IMPROVEMENTS IN THE METHOD OF PROTECTING SUBMERGED STRUCTURES OF IRON AND STEEL FROM CORROSION AND FOULING to be as follows:
Year: 1884

page_text: I FARNHAM MAXWELL LYTE, of Cotford, Oakhill Road, Putney in the County of
Surrey, Analytical Chemist do hereby declare the nature of the said invention for
"IMPROVEMENTS IN THE METHOD OF PROTECTING SUBMERGED STRUCTURES OF
IRON AND STEEL FROM CORROSION AND FOULING to be as follows:-
"
This Invention relates to an improvement on the Invention for which I made
former application for Letters Patent (No. 5375 of 1883) and which consisted in a
method of protecting submerged structures of iron and steel from corrosion and
fouling by the application to the structure of an inert or nonconducting paint,
or a paint having for its basis a metallic oxide the metal of which is electro
positive to iron, followed by a paint having anti-fouling qualities or qualities
poisonous to weeds, barnacles, &c.
As is explained in the specification of my aforesaid application, it is necessary to
interpose between the anti-fouling paint and the metallic iron a coating serving
to isolate the anti-fouling paint from the iron so as to avoid the rapid destruction
of the former and the corrosion of the latter. I have since found that bitumen
with or without the other substances hereafter described forms an admirable
undercoating both in respect of cheapness and efficiency.
I produce this paint or compound by dissolving natural bitumen (not artificial
pitch or tar which contain a different series of hydro-carbons less coherent than
those contained in bitumen and contain besides acids prejudicial to the iron,) in
turpentine, benzine, or benzoline to the requisite thickness and add thereto if
desirable zinc oxide or hydrated oxide of zino; or glass, porcelain, burnt clay,
silica, alumina, magnesia, powdered chalk or calcareous rock, asphalte, sulphate of
baryta, powdered coal, anthracite, coke or graphite, or the so called silicate paint
and add if considered necessary drying oil so as to constitute a paint with which
the iron is first coated and on which the anti-fouling paint is applied.
The bitumen should be of the hard resistant kind such as is generally found in
the natural state not the softer more pliant or friable kind of bitumen. It may be
mixed or not with stockholm pitch or the residue from Petroleum distillation which
indeed may be substituted for it but are not quite so good as they do not dry quite
so firm

page_text: The material may either be used by itself in which case it must be made thick
enough or it may be thickened by the addition of one of the above mentioned
substances. If Benzoline is used as a solvent it should also be of the best quality
it should evaporate easily to the last drop and not be of Sp, gr more than 720.
Red lead or one of the oxides of lead, or the oxide of iron may here be used to mix
with this bituminous priming as the bitumen being an excellent non-conductor the
metallic oxides are insulated from the iron to which the metals they contain are not
very electro negative, and reduction is prevented from taking place.

page_text: I FARNHAM MAXWELL LYTE of Cotford Oakhill Road, Putney in the County
of Surrey, Analytical Chemist, do hereby declare the nature of my invention for
"IMPROVEMENTS IN THE METHOD OF PROTECTING SUBMERGED STRUCTURES OF
IRON AND STEEL FROM CORROSION AND FOULING" and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :--
This Invention relates to an improvement on the invention for which former
Letters Patent-were granted to me N° 5375 of 1883 and which consisted in a
method of protecting submerged structures of iron and steel from corrosion and
fouling by the application to the structure of an inert or nonconducting paint or &
paint having for its basis a metallic oxide the metal of which is electropositive to
iron, followed by a paint having antifouling qualities or qualities poisonous to
weeds, barnacles &°,
As is explained in the Specification of my aforesaid Patent it is necessary to
interpose between the antifouling paint and the metallic iron, a coating serving
to isolate the antifouling paint from the iron, so as to avoid the rapid destruction
of the former, and the corrosion of the latter. I have since found that the kind of
bitumen known as " asphaltum" with or without the other substances hereafter
described, forms an admirable undercoating both in respect of cheapness and
efficiency.
I produce this paint or varnish by dissolving natural asphaltum (not artificial
pitch or tar which contain a different series of hydrocarbons, less coherent and
consistent than those contained in natural bitumen, and which contain besides acids
prejudicial to the iron) in turpentine, benzol or benzoline known sometimes as
mineral naphtha or petroleum spirit, to the requisite thickness, and I add thereto, if
desirable, alumina or magnesia in powder, adding, if considered necessary, drying
oil so as to constitute a paint with which the iron is first coated and on which the
anti-fouling paint is applied.
The bitumen should be of the hard resistant kind such as is generally known as
asphaltum, not the softer more pliant kind. It may be mixed or not with
stockholm pitch or the residue from Petroleum distillation which indeed may be
substituted for it; but these latter are not quite so good as they do not dry quite
so firm.
The material may either be used by itself, in which case it must be made thick
enough, or it may be thickened by the addition of powdered magnesia or alumina.
If benzoline or as it is sometimes called, crude mineral naphtha, is used as a solvent,
it should be of the best quality, should evaporate easily to the last drop and not be
of a sp: gr, of more than from 0-629 to 0.723.
A good way of proceeding is as follows:-The alumina or magnesia, in fine
powder, mixed with a sufficiency of manganese, borate or lead peroxide or other
driers, is made up into a thick paint by being ground with drying oil and raw
linseed oil, half and half, while on the other hand a quantity of asphaltum about
one-third the weight of the paint, or rather less, is fused in an iron pot, and the
paint poured into it, and well mixed over a clear fire. It is then withdrawn to a
distance from the fire, and thinned down to the required density, when sufficiently
cool, but when still quite liquid, with crude mineral naphtha added gradually. The
following directions should be observed:-(1.) On adding the paint to the fused
asphaltum, the latter should be very liquid, and the paint added by small portions
at a time, keeping the pot on the fire, and with constant stirring. (2.) Be

page_text: particularly careful of the mineral naphtha, which is very volatile, and inflammable,
and the vapour being heavier than air, creeps along the ground, and will take fire,
when least expected. Turpentine spirit or benzol may be used in place of the
naphtha, only it is more costly, and so may any of the lighter petroleum oils,
crude mineral naphtha being a mixture of these last. (3.) When all the paint has
been added to the asphaltum, a drop may be placed on a slip of glass, and allowed
to cool. When cold, it should be able to be pinched up between the finger and
thumb, and rolled into a pill; if it only strings, it has not been boiled enough. If
too thick, some boiled oil may be added, or more paint. (4.) It should stand
1 hours at least, before adding the naphtha, and 40 to 50 gallons, is a good
quantity to make at a time. Red lead or one of the oxides of lead does no harm
mixed with this bituminous priming, as the asphaltum it contains, being an
excellent non-conductor, the metallic oxides are insulated from the iron and the
-metal they contain being not very electro-negative to it, reduction is therefore
prevented from taking place.-The consequence is a lead drier may be mixed with
the magnesia or alumina used for thickening the varnish and promotes the more
rapid drying of the oils it contains.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed, I declare that what
I claim is
1 The application to submerged structures of iron or steel, of a sufficiently
thick first coat or layer of natural asphaltum, stockholm pitch, or the residue from
petroleum distillation alone or mixed together, followed by a coat or layer of a
paint having antifouling or poisonous qualities to growths, substantially as and for
the purpose specified.
2nd The application to submerged structures of iron or steel of a first coat or
layer of a paint or varnish composed of natural asphaltum, stockholm pitch or the
residue from petroleum distillation (either alone or in admixture) and magnesia or
alumina, followed by poisonous or antifouling paint substantially as specified.
44
"
1001