Iж- PROVEMENTS IN COATING WROUGHT OR OTHER IRON TO PROTECT IT FROM CORROSION OR OXYDATION
Year: 1863

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County
of Middlesex, Engincer and Patent Agent, for the Invention of "Iж-
PROVEMENTS IN COATING WROUGHT OR OTHER IRON TO PROTECT IT FROM
CORROSION OR OXYDATION."-A communication from abroad by George
Washington Holley, of Niagara, in the County of Niagara and State of
New York, United States of America.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the
8th May 1863.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN COATING WROUGHT OR OTHER IRON TO PROTECT IT
PROM CORROSION OR OXYDATION," to be as follows:-
This Invention consists in a process for securing upon the surface of iron a
coating consisting in part or wholly of metallic aluminium.
One mode of carrying out this Invention is as follows:-First, make the
surface of the iron to be coated perfectly clean; then take of any porcelain frit,
composed in part of feldspar, silex, and china clay, sixty pounds, and add
thereto ten pounds of feldspar, and not less than twenty nor more than forty
pounds of dry white lead, mix them together, and add sufficient pure water to
make them of about the consistency of ordinary cream; then put the whole

page_text: into a common porcelain or frit mill, and grind it until a thorough incor-
poration is produced. Next tako not less than ten nor more than fifteen
parts by weight of this mixture, and add to it not less than one nor more than
ten parts of any of the fat alum or potash clays so called, first having calcined
and pulverized the clay, and added sufficient water to make it of the same
consistency as the mixture of frit, feldspar, and white lead; then add suffi-
cient water to the whole compound to reduce its consistency to such a degree
as will just permit it to adhere to and cover the whole surface of the iron to
be coated, either when the iron is dipped into the compound or when the
compound is poured on to the iron. When the iron has had the compound
applied by either of the above modes, the compound is poured or drained off to
leave only a thin covering on the iron, and after this covering has been
thoroughly dried, the iron is placed in a reverberatory furnace or oven and
baked until the surface presents a glassy or glazed appearance, when the iron
is removed from the furnace or oven and allowed to cool gradually. It will
then be found to be covered with a vitreous coating, which is hard, glossy,
strongly adhesive, elastic, and tough enough to resist any bending of the
iron less than at a right angle, and indestructible by the ordinary acids
or alkalies, apparently owing its elasticity, flexibility, and adhesiveness to the
fact that the compound is caused by the baking process to yield metallic
aluminium, which lies between the iron and the outer glaze, firmly adhering
to both.
A frit employed as above described in producing the glazed coating
may be formed of the following materials in the following proportions by
weight: :-
Fifty parts
Feldspar.
Flint or silex.
Thirty parts
Ten parts
Twenty-five parts
Twenty parts
-
-
China clay or kaolin.
Sal soda.
"
Spanish white.
Ton parts
Boracic acid.
These materials are mixed together, melted, and drawn off into clean water
or clean seggars. I do not confine myself, however, to the above frit, as any
equivalent frit may be used. To coat iron with aluminium alone, and make
it more efficacious for use under salt water, take from two to three parts by
weight of any of the fat alum or potash clays prepared by calcination and pul-
verization, as herein-before mentioned, and add thereto from one to two parts
of pure boracic acid. Mix them thoroughly in water, and run them through
any common paint mill, leaving the mixture, when it comes from the mill, of

page_text: about the consistency of thick cream. Dip the iron into this mixture or
paste, and then dry the paste until all the moisture is expelled from it. Then
bake, as before directed, until the surface appears glossy and friable or pitted,
that is, until the paste is reduced, as it is termed, by the heat, when the iron
should be removed from the furnace or oven, care being taken not to permit
anything to come in contact with the paste, since in its soft state it would be
removed from the iron. As the iron shrinks by cooling, the slag will throw
itself off by decrepitation, leaving the iron covered with metallic aluminium:
Then put upon the whole surface thus covered three coats of common coal oil
or kerosene, which increases the resistance to corrosion, and also from its
offensive odor repels the attacks of animalculæ and molluscs.
The iron may also be coated with the aluminium by melting the clay and
boracic acid, mixed as above stated, either with or without the addition of one
part of sulphate of baryta (heavy spar), and then heating the iron to redness,
dipping it in this fluid mixture, and then allowing it to cool off slowly.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Clark in the Great Seal Patent Office on the
4th November 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Iler Letters
Patent, bearing date the Eighth day of May, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year
of Her reign, did, for Herself, Her heirs and successors; give and grant
unto me, the said William Clark, Her special licence that I, the said
William Clark, my executors, administrators, and assigns, or such others
as I, the said William Clark, my 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 Inven-
tion for "IMPROVEMENTS IN COATING WROUGHT OR OTHER IRON TO PROTECT IT
PROM CORROSION OR OXYDATION," a com". to me from abroad by George Wash-
ington Holley, of Niagara, in the County of Niagara and State of New York,
in the United States of America, upon the condition (amongst others) that

