IMPROVEMENTS IN COATING IRON AND OTHER METALS WITH LEAD
Year: 1855

page_text: LETTERS PATENT to James Hulls, of Plaistow, in the County of Essex,
and John Lowe, of Lambeth Road, in the County of Surrey, for the
Invention of "IMPROVEMENTS IN COATING IRON AND OTHER METALS WITH
LEAD."
Sealed the 8th May 1855, and dated the 12th March 1855.
PROVISIONAL SPECIFICATION left by the said James Hulls and John
Lowe at the Office of the Commissioners of Patents, with their Petition,
on the 12th March 1855.
I, JAMES HULLS, of Plaistow, in the County of Essex, & I, JOHN LOWE,
of Lambeth Road, in the County of Surrey, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN COATING IRON & OTHER METALS WITH
LEAD" to be as follows:-
Our improvements in coating iron & other metals consists in so preparing
& treating them as to cause lead in a melted state to adhere firmly to their
surfaces, and thereby form a durable coating or covering of lead. To effect
this, we first steep the iron or other metal to be coated in dilute sulphuric
acid, in order to remove impurities from its surface; we then wash it in clean
water, and subsequently steep it in a solution of muriatic acid & zinc, which
thoroughly cleanses the metal surface & adapts it to receive the lead. The

page_text: iron or other metal thus treated is then dipped in a bath of melted lead of a
proper temperature; during the dipping we remove the article from the lead
bath, and apply dry sal-amoniac or sal-amoniac in solution to it, which causes
the lead to adhere uniformly & firmly to the iron. To apply a thick coating
the article may be dipped a second or third time. Lead may be applied and
caused to adhere to other metals, such as copper, brass, or Muntz's metal, by
the same process.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Hulls and John Lowe in the Great Seal Patent Office
on the 12th September 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
HULLS, of Plaistow, in the County of Essex, and I, JOHN LOWE, of Lambeth
Road, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of March, in the year of our Lord. One
thousand eight hundred and fifty-five, in the eighteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
James Hulls and John Lowe, Her special licence that we, the said James
Hulls and John Lowe, our executors, administrators, and assigns, or such
others as we, the said James Hulls and John Lowe, our executors, adminis-
trators, 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 AND OTHER METALS
WITH LEAD," upon the condition (amongst others) that we, the said James
Hulls and John Lowe, by an instrument in writing. under our hands and
seals, should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, 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.
NOW KNOW YE, that we, the said James Hulls and John Lowe,
do hereby declare our nature of our said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement:-

page_text: Our Invention of improvements in coating iron and other metals with lead
refers principally to the preparation or treatment of the metal to be coated,
whereby the surface is reduced to such state that, on its being immersed in
melted lead, the lead will have an affinity for and combine with and adhere to
the metal so prepared and immersed, and will retain a coating of lead similar
to the coating of tin applied in the well-known process of tinning. The
lead becoming incorporated with the body to be coated, it is thereby firmly
united, and is not liable to scale off which has been the case in any attempts
made heretofore to apply coatings of lead to the metals herein-after mentioned:
The process of preparing and coating has to be modified in some degree
according to the kind of metal to be coated, and the purposes for which the
coated metal is to be employed. In coating iron for roofing or other purposes,
where it will only be subject to the atmosphere in its ordinary state, we
prepare and coat the sheet metal as follows, which treatment is also adapted
for coating steel or forged iron, wrought or fashioned of the shape required
for its ultimate purpose:-
The métal is first submitted to the action of dilute sulphuric acid, in order
to remove the scale from the surface of the metal. This bath consists of one
part by weiglit.of sulphuric acid mixed with three parts of distilled water.
The metal is allowed to remain in this from five to eight hours, according
to the state of its surface, which may be judged by examining it from time to
time as the work progresses. The cleaner the surface of the metal is at the
commencement, the shorter need, be the duration of the bath. The metal
when removed from this bath is to be thoroughly. scoured with fine sand and
otherwise cleansed. in distilled water to frée them from all trace of the
sulphuric acid, and to remove loose matters from the surface. The metal is
now to be immersed for a few minutes in a bath consisting of one part of
ammonia to sixteen parts of distilled water. The metal when removed from
this bath is then submitted to the action of chloride of zinc by immersion
during one hour in a bath formed by dissolving one part by weight of zinc
in seven parts of hydrochloric acid. The metals under treatment are now
plunged in a solution of sal-ammoniac in the proportion of one part of
sal-ammoniac to twenty parts of distilled water. They are simply plunged in
this bath for a few minutes, and are then in a fit state to receive and adhere
to the coating of lead. . When the metals to be coated are in considerable
masses, the heat of the lead should be but little below a red heat, but for thin
plates or sheets the degree of heat need not be so high; the exact tempera-
ture-for the different. articles will, however, be readily, ascertained by practical
experience.

page_text: In plunging the metals in the lead bath they are allowed to remain
sufficiently long to allow the surface of the object to be coated to attain the
requisite heat to cause the lead to unite with the metal and adhere firmly
thereto. When the lead coating is required to be of a greater thickness than
a single coat obtained by dipping as before described, the metal must first
receive the coating as herein-before stated. The coated article is then placed
in a mould with a space between the coated article and the mould according
to the thickness of lead required as a further coating; melted lead is then
poured into the mould at a sufficient heat to fuse the previous coating, with
which it combines and gives the thickness of coating required. In this manner
an extra thickness of lead may be applied only in parts according to the
formation of the coating mould. In coating cast iron, a difference has to be
observed in the preparatory process.
The surface of cast iron to be coated is first covered with powdered sulphur,
and on this hot ashes are strewn until the sulphur is dissolved, after which it
is treated in a manner precisely similar to that before described. When the
metals to be coated are to be placed in situations where they will be subject
to aciduous vapours, or to salt water, or in situations where any chemical
agent is liable to operate actively on the covered metal, we prefer to dispense
with the chloride of zinc in the preparatory treatment of the metals to receive
the coating of lead, substituting for that part of the process the bi-chloride of
tin in the same proportion, into which the metals are to be immersed. Metals
prepared in this way when coated with lead are not so subject to the chemical
action of vapours or fluids which decompose more or less rapidly such metals
as iron, brass, copper, steel, or Muntz metal, when unprotected by the lead
coating. With the exception of substituting bichloride of tin for the chloride
of zinc, the cleansing and the whole preparatory process is precisely similar
to that first described, and the result of the coating the same in appearance,
but with the advantage before alluded to.
In applying a coating of lead to sheet copper, brass, or Muntz's metal, or
other articles made of those metals or materials, the same process of operation
is to be observed, with this difference in the strength of the sulphuric acid
bath. For this purpose the bath is prepared of a strength of one part of
sulphuric acid to nineteen parts of distilled water, and the time of immersion
reduced to about fifteen minutes, more or less, according to the state of the
metal's surface.
Having described the nature of our Invention, and the manner in which
the same is, to be performed, we would have it understood that what we claim

page_text: is, the preparing to be coated and coating the metals, and combination of
metals, herein-before mentioned, with lead, as herein-before described.
In witness whereof, we, the said James Hulls and John Lowe, have
hereunto set our hands and seals, this Twelfth day of September, in
the year of our Lord One thousand eight hundred and fifty-five.
Witness,
W. CLARK, Patent Agent,
53, Chancery Lane, London.
Agent, W. CLARK.
JAMES HULLS: (L.S.)
(L.S.)
JOHN LOWE.