Year: 1898

page_text: A communication from GUILLIAM H. CLAMER, Chemist, of 46, Richmond Street,
Philadelphia, Pennsylvania, United States of America.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
Objects of the invention are, first; to provide a coating essentially of lead adhering
to and covering a metal surface whereby the same is caused to present an appearance
which may be described as frosted, ripple-marked or crystalline and which is an
acceptable substitute for the characteristic appearance of metal surfaces coated with a
naturally crystalline metal, as zinc, and at the same time to improve the wearing
quality of the coated article, and second; to provide an expeditious and com-
paratively inexpensive method of producing such a lead coating upon metallic
surfaces. To these ends the invention consists in a coating essentially of lead having
form or structure and characterised by a crystalline appearance and adhering to and
covering the metallic surface of a base or body in contra-distinction to a structureless
or amorphous coating characterized by a smooth tin-like and shiny appearance. The
invention further comprises the process of producing an adherent and covering coating
essentially of lead having form or structure which consists in applying to a metal
surface a coating of lead containing a small proportion of phosphorus such as
would naturally be amorphous or structureless, and then imparting form or structure
to such coating by the combined action of wind, cold and gravity.
The nature, characteristic features and scope of the invention will be more fully
understood from the following description taken in connection with the accompanying
drawings forming part hereof and in which
Figure 1, is a view illustrating the appearance presented by a lead coated
object embodying the invention diagrammatically and as well as it is possible to
do so in a line drawing.
Fig. 2, is a diagrammatic and exaggerated edge view of the same.
Fig. 3, is a sectional view hereinafter referred to, and
Fig. 4, is a view partly in section and partly in elevation of apparatus by means of
which the improved method may be practised.
Referring to Figs. 1 and 2, 1, is a body, base or object which may be of any size
and shape and of which the surface is of metal. 2, is a coating essentially of lead
covering and adhering to the metallic surface of the base, body or object 1, and
characterized by form or structure in contra-distinction to amorphism. An amorphous
or structureless coating essentially of lead has heretofore been applied to a metal
surface and presented a smooth tin-like appearance, but this coating 2, of the
invention has form and is at least in part crystalline or may be ripple-marked or both
and therefore imparts to the object a novel appearance which may be described as
frosted. Such an appearance is very desirable because among other things it is
intrinsically attractive and also imparts to the object a close resemblance to galvanized

