PROCESS OF CLEANING, PREPARING, AND COATING METAL PLATES AND OTHER METAL SURFACES
Year: 1887

page_text: Date of Application, 25th May, 1887.
Specification Accepted, 22nd July, 1887.
13.
and Coating Metal Plates and
other Metal Surfaces.
We, FRANCIS JULIUS CLAMER and JOSEPH GREGG HENDRICKSON, both of Philadel-
phia, Pennsylvania, U.S.A. Gentlemen, do hereby declare the nature of our invention
for "PROCESS OF CLEANING, PREPARING, AND COATING METAL PLATES AND OTHER
METAL SURFACES," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
Our invention relates to a process of cleaning, preparing and coating iron, steel,
or other metal plates, surfaces and articles.
Our present invention contemplates the complete chemical cleaning and preparation
of such metallic plates etc., for the reception of a coating or bath of molten metal ;
and we prefer to use as the bath for depositing the coating on such plates etc., the bath
prepared under the patent granted to Francis J. Clamer, U.S. No. 283077
August 14-1883, as we have found that the bath named therein gives a better and
more perfect coat than we can otherwise obtain; but we would not be understood as
confining ourselves to the use of the herein-described process of cleaning and preparing
the plates etc., in connection with the metallic bath set out in the said patent, alone,
as it can be used with equally good effects so far as the cleaning and preparing of the
plates etc., go, when followed by a metal bath of any character.
The principal object of the present invention is to thoroughly chemically clean and
prepare metal plates etc., for the reception of the coating of molten metal.
We have found that where acids alone are relied upon to clean the plates etc., as is
commonly done in the methods at present pursued in coating metal surfaces, that the
surface or plate will not be entirely freed from the ferric oxide and will not be
chemically clean, so that the said plate etc., will not have a complete and perfect
affinity for the molten metal of the succeeding metal bath.
And we propose to use the said acid bath, when employed at all, only as a prelimi-
nary step in the cleaning process, for quickly removing the greater portion of the
oxide before the thorough cleaning is effected by other means which form the essential
features of this invention. And in instances where time is not an object and in case
of cleaning hollow ware, we dispense with the acid bath entirely.
The plate or surface to be chemically cleaned, whether having been first treated
or immersed in the acid bath or not, is placed in a cyanide bath composed of cyanide
of potassium and water in about the proportions of six (6) ounces of the former to

page_text: one (1) gallon of the latter, more or less, with or without caustic potash or ammonia,
where it is connected with a galvanic current and placed in the position occupied by
the anode in an ordinary electro-plating bath; and we place a suitable surface on the
negatior pole or kathode, and apply the current.
The plate on the anode side is thereby thoroughly and perfectly chemically cleaned
and stripped of every particle of ferric oxide, acid or other impurity.
The action of the galvanic current in the cyanide bath (which of course is an
alkaline bath), removes all the sulphuretted hydrogen which is always produced by a
previous cleaning in an acid bath, and thereby precludes the possibility of the re-
formation of oxide in a space of time, which is ample for the prosecution of the
subsequent steps of the process.
When the plates are first treated in an acid bath before the immersion in the cyanide
bath, we prefer to rinse them in water, after removing them from the acid bath before
placing them in the cyanide bath.
After being thus chemically cleaned by being made the anode in a galvanic current
in a cyanide bath the plates or other articles are immersed in a suitable flux, as for
instanco a bath of muriate of zine, which may be made by dissolving metallic zinc in
muriatic acid until it is thoroughly saturated and will take up no more of the metallic
zinc.
The flux prepares the plates or surfaces for a more ready adhesion of the molten
metal and constitutes an important step in the present process as it completes the
preparation of the plates for the reception of the coating of molten metal, after they
are cleaned in the cyanide bath.
From the flux the plates or surfaces are passed to the bath of molten metal with
which they are to be coated, where they are treated in the usual way, by being
immersed therein and withdrawn therefrom.
This bath of molten metal may be any of the well known coating baths, but as
above stated we have had the greatest success with the bath described in the patent
above mentioned, which consists of lead or similar metal mixed with sal-ammoniac,
arsenic, phosphorus and borax or a similar flux in the manner set forth in the said
patent.
Any strength of current sufficient to create action in the cyanide bath can be used
and increased as desired.
The preliminary acid bath is composed of sulphuric or muriatic acid.
We are aware that metal plates and surfaces have been stated to have been cleaned
by being made the kathode of an electric current in a cyanide bath and we do not
claim such.
Having now particularly described and ascertained the nature of our said invention,
and in what manner the same is to be performed, we declare that what we claim is :-
1st. The herein described process of treating metal plates or other metal surfaces,
consisting in cleansing the same by making them the anode in a cyanide bath through
which a galvanic current is passing, then immersing them in a flux and finally
immersing them in a bath of molten metal, substantially as set forth.
2nd. The herein described process of coating metal plates or other metal surfaces
consisting in cleansing the same by making them the anode in a cyanide bath, through
which a galvanic current is passing, then immersing them in a flux and finally
immersing them in a bath consisting of lead or similar metal, sal-ammoniac, arsenic,
phosphorus and borax or a similar flux, as set forth.
ALLISON BROS.,
Agents for the Applicants.