Improvements in or appertaining to Preservative Coatings for Iron or other Structures.
Year: 1891

page_text: Date of Application, 7th Apr., 1891
Complete Specification Left, 5th Jan., 1892-Accepted, 20th Feb., 1892
Improvements in or appertaining to Preservative Coatings for
Iron or other Structures.
I, JOHN ROBSON of Shandon, Merton Road, Southsea in the County of Hauts,
Engineer R.N. (retired) do hereby declare the nature of this invention to be
as follows:-
This invention is designed to form a coating that shall be cheap casy of applica-
tion & more durable than most preservative coatings. I take rosin-pitch alone or
preferably mixed with the residuum obtained in the distillation of mineral oil
or ozokerite, or other pitch-and melt it with sufficient paraffine wax or scale to
give the required fluidity & freedom from stickiness when hot.
By using the paraffine wax as the principal ingredient with pitch in much
smaller proportion a mixture of the two alone will when painted on hot adhere
sufficiently but a compound consisting mainly of paraffine wax is necessarily
expensive and has no advantage over the cheaper compound which I prefer
to make in which a much smaller percentage of paraffine wax is used & its
place supplied for the other part by mineral or other oil or fat which will give the
necessary adherence to the metal-mineral colouring matter can be added &
ozokerite & other mineral waxes natural and artificial can be substituted for
paraffine scale. When it is desired to paper or paint over the coating two
plans can be adopted. 1st smooth it with a warm iron and apply a suitable spirit
varnish or 2nd make the paint or composition sufficiently sticky when used to stick
well to surfaces when freshly exposed though cold and spread it on the paper
or other fabric & apply the latter paint side to the surface to be coated. In order
to form it sufficiently sticky I use rosin in a less distilled state than rosin pitch, the
paraffine wax or scale & mineral oil and other materials remaining about the same
as above stated.
.
The paper felt or other fabric whichever way it be applied can further be
painted varnished waterproofed or ornamented as desired on the outside.
Dated thin 6th do Anvil 1001
WM. P. THOMPSON & Co.,
6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or appertaining to Preservative Coatings for
Iron or other Structures.
I, JOHN ROBSON of Shandon, Merton Road, Southsea in the County of Hants,
Engineer R.N. (retired), 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 :--
This invention is designed to form a coating that shall be cheap, easy of applica-
tion, and more durable than most preservative coatings.
I take rosin pitch alone or preferably mixed with the residuum obtained in the
distillation of mineral oil or ozokerit or other suitable pitch miscible with paraffin
wax as American asphaltum and melt it with sufficient paraffin wax to give the
required fluidity and freedom from stickiness when hot for application with a brush.
By using the paraffin wax as the principal ingredient with pitch in smaller
proportion, a mixture of the two alone will, when painted on hot, adhere sufficiently,
but a compound consisting mainly of paraffin wax is soft and necessarily expensive,

page_text: and has no advantage over the cheaper compound which I prefer to make, in which
a much smaller percentage of paraffin wax is used, thick mineral or other oil or fat
being added when required to give the necessary adherence to the metal. Mineral
colouring matter can be added, and ozokerit and other mineral waxes, natural and
artificial can be substituted for paraffin wax.
In carrying out my invention, the object of which is the production of a cheap
preservative compound capable of being applied with a brush direct to the surface
of the metal, without the addition of any drying oil or volatile solvent or both, it is
necessary that it, when liquefied by heat, have little viscosity, and no greater
stickiness than is required for its satisfactory adhesion to the metal, so that it may
flow as freely as possible under the brush. The mineral wax in the compound I
produce, thins and removes all undesirable stickiness from the rosin pitch and thus
I am able to produce a cheap, impervious, elastic and very durable coating satis-
fying these conditions.
I do not limit myself in the proportions, but generally they will lie within the
following
-
60 to 80 per cent. of rosin pitch alone or mixed as described above.
20 to 40 per cent. of paraffin wax alone or in admixture with other mineral-wax
with or without the addition of thick mineral or other oil.
Mineral colouring matter may be added as desired.
The proportion of mineral wax to be used varies with the pitch and degree of
liquidity desired. The minimum quantity desirable for any particular pitch is
easily ascertained by a small trial on a piece of sheet iron.
If the compound is not found to adhere sufficiently, satisfactory adhesion is
preferably given by the addition of thick mineral oil.
When it is desired to paper or paint over the coating, two plans can be adopted:
1. Smooth it with a warm iron and apply a suitable spirit varnish;
:-
2. Make the paint or composition sufficiently sticky, when used, to stick well to
surfaces when freely exposed though cold, and spread it hot on paper or other
fabric and apply the latter paint side to the surface to be coated.
In order to form it sufficiently sticky, I use the rosin pitch in a less distilled
state, mixed with 15 to 25 per cent. of thick mineral oil and paraffin wax in about
equal proportions, or as may be found most suitable to give the degree of stickiness
desired.
The paper, felt or other fabric, whichever way it is applied, can further be
painted, varnished, waterproofed or ornamented as desired on the outside.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In the manufacture of preservative coatings for the purposes described, the
combination of pitch such as described and mineral wax with or without mineral or
other oil and with or without colouring matter, substantially as described.
2. In the manufacture of preservative coatings, the combined use of a liquefiable
sticky waterproof material, such as described, forming an interior layer and
paper, canvas, felt or other like fabric forming an outer coating, substantially as
described.
Dated this 4th day of Janua1000
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.