PROCESS OF ENAMELLING CAST IRON
Year: 1883

page_text: LETTERS PATENT to George James Rhodes, of Wolverhampton, in the County
of Stafford, Enameller, for an. Invention of
PROCESS OF ENAMELLING CAST IRON
"
"AN IMPROVED METHOD OR
PROVISIONAL SPECIFICATION left by the said George James Rhodes at the
Office of the Commissioners of Patents on the 7th May 1883.
GEORGE JAMES RHODES, of Wolverhampton, in the County of Stafford,
Enameller, "AN IMPROVED METHOD OR PROCESS OF ENAMELLING CAST IRON
"
My invention relates to an improved method or process of enamelling cast iron,
whereby I improve the appearance and increase the durability of the same, and
whereby I am enabled to apply colored enamels.to cast iron.
By my invention iron can be enamelled without the necessity for scraping or
pickling, or cutting the outer surface away, thus enabling ornamental castings' to
be enamelled without obliterating or impairing the design or ornamentation.
In carrying my said invention into practice I employ the process known as the
Bower-Barff rustless iron process."
In applying enamels directly to the surface of cast iron as heretofore practised,
upon the enamel being melted into a glaze the surface becomes covered with
bubbles or blisters caused by the gases imprisoned in the iron and expelled under
the action of heat in the muffle, thereby destroying the appearance of the enamel
and rendering it useless as a protection to the iron. The object of my invention is
to prevent the formation of these bubbles or blisters. I accomplish this by partly
expelling the gas from the pores of the iron and filling the said pores with oxide
by the "Bower-Barff" process and then completely expelling the gas and filling
the pores by applying to the surface of the iron in any suitable manner, a glaze
which will act upon the oxide and dissolve a film of the same with which it will
become chemically combined, thereby forming a smooth surface well adapted to

page_text: receive the enamel. Amongst glazes which I have found suitable for my purpose
may be mentioned the following, viz:-Borax 3 parts by weight
Red Lead 7
Sand
Saltpetre
Cullet
"
"
2
"
"
1
"
"
7
ม
"
these materials are melted together in a crucible until a clear glass is formed which
is cooled and pulverized or finely ground. The powder thus obtained may be
dusted upon the surface of the iron, or mixed with water and applied in a liquid or
semi-liquid state thereto by dipping or by means of a brush. It is then dried and
afterwards fired in a glazing oven. In some cases the coloring materials may be
added to the said mixture and ground therewith. The coloring materials are then
applied to the glazed surface in any of the well known manners of applying colors
to wrought iron.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent and of
an Order of the Lord Chancellor filed by the said George James Rhodes in
the Great Seal Patent Office on the 21st November 1883..
GEORGE JAMES RHODES, of Wolverhampton, in the County of Stafford,
Enameller, "AN IMPROVED METHOD OR PROCESS OF ENAMELLING CAST-IRON
"3
My invention relates to an improved method or process of enamelling cast iron,
whereby I improve the appearance and increase the durability of the same, and
whereby I am enabled to apply colored enamels thereto.
By my invention iron can be enamelled without the necessity for scraping or
pickling the same, or for cutting away or removing the outer surface thereof.
Ornamental castings can, therefore, be enamelled without obliterating or impairing
the design or ornamentation.
In applying enamels directly to the surface of cast iron as heretofore practised,
when the enamel, which is applied either in a liquid state or in the form of powder,
is being fired to produce a glazed surface, the said surface becomes covered with
bubbles or blisters caused by the expulsion, under the action of heat in the muffle,
of the gases imprisoned in the iron, thereby impairing the appearance of the
enamel and rendering it useless as a protection to the iron from rust.
The object of my invention is to prevent the formation of these bubbles or
blisters, and I accomplish this result as follows, that is to say:-I expel nearly the
whole of the gas from the pores of the iron and partially fill the said pores, with
oxide of iron by the process known as the "Bower-Barff rustless iron process "; or
I take iron which has been previously treated by this process. I then completely
expel the said gas and fill the pores of the iron as follows, viz;-I apply to the
surface of the iron, in any suitable manner, a glaze or enamel containing one or
more materials, such as borax, or oxide or carbonate of lead, which will act upon
the oxide and dissolve a film of the same, with which it will become chemically
combined, thereby forming a smooth surface well adapted to protect the iron from
rust. The heat to which the iron is subjected during this process of enamelling
expels the gas from the said iron.
One glaze or enamel which I have found very suitable for my purpose is
composed of the following ingredients, in or about in, the proportions named, that
is to say
of
Cullet 7 parts by weight
To make white enamel I add to the above mixture from 2 to 5 parts by weight
pure oxide of tin and a small quantity (say 1 per cent) of antimony.
To make blue enaniel I add to each pound of the said mixture from half an
ounce to one and a half ounces of pure oxide of cobalt according to the shade
required.
To make yellow enamel I add to the mixture from 5 to 15 per cent of oxide of
antimony according to the tint desired, and from 10 to 15 per cent of oxide of tin.
To make green enamel I add to the said mixture from 5 to 10 per cent of oxide
of copper according to the shade desired. This enamel may be modified in color
by the addition of more or less of the blue or yellow enamel above described.
To make black enamel I add to the mixture from 5 to 10 per cent of oxide of
nanganese.

page_text: These materials are placed in a crucible and are maintained for about four hours
at a temperature sufficient to form them into a clear glass, which is cooled and
pulverized or finely ground. The powder thus obtained may be dusted upon the
surface of the iron or mixed with water and applied thereto in a liquid or semiliquid
state by dipping or by means of a brush. It is then dried and afterwards fired in
a glazing oven.
In some cases coloring materials may be added to the said glaze and ground
therewith. For instance, it is advantageous in using light colours, such as white,
light blue or yellow, to add to the above described glaze, while the same is being
ground, about an equal quantity of calcined bone-dust, (phosphate of lime) and a
small quantity of china-clay and ground calcined flint. This mixture is applied in
the usual manner and fired, and the colored enamels are afterwards applied.
If two or more coatings of the glaze are required, the process of enamelling
above described may be repeated, the enamels each time being fired to form a
glazed surface.
+
Having thus fully described my said invention, and the manner of performing
the same, I wish it understood that I have hereinbefore described the enamels
which I have found most advantageous for my purpose, but I do not limit myself
to the employment of either of these enamels in carrying my said invention into
practice. Nor do I claim any of the said enamels, but I claim:
.
The herein described improved method or process of enamelling cast iron by
applying a glaze or enamel to the surface thereof after a coating of oxide of iron
has been formed thereon, for the purposes above specified.
In witness whereof I the said George James Rhodes have hereunto set my
hand and seal this seventeenth day of November in the year of our Lord One
thousand eight hundred and eighty three.
ARADAR TAM
DIANES