IMPROVEMENTS IN COATING IRON WITH COPPER AND BRASS
Year: 1853

page_text: LETTERS PATENT to Charles Watt, of Selwood Place, Brompton,
and Hugh Burgess, of 27, Grove Terrace, Kentish Town, both
in the County of Middlesex, for the Invention of "IMPROVE-
Sealed the 8th July 1853, and dated the 17th February 1853.
PROVISIONAL SPECIFICATION left by the said Charles Watt
and Hugh Burgess at the Office of the Commissioners of
Patents, with their Petition, on the 17th February 1853.
We, CHARLES WATT, of Selwood Place, Brompton, and HUGH
BURGESS, of 27, Grove Terrace, Kentish Town, both in the County
of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN COATING IRON WITH COPPER AND BRASS " to be as
follows:-
This Invention consists of causing sheets, bars, and other forms.
of iron to be first cleaned, then coated over with a solution of cad-.
mium or.zinc, then dried and dipped into a bath of melted copper
or brass, then raised out of the bath into an atmosphere of steam
and carbonic acid flowing in in jets; and when the form of the iron
will admit of it, a pair of rollers is the best mode of raising it out of

page_text: the bath, and of equalizing the surfaces, and the reheated sheets or
bars may be further rolled, and by like means the two surfaces of
iron may be coated and joined.
SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said Charles Watt and Hugh Burgess
in the Great Seal Patent Office on the 17th August 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we,
CHARLES WATT, of Selwood Place, Brompton, and HUGH BURGESS,
of 27, Grove Terrace, Kentish Town, both in the County of Mid-
dlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of February,
in the year of our Lord One thousand eight hundred and fifty-
three, in the sixteenth year of Her reign, did, for Herself, Her
heirs and successors, give and grant unto us, the said Charles
Watt and Hugh Burgess, Her special licence, that we, the said
Charles Watt and Hugh Burgess, our executors, administrators,
and assigns, or such others as we, the said Charles Watt and
Hugh Burgess, our 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 COATING IRON WITH
COPPER AND BRASS," upon the condition (amongst others) that we, the
said Charles Watt and Hugh Burgess, or one of us, by an instrument
in writing under our hands and seals, or under the hand and seal
of one of us, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be
per-
formed, 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.

page_text: NOW KNOW YE, that I, the said Hugh Burgess, on behalf of
myself and the said Charles Watt, do hereby declare the nature of
the 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 thereof, that is to say:
This Invention consists of causing sheets, bars, and other forms
of iron to be first cleaned, then coated over with a solution of
cadmium or zinc, then dried and dipped into a bath of melted
copper or brass, then raised out of the bath into an atmosphere of
steain and carbonic acid flowing in in jets; and when the form of
the iron will admit of it, a pair of rollers is the best mode of
raising out of the bath, and of equalizing the surfaces, and the
reheated sheets or bars may be further rolled, and by like means
two surfaces of iron may be coated and joined.
And in order that our Invention may be most fully understood,
and readily carried into effect, we will proceed to describe the means
pursued by us.
In order that all parts of any article of iron may be well and
completely coated with copper or brass by this process, care must
be taken in the selection of the iron from which the article to be
coated is made, since from the use of dirty scrap iron, of which
much bolt and bar iron is formed, imperfect welding of the parts
results, and when the mass of forged iron is rolled into bar or bolt.
iron, the imperfect wielding is shewn by longitudinal cracks and
flaws down the rod or bar, which are not only impossible to clean,
so as to prepare the bar for the process herein-after described, but on
being suddenly heated by being immersed in the molten copper or
brass, the flaws open, and the dirty surface of the iron prevents the
coating being effect in such parts.
We will now proceed to describe the process by which a coating
of copper or alloys of copper is effected. The articles to be coated
are to be first well cleaned in dilute sulphuric acid, as is well under-
stood; they are then to be carefully washed in a dilute solution of
chloride of zinc. The strength of the solution we have used is made
by adding about five parts of water to a saturated solution of the

