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Thesis/Dissertation Collections
1971
Lusters and the slab form in raku
Richard Hirsch
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LUSTERS AND THE SLAB FORM IN RAKU
Richard A.
Hirsch
Candidate for the Master
in the College
of
of
Fine
and
the Rochester Institute
of
Fine Arts
Applied Arts
of
Technology
1971
Advisor:
Professor Hobart Cowles
-1-
CONTENTS
Index
of
iii
Slides
Introduction
v
Reasons for the Investigation
1
Background
2
4
Error Period
Chapter I
Trial
Chapter II
Further Technical Research
and
Chapter III Correlation
of
Lustered Glazes
on
Slab Forms
15
18
Some Observations
Chapter IV
10
Continued Glaze Research
20
Appendix
26
Conclusion
27
Bibliography
28
ii
SLIDE LIST
1.
Lusterd Plate
"Rainbow"
RICHARD HIRSCH
1/2"
20
21"
2. Gold Luster Plate
3.
-
Plate
18
long
long
1/2"
long
10"
high
Lustered Plate
18"
long
6.
Lustered Plate
19"
long
7.
Bowl
9
8.
"Landscape"
9.
Lustered Bowl
4. Footed Bowl
5.
Plate
10. Big Bowl
11.
12.
"Walking"
1/2"
high
20
1/2"
long
10
1/2"
high
28
1/2"
long
Goblet
Luster Goblet
11"
high
10"
high
1/2"
13. Spray Luster Goblet
12
14. Raku Goblet
10 1/2 high
high
12"
high
15"
ht.
17. Gold Goblet
16"
ht.
18. Gold Goblet
15"
ht.
19. Crackle Bottle
10 1/2 ht.
20. Luster Bottle
8"
15.
Footed Goblet
16.
"Mother
21.
of
Pearl"
Goblet
Precious Object Box
ht.
(Orange)
4x4x5"
22. Object Box
4x4x5"
23. Black Box
4x4x5"
24. Gold Precious Box
5x5x5"
25. Shell Box
6x5x5"
26. Gold Coil Box
14x4x3"
27. Gold Box
28. Raku Box
with
flocking
16
1/2"
ht.
15
1/2"
ht.
Ill
6"
high
1/2"
29. Covered Form
21
30. Covered Form
21"
ht.
31. Covered Form
22"
ht.
32. Covered Form
26"
ht.
33. Covered Form
30"
ht.
iv
ht.
INTRODUCTION
My
thesis is
break-through in
with
Raku
that
not one
ceramics.
slab
the thesis was to
built forms using
rather
begin to investigate
Pride
Failures
were not
pottery in
Raku process.
a
and
was
Trial
develop
depressing,
and
A
major goal was
of
This
lustered
concentrate
and error seemed
long
to
The pur
glazes with
in
fit my
hours
because in them knowledge
inquiry led
of
to give
one
area,
me a
person
testing.
was acquired.
experience and understanding.
accomplished was
to
to be the only way to
approach
for
new
my involvement
particular process.
I decided to
techniques.
to be a
better
What
understand
general.
Throughout my
Cowles
a report on
my investigations
correlate
the involvement actually
of
it is
nor professes
of accomplishment was a reward
Experimentation
ing
Basically,
knowledge in this
than dabble in many.
ality.
point,
The School for American Craftsmen.
at
attain practical and usable
pose of
proves a
entire
primarily
into the Raku process.
learning
responsible
More
experience at
for
directing
importantly,
-v-
he
SAC Professor Hobart
my insights
offered me
and
discoveries
inspiration.
REASONS FOR THE INVESTIGATION
When I
was
limited to
weeks at
at
to the School for American Craftsmen my background
SAC I
Sale I had
Strange
potter
colors made
only
display
seen a
the
Frisenda.
known
Raku.
as
A few
9.
pottery
and
from
lusters
of aesthetic goals relied
heavily
an
The
seen.
obtained
and
expressed a willingness
became
joint
run, but
my interest.
Drew Krouse
venture
started out as a
I had
all
glazes were metallic
Frisenda
were
which stimulated
graduate students were
Both Krouse
tests
glaze
the first few
the Rochester Clothesline Show
During
work stand apart
that the
What
Raku.
of
mentioned
a process
During
reduction stoneware.
continued with cone
Included among the
in
9
some cone
the time I lacked enthusiasm.
and
by
came
to
individual
John
try
effort
self expression.
Achievement
During my
siderations.
were
dealt
with.
three
sists of
after all
to his ideas.
on slab
like
most other
main components:
these
the technical
Raku,
investigation all
aspects of
Eventually
phase
forms
grew
pottery
elements of a
forms
naturally
of
technical con
Raku
process
con
pottery making,
the clay, the glaze,
and
the fire.
are understood can a person give
aesthetic concerns
had been
upon
comprehended.
out of
dominated my thoughts
The
use of metallic
my involvement
with a
Only
form
after
lusters
Raku process.
BACKGROUND
Before starting the experimentation, the many
Associated
were examined.
philosophies of
Raku
Raku is the Oriental Zen tradition
with
of
the tea ceremony.
"The tea masters,
in the
unique pleasure
of clay.
In
influenced
Zen Buddhist philosophy, took
by
to direct
conscious return
a
treatment
and primitive
n1.
this is the
accord with
emphasis on
the simple,
beauty,
and
the
natural.
"The
tance
cult of
tea
Teaism,
or
and veneration of
is
a
way
the imperfect in
place surroundings with great
of
an attempt
and
meaning
life that
the inherent
the
beauty
of
the
beauty.
It
derives its
phenomena,
transitory
and
middle
American
different from the
Raku pots
"Nothing
pots.
shown
style
potters
strict
Japanese
is home grown,
Potter's
Arts, 1967),
2Hal Reigger,
Co., 1970),
3Rose Slivka,
(New York:
Raku:
p.
