IMPROVEMENTS IN THE COATING OR COVERING OF METALS OR SURFACES WITH PLATINA
Year: 1876

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
THE COATING OR COVERING OF METALS OR SURFACES WITH PLATINA." A com-
munication from abroad by Jean Baptiste Alexandre Dodé, of Paris, in the
Republic of France.
Sealed the 5th January 1877, and dated the 21st July 1876.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 21st July 1876.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THE COATING OR COVERING OF METALS OR SUR-
FACES WITH PLATINA." A communication from abroad by Jean Baptiste Alexandre
Dodé, of Paris, in the Republic of France.
The processes hitherto known for the coating or covering of metals, and which are
now employed, have only imperfectly attained the object in view, viz., the effecting
an impervious coating upon other metals either of copper, nickel, silver, or tin,
obtained either by immersion alone, or in conjunction with the employment of
galvanism or of magneto-electricity especially applicable to the coating of cast iron,
and it consists in the employment of platina in such a state of division, so as to
enable it to be employed as a preservative against the oxidation of metals.
In carrying out this Invention, I firstly employ a mixture composed of about
22 lbs. of borate of lead, and of about 4 lbs. of oxide of copper, the intimate
inixture of which may be effected by means of an incorporator or other suitable
machine, adding to the constituents the necessary quantity of essence of turpentine,
so as to render the product sufficiently liquid to be spread upon the articles or
objects. When the mixture is complete it may be mixed with neat's foot or
other oils.
The vessel containing the constituents before mentioned is then placed over a
gentle fire in order to render the mass very fluid, and to obviate the necessity of
adding a great quantity of essence of turpentine, when the mixture or composition
is warm it may be employed as follows:-The article or surface to be coated must,
firstly, be cleaned, that is to say, the sand adhering to the article or material to be
coated must be removed, if for example, the article to be treated is of cast iron.
If articles of wrought or rolled iron are to be operated upon, it suffices to remove
Doing 73

page_text: the dust or foreign bodies which might be attached thereto. In order to cleanse
and prepare the objects or articles to be coated they may be firstly submitted to
the action of essence of turpentine. For this purpose the operator provides him-
self with a large and rather hard brush, this brush is dipped into the composition
and the composition is applied to the object or article. Care must be taken to lay
on the coating or composition as evenly as possible. The coat or coating before
mentioned should be thin for its sole object is to prepare the metal upon which it
is applied prior to receiving the platiniferous covering, and to prevent in the case of
cast iron the employment of a large quantity of platina. It is, therefore, advisable
to make this preliminary coating thin, in order not to fill up the hollows or designs
of the moulding or casting which would detract from their merit. The articles or
objects are then to be placed in a heated chamber. The chamber is highly heated
so as to fix the composition, which by the action oft he fire should become of a dark
green color.
The chamber being allowed to cool, and the coated article will be
found ready to receive the coating of platina which is effected in the following
manner: I employ for example about 20 lbs. of borate of lead and about 11 lbs.
of litharge, and after thoroughly grinding and mixing these two products, taking
care to damp the mixture to be ground with a certain quantity of essence of
lavender, and I then prefer to collect the product in a vessel of enamelled cast iron,
and allow it to stand for some hours.
I then employ a solution or mixture in the manner following:-I take about
10 lbs. of platina, previously having been brought to the condition of dry chloride,
upon which I pour about 5 lbs. of ether, taking care to stir the mixture. When
the mixture is complete the vessel is to be covered and allowed to stand for 30
minutes, the vessel should then be carried into the open air, and the cover removed
so as to allow the ether to evaporate, the essence of lavender then remains in con-
junction with the platina. The platiniferous product thus obtained is poured slowly
during agitation of the same into the mixture of borate of lead and litharge, and
when the mixture is completed about 50 lbs. of amylic alcohol are to be added,
the whole is then mixed and the platiniferous composition is ready for use.
In order to effect the platinizing of the articles or objects, it is sufficient to take
an object or article prepared as indicated and to immerse it in the platiniferous
compound obtained as before mentioned, the article covered with a thin coating is
then allowed to dry, and when the immersed object or article has become some-
what plastic, and should there be any large hollows in the moulding care is to be
taken to remove with a brush the exudations which might produce a bad effect,
the article is then to be carried to a drying chamber, taking care not to raise the
temperature to too high a degree; it is then allowed to cool, and the articles will
then present to the eye a beautiful silvery white appearance.
By applying the second part of my Invention to articles of cast iron covered
with enamel results may be obtained which are analogous to those formning the
object of this Invention.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed by
the said John Henry Johnson in the Great Seal Patent Office on the 19th
January 1877.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in, the County of Middlesex,
Gentleinan. "IMPROVEMENTS IN THE COATING OR COVERING OF METALS OR SUR-
FACES WITH PLATINA." A communication from abroad by Jean Baptiste Alexandre
Dodé, of Paris, in the Republic of France.
The said Invention relates more particularly to the coating or covering of articles
or objects of cast iron, but it is also applicable to the coating or covering of other

