AN IMPROVED ANTI-FOULING COMPOSITION FOR COATING SHIPS BOTTOMS AND SUBMERGED METAL STRUCTURES
Year: 1884

page_text: We JOHN PICKERING of 21 New Bridge Street in the City of London, Gentleman
and HEINRICH ERNST ADOLPHE SAALE of 67 Linden Gardens, Chiswick in the
County of Middlesex, Decorator do hereby declare the nature of our Invention
for AN IMPROVED ANTI-FOULING COMPOSITION FOR COATING SHIPS BOTTOMS AND
SUBMERGED METAL STRUCTURES, to be as follows:-
○
The object of this Invention is to provide a composition or paint for coating
ships' bottoms and submerged metal structures, whereby the adherence of barnacles,
weeds, grass, or any kind of animal or vegetable substance, the collection of which
is so detrimental to the speed of ocean going ships, is avoided.
In carrying out our Invention, we proceed as follows:-We take shellac, and
dissolve it in methylated or equivalent spirit. We next take boiled oil, turpentine,
spirit of tar and rosin, and heat them together until they become liquid. When
this mixture becomes cold, we mix it with the shellac and spirit, and we then take
the whole and grind it up in any well known manner with arsenic, carbonate of
baryta, quadroxalate of potash, oxide of zinc, red lead, crushed oyster shells, or
equivalent substance, galipot and sugar of lead in varying proportions.
The following proportions we have found to answer well in practice, although
we do not intend to confine ourselves to such proportions, as they may be varied
more or less without departing from the Invention and according to circumstances.
Shellac 25 parts, spirit 115 parts, boiled oil 45, turpentine 15, spirit of tar 5, and
rosin 10 parts. Arsenic 20 parts, carbonate of baryta 5, potash 10, zinc 5, red
lead 15 parts, crushed oyster shells or equivalent substance 75 parts, galipot 5, and
sugar of lead 10 parts.
All the above proportions are by weight. To the composition thus formed may
be added Venetian red or other pigment in proportions suitable to give the required
colour to the composition.
The composition thus formed will give a bright, glossy surface to the article to
which it is applied.

page_text: This vehicle or varnish consists of a shellac or spirit varnish, and of a rosin
varnish made separately and mixed cold.
The shellac varnish consists of about 25 parts of shellac dissolved in about
115 parts of methylated spirit to which is preferably added 5 parts of galipot or its
equivalent to prevent cracking.
The rosin varnish consists of rosin, boiled linseed oil, turpentine and spirit of tar
in or about the following proportions.
Rosin
Boiled linseed oil
Turpentine
Spirit of tar
10 parts
45
15 "
"
"
These ingredients are heated together until they become thin, and the fluid is
then allowed to cool. The two varnishes having been separately prepared and in a
cold or cool state, are mixed together and constitute the vehicle or medium with
which we prefer to incorporate the mixture of dry ingredients above named, as it is
impervious to water and unaffected by variations in the temperature of the sea.
These dry ingredients we use in or about the following proportions :-
Carbonate of baryta
Arsenic
Crushed or powdered oyster shell
Oxide of zinc
Red lead
-
Quadroxalate of potash and
Sugar of lead (or an equivalent dryer)
-
5 parts
-
20
"
-
75
5
در
"
15
-
10
"
10
"
These ingredients with the exception of the powdered oyster shell are procurable
ready for use, but the oyster shells require to be reduced in a pulverizer to a fine
powder before they can be properly mixed with the other ingredients.
It has been found by experiment and research that certain shells such as crushed
or powdered mussel or scallop shells serve to promote vegetable growths and to
attract oysters, barnacles and other shell fish to surfaces coated therewith; but that
it is just the opposite with certain other shells such as crushed oyster shells which
crustaceæ generally, shrink from approaching.
These dry ingredients are then ground in a suitable mill with the varnish or
vehicle above described and we thereby obtain a paint or composition perfectly
suited for protecting submerged metal bodies.
The paint rapidly drys and presents a hard glossy surface. It is found that two
coats are enough, and when this composition is used there is no need for painting
the hull with a separate coat of red lead, as the presence in the composition of the
oxide of zinc and red lead preserves iron and copper from oxydation, and wood
from decay.
Any suitable colouring matter such as Venetian red may be added to the anti-
fouling composition. We find that about 75 parts of Venetian red added to the
composition makes a serviceable paint of an agreeable colour, but other pigments
may be added to the composition at the discretion of the manufacturer.
It may be mentioned that the proportions of the several ingredients above given
are calculated by weight and are those which we have found to answer well in
practice. We do not however limit ourselves to the precise proportions given for
the dry ingredients, nor to the precise proportions and ingredients of the vehicle or
varnish with which such dry ingredients are ground into paint, as the same may
be somewhat varied without departing from the scope of our Invention and
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is:-
1. The use in the manufacture of an anti-fouling composition or paint for ships
bottoms and submerged metals, of baryta, arsenic, crushed or powdered oyster

page_text: shells, or their equivalent, oxide of zinc, red lead and quadroxalate of potash,
substantially as and for the purpose set forth.
2. The improved anti-fouling composition for ships bottoms herein above described
and consisting essentially of carbonate of baryta, arsenic, crushed or powdered
oyster shell or its equivalent, oxide of zinc, red lead, quadroxalate of potash and a
suitable dryer such as sugar of lead, in admixture with a vehicle or medium
composed of shellac varnish and rosin varnish, substantially as described.
3. The use in the manufacture of anti-fouling compositions for ships bottoms
and submerged surfaces, of crushed oyster shell or its equivalent in admixture with
quadroxalate of potash or its equivalent, for the purpose of preventing animal and
vegetable growths and repelling barnacles and crustaceæ generally, substantially as
described.
4. The use in the manufacture of anti-fouling compositions for ships bottoms of
carbonate of baryta, arsenic and crushed oyster shell or its equivalent substantially
as and for the purpose described.
5. In the manufacture of an anti-fouling composition for ships bottoms the use of
a varnish impervious to water and unaffected by changes of temperature in the sea,
prepared substantially as above described, in admixture with crushed or powdered
oyster shells or their equivalent, and quadroxalate of potash substantially as set
forth.
11
Ol
100