Year: 1887

page_text: I, WILLIAM DICK of Eagle Villa, Cann Hall Road, Leytonstone, in the County of
Essex, Engineer, 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:-
My invention has for its object the production of a varnish for the protection of
steam boilers, the hulls of iron and steel ships, iron tanks, and for iron work
generally.
In proceeding to manufacture the protective varnish according to my invention I
take twelve pounds of Egyptian Asphaltum kept at the boiling point for four hours;
to this is added during the first two hours, three pounds of red lead, and four pounds
of litharge. When thoroughly incorporated I add three gallons of boiled oil. Into
this composition which is kept constantly agitated I then introduce three pounds of
very finely ground black lead or Plumbago, and six pounds of Asbestos, by preference
Italian Asbestos, finely pulverised. These two last ingredients, having been intimately
incorporated together, must be added to the mixture of Asphaltum, red lead and
litharge, in small quantities only, at a time. I also add to the varnish at this stage,
very gradually, whilst still kept at the boiling point, (so as to ensure the thorough
admixture and assimilation of the whole of the ingredients) a solution of India Rubber
made by dissolving one pound of finely cut virgin India Rubber in two pounds of
Bengole, the whole is now kept boiling constantly stirred, for one hour longer,
when it is removed from the fire and allowed to cool. If necessary, the varnish may
be thinned off with turpentine to a consistency to suit various requirements.
Varnish produced by the admixture of the ingredients, and in the manner above
described, may be used as a protective coating for iron work generally, exposed to
atmospheric influence, but is especially adapted as a protective coating to both the
outside and inside of steam boilers, and more particularly for protecting Marine
boilers from the action of salt water; and when employed for coating or varnishing
the interior of such boilers, it will be found that being unaffected by either sea water,
or by the acids which attack from time to time the plates of boilers, in which impure
waters are used, it forms a perfect protection against "pitting" and corrosion, thus

page_text: obviating the necessity for the constant attention otherwise required to check the
progress of said "pitting" and corrosion.
Boilers, whether Marine or land, but especially the former, when coated externally
with my protective varnish before being placed on their seatings or set in brickwork,
would be completely protected from corrosive action.
By the admixture and incorporation of Black lead or Plumbago with the other
ingredients as herein before described, the varnish becomes more protective and fire-
proof, and I find by experience also, that the addition of Asbestos-which is almost
indestructible the varnish lasts much longer upon surfaces exposed to heat, in
addition to which, the Asbestos imparts to the varnish a better body, and renders it
more elastic.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I wish it to be understood that
I do not claim separately the use of any of the ingredients above named, but what I
do claim is :-
:-
A protective varnish produced in the mode and manuer herein described by the
incorporation or assimilation of the various ingredients herein named and in or about
the proportions herein specified.
JAMES STEVENSON,
Gray's Inn Chambers,
20, High Holborn, London, W.C.,
Agent for Applicant.