Improved Preservative Coating for Iron and Steel.
Year: 1893

page_text: Date of Application, 27th Oct., 1893
Complete Specification Left, 27th July, 1894-Accepted, 1st Sept., 1894
PROVISIONAL SPECIFICATION.
Improved Preservative Coating for Iron and Steel.
We WILLIAM MILLER WALTERS of 51 Upper Parliament Street, Liverpool,
Master Mariner, and FREDERICK RICHARD STONE of 58 Upper Parliament
Street, Liverpool, Brewer, do hereby declare the nature of this invention to be
as follows:-
The object is to provide an improved coating for preserving iron and steel from
rust and oxidation.
We have ascertained by experiment that tannic acid has a strong affinity for iron
and steel, and our invention consists in providing means whereby the said fact may
be utilized for obtaining a resisting coating for iron and steel.
In carrying our invention into practice we take tannic acid dissolved in water, oil
glycerine, or other suitable solvent, and add gums, glues, resins, or other convenient
materials to the above mentioned menstruum.
The mixture is applied to the iron and steel when fluid and forms thereon a
durable and efficient coating.
Dated this 26th day of October 1893.
Per pro J. T. KING,
J. Johnson,
Agent.
COMPLETE SPECIFICATION.
Improved Preservative Coating for Iron and Steel.
We WILLIAM MILLER WALTERS of 51 Upper Parliament Street, Liverpool,
Master Mariner, and FREDERICK RICHARD STONE of 58 Upper Parliament
Street, Liverpool, Brewer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
The object is to provide an improved coating or liquid for cleansing and preserving
iron and steel from oxidation, and also for acting as a primary coating to be
afterwards painted over or varnished.
We have ascertained by experiment that tannic acid has a strong affinity for iron
and steel, and that it so acts on iron or steel oxide or rust as to render the same
innocuous, but that by itself the resulting coating is not sufficiently permanent.
Now our invention consists essentially in providing means whereby the said facts
may be utilized for obtaining a sufficiently permanent and adhering coating for iron
and steel.
In carrying our invention into practice, under one modification we dissolve tannic
acid and a gum, such as gum acacia commonly known as gum arabic, dextrine, or
the like separately in water, and mix the acid and gum solutions together in the
required proportions. The gum is preferably reduced to a fine powder before
solution, and the water in which the said gum is dissolved is advantageously heated
by steam or otherwise.
Under a second modification of the process the required quantity of tannic acid
is added to the mucilage or gum solution when partially cooled.
We find in practice, that in order that the tannic acid may act on the iron and
steel so as to render any rust innocuous and also to prevent oxidation it is

page_text: inadvisable to have less than half a pound of the acid to a gallon of the fluid,
and it does not appear to be of advantage to have more than three pounds to
the gallon, in practice we find one pound answers well. To render the coating
more adherent and permanent, gum weighing about one half of the weight of the
acid to the gallon of coating, should be used. Glycerine or a mixture of glycerine
and water may be used instead of water.
The coating or liquid mixture is applied to the iron and steel by a brush, cloth,
or the like and forms thereon a durable and efficient coating, mainly insoluble in
water, and also a good ground work on which to paint or varnish.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
First. A coating for cast and wrought iron and steel consisting of a solution of
tannic acid and gum substantially in the proportions named.
Second. Preparing a liquid for coating iron and steel by dissolving separately the
acid and gum substantially as herein set forth.
J. T. KING,
Agent.