AN IMPROVED METHOD OR PROCESS OF ENAMELLING IRON
Year: 1876

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for the Invention of
"AN IMPROVED METHOD OR PROCESS OF ENAMELLING IRON." A communi-
cation from abroad by Frederick G. Niedringhaus and William F. Nied-
ringhaus, both of Saint Louis, Missouri, United States of America,
Manufacturers.
Sealed the 4th August 1876, and dated the 14th June 1876.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 14th June 1876.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED METHOD OR PROCESS OF
ENAMELLING IRON." A communication from abroad by Frederick G. Niedringhaus
and William F. Niedringhaus, both of Saint Louis, Missouri, United States of
America, Manufacturers.
The present Invention relates to improvements in the enamelling of sheet iron
ware, by means whereof a beautifully mottled and more durable enamel is obtained.
I obtain this effect by causing an oxidation of the metallic base during the
enamelling process. The preferable way of doing this in practice is by omitting the
washing of the metal in the alkaline bath after it has for the purpose of cleansing it
been immersed in the acid bath, and by utilizing the acid which forms an element
in the enamelling glaze to oxidize the metal.
The procedure is as follows:-The metal is cleaned in the usual way in an acid
bath, then without employing an alkaline bath it is after the usual scouring to
remove the scale placed in clear water and allowed to remain say at least
half an hour to remove the acid. As soon as it is taken from the water it is
immediately coated with a liquid glaze, and placed in the drying room where the
glaze is slowly dried thereon. The appearance and character of the enamel is
determined during this drying of the glaze as according to the length of the time
taken in the drying and to the temperature of the drying room will be the amount
of oxidation. No definite rule can be given for either as the process is effected by
many circumstances, as for instance, the degree of humidity of the atmosphere. The
iron ware must be carefully watched during the process, and the temperature and
time regulated by the appearance of the iron. I prepare my glaze from the
ordinary ingredients taking care to have the said ingredients mixed and thoroughly

page_text: smelted together in bulk to expel all carbon and other elements that would impede
oxidation, and in order that the acid in the glaze may have free action. They are
then ground in water and applied in the usual way. Now by reason of the presence
of the acid of the glaze an oxidation of the metallic base takes place freely during
the drying process, appearing in and throughout the glaze as reddish spots.
This oxidation causes the enamel when it is finally formed in the usual way by
baking the iron in the oven to assume the desired mottled appearance. By reason of
this oxidation also the enamel is caused to enter the pores of the iron and become
more intimately incorporated in the metal, thus rendering the enamel more durable.
Another manner of accomplishing these objects when the use of the ordinary alkaline
bath is retained is to, increase the borate and reduce the alkaline fluxes in the com-
position of the glaze, thereby overcoming the alkali and insuring the oxidation of
the metal, and the character of the mottling and the durability of the glaze are
effected by the amount of acid present in the glaze when applied to the ware.
This process does not prevent the addition of the usual coloring matter to the glaze
if desired.
Having thus fully described the said Invention as communicated to me by my
foreign correspondents, and the manner of performing the same I wish it understood
that I claim the method or process of enamelling iron, as above set forth.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Fourteenth day of June, in the year of our Lord One
thousand eight hundred and seventy-six.
Witness,
ROWLAND GEORGE BROWN,
8, Southampton Buildings,
London, W.C.
WM. ROBT. LAKE. (LS.)