AN IMPROVED METHOD OF ETCHING AND PRODUCING INEXTINGUISHABLE METALLIC DEPOSITS UPON BRIGHT METAL SURFACES
Year: 1883

page_text: LETTERS PATENT to Ernst Nienstaedt of Berlin Prussia German Empire for
an Invention of "AN IMPROVED METHOD OF ETCHING AND PRODUCING
INEXTINGUISHABLE METALLIC DEPOSITS UPON BRIGHT METAL SURFACES "
PROVISIONAL SPECIFICATION left by the said Ernst Nienstaedt at the
Office of the Commissioners of Patents on the 30th January 1883.
ERNST NIENSTAEDT of Berlin Prussia, German Empire
"AN IMPROVED METHOD
OF ETCHING AND PRODUCING INEXTINGUISHABLE METALLIC DEPOSITS UPON BRIGHT
METAL SURFACES
»
My invention relates to an improved method of etching and producing
inextinguishable metallic deposits upon bright metal surfaces.
The method hitherto practised to etch upon metal consisted in printing a suitable
varnish upon the surface to be etched leaving free the lines and places where the
corrosive fluid was intended to act. The back of the metal plate or article having
been also coated with varnish, the article was submerged into the corrosive fluid,
or the latter was poured upon the surface and the incision was obtained in all
places not covered by the varnish. The mordants usually employed for etching are
sulphuric acid, nitric acid, oxymuriatic acid and other acids, also diluted acid
solutions of metallic salts of iron, copper, silver, gold, platinum and other metals.
In using pure acids such as indicated, the effect obtained is only that of eating
away the metal in the free or non-covered lines or places, this is simple etching;
but in using the solutions of metallic salts as before stated, metallic deposits are
obtained on the etched lines or places, such deposits being either bright, or brown
or black according to the composition and the more or less concentrated state of the
solution. The varnish subsequently is dissolved by oil of turpentine or any other
suitable solvent and the figure or design appears plainly visible upon the bright
metallic surface.

