Improvements in or relating to Aluminium Solder.
Year: 1892

page_text: Date of Application, 5th May, 1892
Complete Specification Left, 6th Feb., 1893-Accepted, 8th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in or relating to Aluminium Solder.
A communication from Professor CARL SAUER, of Berlin, in the Empire of
Germany, Dentist.
I, ALFRED JULIUS BOULT, of 323 High Holborn in the County of Middlesex,
Member of the Institution of Mechanical Engineers, do hereby declare the nature
of this invention to be as follows:-
'
An aluminium solder of practical value, capable, without the employment of any
flux, but simply by means of a soldering iron, of being successfully applied to
aluminium has hitherto been an unattained desideratum; for the article now known
as "aluminium solder "-an invention of M. Th. Mowny, a goldsmith of Paris-is
an alloy or mixture of predetermined quantities of aluminium, copper and zinc,
which, in the molten condition, has such a heavy flow and sets so quickly, that
actual soldering with it is out of the question.
Now by careful experiment, extending over a great many years, during which
the inventor has tested a considerable variety of alloys of aluminium with other
metals, he has come to the conclusion that the aluminium soldering compound
presently to be described is alone fitted for effective use in practice..
The improved aluminium solder consists of an alloy of aluminium, silver and
copper in the following proportions,-
9 parts of aluminium,
1 to 3 (or even 4) parts of silver, and
2 to 4 parts of copper (and even 5 parts according to recent experience).
Not only has this solder an easy and uniform flow, but it also offers the material
advantage-not realised before of requiring no flux in soldering aluminium with
the same or other metals, an ordinary soldering tool of any suitable material being
sufficient for the purpose.
It is not impossible to employ brass instead of copper in preparing the alloy; or
a very small, proportion of zinc may be added to the ingredients already named,
viz. aluminium, silver and copper.
The zinc contained in the aluminium-tin-and-copper-alloy does not exceed 25%
of the quantity of tin contained therein by weight, so that there is 1 part of zinc
for every 4 parts of tin. In alloys containing silver the proportion of zinc is
still less.
All trials made with a so compounded solder have given the most satisfactory
results.
An alloy of tin, copper and aluminium (tin being employed instead of silver) will
also make a very good aluminium solder which however is fit only for soldering
comparatively large pieces.
To aluminium solder containing tin or zinc (or tin and zinc) and copper, gold may
be added, say in the proportion of from 0.03 to 0.10 gramme of gold to 15 gr. of the
main alloy of copper and aluminium, with or without the addition of silver. The
resulting solder, owing to the readiness with which it liquefies, will be found
particularly serviceable for delicate work.
In the silver-tin-copper-and-aluminium-alloy the zinc may be replaced by either
cadmium or bismuth, or by an alloy of from 1 to 3 parts of cadmium and from 4 to
10 parts of bismuth, or again by one of the well-known readily fusible metal alloys
such as what is generally termed "wood metal" (1 part of cadmium, 1 of zinc, 2 of
lead and 4 of bismuth). Of course where the proportions of the other metals are
increased in "wood metal," the proportion of the zinc must be correspondingly
greater. In adding cadmium or bismuth the boiling point is to be taken into