Art
form.
from
awareness
It
celebrates
nature
inspired
spontaneous creative process
receive much attention
their
of
own contribution
Japanese potters.
in the Twenty-Third Ceramic
^Bernard Leach, A
Transatlantic
made
interpretation
Japan in
s common
"
have
of
the Raku pottery
the
fifties Raku didn't
would amaze a
Our
a part of
though it may be.
Until the
Recently
it becomes
developing
character
accep
places great emphasis
non-perfect asymmetrical
excitement of surface which
man'
to imbue
on meditation and quiet contemplation as a means of
of
expresses an
potter
and
spite of
Book,
p.
and
more,
has little
the
name.
(3rd ed;
National,
however,
or
in this
country.
in Raku quite
Describing
the
a critic wrote
than these Raku
nothing in
common with
uU'
Hollywood-by-the-Sea,
Florida:
29.
Technique,
(New York: Van Nostrand Reinhold
9.
"The Twenty-third Ceramic
American Craftsmen's
-2-
"
Craft Horizons
National,
Council, January-February, 1965)
p.
21.
Daniel Rhodes feels "The
original
meaning
Raku has
of
The more immediate response from the fire has
pottery making
the ideals
of
traditionally,
and
brought
a new excitement
but to
seek
my
tions the Tea-Zen philosophy
involvement,
Daniel
own
forms,
would
Rhodes,
Kilns :
Chilton Book Co.
,
1969),
181.
*
up the
While I
was made not
After
process of
considered
to
use
some
the
Raku
restric
investigation
and
develop.
Design, Construction,
p.
"
been forgotten.
and experiment without
impose.
a personal concept would
speeded
to it.
the Japanese
potters, the decision
almost
and
Operation, (Philadelphia:
CHAPTER I
TRIAL AND ERROR PERIOD
The investigation began simply
Charles
Lakofsky describes
application of
fired pieces,
heated
says
and
that Raku is
rapidly
and when
Most
because
after
the
melted
kiln
was
with
built
glazes are
were
was a
just
Within
and
as
one
comedy
smooth and
the
low biscuit
into a
pre
and rapidly.
Black Raku
were
and
of errors
!
period
the
and
then
kiln,
In
firing,
are observed
ten
pots are
minutes.
that
all
at once
were made
they
From then
as
one or
drawn
the
out
use
glazes of
from plumbing
Several lead
were
! A top loading-
glazed,
based
on
in any
glazes
all were
What
I knew that fundamentals
other method or
technique.
was experienced:
Iowa: (W. M. Brown Co.
Glaz
Glazes
for the
a
""
the best to
glazes were
notes
with
through
the gas pressure was turned up.
following
192-193.
hot
red
lead based.
the fuel.
After
way, but in the
usual
melted.
about
ELeach
Burners
to the ware.
a specific color or
shiney, the
usually takes
important in this process
Rhodes, Clay
1957) pp.
,
Book Co.
has
The pots
tongs.
firebrick.
5Charles Lakofsky, Pottery,
Daniel
glaze
felt that lead base
into the hot kiln
firing
than
this knowledge it was decided to fire
out of soft
directly
followed
firing
smoothly
were mixed and applied
placed
with
the
and propane gas was used as
supplies,
involving
directly
glazed pieces
glazing, directly in the
in the kiln
the traditional Red Raku
Armed
process was.
to porous,
glazes
a procedure rather
sources researched
they
bearing
the pottery is bisqued in the
The glaze
the tongs.
with
Raku
what a
Japanese technique
freshly
cooled as soon as
pots are placed
spy hole
reading
"5*
fire it is placed,
drawn
the
of
placing
"In making raku,
effect.
two
and
a
usually lead
firing,
hot kiln.
red
Rhodes
glaze
low
it "as
by
,
1968)
p.
25.
Potter, (Philadelphia Chilton
1. Glaze
exploded off
2. Glaze
melted and ran off
3. The
the
pot when placed
the
in the
if slightly
ware
glaze surface was pitted and scarred
hot kiln.
red
over-fired.
from the
combustible material.
glazes were melted while others were still immature on the same
4. Some
piece.
5. The clay ody
in the hot kiln.
cracked when placed
In addition to these technical difficulties there
smoking
or
reducing
aspects of
little
while others received
duced,
was
while
the
dangerous
There
firings.
there
was a
began
The clay
By
and
clumsy
a
the
and
For the first time in my
and a need
for the
reasons
body first
to do
that
The
of
use of a
the pot
was re
top-loading kiln
ware with
involvement
tongs.
with
in
pottery,
technical experimentation.
contribute
the
black,
same awful results continued
short
some
I
to the failures.
used was a regular cone
9 stoneware.
volume:
Jordan
2
Cedar Heights Redart
1
North American Fire
1
Clay
XX Sagger
Unfortunately,
shock.
pots were smoked
few cases, half
unloading the hot
when
beginner 's luck
desire
looking
Ih
other remained unaffected.
was no
other
Some
the process.
smoke.
was no control over
1
this clay
Raku clay formulas
contraction
sand added
in the
rapid
to the clay
to escape, preventing
body
couldn't withstand
need sufficient
heating
and
body keep
cooling
the pores
cycles..
of
cracks and explosions.
one-third non-plastic material added
these needs the
non-clay
following
clay
to
material
the clay
Usually
a white
Clay
Cedar Heights Goldart
#5 Ball Clay
to lessen the
Grog, flint,
and
fine
open and allow moisture
a
Raku
clay recipe.
recipe was used.
North American Fire
Tennessee
the tremendous thermal
100
120
60
body
has
about
To comply with
Spodumene
20
Flint
20
Grog
80
The only problem
first
cone
04
tried
was
into the kiln exploded
Next it
in
that,
was
the
Most
glazes.
They
that
to find
and
the
08,
at cone
was porous
was
were
also a
before the
and
enough,
the
produced some
blues,
what temperature
dull
to biscuit fire.
disastrous.
results were
or cracked
disappointing
greens and
glazes
biscuited
body
was
firing
galena when
browns,
heavily
garish
reduced.
