IMPROVEMENTS IN CUTTING OR PERFORATING STEEL AND OTHER METALS
Year: 1856

page_text: LETTERS PATENT to Julien Denis, of Queenhithe, in the City of London,
for the Invention of "IMPROVEMENTS IN CUTTING OR PERFORATING STEEL AND
OTHER METALS."-A communication.
Sealed the 23rd January 1857, and dated the 25th July 1856.
PROVISIONAL SPECIFICATION left by the said Julien Denis at the
Office of the Commissioners of Patents, with his Petition, on the
25th July 1856.
I, JULIEN DENIS, of Queenhithe, in the City of London, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN CUTTING OR PERFORATING
STEEL AND OTHER METALS," "a communication," to be as follows:-
These improvements consist of first coating the metals to be cut or per-
forated with certain varnishes & wax composition, as herein-after described,
& then subjecting the sd metals to the action of certain acids; these acids are
varied according to the kind of metal to be cut or perforated.
In some cases electricity is used to act on the metal in combination with
the acids.
Two kinds of varnishes are used, one of which the Inventor terms a pro.
tecting varnish, the other a decorative varnish.

page_text: which the designs are made. 2 consecutive coatings are given. The said
coatings must dry separately, at a heat not exceeding 50 degrees.
For the designs to be cut out clear they must be made on the rough side
of the metal, the protecting varnish being spread on the polished side, unless
through some reason the operator judge fit to act otherwise. This varnish
being dry, the protecting wax is laid on in manner following:-The wax com-
pound being placed in a recipient, is kept in a melted state in any suitable
manner and laid on with a brush on the metallic parts that most especially
require to be protected from the action of the acids, such as the angles. Flat
metal plates on which designs are to be cut out may be fixed on sheets of glass
coated with the protecting varnish & then with the protecting wax com-
pound. Care must be taken to fix the metal plates in such manner that the
acids cannot pass between the plates & the glass. In this manner several
plates may be perforated at the same time with great facility. The plates
must be thin in proportion to the minuteness of the cuttings to be effected.
The metal may be thinned by exposing one surface during a certain time to
the action of the acids.
MANNER OF USING THE DECORATIVE VARNISH.
This varnish is employed with ease, and may be laid on in the finest strokes,
the same as paint is laid on by decorators. It must, however, be recollected
that the finest of the strokes must be in proportion to the finess of the metallic

page_text: plates. This varnish is taken up from off a glass or crystal pallet. The
designs or tracings being made, they are dried at a heat that must not be
above 30°, and they must then be left exposed to the atmosphere during about
24 hours. Before plunging the metal articles or plates in the acids, a brush
impregnated with yellow wax is rubbed over them, thus giving a brilliancy to
the designs, & further strength to the varnish.
PREPARATIONS FOR THE ACIDS ACCORDING TO THE KIND OF METAL.
For tempered steel, rough or polished nitric acid at 40° diluted with water
and brought to 8°. This proportion is not absolute, but the one recommended.
Untempered steel, rough or polished: nitric acid at 5°; time rather longer
than for tempered steel.
Rough or polished iron: the same as for as untempered steel, in adding 1°
of sulphuric acid; but the difference of price between the price of steel or iron
being slight, it is always preferable to employ steel.
Copper or brass and German silver nitric acid diluted with water to
20 degrees with a 10th of oxalic acid.
Zinc equal parts of sulphuric and nitric acids diluted with water at 8°.
Silver nitric acid diluted with water at 25°, with an addition of sulphuric
acid 1°, to have the total 25°.
Gold: eau regale, but it requires great habit to succeed. with this
metal.
The metallic plates or articles being prepared, they are placed in a vessel
containing the acids suitable to act upon them. The parts on which the designs
are made must be placed downwards. Care must be taken that there be not
sufficient acid in the vessel for it to become heated during its action on the
metallic articles. Now and then the said articles must be quickly withdrawn
from the recipient so as to allow the hydrogen to evolve, hydrogen forming in
small bubbles on the metal surfaces, which is injurious to the proper action of
the acids. The articles must be placed at a sufficient distance from the bottom
of the vessel, so as to allow space for the falling metal.
For great metallic surfaces they can be made to communicate with an
electric battery of small power, which facilitates the cutting operation. The
positive pole must be of course immersed in the bath, and the negative pole.
is made to communicate with the metallic articles. The metallic articles being
perforated, are finally withdrawn and washed in clear water, after which they
must be all freed grease adhering to them. The following method of effecting
this is the best:-Two large slabs of cast iron must be heated at 80°; and
after having brushed the articles in clean water and then in spirits of tur-
5.

