IMPROVEMENTS IN COMPOUNDS FOR PLASTIC AND OTHER PURPOSES
Year: 1875

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company
Patent Agency, of Frankfort-on-the-Main, in the Empire of
Germany, for the Invention of "IMPROVEMENTS IN COMPOUNDS FOR
PLASTIC AND OTHER PURPOSES."-A communication from Joseph
Kreittmayr, Formator of the Bavarian National Museum, residing
at Munich in the Empire of Formant
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the
Office of the Commissioners of Patents, with his Petition, on the
15th March 1875.
I, FRANK WIRTH, of the Firm of Wirth and Company, Patent
Agency, of Frankfort-on-the-Main, in the Empire of Germany, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
COMPOUNDS FOR PLASTIC AND OTHER PURPOSES," a communication, to bo as
follows:-
The method which I use is based on the fact that hydrate of lime
when brought together with silicate of potash produces a cement-like

page_text: Compou
the silicic acid.
p
The chemical reaction takes place so quickly that a practical use
could scarcely be made of it if the same could not be retarded by some
addition without diminishing the adhesive force.
Although castings have already been produced with these or similar
materials I have discovered that this retardation can only be accom-
plished by a mixture of 7 volumina dried hydrate of lime, and 5 volumina
white tale. The latter is at first exposed for three-quarter hours to a dull
red heat, then poured in water, finally ground, and mixed with the lime.
1 volumina of this mixture with one-9 parts of the materials to be
mentioned (excepting fine sand), everything finely ground and sieved,
is mixed with so much concentrated solution of silicate of potash that a
liquid of a syrupy consistence is formed. This liquid mass can be
readily poured in moulds of glue. Castings thus produced solidify in
from ten to forty minutes.
By my experiments, which extend over fourteen years, I have become
convinced that only with a silicate of potash, produced according to
Kuhlmann, weatherproof castings can be made, and I have found
that all others made with differently prepared silicates are of no avail.
I have also found that only moulds prepared with equal parts of blue
and glycerine will suit my purpose.
I claim also as new the coating of the castings. When air dry they
are alternately brushed with dilute water glass (i.c., a solution of silicate
of potash containing one part in from six-ten parts of water) and diluto
hydrofluoric acid with the proportion of one: ten. Before brushing the
castings, with the acid it is well to add a nice point full of powdered
marble to it. Afterwards the acid should be diluted. The castings thus
receive a beautiful white colour. The application of the acid increases
the insolubility of the casting, and prevents an efflorescence of the
potash.
By the action of the carbonic acid of the air the castings attain a
considerable hardness.
11
Wal
onents

page_text: The following is a mixture which yields castings that equal in beauty
with ivory, or even surpass it. They are absolutely insoluble in water
and weatherproof, and remain unattacked by dilute hydrochloric
acid:-
Unc
"
taic.
This mixture is intimately compounded with the necessary quantity
of potash water glass, which must be of a syrup-like consistency.
For some purposes a mixture consisting of equal parts of finely
pulverized flous spar and quartz or glass powder with potash silicate is
preferable. When air dry these castings are to be treated like the
former.
Considering their cheapness, their resistance against the weather,
dilute hydrochloric acid and fire, they are certainly to be preferred to
gypsum and cement or pottery. A satisfactory result can be obtained,
no matter whether the proportions are always exactly chosen or not.
The many inconveniences and difficulties which attend the stereo-
chronic method at present in use caused the Inventor of the new
process to be described to try to use the substances for fixation
directly with the colours.
Instead of using the binding materials hitherto employed I take
sulphate of baryta, fluor spar, or cryolithe. For one part of said minerals I.
take one finest quartz, powder glass or sand previously heated and
afterwards cooled in water, one part of the so called stereochronic colours,
and mix the whole with so much concentrated silicate of potash that a
liquid of the consistency of thin oil colour is obtained. This mixture is
prepared one hour before use. In consequence of the intimate chemical
combination these colours adhere with great tenacity on the ground.
This latter may be of wood, cement, glass, stone, or metal, but must
previously be brushed over with dilute silicate of potash (proportion 1-6
or 1-10), as it is always more or less porous. There being sufficient
fluorine in the fluor spar or cryolithe in order to bind a surplus of potash
if present no efflorescence will take place. Hence the brushing over
with hydrofluoric acid is with few exceptions not necessary.

page_text: It is desirable however to protect the frescoes and paintings executed
in the respective manner from humidity at least for cight days. After
this time they will be perfectly weatherproof.
On the application of my mixture to wood, linen, dresses, and the
like. Although many trials with silicate of potash have been made to
protect wood against fire no satisfactory result has thus far been.
obtained, but this was always owing to an improper treatment. In my
process it is new and peculiar that the wood in order to protect it from
fire is coated with dilute silicate of potash (1:6 or 1: 10); as long as it
will absorb any; when air dry it is coated a second time with a more
concentrated solution (1:4), and at last with pure silicate of potash.
In order to make the wood still less inflammable it is to bo brushed over
finally with dilute hydrofluoric acid (1:10). If to be painted, 2 parts of
fluor spar and 1 part of glass powder are to be mixed with 1 part of the
so-called stereochronic colors, and the whole is to be compounded with
concentrated silicate of potash to the consistency of thin oil color. In
separately standing buildings this composition is easily applicable, and
wherever applied the fire will not be able to spread.
Wood which is treated in the indicated manner by means of pressure
is also uninflammable, and the wood in becoming entirely petrified will
not be exposed to putrefaction whenever in damp places. The described
process may also be applied to decorations of theatres, linen, and
dresses.
The following process is especially recommendable:-1), repeated
immersion in dilute silicate of potash (1:4): 2). drving: 3). immersion
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frank Wirth in the Great Seal Patent Offico
on the 11th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK
WIRTH, of the Firm of Wirth and Company, Patent Agency, of
Frankfort-on-the-Main, in the Empire of Germany, send greeting.
3