White
White lead
60
Flint
20
Frit 25
20
3
Orange
White lead
60
Frit 25
40
Lead
4
chromate
Blue
Frit 529
Gerstley
70
Borate
5
Flint
10
Soda Ash
10
Kaolin
Copper
5
carbonate
3
Black
White lead
60
Flint
20
Frit 529
20
Cobalt
Copper
2. 5
oxide
Red Iron
4
oxide
carbonate
-6-
satisfactory,
from the lead base
tried:
Tin Oxide
seemed
too brittle.
poor result obtained
uninteresting
piece put
cycle was completed.
this temperature
yet not
Every
At
2
oranges,
weak
Some lead
Most
over
of
fired.
This
Color burnt
have
glazes
these lead glazes
a nice smooth
resulted
in
developes if
but because
other
kinds
I had
I
use.
of
of
quickly in the
surface, they
a poor surface
soft glaze surface.
scum
out
High lead
the
melted and ran off
quality
short
firing
While lead
range.
remain soft and set
if slightly
easily reduced,
Some luster
yet a
was produced
by
dirty
reasons stated and
the fact that lead is extremely
low
firing
investigated.
acquired a
list
of alkaline glazes
the
experimented with
that Paul Soldner is
the
metallic
these
the
glazes were
slowly.
up very
when sawdust pitted and scarred
glazes are
over-reduced.
ware even
glazes,
toxic,
reputed
to
following formulas,
Basic
Gerstley
50
Borate
Borax
50
Runny Iron
Gerstley
Yellow
Borate
50
Borax
50
Iron
10
Rutile
3
Yellow
Gerstley
Borate
80
Burnt Umber
20
Brown
Gerstley
Borate
80
Yellow Ochre
20
Glass Red
Gerstley
Borate
50
oxide
10
Borax
50
Red Iron
Copper
These
firing
scarring
duced
glazes melted at a
range was
longer,
occurred.
a reddish
5
carbonate
higher temperature than the lead bases.
and while
they
were
fairly soft,
Glass Red was most successful.
copper; if left to
air
-7-
cool, it
less pitting
and
When smoked, it
remained copper green.
Their
pro
the Japanese do
Traditionally,
the kiln.
outside of
the process.
Practical
are used
Clay,
break"
Reoxidation
pine
part of
step in the
needles, sawdust,
create an atmosphere
subjected
the
of
to this
glaze, is
as well as
occur because
change
temperature.
to
Pottery
carbon.
a chemical change.
face does this
leaves,
materials such as
straw,
containing free
out of
important
ware
en
no substitute and control was
had
experience
or
most
their Raku
time.
Combustible
paper and
in America it is the
However,
It is the critical point, the "make
tire process.
gained with
not smoke or reduce
the
of
this reducing atmosphere,
while still
oxygen and
Only
reducing time
take
hot
in
atmosphere undergoes
affected.
short
glazes will
lacking
news
place
if the
to
enough
on
the
and
ware
sur
low
is taken
effect a chemical
change.
is
Practically speaking, timing
the hottest
kiln
will reduce
to Paul Soldner
at
Geneseo last
quick reduction
is
critical
the
ware
glaze
with
Heavy
Cooling
should
reducing
should
be
January 21, 1970, he
reduction
be done slowly
and
a
reducing
should not
of
Raku.
Reliance
of
Raku.
During
developes.
"What
The
Lakofsky,
the
in the form
this dramatic period
romantic nature of
remains
emphasis on
7
upon nature
minutes
is
a
philosophy
discovery
Pottery,
p.
of
37.
things
a
the
is the
of
fire
"feel"
is
not
on
be
to scar the
direct
is
entire
contact
necessary.
removed
longer
good
While getting
atmosphere
chamber until a chemical change can no
Contained:in these few hurried
that "a
lusters".
depend
always
the pot
When I talked
said
a main concern
doesn't
Only
of
which are
from the hot
removed
immediately.
for the development
combustible material.
Surfaces
important.
atmosphere
to the reducing atmosphere,
surface.
the
Pots
the best.
in the reducing
and placed
most
from the
occur.
Zen philosophy
and smoke
is the; essence
for the captivating
whole process
or a state of mind
not planned.
"
'
process
is realized.
that for
me places
Four
Ware
bers
months
was glazed
were cooled
duced.
had
gone
days in
Less
Unexpected
and
advance
many individual techniques
to allow for
complete
down considerably before the
Sometimes only
results.
by
and
less
one pot at a
control was obtained
by
develpoed.
Kiln
drying.
cham
next cycle of pots were
time was fired in
order
combustible material was used
and accidental effects were
were
taken into
to get
intro
maximum
in the smoking
stage.
consideration and a certain
practical experience and knowledge of the entire pro
cess.
Still,
Also,
the development
of metallic
the forms were not in
evidence of a need
for
more
luster
accord with
technical
glazes
had
the spontaneity
not yet
of
been
Raku.
realized.
There
was
research and aesthetic considerations.
9-
CHAPTER II
FURTHER TECHNICAL RESEARCH
Glaze
The process,
Most
trol.
its
by
its
own
glazes never
be
effects can
with
in Raku
effects
to this
time,
many
variable
certain elements
conditions,
impossible to
con
although some colors and
However,
"happenings",
because
absolute
of
the process,
duplication is impossible.
in different effects.
result
very few
Now,
effects.
upon
fire exactly the same,
margin of so called
desired
of
the
glazes experimented. with produced
the formulation
own glazes was
the
necessary to
of
my
A
saturated amount was
the kind I wanted.
produce
I first
lieved to
added
nature, has
controlled and repeated.
Individual techniques
Up
dependent
are
experimented with copper.
to
cause some glazes
to this base
student at
glaze which
develop
I
a metallic
acquired
luster.
from Robert
The
Jarvis,
first be
copper was
a graduate
S. A. C.
Base C. M.
Frit P-25
43.6
Frit 3134
26.3
Lithium
Copper
Kaolin
10.2
Flint
14.0
Unfortunately,
a
because there
very dense
were attained except where
of
tests,
reduced,
were
Red Copper
better.
