AN IMPROVED ENAMEL APPLICABLE TO WOOD, PAPER, TEXTILE FABRICS AND OTHER SURFACES TO RENDER THEM IMPERVIOUS TO SPIRITS, OILS, GASES, OR OTHER SIMILAR FLUIDS
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Nicolas Tchepelevsky at the
Office of the Commissioners of Patents, with his Petition, on the
6th October 1868.-A communication from abroad by Otto Carl
Ramstedt, of Helsingfors, in the Empire of Russia.
I, NICOLAS TCHEPELEVSKY, of Moscow, in the Empire of Russia, at
present residing at Beaumont Street, Marylebone, in the County of
Middlesex, Colonel of Artillery, do hereby declare the nature of the said
Invention for "AN IMPROVED ENAMEL APPLICABLE TO WOOD, PAPER, TEXTILE
FABRICS AND OTHER SURFACES TO RENDER THEM IMPERVIOUS TO SPIRITS, OILS,
GASES, OR OTHER SIMILAR FLUIDS," (a communication to me from abroad by
Otto Carl Ramstedt, of Helsingfors, in the said Empire,) to be as
follows:-
The object of this Invention is to manufacture an enamel insoluble in
spirit, oil, or water, and to apply the same to the interior of casks or
other vessels made of wood, paper, or textile fabrics and intended to
contain hydrocarbon oils, volatile spirits, or other quickly evaporating
fluids so as to render them impervious and prevent the loss of their
contents by leakage or evaporation.

page_text: The enamel consists of two separate solutions, firstly, a warm solution
of animal size with the addition of glycerine and white alum; and,
secondly, a chemical production invented in Russia, and known there
as "Ramstedt's verdine," consisting of a mixture of sulphate of potash
and sulphate of chromium dissolved in cold water.
The first solution is prepared in the following manner :-Take one
part by weight of animal size in a dry state and immerse it in water
for twenty-four hours, after that the size must be removed and placed
in boiling water, the quantity of which must be equal to one-half the
original weight of the size. To this must be added one-sixteenth of
glycerine and one hundred and sixtieth of alum previously dissolved in
one-fortieth of hot water. The whole must then be boiled once, and
after the scum arising from the alum has been taken off it must be
poured through a metallic sieve into a clean vessel. The kier or vessel
in which this composition was boiled must then be carefully cleaned out,
and the composition must again be poured into it and kept at a
temperature not lower than twenty-six degrees (Reaumur) by means of
a small fire beneath the kier.
The second solution (that is, the verdine) is prepared from potash,
oxide of chromium, and sulphuric acid, and its composition will be
readily understood by any chemist from the following formula :-
KO, SO, Cr, O₂, 3SO,+8HO.
It is dissolved in fourteen parts of water without any remainder. If
five parts of this solution of "verdine" be well mixed with one hundred
parts of the size solution, a hard mass is obtained when cold that is
insoluble in spirit, water, or oil. In most cases the article that is to be
covered over with this enamel is first coated with the size fluid, after
which the "verdine" solution is applied. The proportions given above
are invariable, excepting in the case of the glycerine, the quantity of
which may be increased when a very flexible enamel is required.