IMPROVEMENTS IN COATING OR COVERING METALS
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, EDMUND
MOREWOOD, of Enfield, in the County of Middlesex, Gentleman, and GEORGE
ROGERS, of the same Place, Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twelfth day of Decem-
year
ber (One thousand eight hundred and fifty), in the fourteenth of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, th
said Edmund Morewood and George Rogers, our exors, adñors, and assigns,
Her especial license, full power, sole privilege and authority, that we, the said
Edmund Morewood and George Rogers, our exors, adñiors, and assigns, or
such others as we, the said Edmund Morewood and George Rogers, our exors,
admors, or assigns, should at any time agree with, and no others, from time to
time and at all times during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, our Invention of "IMPROVEMENTS IN COATING OR
COVERING METALS;" in which said Letters Patent is contained a proviso, that
we, the said Edmund Morewood and George Rogers, or one of us, should
cause a particular description of the nature of our said Invention, and in what
manner the same is to be performed, by an instrument in writing under our
hands and seals, or under the hand and seal of one of us, to be inrolled in Her
said Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said in part recited Letters Patent, as in

page_text: appear.
NOW KNOW YE, that in compliance with the said proviso, we, the said
Edmund Morewood and George Rogers, do hereby declare that the nature of
our said Invention, and the manner in which the same is to be performed, are
fully described and ascertained in and by the following statement thereof, that
is to say:
We proceed as follows in coating zinc with lead by casting:-We first pour
a quantity of lead into the bottom of a flat shallow pan, oblong in form and
about an inch deep, the dimensions to be governed by the size of the sheets
which it is intended to produce; the temperature of this pan should be a little
above the melting point of zinc. This pan may be of iron or other suitable
material, having then a stratum of lead upon the bottom of the pan; we either
lay upon it a sufficient quantity of solid zinc and allow it to fuse, or we pour
the requisite quantity of molten zinc into the mould or pan, and having allowed
the two metals to remain in a fluid state some little time, in order that the
impurities which come to the surface may be skimmed off, and that the metals
may separate from each other (if mixture should have taken place), we set
the pan aside in order that its contents may cool. This slab may either be
allowed to cool completely, or when it has cooled down to the point at which
zinc is rolled (about three hundred degrees Fahrenheit,) it may be passed
through between rollers and extended. The proportions of lead and zinc in
the slab may be varied, but we consider the best proportions to be about
one-fourth lead and three-fourths zinc. The thickness of the slab may also
be varied, but we consider that from half an inch to five-eighths is a good
thickness for the slab.
Coating on both sides.-If we wish to give a coating of lead on both sides of
the slab of spelter, we then, after the slab has been prepared as above, and has
cooled down to a little above the melting point of lead, we proceed to sprinkle
salammoniac on its surface, and then, taking a stick or piece of lead, wo
proceed to rub the stick of lead on the surface of the hot spelter, and melt it
in such quantity as will make the required thickness of coating on the upper
surface of the spelter or zinc slab, which should first have been secured in its
place by wedging or otherwise, in order to prevent the lead on the surface
passing below and floating the zinc. Such slabs may be extended as before
explained. This method of coating is convenient when thin coatings are re-
quired on either side. We prefer to use lead, but lead alloyed may be
employed.
In coating zinc or the ductile alloys of zinc and copper with copper, we first

page_text: make a thin slab or stratum of copper in the manner just described. For
making one of lead, we allow it to cool to a little above the temperature neces-
sary for fusing the zinc or alloy, keeping the surface as clean as possible; or
we take a forged plate of copper, and having cleaned its surface we heat it to
the necessary temperature. We sprinkle a little powdered salammoniac, or
other suitable flux, on the surface of the copper, and work zinc or alloy on to
its surface by rubbing a stick of such metal all over it, until a coating of melted
zinc or alloy to the extent required is formed on the surface of the copper.
We then clean the surface of the zinc or alloy by skimming, and afterwards
allow it to cool. If we wish to give a coating of copper to both sides of zinc
or alloy, we take two plates of copper, thinly coated as above described, and
place them vertically on the end or edge in a wrought-iron or fire-clay mould,
having their zinc faces towards each other. We then place the mould in a
reverberatory furnace, and heat the slabs or plates in it to near the melting
point of the zinc or alloy. We then pour into the mould sufficient molten
zine or alloy to fill up the moulds. The molten zinc or alloy must be sufficiently
hot to cause the zine or alloy on the copper to melt, and there is, before pouring,
to be such a space between the zinc faces that the desired thickness of zinc cr
alloy may be obtained, and that the impurities may come to the top of the fluid
metal. Moderately thin plates of copper are better than thick ones in this
process, if zinc be used, on account of their annealing more easily and without
injury to the zinc; but if an alloy be used, then the higher melting point will
allow greater thickness of copper to be used.
The back of the copper-plates should fit up to the mould, or the space, if
any, between it and the mould should be filled up with sand, to prevent the
zinc running to the back of the copper-plate. Compound plates or slabs thus
produced by coating either on one side or both, are then to be rolled, to extend
the same annealing from time to time as necessary; and although we prefer
copper to coat one or both surfaces of zinc or alloy, yet the copper may be
alloyed, if desired particularly, when one side or the middle metal is to be
zinc.
In making a compound slab of tin or solder upon lead we proceed as
follows: We cast a quantity of lead into the bottom of an iron pan, we then
skim the surface clean, and allow the metal to set. When the temperature
has fallen to somewhat above the temperature necessary for fusing the solder
or tin to be used, we sprinkle a little powdered salammoniac upon the surface
of the lead, and then lightly rub it with a piece of solder or tin; this coats the
surface of the lead. We then either continue in this way melting the solder
or tin on the surface of the lead, or pour some from a suitable vessel upon it,

