IMPROVEMENTS IN THE MANUFActure of HARDENED ASBESTOS
Year: 1885

page_text: CHARLES JACKSON Engineer 134 Robin Hood Chase Nottingham do hereby
declare the nature of my invention for IMPROVEMENTS IN THE MANUFActure of
HARDENED ASBESTOS to be as follows:-
The object of this invention is to solidify Asbestos.
For this purpose I mix with the asbestos a resinous or other binding material
such as shelack in solution or otherwise for some purposes I also mix a certain
amount of metal with the asbestos and binding material in any desirable form
such as wire and evaporate by vacuum or by cold blast untill the whole is in a fit
state to press or mould after which I subject the article to a sufficient heat that
will render the adhesive substance insoluable While still hot I put the article into
heated dies subjecting it to great pressure heating it untill the adhesive substance
is perished or converted into a kind of slag.
Formerly I have had great dificulty in solidifying the asbestos as the adhesive
substance when heated and dried up contracted in size thus leaving the asbestos
not in such close contact a I get when pressed in a heated state at a time when
the adhesive substance is perishing.

page_text: I CHARLES JACKSON Engineer of 134 Robin Hood Chase Nottingham 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 has for its object improvements in the manufacture of hardened
asbestos.
I mix asbestos with a binding material such as shellac dissolved in spirit; I mako
up the material into the form required and expose it to heavy pressure I also
expose the material to heat to perish the binding material and render it insoluble.
Formerly I have had difficulty in thus solidifying asbestos as the material when.
heated contracted and the asbestos remained in a state less compact than is
desirable.
According to my present invention I apply heat to the material at the same time
that it is subjected to pressure. After the material has been exposed to pressure
to mould it into form and has been heated to partly perish the adhesive
material I expose it to a heavy pressure in heated dies and afterwards I again heat
the moulded article in an oven preferably at a higher temperature than previously
to complete the perishing.
Also according to my present invention I combine metal with asbestos and a
binding material and harden the preparation by pressure and heat. Thereby
I impart to the hardened asbestos greater strength and durability and obtain other
advantages.
In order that my invention may be fully understood and readily carried into
effect will proceed to describe the manner in which I prefer to operate.
I sometimes commence by forming the asbestos fibre into a coarse thread at other
times I use the asbestos fibre without this previous preparation.
Where it is necessary to resist wear by friction the fibre should be spun and as
far as possible the fibre should be exposed end wise in the finished article.
I saturate the fibre or the yarn with the binding material, a thick solution
of shellac in spirit is suitable, except that for articles which when in use are
exposed to a high temperature as the bushings for steam cocks I prefer to
employ a stoving varnish. I then dry the fibre or yarn for a period of several
days in a drying shed through which a current of air is constantly passing or if
Where the fibre is made
necessary the drying may be hastened by a low heat.
into yarn it is often convenient at this stage to weave the yarn into a fabric. If
this course be resorted to pieces are afterwards cut from the fabric and superposed
the one on the other to build up the form required and they are consolidated
by pressure in a mould. When the form required is intricate it is often more
convenient to wind the loose fibre about a mandril to obtain a suitable mass and
then to further shape it by pressure in dies. In the process of building up the
form I repeatedly saturate the asbestos with the binding material and after each
The
treatment I submit the mass to long drying in the ventilated drying room.
harder and closer the product required the more of the binding material should

page_text: -
be incorporated with the asbestos in those earlier stages. When thus built up and
dried the article is reduced approximately to the form required by pressure in
metal moulds. At this stage a moderate pressure only is required. The moulded
article then goes back to the ventilated drying room where it should remain for
some weeks. It is then again pressed and this time it should be exposed to a very
heavy pressure amounting to many tons on the square inch and the heavier the
better. The moulded article is then passed into an oven heated to about
250 degrees Fahrenheit where it remains for eight or ten hours until it appears
hard and dry. After the article comes from the oven it is again exposed to pressure
and in this case heat is also necessary as the material would not be condensed
sufficiently by a cold pressure. The moulds employed (of which the shape of
course depends on that of the article to be produced) are heated to 350 or 400 degrees
and in these moulds the article is exposed to the same heavy pressure as before-
the higher the better. If the moulded article requires to be fitted into a piece of
metal, for example if it be a valve facing and is to be set into a groove in the
metal valve it is at this stage that the moulded asbestos is set into its place. The
mould is made to receive the metal valve (which is also heated) and the pressure
drives the asbestos home into its recess.
After the hot pressure the article is again passed into an oven where a tempe-
rature of 300 to 400 degrees is maintained say for 10 hours.
for use.
After leaving the oven the article is if necessary smoothed and polished ready
When the article is to be exposed to high temperatures in use the
temperatures employed in the manufacture should be such as to exceed by at least
50 degrees the temperature to which the article will be afterwards exposed. For
high temperatures stoving varnish is more suitable than shellac solution.
I sometimes combine metal with the asbestos and binding material; thus I form
a stout and durable board or panel with a surface of hardened asbestos by taking
a sheet of iron and perforating it, by preference with small holes leaving the edges
of the holes preferably rough and jagged. I then lay on the metal sheet sheets of
thin asbestos felt saturated with binding material and dried. I consolidate the
whole by a moderate pressure, then dry the compound sheet further and expose it
to a heavy pressure; next I stove it, then I expose it to pressure between heated
surfaces and finally again stove it all in a similar manner to that previously
described.
Also I combine metal in some cases in the form of wire with the prepared
asbestos. I use soft steel wire usually in the form of spirals. The spirals are
embedded in the prepared asbestos when this is put together into the shape required.
The wire together with the prepared asbestos goes through all the processes as
already described and becomes embedded in the article to which it gives strength
and toughness. I also combine metal with asbestos by drawing down small tubes
of steel or other metal on to cords of prepared asbestos. I cover such tubes
externally with prepared asbestos and then accumulate them side by side into a
block. I expose the block to heat in an oven and thus form the whole into a solid
mass. This method is applicable where a very durable material under friction is
required; the asbestos is exposed only at the ends of the tubes.
Another way in which I combine asbestos with metal is to take threads of the
prepared asbestos and coat them with metal by electro deposition a process well
understood. Thus I coat asbestos threads with gold and I use such threads to
make gold lace. Such gold lace when it becomes tarnished or discolored can be
cleaned with acid.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
(1.) In the manufacture of articles of hardened asbestos exposing a mixture of

page_text: (2.) The manufacture of articles of hardened asbestos by moulding or forming
a mixture of asbestos with a binding material to the shape desired, then partly
perishing the binding material by heat, then exposing the article simultaneously
to heat and heavy pressure, and afterwards again exposing the article to heat
substantially as described.
(3.) The combination of asbestos and a binding material consolidated by pressure
and-changed-or-perished_by_heat with metal whereby strength and durability is
obtained substantially as described.
(4.) My improvements in the manufacture of hardened asbestos substantially as
described.