page_text: This method, however, is very circumstantial and cumbersome the operation of
varnishing and treating with acids or acid solutions requires separate rooms and
principally the evaporation of the acids and acid solutions is very dangerous to the
health of the operator.
My improved method of etching and producing inextinguishable metallic
deposits upon bright metallic surfaces does away with the varnishing and coating
of the article to be etched, and not the least unwholesome evaporations are
developed. My improved method may be worked by any body without any
previous knowledge of the art.
To carry my improved method into effect I use the neutral metallic salts as dry
as possible in which state the salts have the property of attracting the humidity
of the air. Such salts for instance are chloride of antimony, dichloride of platinum,
perchloride of iron, nitrate of copper, and similar metallic salts, also chromic acid
and the like. The dry crystals of such salts are finely ground and spread in a
thin layer upon any convenient elastic stamping cushion or upon a hard plate of
convenient material such as glass (preferably unpolished) porcelain or the like. From
the cushion or plate the pulverized salt which rapidly becomes moist by attraction
of humidity from the air, is taken off by a rubber stamp or any other suitable
preferably elastic stamp and printed or stamped upon the metallic surface to be
etched. If such surface be cylindrical or globular I generally roll it over the
rubber stamp with a slight pressure, thus producing the same effect as by stamping.
The design or figure of the stamp thus printed upon the bright metallic surface
will at once appear in a metallic deposit which inextinguishably adheres to the
metallic surface owing to the corrosive or etching quality of the salt. No coating
or covering is necessary for the surface where no etching is required..
Where I wish only to etch the metallic surface of an article without metallic
deposit I mix up a suitable acid with any suitable intermedium, to form a paste
which I print or stamp upon the metallic surface as before stated.
It will be evident that this method of printing or stamping directly upon any
metallic surface may be usefully applied without any difficulty for a vast variety of
purposes for example for gauging metallic scales, weights and measures and for
stamping or embellishing the metallic surface of any articles whatsoever in as rapid
as convenient a manner and without any unwholesome effect to the operator.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Ernst Nienstaedt in the Great Seal Patent Office on the
25th July 1883.
ERNST NIENSTAEDT, of Berlin, Prussia, German Empire, " AN IMPROVED.METHOD
OF ETCHING AND PRODUCING INEXTINGUISHABLE METALLIC DEPOSITS UPON BRIGHT
METAL SURFACES
"
:
My invention relates to an improved method of etching and producing
inextinguishable metallic deposits upon bright metal surfaces.
The method, hitherto practised to etch upon metal consisted in printing a
suitable varnish upon the surface to be etched, leaving free the lines and places,
where the corrosive fluid was intended to nct. The back of the metal-plate or
article having been also coated with varnish, the article was submerged into the
corrosive fluid, or the latter was poured upon the surface and the incision was
obtained in all places not covered by the varnish. The mordants usually employed
for etching are sulphuric acid, nitric acid, oxymuriatic acid, and other acids, also
diluted acid solutions of metallic salts, of iron, copper, silver, gold, platinum and
other metals. In using pure acids, such as indicated, the effect is only that of
eating away the metal in the free or non-covered lines or places; this is simple
etching; but in using the solutions of metallic salts, as before stated, metallic
deposits are obtained on the etched lines or places, such deposits being either bright,
or brown, or black, according to the composition and the more or less concentrated
state of the solution. The varnish, subsequently, is dissolved by oil of turpentine
or any other suitable solvent, and the figure, or design, appears plainly visible
upon the bright metallic surface.
This method, however, is very circumstantial and cumbersome, the operation of
varnishing and treating with acids, or acid solutions, requires separate rooms and,
principally, the evaporation of the acids and acid solutions, is very dangerous to
the health of the operator.
My improved method of etching and producing inextinguishable metallic
deposits upon bright metallic surfaces does away with the varnishing and coating
of the article to be etched, and not the least unwholesome evaporations are
developed. My improved method may be worked by anybody, without any
previous knowledge of the art.
To carry my improved method into effect, I use the neutral metallic salts, as dry
as possible, in which state the salts have the property of attracting the humidity
of the air. Such salts, for instance, are chloride of antimony, dichloride of
platinum, perchloride of iron, nitrate of copper, and other similar metallic salts,
also chromic acid and the like. The dry crystals of such salts are finely ground
and spread in a thin layer upon any convenient elastic stamping-cushion, or upon
a hard plate of convenient material, such as glass (preferably unpolished),
porcelain or the like. From the cushion or plate the pulverized salt, which rapidly
becomes moist by attraction of humidity from the air, is taken off by a rubber-
stamp or any other suitable, preferably elastic stamp, and printed or stamped upon
the metallic surface to be etched. If such surface be cylindrical or globular, I
generally roll it over the rubber-stamp with a slight pressure, thus producing the
same effect as by stamping. The design, or figure, of the stamp thus printed upon
the bright metallic surface, will at once appear in a metallic deposit, which
inextinguishably adheres to the metallic surface, owing to the corrosive or etching
quality of the salt. No coating or covering is necessary for the surface where no
etching is required.

page_text: Where I wish only to etch the metallic surface of an article, without metallic
deposit, I mix up a suitable acid, such as sulphuric, nitric, oxymuriatic acid or the
like, with a suitable intermedium to form a paste, which I print or stamp upon the
metallic surface, as before stated.
It will be evident that the method of printing or stamping directly upon any
metallic surface may be usefully applied without any difficulty for a vast variety of
purposes, for example, for gauging metallic scales, weights and measures, and for
stamping and embellishing the metallic surface of any articles whatsoever in as
rapid and as convenient a manner and without any unwholesome effect to the
operator.
Having thus fully described my invention and how it may be carried into
practice, what I claim is:
The method of etching and producing inextinguishable metallic deposits upon
bright metal surfaces by the use of dry, hygroscopic metal-salts, such as chloride of
antimony, dichloride of platinum, perchloride of iron, nitrate of copper and the
like, as also of chromic acid and the like, such salts being finely ground and
printed or stamped directly upon the metallic surface, substantially as described.
In witness whereof I, the said Ernst Nienstaedt, have hereunto set my hand
and seal this eighth day of June in the year of our Lord one thousand eight
hundred and eighty three.