An Improved Method of Preparing Solder, principally for Soldering Aluminium.
Year: 1892

page_text: Date of Application, 21st Nov., 1892
Complete Specification Left, 28th July, 1893-Accepted, 16th Sept., 1893
PROVISIONAL SPECIFICATION.
An Improved Method of Preparing Solder, principally for Soldering
Aluminium.
I REGINALD HADDAN of the Firm of Herbert Haddan & Co. Consulting
Engineers of 18 Buckingham Street Strand London W.C. Patent Agent do hereby.
declare the nature of this invention, a communication to me from abroad by
Felix Singer of Breslau in the Empire of Germany Merchant and Heinrich
Barthel of the same place Merchant to be as follows:-
This invention comprises an improved method of preparing solder which is not
only generally applicable to the union of different pieces of the same or of
different metals but is especially suitable for the soldering of aluminium to itself
or other metals, a metal which up to the present has proved repellant to ordinary.
solder.
;
The improved solder is made as follows: A metal or mixture such as is usually'
employed for soft or hard solder for instance tin, or tin with zinc or lead, is
melted, and to each 10 lbs. or thereabouts of the fluid mixture is added a table-
spoonful of crystallized saltpetre or similar cleansing material the mixture being
well stirred.
The scum which will come to the surface is from time to time carefully skimmed
off until only a very small amount of scum is given off. The metal is then poured
into moulds as solder.
COMPLETE SPECIFICATION.
An Improved Method of Preparing Solder, principally for Soldering
Aluminium.
I, REGINALD HADDAN, of the Firm of Herbert Haddan & Co., Consulting
Engineers, of 18 Buckingham Street, Strand, W.C. London Patent Agent do
hereby declare the nature of this invention a communication to me from abroad
by Felix Singer, of Breslau, in the Empire of Germany, Merchant, and Heinrich
Barthel, of the same place, Merchant, and in what manner the same is to he
performed to be particularly described and ascertained in and by the following
statement:-
Heretofore it has been found that ordinary solders such as tin or alloys thereof
with lead or with zinc and lead are useless when applied to soldering aluminium to.
itself or to other metals since aluminium will not make a firm junction with such
solder. It has therefore been presumed that ordinary solders are inapplicable.
The object of the present invention is to prepare a solder of the ordinary kind
which, while useful for all ordinary purposes of soldering, can also be used for
efficiently soldering aluminium to itself, or to other metals.
For this purpose I take ordinary solder, whether tin, or alloy of tin and lead,
with or without zinc and melt the same; or I make the solder by melting together
the ingredients and while they are still molten in either case I add an oxydising
or cleansing material such as any of the following substances namely, nitrate of
potash, of soda, or of ammonia, chloride of lead or of soda, chlorate of potash,
hydrate of soda, or nitrate or sulphate of lead, the object of which addition is to
oxidise or chemically cleanse the solder. The amount to be added being about one
tablespoonful for each 10 or 11 lbs. of the solder.

page_text: The added substance or substances is or are stirred with the inolten metal and
the scum rising to the surface is skimmed off and removed from time to time until
no further or but very slight further scumming is observed.
The operation should be repeated several times prior to easting the solder in
suitable moulds.
•
The resulting solder is clean and thin flowing and has proved to be so efficacious
in the soldering of aluminium that the joint is stronger than the aluminium itself.
I have found that solder contains among its impurities, as do tin and lead, small
but very disturbing quantities of arsenic and antimony and that the above process
removes these or reuders them harmless as regards the soldering power of the
metal for aluminium, and although oxydising materials have been used to refine
lead, no such process has been used for tin much less for solder. Nor has the
harmfulness of the above noted impurities in soldering ever been before noticed.
A specially good solder is made of equal parts of tin and lead treated as before
described.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A method of preparing solder, consisting in adding to the molten tin or alloy of
tin and lead an oxydising or cleansing substance such as nitrate of potash, of soda,
of ammonia or of lead, chloride of soda or of lead, sulphate of lead, chlorate of
potash or hydrate of soda, and removing the scum, and repeating this operation
several times prior to casting the solder in suitable moulds.
JT..1 1002
R. HADDAN.