page_text: An admixture of
iron, and this, for the following reasons, is quite remarkable.
phosphorus and lead will, upon slow cooling, crystallize provided the phosphorus is
present in sufficient quantity, for example, more than six or eight ounces of
phosphorus and one hundred pounds of lead. However, if the phosphorus exceeds
approximately two cunces to one hundred pounds of lead, the material will not cover
other metals dipped into a fused bath of it. It is known that phosphorus with or
without arsenic is used in the production of an efficient lead coating, however, to
permit of covering, the phosphorus must be used in comparatively small proportions,
not sufficient to change the amorphous character of the lead, so that the coating of
lead is amorphous, not dense and presents a smooth appearance. In this invention
phosphorus is used in the proportion of, for example, two ounces to one hundred pounds
of lead with or without arsenic, and tin is also used, bearing in mind that the coating
will not adhere properly unless at least about eight ounces of tin is employed to one
hundred pounds of lead and two ounces of phosphorus. Of course more tin may be
used but it is comparatively expensive, and if used in excess would be detrimental
because it would produce a coating which would be corroded. The described coating
is comparatively thick and dense and is therefore durable. Since the structure or
form which imparts the described appearance is produced at least in part by the
application of cold, as will be hereinafter more fully described, the following
improvement is effected. Should dust or hard particles of extraneous matter adhere
to the base or body which is to be coated, then the lead in slow cooling would tend
to draw away from them, thus leaving minute openings through which dampness
would enter and cause the body to rust. However, the effect of the application of
cold is to cause the lead coating to set before it has time to shrink away from such
particles, so that the coating overlies the same and the defect above referred to is
obviated. In Fig. 3, 4, indicates particles which are covered by the coating 2, as has
been described.
To practice the improved process, a coating consisting essentially of lead must be
applied to a metallic surface or surfaces. To this end, the metallic base, body or
object may first have its surfaces thoroughly cleaned, for example, in the manner
described in the Specification of British Patent, No 7533 of 1887, granted to Francis J.
Clamer, for a process of cleaning, preparing and coating metal plates and other metal
surfaces. A coating consisting of approximately one hundred pounds of lead, two
ounces of phosphorus and eight ounces of tin with or without two ounces of arsenic
may be applied to the metallic surface or surfaces of the base, body or object by
immersing it in a molten bath thereof. The phosphorus produces fluidity, and the
tin increases the affinity of the bath for the metal to be coated. Such a coating if
simply allowed to cool upon the base, body or surface would be amorphous or
structureless and present a smooth shiny appearance. The temperature employed
for the bath should be approximately 950 to 1050 degrees F. The body, base or
object having received such a coating is now subjected to the action of gravity, wind
and comparative cold in order to oppose its tendency towards amorphism by
impressing upon. it such form or structure as will produce the described characteristic
frosted appearance. To this end the object, body or base may be lifted or drawn from
the bath, thus permitting gravity to operate upon the coating. It is also subjected
to the action of comparatively cool wind. This may be accomplished in the well
known manner of coating iron with zinc, in which sheets of zinc are passed through a
flux of sal ammoniac, then through molten zinc, again through the same flux, then
through smoothing rolls, and finally impinging thereon a current of cold air.
ever, the described process differs from such known processes in that in the described
process a naturally amorphous coating is made to take on form or structure, for
example, ripple-marks are produced by reason of the fluidity of the lead coating
combined with the action of gravity, cold and wind, or the phosphorus actually gives
rise to crystals of phosphide of lead or tin or both which are mixed through the
amorphous lead, whereas in them no such result is sought or attained. The described
treatment also prevents undue running of the coating which is its expected result, in
contra-distinction to the production of form or structure as opposed to amorphism
How-

page_text: which is a most surprising and unexpected result. Moreover, it prevents the coating
from shrinking away from particles of dust as has been stated. Referring to Fig. 4, 5,
is a receptacle to which heat is applied by means of the furnace 6. This receptacle 5,
contains the molten bath which consists essentially of lead and has been above
described. The rollers 7, constitute means for lifting the object, for example, a sheet
of metal, as iron, out of the receptacle 5, with the result that the lead coating is
subjected to the influence of gravity, 8, are means by which the coated sheet is
subjected to cold blasts of air induced by the blower 9. 10, indicates means for
rolling and removing the ripple-marked or crystalline coated sheet.
The invention may be said to be based upon the discovery that the combined action
of gravity, cold and wind on a fluid adherent coating essentially of lead and known
only as amorphous or structureless results in the abolition of amorphism and the
production of form or structure describable as ripple-marked or partially crystalline, and
the application of this discovery imparts to a lead coated object a crystalline appear-
ance which is an anomaly in that lead coatings as heretofore known present only a
smooth amorphous appearance.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, declare that what I claim is :-
1. As an improved article of manufacture a coating consisting of the following
materials in the following proportions by weight, lead 800, tin not less than 4, and
phosphorus not less than 1 nor more than 8, and presenting a crystalline appearance,
as contra-distinguished from amorphism, and covering a metallic base or body,
substantially as described.
2. The process of producing upon a metallic base or body a coating essentially of
lead presenting a crystalline or frosted appearance which consists in applying to the
metallic hase a coating of lead 800 parts by weight and tin not less than 4 parts by
weight containing phosphorus within the limits of 1 and 8 parts by weight which
permits of covering and tends to cause amorphism upon slow cooling, and then
producing a crystalline appearance by subjecting such coating to the combined action
of gravity, wind and cold.
Dated this 6th day of December 1898.