An Improved Process of Soldering, applicable to the Soldering of Aluminium to Aluminium or to other Metals.
Year: 1892

page_text: Date of Application, 20th Dec., 1892-Accepted, 21st Jan., 1893
COMPLETE SPECIFICATION.
An Improved Process of Soldering, applicable to the Soldering of
Aluminium to Aluminium or to other Metals.
I, REGINALD HADDAN of the firm of Herbert Haddan & Co. of 18 Bucking-
ham Street Strand W.C. London Patent Agent do hereby declare the nature
of this invention a communication to me from abroad by Ludwig Oliven of
39 Wilhelmstrasse Berlin in the Empire of Gerinany Merchant and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement:-
It has been found that the usual process or method of soldering is inoperative or
ineffectual when applied to aluminium, and many attempts have therefore been
made to find a suitable substitute for ordinary solder for the purpose of giving a
strong and lasting joint when applied to aluminium either in soldering this metal to
itself or to other metals, since it has been generally considered that the ordinary
low melting point solders have proved to be entirely inapplicable.
This invention however consists in a process or method of soldering by which a
strong and lasting soldered joint may be made between aluminium and aluminium,
or aluminium and other metals, with or by means of no other than ordinary solder,
namely, the tin of commerce, or any of the usual alloys of tin with lead, or zinc.
The improved process is as follows;-The solder must be kept hot while it is
applied to the places to be soldered so that it remains liquid, while the places to
be soldered are scraped or scratched with a suitable hard scratching or scraping
instrument such as a brush of steel or brass wire, briskly for a short time until
the surface takes a thin layer of the solder. Specially attention must be given
to keeping the solder applied perfectly liquid during the treatment of the surface
under the solder. If the piece of metal to be soldered on is also of aluminium,
this must be similarly treated on the surface to be joined and provided with the
adbering layer of solder. This may conveniently be done by dipping the aforesaid
surface of the article to be soldered into the molten solder so that the place where
the solder is to adhere is immersed therein, and briskly brushing scraping or
scratching the immersed surface until it "takes" the solder; or the article or piece
to be soldered on may during the solder taking operation be placed on a metal
plate or bed heated equally to a temperature above the melting point of the
solder with the solder which is to provide the layer which the surface will take.
It is preferable to use for this purpose a copper plate since this metal better holds
and conducts the heat equally in all parts, and the success of the process is greatly
dependent on the equable maintenance of the heat. Thus if an iion plate is used
the soldering will be unequal and subsequent breaking of the joint will frequently
take place. Where the pieces to be soldered on or the surfaces to be connected by
solder are small they may be heated by the soldering flame during this preliminary
operation of taking the solder.
When the surfaces to be connected by solder have been subjected severally to
the above preliminary treatment, they are soldered together as follows;-
These surfaces will either have been kept hot or they will now be again heated
preferably by means of the aforesaid copper plate, and after a small further
quantity of solder has been applied between them they are pressed together and
suffered to cool.
The preliminary treatment of the surfaces to be connected by solder rests upon
the same foundation or principle that underlies the improved process for coating or
plating aluminium with tin, zinc or lead for which application for Patent of the
same date herewith has also been filed.
The process is the same whether any one of the low melting point metals

page_text: previously mentioned is employed, or any alloy of two or more of them, care being
always taken that the places to be served with solder are kept heated throughout
the preparatory process and when connected one to the other, also that during the
preparatory process the places to be served with solder are kept covered by the
solder during the rubbing or scratching of the surface and until the surface every-
where "takes" the solder. It will be noticed that all use of acids, soldering liquids,
fluxes, etc. is avoided also that the employment of a soldering cylinder is entirely
superfluous and is dispensed with.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is ;-
A process for soldering aluminium to aluminium or to other metals in which
those places of the aluminium which are to be served with solder are subjected to
a preliminary treatment consisting in subjecting them, while heated and under
covering of solder either upon a hot plate or while immersed in the molten solder,
to a rubbing scratching or scraping action of a steel wire or brass wire brush or
other suitable instrument until such surface "takes" a layer of the solder; where-
after the surfaces to be joined are while still, or again, heated brought into contact
and caused to adhere by pressure coupled with a further application of the solder.
Dated this 20th day of December 1892.
K. HADDAN.