
a, you can see a few of
my pieces at my web site: http://www.danfogelbergart.com/ It's still under=
construction, but if
you scroll down to the bottom and click on the Diane Grimshaw Gallery link, =
there are some
thumbnailed images. Note that there isn't a section on the site called "crap=
py pots that didn't
come out." That would be a big one.
Have fun and good luck,
Dan Fogelberg
Longmont, Colorado (where it's been cold, but sunny)
Lily Hume on wed 21 dec 05
Dan,
Your work is beautiful and has motivated me to start working on my raku
ideas with stannous chloride. I've been using ferric chloride with
successful results but really admire the look of tin.
I'm curious, the melting point of stannous chloride is 477 F and the
boiling point is 1123 F. I'm thinking the fumes would come off at the
boiling point. Have you tried starting with a cool kiln and heating to
temp?
Thanks,
Lily (the lurker)
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