page_text: chloride formed by dissolving zinc in hydro-chloric acid till action
has ceased. We may here state that we do not confine ourselves to
the use of chloride of zinc. We find the other soluble salts of zinc
and tin may be used; and oxide of zinc deposited on the article to
be coated, by holding it: in the fumes of zinc during combustion,
produces a similar result. Oxides of zinc made into a very thin
cream with water, and applied to the iron article, carbonates of
zinc treated in the same way with dilute hydrochloric acid, are all
applicable for the process herein described; or, in place of zinc,
cadmium may be used in like manner.
The articles, after having been well dried when any of the above
solutions have been used, may be heated to about 250°, or to any
temperature short of driving off or decomposing any of the
above-named preparations, may be plunged into melted copper
or alloy of copper.
We may state that we do not find it advisable to use pure copper
alone, but we find a mixture of about two per cent. of zinc, and one
per cent. of tin, to ninety-seven parts of copper, answer the purpose
better than copper alone..
The length of time which the articles should remain in the molten
metal depends on the bulk of the articles, and the temperature of
the molten metal, and can only be determined by the eye and
experience; a three-quarter-inch bolt requires about three seconds.
The upper. surface of the molten metal should be the hottest, and
we have found it desirable to cover the top of the metal with
powdered charcoal, sand, or some such substance, to prevent oxida-
tion, and the chilling effect of the air. Immediately on the article
being taken out of the metal, it is at once introduced into a reservoir
or tank containing an atmosphere of steam and carbonic acid
flowing into it in streams; or, in place thereof, it may be of carbu-
retted hydrogen, or any deoxidizing vapour, and there allowed to
cool. Should carburetted hydrogen be used, care must be taken
that no atmospheric air be admitted into the reservoir, and for this
purpose the entrance by which the coated articles are introduced
must be double valved, and the gas kept to a slight pressure, so

page_text: that the pressure of the gas outwards will prevent the introduction
of atmospheric air into the tank or vessel, and the double valves
will prevent the loss of much gas, the articles being introduced
between the valves, one being shut when the other is open. The
tanks should be in sets of two, so that all the gas may be with-
drawn from one, and passed into the other, when it is requisite to
remove the coated articles. It is advisable to cover the floors of
the tanks with fine sand, to prevent the articles being injured on
passing into the reservoir. The advantage of using carburetted
hydrogen or other deoxidising agents is, that the heat from the
melting furnace is quite sufficient to produce all the carburetted
hydrogen required, a small retort to distil the coal being placed in
the fire of the furnace.
In some instances it may be desirable to protect the coated
articles from oxidation, by drawing them through a covering of
flux on the surface of the molten metal. We effect this by drawing
the flux on one side by a fire clay scraper, immersing the article in
the copper, and then allowing the flux to again cover the surface of
the metal, and withdrawing the article through the flux; we have
found glass answer the purpose well.
Iron being lighter than copper or the alloys of copper, we take
advantage of this circumstance, and by loosely placing a bolt which
is to be coated in an instrument consisting of two cones or rings (at
a distance apart, according to the length of bolt) that receive the
head and point, and which allow it play, the bolt will rise and fall
as it is introduced or withdrawn from the molten metal, and thus
all parts are exposed to the hot metal. The cones are made
of fire clay, or iron coated with a mixture of some fire clay and
a little borax, and are made as open as is consistent with suffi-
cient strength..
The lower cone is attached to a rod of iron, protected as the
cones, and standing out a little from it. The upper cone is attached
to a slide, which is retained at any height on the rod by a screw,
the two cones being opposite and above another. A bolt is placed
with the head in the lower cone, and the upper one is brought down