It
In
a gas
a gas
kiln
it
seemed
heavy
mixes
copper, it
to greenish black.
reduction occurred.
poorly
This form
No
5%-25%.
reoxidized
metallic
During
of copper
with water and other
the
easily,
lusters
next series
is already partially
chemicals,
results
to luster more successfully.
realized
produced
kiln there is
green
was so much
oxide was used.
and although
At this time I
Using
to the base in these percentages:
carbonate was added
thus producing
9.9
carbonate
the difference in results
using two kinds
better lusters from
a slight
reducing
copper
than
atmosphere in the
-10-
of
an electric
firing
stage.
kilns.
kiln.
This
helps to develop the
Less Red Copper
Inquiry
a
type
was now made as
decoration
of
ration rather
lusters is
than
and
luster.
they
I
form
for
It
media.
saw a
from the kiln.
produce metallic
to
what other ceramic chemicals
on metallic
lusters
Lusters
centuries.
to be the
firing
of metallic
luster
as a
transparent,
over a
the
culmination of
in the Royal Ontario Museum in
examples
were
final deco
the development
ceramicists used
in a final
copper
that lusters
were employed as a
Persian
was employed
lusters.
beside the
revealed
Historically,
wares are reputed
few
removed
over-
art of
Toronto,
are magnificent.
this form
Describing
a
to
to the Islamic potters.
These
alkaline glaze.
glaze was needed
Literature
used
before it is
even
as a complete glaze.
credited
purely decorative
glaze
in the
oxide
develop luster.
oxides
luster
metallic
of
decoration
decoration,
of
one source states
on ceramics and glass
consisting
of
that "Luster
constitutes
extremely thin films
of
Q
metal which are
as
being
method.
deposited
on
the
surface of
either colored or colorless and
^'
The
most expensive of
the ware.
their
"
Hainbach
preparation
these lusters
are what
by
he
classifies
either
calls
the
dry
lusters
or wet
"The Noble
Metal Lusters".
For the preparation
with pine resin and
heat,
ited
carbon
on
the
these
lavander
formed
glaze
of
by
the
oil.
over-glaze
In this
lusters,
method
resin and oil reduces
a metallic
during
the
an
salt
is
combined
oxidizing fire to
metallic
salt,
which
red
is depos
surface.
Q
Shaw, Ceramic
Praeger., 1968), p.
Kenneth
A.
Colors
and
Pottery
Decorations (New York:
80.
^Rudolf Hainbach, Pottery Decorating, (London: Scott Greenwood
p.
Frederick
202.
11-
and
Son.
,
1924)
Preparation
of
these kinds
Expensive
and procedures.
banding
of
Most
this quality
chemical compounds such as
adapted to
A
in the "noble
lusters",
manners are
Luster
solutions of
are expensive and produce a
the
metal
now,
ornamental ware and are used
dinnerware.
was not
formulas
my intention.
metallic
salts,
were
this type
flat luster.
However,
the
investigated
in
De
use of
the
and
my Raku technique.
partial
lusters
souvenir,
common mass-produced
veloping lusters
entails complicated
Lusters developed in these
associated with
are sold commercially.
lusters
materials are used
such as gold and platinum.
unfortunately,
of
list
of metallic salts
associated"
generally
with over-glaze
was acquired.
Metallic Salts
1. Silver Nitrate
2. Bismuth Sub-nitrate
3.
Gold Chloride
4. Ferric Chloride
5.
Zinc Acetate
6. Tin Chloride
In
addition
tested.
All the
put
through
a
to these
metallic
range
Raku process
the
other metallic compounds were
metallic colorants were added
failed to develop any luster
1-10%
salts,
following
including
by
to the C. M.
the smoking
themselves
or
or
base,
reducing phase.
in combination.
chemicals were added
and
then
They
Within the
to the base.
1. Cobalt Carbonate
2. Cobalt
oxide
3. Chromium
4. Red Iron
oxide
oxide
5. Iron Chromate
6. Nickel
oxide
7. Manganese dioxide
8. Tungstic
9.
Sodium
acid
uranate
10. Potassium dichromate
After
testing those,
a
few
metallic sulfates were
process.
-12-
tried with the same
Copper Sulfate
Cobalt Sulfate
Nickel Sulfate
Manganese Sulfate
With the
noticeable
tallic
new
luster.
glaze was
Sulfate,
I began to
Finally,
in the
salts used
base
Copper
exception of
over-glaze
tested
being
none of
these developed any
experiment with some of
luster
and all
me
At this time
preparations.
the
the
salts were added
a
directly
to it.
C Base
Soda Ash
44. 2
Frit W-15
30. 9
Borax
18. 6
Kaolin
24. 0
Flint
65. 0
All the tests
Silver Nitrate
stage.
ivory
to
metallic
yellowish
luster.
with a
was added
golden
Raku process
combined with
luster
was
in
color
along
modulation and
awhile people
(See Slide
with a purple
"Beatrice"
pearly
results were quite
1% Silver Nitrate
and
1%
glaze was yellowish
Smoking
over-all
was also
provided color
irridescence.
because
of
(For
this glaze!)
tried with Red Copper oxide.
irridescence to the copper luster
to prevent the
duced every
These two
called me
produced an
2)
Bismuth Sub-nitrate
parted an
with
irridescence.
the reducing
alone produced a
At its best this
the Bismuth developed the
in the shop
It
Silver Nitrate the
developed
Bismuth Sub-nitrate in the C base.
gold
including
to the C base in 1-2%.
Bismuth Sub-nitrate
luster.
When
A
satisfactory.
done
were
#
copper
from
metallic color
glazes were
my
reoxidizing.
and
The
helped
standard
as a stabilizer
result was a glaze
imaginable from copper.
(See Slides
in the investigation.
