Improvements in the Manufacture of Composite Metal Plates.
Year: 1897

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Composite Metal Plates.
I, HEINRICH WACHWITZ, of 14 Parkstrasse, Nuremberg, in the Kingdom of Bavaria
and the German Empire, Foreman 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 :-
Heretofore the use of aluminium for any purposes for which it would be particularly
serviceable on account of its light weight has been impossible, because this metal
could not be plated nor brazed durably in a simple way, and by its offering when in
its normal state but little resistance to the influence of the weather or chemicals with
which it might come into contact.
The methods and processes employed for altering this state by coating or plating
the surface of the aluminium with another metal have been unsuccessful, because
aluminium has but little affinity to other metals and the coatings produced in a
mechanical way have not been permanently fixed to their base.
When plating aluminium in the ordinary manner there is great liability of a flaw
and of its texture being impaired, and the oxydation set up in consequence of the
heat prevents a sufficiently close alliance with the metal used for plating and the
aluminium.
The object of the present invention is to produce a durable metal coating on
aluminium, which can be made so thin that the advantages of the light weight, of the
aluminiumn is not materially impaired, and for this purpose aluminium is plated with
copper or other suitable metals in the following way.
Thin sheets of copper of about 0.1 millimetres are laid on aluminium sheets of
about 10 millimetres thick and are heated between red hot plates, and in this way
the coating sheets will be heated and the sheet of aluminium will be heated as much
as is necessary in order to produce the temperature and ductility required for plating.
As this method of heating prevents oxydation, a close adherence of the metals will
take place when they are pressed together, and this without the aluminium being
overheated in its case, and in consequence the material will undergo no change detri-
mental to its texture or other qualities. The pressing may be done by rollers or
presses.
As by heating the copper coating gets soft and the aluminium retains its original
hardness through not been affected by the heat, the metals joined in this way may
be rolled, so that an equal stretching of both will be the result, that is to say, the
size of the aluminium and the copper sheets diminish at the same ratio, so that at
last the whole surface is covered with a thin but sufficient layer of copper. The
sheets produced in this way can be worked just as sheet copper can, and they can
also be brazed.
These plated sheets can also be tinned in the usual way, or galvanically coated
with other metals, which will increase the use of the sheets.
Having now particularly described and ascertained the nature of my said

page_text: invention, and in what manner the same is to be performed, I declare that what
I claim is
The improved manufacture of composite plates, consisting of aluminium sheets
coated or plated with thin layers of other metals in the manner. herein described.
Dated this 15th day of June 1897:**
HEINRICH WACHWITZ,
By his Agents, Brierley & Howard,
Penny Bank Chambers, Halifax.
HEINRICH WACHWITZ,
By his Agents, Brierley & Howard,
Penny Bank Chambers, Halifax.