page_text: so as to just take in the point, allowing it to rise about an inch and
a half, but not sufficient to allow the head to rise out of the lower
cone. On being introduced into the molten metal, when at a cer-
tain depth the bolt rises, and allows the metal to touch all parts of
the head. The reverse takes place on withdrawing the bolt. More
than one set of cones may be attached to a rod.
.
For coating small articles, we have found a pot with its mouth
built into the furnace mouth like a glass pot do very well. The
principal object is to keep cold air from the surface of the metal,
which must be the hotest part, and to exclude all dust and dirt
from the metal. For large processes, an air or reverbatory furnace
is preferable.
In order to give to the coated iron bolts points of mixed
metal, the coated bolts are treated in the following manner:
We
find a mixture of two per cent. of tin, and one of zinc, best
for this purpose. The bolts, after having been coated with copper
or brass, have their end or ends brought up to a blunt point, cleaned
or brightened. They are then fitted into a casting box, having a
bottom perforated with holes; each hole has a screw attached to it,
so that the bolts may be held in the holes by the screws at any
desired height; the casting box is provided with an outlet, the bolts
being placed in the box at the desired height. About two inches of
loam is sifted over the bottom of the box, the bolts standing out of
the loam, and shewing a little of the coating above the loam; about
of inch is sufficient; runners, are then made in the loam
from each point, and all terminate in the outlet of the box before
named. The upper box being of the height of the desired metal
points or ends, is placed on the other, as is done on brass casting;
a thin piece of pipe is slipped over the iron end of the bolts, the
thickness of the pipe determining the size of the intended point
(the point should be about of an inch larger than the size
of the bolt, and rolled down to the same diameter); the upper box is
now filled up with loam, as is well understood by brass founders.
We have found it desirable to have a flat top, with holes exactly the
size of the pieces of pipe which form the pattern for the inétal joints

page_text: and directly above the holes through which the bolts are placed at
the bottom of the box, fitted on the top of the upper box, so as to
prevent the patterns being placed out of their place by the ramming;
the patterns are withdrawn, and runners made from one main to all
the inoulds. The bright iron points are now moistened with any
of the above-mentioned solutions or matters, and dried by placing
a coke fire over them in an iron basket. The molten copper or alloy
of copper may be run from an air furnace. Sufficient metal must
be allowed to flow upon the iron points till they are red hot. The
aperture or outlet of the lower box may now be closed with, a plug
of loam, and the points allowed to cool.
Another part of our Invention consists in casting copper or brass_
round iron bar or bolt sheet, and rolling the combined metals when
at the requisite temperature. In carrying out this part of our
Invention, we proceed as follows:-
The iron to be coated must be cleaned and washed, or covered
with any of the substances before mentioned. A mould is prepared
of well dried loam, the same as is used for cores by brass-founders,
having a foot at the lower end for the iron to fit into, to keep it in
its place. An iron bar formed to receive the upper end of the iron
serves the same purpose. At the top a small runner is left from the
bottom of the mould. The iron being dipped into the metal it is
desired to cover it with, it is plunged at once into the mould, which
is at the same time filled with molten metal. A little metal is allowed
to flow through the lower runner, it is then closed, and the mold
and feeder filled up with molten metal. A small but strong jet of
coal gas may be made to play upon the iron as it descends into the
molten metal in the mould, the form of the jet being circular,
and is brought into close contact with the coated iron by means of
a hollow ring, the aperture being just the size of the coated iron,
the gas entering the collar by a series of holes in the outside edge
of the collar. The combined metals should be rolled as soon
as they have cooled to the proper temperature; this varies with
the alloy of copper.
In rolling headed bolts we use rollers having a groove in each

page_text: the size of half the bolt head; so that when the corresponding.
grooves in the two rollers come together, they are equal in size
to the head of the bolt. The bolts are placed head first between
the rollers.
In witness whereof, I, the said Hugh Burgess, have here-
unto set my hand and seal, this Twelfth day of August,
in the year of our Lord One thousand eight hundred and.
fifty-three.
Witness,
JNO. COOK.
HUGH BURGESS. (L.S.)