-13-
It im
that
pro
1, 3, 6)
Base
Soda Ash
44. 2
Frit W-15
30. 9
Borax
18. 6
Kaolin
24. 0
Flint
65. 0
Gold Luster
1% Silver Nitrate
1% Bismuth Sub-Nitrate
Copper Luster
2% Red Copper
2% Bismuth Sub-Nitrate
Along
with
these two luster
glazes a vitreous englobe was
Tennessee #5 Ball
Clay
20
Flint
30
Frit 3191
25
Talc
10
Borax
7
White
Opax
10
Red
Red Copper
5%
Red Iron
5%
oxide
-14-
developed.
CHAPTER III
CORRELATION OF
LUSTERED GLAZES ON SLAB FORMS
Development
display
After
At
them.
in
Glazes
of
the tongs
led
glazes
easily
a
Large,
round shapes
unless grabbed
I tended to
once
vertical
had
would
new glazes.
the
glazes.
influenced the form.
The
forms.
they
This
middle.
was comprehended and
disadvantage
hard to
maneuver
to
tendency
was one of
Size had only
Ware
firing.
glaze
major
were
an even greater
round shapes.
the process
forms that
surviving the
that
was
exactly in the
large,
avoid
chance of
forms
of
seek
as significant as
process also
better
large
on
these types
with
limitations,
the Raku
had
to
me
became test tiles for the
shapes
aspects of
reoxidized
tongs.
sons
first,
a single piece
working
with
these luster
involvement the forms became
some
Technical
made
of
roll off
the
rea
reasonable
facility
with
the tongs
acquired.
Clay
investigated to
slabs were
Slab forms
of stoneware.
lent themselves to many
The investigation
form
and
the
with
forms
not associated with
to the Raku process
the philosophies
was an attempt
excitement of
surface,
to
hand-building
Raku.
of
correlate
supplied
and
those
by
the asymmetrical slab
the
metallic
luster
glazes
the Raku process.
Slab forms
exhausted,
a
were
new,
and glaze was of
of
quality
was achieved
clay
mattness of
be rolled,
form
and
developed in
the
by
With
After
begun.
clay body.
of
Throughout,
urging
shiney
Soft
squashed, pressed,
gentle
most possibilities were
primary importance to
the juxtaposition
smoked
bent, folded,
texture.
series.
related sequence was
quality
dull
of
related
create
-15-
A
me.
surface
metallic glazes and
and malleable
impressed,
and good
the tactile
timing
clay
and
slabs could
joined to
the clay
the
create
slab could
be
shaped
using its vitality to
The procedure
Each
Molds
Soft clay
casts.
slabs were
tubular shapes.
natural
it
tendencies
was part of
tion
draped
wet
of soft
my philosophy
for my
order
clay
basic form to
work
in the
or canvas.
support
biscuit pots,
domes,
on or
burlap
molds or wrapped around
inside
slabs were rolled
Forms
than force.
were created
I tended to
Organic
by
work with
to be disassociated from the
boxes.
cardboard
were guided and controlled.
Raku.
of
the wet
and plaster
slabs were utilized and encouraged
clay
and modification rather
forms in
slabs on either
clay
-metal
Sometimes clay
Qualities inherent in the
a visual strength.
of armature or
from
were made
the form
roll out
kind
series used some
clay.
to
was
give
and
because
direc
subtle
large
fairly
the
small scale of
traditional Japanese Raku.
Glaze
forms
eager
were
to
smoked
entirely
clay
body
shape was
became
the platters,
slab plates and
and
color
bare
gently
fields
negative space of
form.
The luster
thrown
same
treatment
the
rather
Large
of metallic
unglazed
and
less
was
At
the
first,
because I
was so
The
glaze was used.
These
areas
their final
and consideration of
more
than to dominate.
to visually
separate
When
the best in the
to the
the
upon
the inter
pools of raw glaze were poured
clay body.
fired,
They
use of
of
the
were enhanced
important,
top from the
16-
covered
rest of
goblets
and
had
the
forms.
glaze was used
With the large
the
a soft malleable
Although the
next series of covered
independent,
by
1-6)
the slab as
slab was
into
this produced large
(See Slides :
decoratively.
the treatment
proceeded
solely dependent
lusters.
glazes were used
elements
were
rolled around.
As the forms became
used
less
in painting
bowls
clay.
goblet series was
some
them,
Perhaps it
important "negative space".
negative space
action of glaze and
The
an
dipping.
important.
The large
modulating
Eventually,
or
pouring
covered with glaze.
them all.
display
treated like
were
by
was almost always applied
to describe
forms
the form.
glaze was
(See Slides
29-30)
Shiney
glaze zones were employed
unglazed,
smoked
Each kind
of
with
duced
by
themselves
size and
were
intricate
the piece,
were
the
seemed
enough.
smoking techniques.
shape of
of
Detailed brushwork
31, 32)
required special
the
The
intensity
factors in devel
it
some nice effects.
be
proved to
glaze
thrown
on
the
It
However,
sawdust was more
readily
pro
available
easier to control.
surface, the
the ware.
Occasionally, they
pine needles and grasses were used.
To prevent pitting
the
glazes
the blackness
certain methods.
Initially,
and
form
of
smoke, along
oping
the
contrast with
(See Slides
areas.
since
unnecessary
to
and
scarring from direct
plates and
unglazed area.
created a
bowls
A large
contact with sawdust on
Sawdust
turned over.
were
dome
metal
was
then placed
over
the smoke,
contained
reducing atmosphere,
was
and
prevented reoxidation.
With the
goblets and small
or sawdust was made.
small
heap.
A
The
red
short can or
boxes,
hot
barrel
little
a
mound of shredded paper
piece was placed
was
then placed
in the
over
center of
the
ware
to
the
con
tinue the reducing process.
Most difficult to
Smoke
A
patterns
Best
Sawdust
This
of
broke up the verticality
monochromatic
form.
smoke and control were
tone in the
the
covered
destroyed the
unglazed areas was needed
results were achieved when a
was packed around
wedged
and
the large
the form
after
combustible material
clay
it
17-
visual
impact.
to describe the
sewer pipe was used.
was placed
between the form
the pipe.
forms.
inside the pipe.
and
the inside
SOME OBSERVATIONS
"Craftsmen
of all
the difficulties
with
of
times have battled
the
techniques,
sion.
