IMPROVEMENTS IN THE PROCESS OF AND MEANS FOR ETCHING ON GLASS
Year: 1876

page_text: LETTERS PATENT to John Unwin, of Sheffield, in the County of York,
Merchant, for the Invention of "IMPROVEMENTS IN THE PROCESS OF AND MEANS
FOR ETCHING ON GLASS."
Sealed the 6th April 1877, and dated the 12th October 1876.
PROVISIONAL SPECIFICATION left by the said John Unwin at the Office of
the Commissioners of Patents on the 12th October 1876.
JOHN UNWIN, of Sheffield, in the County of York, Merchant.
IN THE PROCESS OF AND MEANS FOR ETCHING ON GLASS."
"IMPROVEMENTS
This Invention consists in the application or use of flexible moulds or blocks for
etching, or printing, or producing designs on glass. These blocks or moulds are
composed of certain proportions of glue and treacle, or india-rubber, or gutta
percha, or any other suitable material or composition that will make an elastic or
flexible mould, and such as are in common use. The glass after being made per-
fectly clean is caused to receive an impression from the flexible mould, which has
been covered with a suitable ink or adhesive matter, and when conveyed to and
deposited upon the glass the same is then covered with powdered resin, and after-
wards submitted to the action of fire, and melted or incorporated into the im-
pression; and when the same is perfectly set or dried the glass is then ready for
the bath or solution of acid such as is regularly used for the purpose of etching or
biting in the impression or figure required upon the glass. The following is the
kind or description of bath or solution, which I prepare by mixing a certain
quantity of fluoric acid with the same quantity or weight of common soda ash with
a sufficient quantity of water until the soda is dissolved and the whole well mixed
together; the surface of the glass is then wiped very clean, and the back part
varnished completely over to preserve it from the effects of the acid, so that only
the part intended to be acted upon shall come in contact with the biting or
etching properties of the solution. The length of time the same should remain in
the bath will vary in proportion to the strength of solution and the amount of
deadening and biting effect required upon the glass. After the same is taken out

page_text: of the bath or acid solution it should be saturated with clean cold water, and after-
wards cleaned with potash or soda and water.
I wish it to be clearly understood that I do not claim the use of flexible moulds,
which have long been in use for impressing figures and designs upon china, earthen-
ware, glass, and other articles of this nature, neither do I claim the etching with
fluoric acid, which is a well-known article used for such purpose; but my Inven-
tion consists in the combination of the various articles and processes herein par-
ticularly described for the purpose of producing etchings of all kinds of figures and
designs upon glass, and the same being cheaply and quickly done.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Unwin in the Great Seal Patent Office on the 12th April
1877.
JOHN UNWIN, of Sheffield, in the County of York, Merchant.
IN THE PROCESS OF AND MEANS FOR ETCHING ON GLASS."
"IMPROVEMENTS
This Invention consists in the application or use of flexible moulds or blocks for
etching, or printing, or producing designs on glass. These blocks or moulds are
composed of certain proportions of glue and treacle, or india-rubber, or gutta percha,
or any other suitable material or composition that will make an elastic or flexible
mould, and such as are in common use for printing purposes and made from wood
blocks and "stereos." The glass after being made perfectly clean is caused to receive
an impression from the flexible mould, which has been covered with a suitable ink
or adhesive matter, and when conveyed to and deposited upon the glass. If the
common ordinary printing ink be used it then requires the same to be covered with
powdered resin, and afterwards submitted to the action of fire and melted or incor-
porated into the impression made with the ink and when the same is perfectly set
or dried. The surface of the glass is then wiped very clean, and the back and other
parts not intended to be etched are varnished completely over to preserve them
from the effects of the etching solution, so that only that portion intended to be
acted upon shall come in contact with the biting or etching properties of the
solution. The glass is then ready for the bath or solution of acid such as is
regularly used for the purpose of etching or biting in the impression or figure
required upon the glass. The solution or bath which I used is contained in a tank
made of wood and lined with lead, and is prepared by well mixing together equal
weights of fluoric acid and of common soda ash with about six times the combined
weight of water until the soda is properly dissolved; these proportions are very
serviceable, but they may be altered a little in working. The length of time the
glass should remain in the bath may vary in proportion to the strength of the
solution and the amount of deadening and biting effect required upon the glass.
After the latter is taken out of the bath it should be washed with clean cold water,
and afterwards cleaned with potash or soda and water.
Having now described the nature and object of my said Invention, together with
the manner in which the same is to be or may be performed or carried into practical
effect, I wish it to be clearly understood that I do not claim the use of flexible
moulds, which have long been in use for impressing figures and designs upon china,
earthenware, glass, and other articles of this nature; neither do I claim the etching
with fluoric acid and soda, which are well known articles used for such purposes for
a considerable time; but I would remark in conclusion that what I claim as my
Invention is, the process of producing etched designs on the surface of glass by
printing them directly from flexible moulds in ordinary ink and applying powdered
resin to the printed parts and producing the etched and all deadened effects at
one operation by the agency of fluoric acid and soda ash, substantially as herein-
before described, the same being cheaper and more quickly effected than by the

page_text: process of transferring prints from steel, copper, metal, or stone plates, as in previous
inethods used for the purpose of etching on glass.
In witness whereof, I, the said John Unwin, have hereunto set my hand and
seal, this Fifth day of April, in the year of our Lord One thousand eight
hundred and seventy-seven.
JOHN UNWIN. (L.S.)