page_text: pentine, the articles are pressed on one of the heated pieces of cast iron, and
while in this position rubbed with a brush dipped every now and then in
spirits of turpentine, and this operation is continued until the protecting
varnish and wax have disappeared. The articles are then rinced in cleaner
turpentine, and are afterwards thrown in fine sawdust to dry. For delicate
objects that could not bear the action of the brush, they are placed a few
moments in gazeine, and rinced in spirits of turpentine, and passed through
fine sawdust.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Julien Denis-in-the-Great Seal Patent Office on the
24th January 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JULIEN
DENIS, of Queenhithe, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of July, in the year of our Lord Oue
thousand eight hundred and fifty-six, in the twentieth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said
Julien Denis, Her special licence that I, the said Julien Denis, my executors,
administrators, and assigns, or such others as I, the said Julien Denis, my
executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at 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 CUTTING OR
PERFORATING STEEL AND OTHER METALS," upon the condition (amongst others)
that he, the said Julien Denis, his executors or administrators, by an instru-
ment in writing under his, or their, or one of their hands and seals, 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 Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Julien Denis, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement :-
This Invention consists of a certain method for cutting or perforating steel

page_text: and other metals by chemical means. By this process the metal is subjected
to the action of acids, and the parts of metal that are to be preserved are
coated with certain varnishes or protecting. wax.
Two kinds of varnishes. are used, one of which the Inventor denominates
protecting varnish, and the other decorating varnish.
The decorating varnish is composed as follows:-
Bitumen
Thick brown varnish
-
25 parts.
50 do.
100 parts.
15 do.
10 do.
Pure spirits of turpentine
Pure yellow wax
The composition of the protecting varnish is as follows:-
Thick copal varnish
90 parts.
100 parts.
-
10 do.
Pure yellow wax
The protecting wax is thus composed :-
Pure yellow wax
White Burgundy pitch
Tallow
40 parts.
50 do.
100 parts.
10 do 1
For the perforation or cutting of designs in polished steel plates or other
articles of polished steel, a coat of the protecting varnish is first spread over
with a brush the bright side of the metal, & on the opposite or rough side
the designs to be cut out of the body of the metal are traced with a soft brush
previously dipped in the decorating varnish. The designs, however, instead of
being traced, may be printed or stencilled with the aforesaid decorating or
other suitable varnish or material. It is advisable to give two coatings of the.
protecting varnish; each coating must be dried separately in an oven kept at
a temperature of about 50 degrees Reaumur. When the metal is not in
flat plates, & that there are angles or edges to be protected, it will then be
necessary to protect the said angles or edges with the protecting wax afore-
mentioned, which is kept in a liquid state by warming it over a spirit lamp
or otherwise; the wax is also laid on with a brush. The decorating varnish
should be allowed to dry about 12 hours, exposed to a temperature of about
30 degrees Reaumur. For flat metallic plates, it will be advisable to fix them
with protecting wax on glass coated with the protecting varnish'; the side on
which the designs are to be traced is of course placed uppermost. The
metallic plate or article being prepared as herein-before described, is plunged
into a bath of nitric acid diluted at about 8 degrees of the acid weigher or
acidometer. The side on which the design is figured must be placed down-
wards. While the plate or article is immersed in the bath, it will be essential
to raise at short intervals the said plate or article, so as to allow the bubbles

page_text: of hydrogen continually forming under it to escape, as otherwise they would
prevent the regularity of the perforations in the metal. When the cuttings
or perforations are very delicate or minute, certain parts, after having been
some time exposed to the action of the acid, may be slightly coated with
protecting wax, so as not to be too much eaten away or corroded.
For the perforation of copper, the only differences are that the varnishes
should be more completely dried, and the nitric acid diluted at about 20 degrees
& mixed with about 16 oxalic acid. German silver or metal must be treated
in the same manner as copper. For silver, the nitric acid should be at about
25 degrees. For zinc, equal proportions of sulphuric & nitric acids diluted
at 3 degrees. For gold, nitro-muriatic acid or chlorine is to be employed.
It is well-to observe,-that- the thinner the metal plates or articles are the
clearer will be the perforations, and the more easily will they be effected.
I claim the herein-described method of preserving one side of the metal
free and clear from roughness, and retaining even its polish, by commencing
the perforating or cutting operation at the back of the plate or other article
to be perforated; but I do not limit myself to the employment of the herein-
described varnishes and protecting wax, as some other substances or com-
positions may, perhaps, be used with nearly as much or equal advantage;
Deither do I confine myself to the acids named nor the strengths specified.
In witness whereof, I, the said Julien Denis, have hereunto set my hand
and seal, this Twenty-fourth day of January, in the year of our Lord
Eighteen hundred & fifty-seven.