While in
more primitive
in
times
technical
our
form
of
always
main
the
be
must
short experience with
been important.
Clay
for any
responsible
difficulties
the fire and myself.
is
each pot
lay
lie
and expres
in the
technique,
wholly in
almost
Creating
trend.
unique objects
Many
its intrinsic
and
shows
is
in the
past
Other
few
Shows
the reality
nature of
his
materials and
influenced
of
by
thought.
reach object-ness.
n11*
the idea
restore
"Objects U. S. A.
rather
commodities,
and
Paul
(Geneseo:
12Rose Slivka,
(New York:
pp.
object.
it is the
to the
"
and
object
"Coffee,
directly designing
as
he is
the degree to
obsessed
which
he
for
by
can
19
"
"Raku
1970)
the
than any individual.
Wildenhain, Pottery; Form and Expression,
Publishing Corp. , 1962), p. 10.
Soldner,
of
Actually, today
Marguerite
Reinhold
A feel
Due in
the process.
have tried to
such as
himself,
artist
uniqueness of each piece.
have influenced my ideas
of machine made
com
seek, is inherent in the
"The contemporary American Craftsman is less
function,
Each
media.
immediacy
years
for
material
interaction between the material,
the
not an original
value and power.
Cups"
and
the best
it may have.
which we all
through the
to this I have been interested
me
have
aesthetic concerns
another art
a complete
Individuality,
acquired
pottery,
be for
to
Hand-building furthers
Raku process.
the
have used,
form
problems of
real problems
ultimate value
With Raku there has been
ing for
seems
"I consider clay to be just
munication.
Tea
times the
the
they
material
and expression. "h).
Throughout my
part
with
advancement
the
with
p.
Invitational,
"A Catalogue for
an
(New York:
Exhibition;
20.
"
"The Object:
American
Craft Horizons
Function, Craft, and Art,
Craftsmen's Council, September-October
1965)
10-11.
-18-
When my
independent
work
of
is
their function.
using them becomes
a person
and more conscious of
it is
nice
to know
"The Raku
tual
to
13
orbit
renew
Craft
successful
the
the
They
to this very
objects
The
itself in the energies,
have
an
intrinsic value,
nature, in that
on a precious
the function
themselves.
the Zen tea
day.
take
more aware of
some objects are
ware of
objects
In
irreplacable,
our
even
they serve,
throw-away society,
by
their
masters still shows us
object
truly
made
into its
-19-
pp.
spiri
for itself has the
memories and actions of men.
Horizons, (September-October 1965)
maker.
10-11
"
power
CHAPTER TV
CONTINUED GLAZE RESEARCH
Work
ical
compounds
traditionally
in
used
Other
forms developed.
continued on glazes while slab
luster
overglaze
chem
were researched
and explored.
Gold
a
Chloride,
famous
and
in
complex
"Purple
of
Cassius".
color called
fired in
hundredths
shades of
Raku,
it
yields some
red with
tinges
nately, gold, chloride, because
lab!
luster
testing ferric
Three
and exotic colors.
to the base
glaze produced
Unfortu
its expense, is
impractical,
even stock
it in the
except
Chemistry
when added
sawdust a
luster
and
the
light
fuming
irridizing
adherent
form
layer
surface.
to the C base.
in
took place.
Both
A
when
heated
an atomized
the light
of
noticeable
to
was
When the hot
However,
of
the
and placed
spray
of
metal
the
mix a
piece
hit
again no noticeable
in
in
connection with
contact with a metal salt
salt
is formed
solution,
on
the
a
reflected
from it.
This succession
Materials,
Publishing Co.
"
Ceramic
-20-
strongly
glass or ceramic
the irridized film may be gauged
to the well known Newton rings.
Cahners
step
compounds are mentioned
of an oxide of
"Ceramic Raw
second
kind
glass.
The thickness
ent color of
analogous
or
developed any
compound
metallic salt with sawdust.
"Glass surfaces,
vapor
Neither
directly
was achieved.
fuming
chloride and stannous chloride a new
developed.
was
weak solution of
^
to my C base
Nuts!!)
technique
in
of
added
produces
of a purple opalescence.
(They don't
experimentation.
While
the
incredible
When
of a percent of gold chloride added
strawberry
in limited
luster preparations,
when used
by
the appar
of colors
is
14 *
"
Industry, January 1961, Chicago,
My
Just before the
glaze
it
was pulled
in
Glaze
Luster
defining
means
appearance of
the
peculiarities of
in
that
colors
or
shiney, but
"Mother
of
not
may
By
a
not
the
been
Areas
tions
the
where
not
in
surface and
quality
a
difficult to describe
gloss or sheen.
by
or
2. the
dependent
upon
Luster implies a shiney
'
of surface
changing.
"
that
shows more
An irridescent
often used
than
of
one
many
surface can
be
for irridescence is
the
terminology,
Experimentation
As yet,
results were
all
desirable
the possibilities have
will continue after
this
paper
is written.
soluble salts provided me with an element of control.
luster
or
luster
the
light:
"
and rewarding.
irridescence
the spray
contact with
amount of
Usually
exciting
the
are
"
reached.
Spraying
was either air cooled
irridescence.
and
Another term
not always.
method
about six
be irridescent.
Aside from the differences in
and
held
definition irridescence is "a showing
constantly
Pearl.
immediately
the pot
gun was
surface of a mineral as affected
a prism.
are
this technique
a glow of reflected
Irridescence implies
color as
by
the terms luster
"1.
onto
The spray
its reflecting qualities.
that may
surface
directed
metallic
barrel.
effects produced
first
without
was
After spraying the pot, it
a sawdust
the
saturated solution of
hot,
from the hot kiln.
inches from the piece.
or smoked
a
melted,
A fine spray
salt was prepared.
after
fire it up to temperature.
procedure was to glaze the ware and
raw
or
light spray
body
produced
received
by
the best results.