page_text: taking care not to continue pouring upon one place or it would make a hole
in the lead. When a sufficiency of the tin or solder has been put upon the
lead, its surface is cleaned with a skimmer and the slab is left to cool; it is
then extended by rolling.
In coating spelter or zinc with solder or tin, we proceed in the same manner
as in coating lead with solder, substituting spelter for lead.
In coating sheet iron, we take a sheet of zinced or zinced tinned-iron, and
place it upon a hot cast-iron plate, having first wetted the upper surface
of the sheet iron with a mixture of weak muriatic acid and salammoniac.
Then, when the cast-iron plate is about the heat of melting lead we pour
melted lead over it, and while it is in a fluid state we pass a warm roller over
its surface to set it to a proper thickness. We should mention that round the
edges and upon the sheet of iron we lay a square iron frame and sprinkle
a little fine sand under the frame, in order to prevent the escape of the lead
when rolling. One object in preparing lead or zinc with a coating of tin or
solder, as above described, is to coat sheet iron with zinc or lead, and we pro-
ceed as follows:-We roll the slabs out to the desired size or thickness, we
then take a sheet of iron, coated with zinc by preference, and having wetted
its surface with a rather weak solution of muriatic acid, we lay it upon a hot
cast-iron plate a little above the temperature at which the solder or tin em-
ployed will fuse, and then, having wetted the tinned or soldered face of the
sheet of lead with muriatic acid, we lay it with the wetted side upon the zinced
iron, and slowly pass over it a roller heated to about the melting point of the
tin or solder employed. This roller is to be followed by a colder roller or flat
surface to set the solder or tin, and to prevent the sheet of lead from rising or
springing from the surface of the iron. As the setting roller or surface pro-
gresses, we, in order to prevent the solder or tin from remelting, pass a cold plate
of iron under the sheet iron. Lead prepared as described with a tin or solder
face may in the same way be mited to zinc. If we wish to give a coating to
sheet iron on both sides by cementing, we take sheet iron coated on both sides in
the usual way with a tolerably fusible metal, such as tin or solder, and then,
having prepared the necessary sheets of lead or zinc in the way described for
preparing lead with a tin or solder face, we lay one of the sheets of lead or zine,
the solder face being always towards the iron, on a cast-iron plate sufficiently
hot to melt the tin or solder, but not to fuse the zinc or lead; upon the lower
lead or zinc plate we lay the sheet iron, and then upon the iron another lead
or zinc plate, and when they have got up to the melting point of the tin or
solder, we proceed as described for coating iron on one side only with lead
by cementing. If we wish to give a coating of lead on both sides to zinc by

page_text: cementing, we proceed in the same manner, and may afterwards extend it by
rollers.
In putting lead upon zinc by cementing, in order to after extension, we
proceed as follows:-We take a piece of lead, about five pounds to the square
foot, and coat it on one side with solder or tin, always taking care that we
coat it with a more fusible metal. Having done this, we take a slab or thick
plate of spelter or zinc, clean one side of its surface with muriatic acid; this
cleaned surface is then to be washed with clean water, and a mixture of weak
muriatic acid put upon it; it is then to be laid upon a cast-iron plate heated
to a little above the melting point of the sokler, and the tinned or soldered face
of the lead is to be laid upon it. When the zine has become pretty warm, so
as to melt the solder, a roller about or a little above the melting point of the
solder is passed slowly over the lead, which is to be set and kept down to the
surface of the zinc.
The plate or slab so formed is then removed from the hot iron plate and
allowed to cool, either wholly or down to the temperature at which zinc is
rolled, at which temperature it may be extended by rollers. The thickness of
the slab of zinc may be varied, but we consider three-eighths of an inch the
best thickness, and we prefer that it should be what is technically called first
broken down or rough rolled from the spelter.
Another part of our Invention consists of employing a reverberatory furnace
when coating with lead or zine.
In order to carry this part of our process into effect, we place a layer or
bed of powdered coke or charcoal, lamp black, or other suitable matter on
the surface of melted zinc or lead, which is contained in a vessel or pit
made of iron or other suitable material, in a reverberatory furnace. The flame
or heat ignites the charcoal or coke, which is kept in an incandescent state.
If the articles to be coated do not require much depth of vessel, we have
merely a shallow pit or trough built in the bottom of the reverberatory furnace.
If more depth be required, we make use of a bath of wrought iron or other
suitable material, which may or may not be lined or covered inside or outside,
In such case,
or both, with fire tiles, according to the judgment of the user.
however, the bath should be so fixed that the heat or fire may act upon the
sides as well as upon the surface, in order to keep the lower part of the metal
molten..
A suitable opening is to be made in the furnace, by which to introduce and
withdraw the articles to be coated with the molten metal, using long tongs
suitably curved or bent.

page_text: We prefer that the fuel used should be coke, or if of coal that the dipping
take place when there is not too much smoke.
The articles to be coated, prior to coating, are to be dipped in a strong
solution of salammoniac or in muriatic acid.
In witness whereof, we, the said Edmund Morewood and George Rogers,
have hereunto set our hands and seals, this Twelfth day of June, in
the year of our Lord One thousand eight hundred and fifty-one.