page_text: I, the said William Clark, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, 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 I, the said William Clark, do hereby declare
the nature of the said Invention, and in what manner the same is to bo
performed, to be particularly described and ascertained in and by the following
statement (that is to say) :-
This Invention consists in a process for securing upon the surface of iron a
coating consisting in part or wholly of metallic aluminium.
One mode of carrying out this Invention is as follows:-First, make the
surface of the iron to be coated perfectly clean; then take of any porcelain frit,
composed in part of feldspar, silex, and china clay, sixty pounds, and add
thereto ten pounds of feldspar, and not less than twenty nor more than forty
pounds of dry white lead. Mix them together, and add sufficient pure water
to make them of about the consistency of ordinary cream; then put the whole
into a common porcelain or frit mill, and grind it until a thorough incor-
poration is produced. Next take not less than ten nor more than fifteen parts
by weight of this mixture, and add to it not less than one nor more than ten
parts of any of the fat alum or potash clays so called, first having calcined
and pulverized the clay, and added sufficient water to make it of the same
consistency as the mixture of frit, feldspar, and white lead; then add suffi-
cient water to the whole compound to reduce its consistency to such a degree
as will just permit it to adhere to and cover the whole surface of the iron to
be coated, either when the iron is dipped into the compound or when the
compound is poured on to the iron. When the iron has had the compound
applied by either of the above modes, the compound is poured or drained off
to leave only a thin covering on the iron, and after this covering has been 1
thoroughly dried, the iron is placed in a reverberatory furnace or oven and
baked until the surface presents a glassy or glazed appearance, when the iron
is removed from the furnace or oven and allowed to cool gradually. It will
then be found to be covered with a vitreous coating, which is hard, glossy,
strongly adhesive, clastic, and tough enough to resist any bending of the iron loss
than at a right angle, and indestructible by the ordinary acids or alkalies,
apparently owing its elasticity, flexibility, and adhesiveness to the fact that
the compound is caused by the baking process to yield metallic aluminium,
which lios between the iron and the outer glaze, firmly adhering to both.

page_text: A frit employed as above described in producing the glaze coating
may be formed. of the following materials in the following proportions by
weight:―
Fifty parts
Feldspar.
Thirty parts
"
Flint or silex.
Ten parts
.
China clay or kaolin.
Twenty-five parts
"
Sal soda.
Twenty parts
-
Ten parts
Spanish white.
Boracic acid.
These materials are mixed together, melted, and drawn off into clean water
or clean seggars. I do not confine myself, however, to the above frit, as any
equivalent frit may be used. To coat iron with aluminium alone, and mako
it more efficacious for use under salt water, take from two to three parts by
weight of any of the fat alum or potash clays prepared by calcination and pul-
verization, as herein-before mentioned, and add thereto from one to two parts
of pure boracic acid. Mix them thoroughly in water, and run them through
any common paint mill, leaving the mixture, when it comes from the mill, of
about the consistency of thick crean. Dip the iron into this mixture or
paste, and then dry the paste until all the moisture is expelled from it. Then
bake, as before directed, until the surface appears glossy and friable or
pitted, that is, until the paste is reduced, as it is termed, by the heat, when
the iron should be removed from the furnace or oven, care being taken not to
permit anything to come in contact with the paste, since in its soft state it
would be removed from the iron. As the iron shrinks by cooling, the slag
will throw itself off by decrepitation, leaving the iron covered with metallic
aluminium. Then put upon the whole surface thus covered three coats of
common coal oil or kerosene, which increases the resistance to corrosion, and
also from its offensive odor repels the attacks of animalcula and mollusks.
The iron may also be coated with the aluminium by melting the clay and
boracic acid, mixed as above stated, either with or without the addition of one
part of sulphate of baryta (heavy spar), and then heating the iron to redness,
dipping it in the fluid mixture, and then allowing it to cool off slowly.
Having described the nature of this Invention, and the manner of per-
forming the same, I declare that what I claim as the Invention to be protected
by the herein-before in part recited Letters Patent, is,―
First, obtaining upon the surface of iron a coating composed in part of
metallic aluminium, by covering it with a compound of porcelain frit, whito
lead, feldspar, and fat alum or potash clay, and subjecting it to a single baking
operation, substantially as herein described.

page_text: Secondly, obtaining upon the surface of iron a coating of metallic aluminium,
either by covering it with a paste of fat alum or potash clay and boracic acid,
and subjecting it to a baking operation, or by fusing the said paste and
dipping the iron heated to a red heat in the molten fluid, and after it is cold
applying the coal or keroseno oil, substantially as herein specified.
In witness whereof, I, the said William Clark, have hercunto set my
hand and seal, this Second day of November, in the year of our
Lord One thousand eight hundred and sixty-three.
Witness,
W. G. E. SWINNOCK,
53, Chancery Lane,
London.
W. CLARK. (L.S.)