Dictionary,
Dictionary,
I
on a given surface.
were enchanced
^5 Webster's Third International
16 Webster's New World
desired
remained uneffected.
irridescence
clay
was
elem.
-21-
Sec
could control
Both the
glaze
certain solutions.
A
heavy
3rd ed. 1965
ed.
the spray.
1961
application was
devoid
surface
irridescence
of
be
maximum control could
there was more
the
irridizing
would
destroy,
variety
in
depth
were achieved
red
hot
sawdust
barrel
the
glaze
atmosphere
low).
to
appearance of
acquired
by
the
use of
These
different
effects
A
the ware.
metallic salt sprays.
in the
to crackle.
to let the
the pot
Periodically
smoke.
great
colorants
Glazes
This
of great
It
Finally,
smoke
the
develop
a
piece was
in the
was placed
spray
in
a
of cold water
left inside the
smok
glaze crackle.
Most
(1800 F and be
not work within
the Raku heat
range
fused to the
glaze surface
but only
compounds
after
from the
was removed
Sometimes
cool air.
done
was
important factor in the spray technique.
an
tested did
would get
because these
me
glaze created another variation.
Temperature is
chemicals
not appeal
pot was sprayed with the metallic salt.
barrel to
the
did
different
inside a kiln chamber,
this technique.
by
and moved about
caused
ing
with
along
be
fuming
gun method
The possibility everything
than enhance, the
rather
glaze
Crackling
the
vapor
With the spray
With
factor.
of glaze effects could
base
a
lustering
luster.
attained.
of a chance
or
or
dry
result was often a
The
the metallic substance.
an overload of
really
produced
white crystals.
Melting
they
points of
the
might work within
the Raku temperature range.
cases, less temperature
ticularly
it just
with stannous
volatilized and
chemicals
The
that
left the
Dr. Fred A.
Institue
of
to
in
However,
some
to produce desireable results.
surface of
less
cancel out most
the
glaze was
Oddly enough,
glaze unaffected.
worked well alone were
separate metallic
ester
was needed
chloride, if the
combination seemed
to whether
metallic salts provide some clue as
too
Par
hot,
some
successful when combined.
identifying
traits
of each
salt.
Elder,
Assistant Professor
Technology,
calls
of
this deposit
"Thin film Phenomena".
-22-
Chemistry,
at
the Roofa?^
of metallic compound a
Metallic
the
in
solutions are either
the glaze.
surface of
bond,
a chemical
A
spray is the
metallic salt
mechanical
bond is
a reaction
between
there is
acid while
feels that
most metallic salts would
deposited
was
Patterns
of
essary to
to
obtain a
develop
an
Absolute
control of
thin enough film in
He
irridescence.
on a ceramic surface
that
was
that different kiln atmospheres
acid and a
related
totally
for
Dr. Elder
as "Interference
solution would
be
nec
some chemical compounds
the idea
of vacuum
plating
metals
'Also he feels
clean and smooth.
might produce
The
base.
irridescence if the film
an
the spray
order
Atmospheres
effects of metallic salts.
an.
whereas
by heat,
is the base.
glaze
develop
caused
He defines irridescence
thin enough.
Light".
the
mechanically bonded to
or
chemically
distinctive
changes
in the
have been
of nitrogen and argon
suggested.
Within my
were
in
investigation,
form.
chloride
The
chlorides
is
stronger
the nitrates.
than
chlorides no oxygen
oxygen,
Inhalation
their toxicity.
tilation
somewhat of a
by
acid produced
glaze surface when
the
by
of
on
these
Care
bond.
is introduced to the
Nitrates
the
the metal in its
glaze
glaze surface.
oxide
form
when
the spray
surface.
compounds
was
the spray hits the hot
a chemical as well as a mechanical
and produce
is deposited
solution
for this is
metallic salts
other acids such as nitric acid produced
the
surface, producing
contain
actual reason
the
Professor Cowles feels that hydrochloric acid from the
metallic chloride etches
With
most successful of
Dr. Elder believes that hydrochloric
mystery.
glaze
the
is extremely dangerous because
taken when spraying
and use of a
strong
of
ven
system was necessary.
Using
icals did
the
methods
described in the spray
not work within
technique,
the Raku temperature
conditions :
1. Cobalt Chloride
2. Nickel Chloride
-23-
these
chem
range or atmospheric
3, Manganese Chloride
4. Barium Chloride
5. Zinc Nitrate
6. Ferric Nitrate
7. Aluminum Nitrate
8. Chromium Nitrate
9. Barium Nitrate
10. Strontium Nitrate
11.
Antimony
Tri-chloride
12. Molybolic Acid
13. Tungstic Acid
14. Potassium Chrom Alum
15. Cobalt Sulfate
16. Nickel Sulfate
17.
Antimony
Nitrate
18. Cadmium Nitrate
The
following
compounds
atmospheric conditions
have
the Raku heat
worked within
range and
using the spray technique:
1. Tin Chloride
2. Zinc Acetate
3.
Ferric Chloride
4. Zinc Chloride
5. Cuprous Chloride
6. Cupric Acetate
7. Cupric Nitrate
Tin Chloride
gave a
glossy irridescence.
produced a
handsome "Mother
variation.
The
ture,
of
glaze used with
Pearl",
Over
extremely
Tin Chloride
a white
it
glaze
in depth
rich
melted at a
base
and
lower tempera
thus preventing the tin from completely volatilizing.
P. White Glaze
Frit P-25
36
Frit 3124
28
Kaolin
8
12
Flint
Lithium Carbonate
8
Opax
Zinc Acetate
blue
10
produced an
and green glazes.
The
irridescent,
main
rainbow effect and was used over
difference between Zinc Acetate
-24-
and
Tin
Chloride
was
that the
zinc produced a mat
while
surface,
the tin
was
very
glossy.