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date tho Fifteenth day of March, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
cighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Frank Wirth, Her special licence,
that I, the said Frank Wirth, my executors, administrators, and
assigns, or such others as I, the said Frank Wirth, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
COMPOUNDS FOR PLASTIC AND OTHER PURPOSES," a communication from Joseph
Kreittmayr, Formator of the Bavarian National Museum, a person
resident at Munich, in the Empire of Germany, upon the condition
(amongst others) that I, the said Frank Wirth, my executors or.
administrators, by an instrument in writing under my, or their, or
one of their hands and scals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Scal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frank Wirth, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
The method which I use is based on the fact that hydrate of lime
when brought together with silicate of potash produces a cement-like.
compound, whereby the potash separates, while the lime combines with
the silicate acid.
The chemical reaction takes place so quickly that a practical use
could scarcely be made of it if the same could not be retarded by some
addition without diminishing the adhesive force.
Although castings have already been produced with these or similar
materials I have discovered that this retardation can only be accom-
plished by a mixture of volumes dried hydrate of lime, and 5 volumes
white tale. The latter is at first exposed for hours to a dull red heat,

page_text: then poured in water, finely ground and mixed with the lime. One
volume of this mixture with 1-9 parts of the materials to bo
mentioned (excepting fine sand), everything finely ground and sieved,
is mixed with so much concentrated solution of silicate of potash that a
liquid of a syrupy consistence is formed. This liquid mass can be 5
readily poured in moulds of glue. Castings thus produced solidify from
10 to 40 minutes.
By my experiments, which extend over 14 years, I have become
convinced that only with a silicate of potash, produced according to
Kuhlmann, weatherproof castings can be made, and I have found that 1
all others made with differently prepared silicates are of no avail.
I have also found that only moulds prepared with equal parts of gluc
and glycerine will suit my purpose.
I claim also as new the coating of the castings. When air dry they
are alternately brushed with dilute water glass (that is to say, a solution 1
of silicate of potash containing 1 part in from 6-10 parts of water), and
dilute hydrofluoric acid with the proportion of 1-10. Before brushing
the castings with the acid it is well to add a knife's point full of
The
powdered marblo to it. Afterwards the acid should be diluted.
castings thus receivo a beautiful color. The application of the acid 2
increases the insolubility of the casting, and prevents an efflorescence of
the potash.
By the action of the carbonic acid of the air the castings attain a
considerable hardness.
As addition, the following materials are suitable:-Talc, quartz, glass 2
powder, heavy spar, and the like.
The following is a mixture which yields castings that equal in beauty
with ivory, or even surpass it. They are insoluble in water and weather-
proof, and remain unattached by dilute hydrochloric acid:-
6 parts fluor spar, purest,
quartz or glass powder,
2
"
2
fine sand,
"
-
lines hall an markle nowdon
3

page_text: . For some purposes a mixture consisting of equal parts of fincly
pulverized fluor spar and quartz or glass powder with potash silicate is
preferable. When air dry these castings are to be treated like the
former.
Considering their cheapness, their resistance against the weather,
dilute hydrochloric acid and fire, they are certainly to be preferred to
gypsum and cement or pottery. A satisfactory result can be obtained,
no matter whether the proportions are always exactly chosen or not.
Improved Stereochromic Process.-The many inconveniences and
difficulties which attend the stereochromic method at present in used
caused the Inventor of the new process to be described to try to use the
substances for fixation directly with the colors.
:
Instead of using the binding materials hitherto employed I take
sulphate of baryta, fluor spar, or cryolithe.. For one part of said minerals
I take one finest quartz, powder glass or sand previously heated and
afterwards cooled in water, one part of the so-called stereochromic
colors, and mix the whole with so much concentrated silicate of potash
that a liquid of the consistency of thin oil color is obtained. This
mixture is prepared one hour before use. In consequence of the
intimate chemical combination these colors adhere with great tenacity
on the ground. This latter may be of wood, cement, glass, stone, or
metal, but must proviously be brushed over with dilute silicate of potash
(proportion 16 or 1·10), as it is always more or less porous. There
being sufficient fluorine in the fluor spar or cryolithe in order to bind a
surplus of potash if present no efflorescence will take place. Hence
the brushing over with hydrofluoric acid is with few exceptions not
necessary.

page_text: will absorb any; when air dry it is coated a second time with a more
concentrated solution (1.4), and at last with pure silicate of potash.
In order to make the wood still less inflammable it is to be brushed over
finally with dilute hydrofluoric acid (1-10). If to be painted, 2 parts
of fluor spar and 1 part of glass powder are to be mixed with 1 part of i
the so-called stercochromic colors, and the whole is to be compounded
with concentrated silicate of potash to the consistency of thin color.
In separately standing buildings this composition is easily applicable,
and wherever applied the fire will not be able to spread.
Wood which is treated in the indicated manner by means of pressure
is also uninflammable, and the wood in becoming entirely petrified will
not be exposed to putrefaction whenever in damp places. The described
process may also be applied to decorations of theatres, linen, and
dresses.
The following process is especially recommended:-First, repeated 1
immersion in dilute silicate of potash (1.4); second, drying; third, im-
mersion in hydrofluoric acid (1 acid, 12 water); fourth, drying; and
fifth, brushing with concentrated silicate of potash.
In witness whereof, I, the said Frank Wirth, have hereunto set
my hand and seal, this Ninth day of September, in the year of 2
our Lord One thousand eight hundred and seventy-five.
TD ANT WITDMIT