The Douglas independent. [volume] (Roseburg, Or.) 187?-1885, 1884-09-06
MAKING CASTS IN PLASTER.
The Model-The Danger.COat-Re-
producing Marbles.
IChicago Tribune.1

Casting in plaster is apparently a
simple process, but in the art centers of
Europe it is really profession, and one
in which years of practice are required
in order to obtain proficiency" So said
Mr.. Howard Kretchmer, the sculptor, in
answer to innumerable questions 1.-The
specimens of celebrated works of sculp-
ture seen in America are good, bad, and
Indifferent. Too often they are the
copies of copies-that is to say, they are
not made in the molds taken directly
from the original. The infnitesimal
variations in the first copies differences
so slight as not to be detected by eye or
measurement-are serious il continued.
Did you ever notice that when a car
penter is saving several lengths of board
he always uses the same piece for a
measured The reason is, that, whatever
difference or error may occur in any
single measurement cannot be continued
or increased if the original measure is
adhered to.
But you wish to know how plaster
casts are made; well, then | must first
impress you with the fact that sculpture
consists of three distinct processes. First,
the clay or wax model; second, the plas-
ter copy; and, third, the finished work
in marble, bronze, or whatever material
is desired. Now, tinted preparation
of plaster of Paris mixed with water, of
the consistency of rich cream, is thrown
in thin layer upon the soft, moist clay
model This is called the danger-coa
and is followed by thicker coating of
coarse plaster, sometimes supplemented
by iron rods or sticks imbedded in it to
give proper strength to the mold. In a
rangement sets and becomes hard, rigid
covering, the inner surface Vi which is
in close, perfect contact with the sur
face of the model, following the very
minutest detail of form and texture.
This covering or mold is divided or sep
arated into such portions as the charac-
ter of the form may render necessary by
pieces of tin or brass set edgewise, like
division wall in the clay, before the
plaster is applied.
"When the plaster is hardened suffi-
ciently the several pieces are separated
from each other and from the clay with
but little difficulty Of course the clay
model is partially and sometimes wholly
destroyed in the process of removal.
Any adhering clay is removed; the sur
face is carefully washed, and after the
application of oil, soap-suds, or a solu-
ton of soda-to prevent adhesion of
the plaster with which the inner surface
of the mold is afterwards covered-the
pieces are adjusted and firmly bound to-
| gether.
'We have now a plaster form akin to
Ill s,1@o oI1
preparation of plaster is thrown and
worked, covering the inner surface to
the necessary thickness, and allowed to
harden. The coarse plaster and bind
| ing irons of the mold are now broken off
by means of dull, blunt chisel and
mallet, leaving the plaster cast covered
| by thin coat of tinted plaster. This
danger coat is then carefully removed
| by the same means, the previous appli-
cation of oil and soda admitting of easy
separation, while the difference in tint
between the cast and the danger-coat
serves as valuable guide in the delicate
operation.
Il have already explained to you the
way in which copy of clay model is
made by means of what is called waste
mold. Both model and mold are de-
stroyed or wasted in the operation. The
method employed to reproduce the cast,
or marble, bronze, or any other rigid
form, without injury to the original is
very different and requires great skill
Indeed, very few of the for
matones-as men who follow this
industry are called in Italy
and only those of exceptional ability,
are permitted to make copies Of the val
liable works contained in the public and
private galleries of Europe. The reason
for this-the danger attendant on the
work. will explain to you presently.
Reproductions are made by what is
called piece mold, which is so arranged
that the various pieces can be readily re.
moved and readjusted.
"Thus, in molding a sphere, or say an
egg, by precision in the dividing line,
the mold might be made of only two
pieces, as both would draw from the OBJ
ject without difficulty. A pear of irreg
ular shape might require three or -four
pieces. And when you consider the in
tricacies of forms in a figure or group
you will not be surprised when tell you
that several hundred or even thousand
r
pieces are held together or keyed by 8
plaster cover of two or more parts
called cask, which serves the same pur
pose as the hoops around the slaves of 6
tub or barrel. or a printers chase fol
type.
when the mold is completed the cash
is first removed, the parts being laid
near the work, and into them the vari
Gus pieces of the mold are adjusted al
they are removed from the figure The
parts of the eask are then fastened to
gether, and we have plaster form simi
lar to waste mold; the cask taking the
place of the heavy coating, the pieces oi
the mold representing the danger coat
When plaster cast has been made ii
this the mold may be removed, as have
just related, and is ready for another
copy. When many copies are to be mad,
} from it it is dried, oiled, etc., details
unnecessary to describe. Gelatin,
molds are now frequently used, the gela
tine being held in position, like the piec
mold, by cask.
"a great danger in making plaste
, molds on marble lies in the fact tina
; plaster expands slightly in setting
While this quality adds to the perfec
ton of the impression, it may, unles
great discretion is used, crack or breal
forms in high relief, such as ornament
or even limbs or delicate masses Q
drapery."
When They VIII Realize.
D The Boston Globe thinks that whe
. the 112 young fellows who have gradu
t ated from Princeton as journalists