Ferric Chloride was the only
irridescence
reddish
(See Slide
brown.
in
which
glossy surface,
The luster
luster.
and a
20)
tested that
some cases
produced
both
color range was yellow orange
Ferric Chloride
Sometimes it completely
neath.
compound
produced an
destroyed the
color of
the base
glaze as
obscured
an
to
extremely
the
glaze
in the
be
case
this glaze:
with
Red Glaze
Ceramic Color
Ceramic Color
and
and
If Ferric Chloride
of
or
irridescence.
the
was sprayed on
Best
clear and
the
Co.
Chemical Mfg.
This thin deposit
iron.
up
over
Chemical Mfg. Co.
was
,
,
Inc. Red Stain 3352
thickly
brown in
there
7
was a noticeable
devoid
color and
results were gotten when
yellow
100
Inc. Special Frit 441
of
build
any luster
Ferric Chloride
was used
base glaze.
Clear Base
74
Soda Ash
310
Frit W-15
38
Kaolin
144
Flint
Yellow
Potassium Bi-chromate
Using
the
yellow glaze underneath
range was yellow
Along
tested.
surface.
with
to
red orange.
these
Actually,
If left to
by
the Ferric Chloride spray, the
Both had luster
air
the spray
and
color
irridescence.
metallic compounds some soluble salts of copper were
the spray just deposited the
tion was necessary to
achieved
1/2-1%
cool, the
copper would
produce a metallic
method.
-25-
metal substance on
stay
luster.
a
A
familiar
the
green.
glaze
Reduc
copper yellow was
APPENDIX
Melting Points
Chemical
of some chemical compounds
Melting
Temperature
Boiling Poi
220.2
Antimony
Chloride
73. 4C
SbCl3
Barium Chloride
925
Bismuth Sub-Nitrate
260 ,
Cadmium Chloride
568
Cobalt Chloride
Cupric Chloride
Cupric Nitrate
114.
Molybdium Chloride
Nickel Chloride
Platinum Chloride
Selenium Chloride
Silver Nitrate
Silver Chloride
Stannous Chloride
Tungstic Acid
960
498
422
Manganese Chloride
-
-
Cuprous Chloride
Ferric Chloride
1560
-
1366
5
-
282
315
650
1190
-
-
973
-
581
-
288
-
212
444
455
1550
246.8
623
1473
-
-26-
CONCLUSION
I have heard Raku described
believe it is
feel it is
a
fad
soon
to
as
luck.
I
that this is true in many
submit
"In every culture,
success of the
have been
a
common.
giving up to the
are
those
seem, in texture
dict.
firing,
ceramic processes on
kiln gods,
and
Placing
one's pieces
forces
coming from the kiln
and
beyond
quite
color,
luck
prayer
the
sticks,
leveL
studio
and offerings
in the kiln is 9, kind
"17.
as strange
involved,
has been involked
power
the fire.
of
Others
ceramic scene.
certain amount of
may be sure, divine
we
metamorphic
one meets
there is a
will admit
Many
Some say Raku depends too
a valid use of ceramic materials.
While I
flamboyant.
quick and
from the American
vanish
much on
for the
being
"The
to
surrender,
greatest pots
objects;
one's power
of
they
may
visualize or pre
"18*
Inevitably,
Hopefully
slighted
be
will
for how it is
made.
two
years
past
glazes on slab
process.
My
the term Raku
America,
this pottery
For the
luster
in
given merit
I have
forms.
for
fade into the background.
what
worked almost
Many
for the
enthusiasm
will
techniques
process
is
it looks like
rather
than
exclusively incorporating
were
developed using
a
Raku
further
still undiminished and
exploration will continue.
which was
"Raku,
become
a vehicle
the power
of
Zen
originally
for the
still at
sudden
work,
With Raku I have been
fire
as
it transforms clay
17Rhodes,
Kilns,
pp.
able
an aspect of a
thrust
perhaps.
Ibid,
p.
intuition
and raw chemicals
189-190
181
27-
and
the playing
of
hunches:
"
to understand
18 Ibid
19
of
Zen-inspired tea cult, has
more
into
intimately
the power
ceramic objects.
of
BIBLIOGRAPHY
"Ceramic Raw
Material,
"
Ceramic
Cahners
Industry, Chicago:
Publishing
1961
Co.,
Earhart, W.
H.
Florida:
Koenig,
and
College Offset
J. H.
Literature Abstracts
,
of
Glazes,
Ceramic
1951.
Press,
Scott Greenwood
London:
Hainbach, Rudolf, Pottery Decorating,
Son,
and
1924.
A Potter's
Leach, Bernard,
Transatlantic
Nelson,
Glen C.
Raku
Kilns:
Co.,
Invitational, A
Art
Rhodes, Daniel, Clay
Co., 1957.
,
and
and
Technique,
Hollywood-by-the-Sea,
Florida:
Reinhart
an
and
and
Winston,
1960.
Exhibition, Geneseo,
Van Nostrand Reinhold
Potter, Philadelphia:
Chilton Book
Operation, Philadelphia:
Chilton
1969.
H.
,
The World
of
Japanese
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Pottery Decoration,
"The Twenty-third Ceramic
1965)
"The Object:
1965)
Ceramics, Tokyo:
Kodansha
1967.
uary-February
October
,
New York:
Glazzes for the
Shaw, Kenneth, Ceramic Colors
erick A.
Praeger, 1968.
,
ed.
Catalogue to
Design, Construction,
Sanders, Herbert
International,
Slivka, Rose,
3rd
Ceramics, New York: Holt,
Reigger, Hal, Raku:
Co., 1970.
Book
Book,
1968.
,
1967.
Arts,
,
Peterson, Allan,
W. M. Brown Co.
Iowa:
Lakofsky, Charles, Pottery,
pp.
Webster's New World
p.
National,
"
New York:
Fred
Craft Horizans (Jan
21.
Function, Craft,
and
Art,
"
Craft Horizons
10-11.
Dictionary, elementary
-28-
ed.
,
196 1.
(September-
Webster's Third New International
Dictionary,
Wildenhain, Marguerite,
Form
Pottery:
America Craftsmen's
Council,
and
Reinhold
-29-
3rd ed.
,
1965.
Expression, New York:
Publishing Corp., 1962.
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