page_text: metals in order to preserve them from oxidation under the action of air, fire, or
acid gases.
The processes hitherto known for the coating or covering of metals have only
imperfectly attained the object in view, the coverings of copper, nickel, silver, or
tin, applied by immersion or with the aid of galvanism not being adapted to
prevent oxidation.
The said Invention consists in the application of platina in such a state of
division as to enable it to be employed as a preservative against the oxidation of
metals, whereby a considerable saving is effected as compared with the systems at
present in use, and much greater efficiency is obtained.
In carrying out the said Invention the following mixture or composition is first
employed, viz.: -About 22 lbs. of borate of lead and about 4½ lbs. of oxide of
copper, the intimate mixture of which may be effected by means of an incorporator
or other suitable machine, the necessary quantity of essence of turpentine being
added to the constituents so as to render the product sufficiently liquid to be spread
upon the articles or objects. When the mixture is complete it is collected in a
cast-iron vessel and say about 13%, oz. of neat's foot or other suitable oil added to it.
The vessel is placed over a gentle fire in order to render the mass very fluid and
to obviate the necessity for adding a large quantity of essence of turpentine. When
the mixture or composition is warm it may be employed in the following manner:
-The article or surface to be coated is first cleaned by the removal of the loam or
sand, if the article or object to be treated is of cast iron, or of the dust or extraneous
matters which may be attached thereto if articles or objects of wrought or rolled
iron are to be operated upon.
In order to effect the cleaning of the article or object a brush of hair is dipped
into essence of turpentine and the article or object is rubbed hard therewith, after
which the article or object is permitted to stand for a short time in order to allow
the composition to be partially evaporated, the prepared mixture or composition
which has been maintained at a gentle heat is then applied. For this purpose the
operator employs a large and somewhat hard brush, and the composition is applied
to the article or object with a brushing and dabbing action so as to draw the
composition out of the brush, care being taken to lay on the coating of composition
as evenly as possible. The coating should be thin, its sole object being to prepare
the metal upon which it is applied prior to receiving the platiniferous covering, and
to prevent, in the case of cast iron, the absorption of an excessive quantity of
platina. It is therefore advisable to make this coating thin in order not to fill up
the hollows or designs of the castings, which would detract from their merit. The
articles or objects so treated are then placed in an oven or drying chamber which is
highly heated, so as to fix the composition which by the action of the fire should
become of a dark green colour. The articles or objects are then allowed to cool
when they will be found ready to receive the coating of platina, which is applied in
the following manner: -About 21 lbs. of borate of lead, and say about 11 lbs. of
litharge are taken and mixed together and reduced to a fine state of division, the
mixture to be ground being damped with essence of lavender, the product is then
collected by preference in a vessel of enamelled cast iron and allowed to stand for
some hours.
A solution or mixture is also prepared in the following manner :-About 11 lbs.
of platina previously brought to the condition of dry chloride is taken upon which
is poured, say, about 4%, lbs. of ether. The ether dissolves the chloride of platinum.
As soon as the solution is effected about 34 lbs. of essence of lavender are added,
care being taken to stir the mixture energetically with a spatula. When the
mixture is complete the vessel is covered, and allowed to stand for, say, about
30 minutes; the vessel is then carried into the open air, and the cover removed so
as to allow the ether to evaporate; the essence of lavender then remains in con-
junction with the platina. The platiniferous product thus obtained is poured
slowly during agitation of the same into the mixture of borate of lead and
litharge, and when this mixture is completed about 45 lbs. of amylic-alcohol

page_text: are added; the whole is then mixed, and the platiniferous composition is ready
for use.
In order to effect the platinizing of the articles or objects it is simply necessary
to take an article or object prepared in the manner herein-before described, and to
immerse it in the platiniferous compound obtained, as before mentioned, the article
or object covered with a thin coating is then allowed to dry, and when the im-
mersed article or object has been coated with the material, should any large hollows
exist in the casting, care is to be taken to remove with a brush the excess which
might produce a prejudical effect. The articles or objects are then placed in a dry-
ing chamber, care being taken not to raise the temperature to so high a degree as
for the preliminary drying operation previously mentioned, after which the articles
or objects are allowed to cool, when they will present to the eye a beautiful
silvery white appearance.
By applying the platiniferous composition either with the brush or by immer-
sion to articles or objects of cast iron covered with enamel similar results may be
obtained.
Although I have only mentioned the essential oil of lavender I have given it
as a type of those essential oils which may be employed either as substitutes for the
same or in conjunction therewith.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is-
First. The application of platina to and in the coating or covering of articles or
objects of cast iron either in their crude condition or enamelled, and in the coat-
ing or covering of other metals by the employment of a composition in which
the platina is held in suspension in essential oils, substantially as herein-before
described.
Secondly. The improved process of coating or covering metal articles or objects
with platina, consisting in firstly coating the metal article or object either in its
crude condition or when enamelled with essence of turpentine, and then covering
the said article or object with a coating composed of a mixture of borate of lead
and oxide of copper, and then drying such article or object in an oven or heated
chamber, and subsequently immersing the article or object thus prepared in or
applying to such article or object a composition (obtained under the conditions
herein set forth) consisting of borate of lead, litharge, platina in the state of chloride,
ether, essence of lavender, and amylic-alcohol, and finally subjecting the coated or
covered articles or objects to the action of heat so as to obtain a metallic coating
thereon, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this Eighteenth day of January, in the year
of our Lord One thousand eight hundred and seventy-seven.
J. HENRY JOHNSON. (L.S.)