page_text: account. These metals should not be added to the liquid alloy until after they have
practically ceased from being incandescent, and where both bismuth and cadmium
are used the former should be added previously to the latter.
The method of manufacture of this new aluminium solder is as follows,―
In a crucible of the best graphite the copper and silver are first melted together,
while the aluminium is melted separately in a second crucible. The molten
aluminium is then added to the silver-and-copper-alloy; while it is being con-
tinuously stirred with a dry piece of wood...
To obtain an alloy of silver, copper, zinc and aluminium, the silver and copper
are first melted together separately, as before stated; molten aluminium melted in
a separate crucible is then added, the mixture being stirred; and lastly while the
alloy is still liquid, unmelted zinc is added to it and, by stirring, caused thoroughly
to mix with the alloy.
To produce an alloy of silver, brass and aluminium, the silver and brass are melted
together whereupon aluminium, melted separately, is added while the mixture is
being stirred.
Where copper, tin and aluminium are to form the alloy, the copper and aluminium
are melted each by itself; the aluminium is then added to the copper which is stirred
the while, and lastly unmelted tin is mixed with the liquid alloy, the stirring being
continued. If zinc is to form part of the alloy it is added previously to tin.
The order in which the metals are melted, as here indicated, is extremely
important where small quantities of a metal, melting with difficulty, are to be mixed
with large quantities of aluminium. And it is necessary that the aluminium, when
added to metal that is not readily fusible, but has been melted previously, should
be in a molten condition also; for if it were added to the molten metal in solid state,
it would absorb so much of the heat inherent to that metal, that it would cause the
latter to solidify, and allow of no thorough mixture, or in other words prevent the
formation of an alloy. Where however the method here described is adopted a
perfect alloy is obtained, because the respective temperatures of the metals when
they meet are as nearly as possible equal.
In order firmly and reliably to solder together pieces of aluminium, or a piece of
aluminium with one or more of other metal or metals, the solder broken up into
larger or smaller particles or grains, according to the size of the articles to be
soldered, is placed over the soldering surfaces of these articles, and each of the
articles is heated separately. When the solder begins to melt it is crushed and
spread by means of a soldering iron, over the respective surfaces which are then
joined; or the surfaces to be united, after being covered with solder, may first
receive a finishing touch with a file or the like, so as more neatly to fit each other,
and then brought together and soldered to each other by means of the .hot
soldering iron.
By such means the solder is caused to form an actual alloy with the articles
soldered and fulfils all the requirements of a perfect solder.
"
or
To solder iron with aluminium it is advisable to cover the iron at the contact
surface first with a layer of brass and then with one of an alloy of ("fine
ordinary) gold, or silver, whereupon the iron is soldered with the aluminium in the
same manner as explained above in reference to the soldering of two pieces of
aluminium.
The same applies to the joining of aluminium brouze with aluminium or of
platina with aluminium. The platina, however, should first be treated with fine
gold or with a suitable alloy of gold or silver, previously to the application of the
aluminium solder. Where pieces made of alloys of silver or gold are to be
soldered together the aluminium solder is employed in the same manner as if two
pieces of aluminium were to be joined, other metals are similarly prepared before
soldering, and if required covered with a layer of tin first. Tin itself, in order to
be so soldered, should be pure.
The pieces of solder to be used may according to the size of the pieces to be
joined be a little larger or smaller though in all cases they must be small. Should

page_text: the pieces of solder be too large in relation to the articles to be soldered the con-
sequence will be that they will not attain red-heat at the same time as the said
articles, and will therefore be too slow in melting, while the articles to be joined
will be liable to be burnt in the process.
The tool used for soldering may, as desired, be made of aluminium, copper, or
iron, being equally serviceable in each case, though an aluminium tool is to be
preferred because, when the solder melts, some of the aluminium of the tool is
absorbed by the solder as it is rubbed in. An iron soldering tool offers the
advantage that it can more readily be made in a tapering or pointed shape and so
prove of better service in cases where the solder is applied in recesses or angles.
Aluminium-bronze tools, however, will generally be found most advantageous.
The performance of this method of soldering with aluminium obviously requires
some skill or practice; but when this is acquired, the joints obtained by means of
this solder will be found so tight and secure, that if the parts joined together were
to be broken asunder by main force and without the employment of heat the
fracture will show no particles of broken solder, or in other words the piece will be
found to have been broken not at the soldered joint, but at some other part.
Dated this 5th day of May 1892
ALFRED J. BOULT,
Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in or relating to Aluminium Solder.
A communication from Professor CARL SAUER, of Berlin, in the Empire of
Germany, Dentist.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I. Mech. E., & Chartered Patent Agent, 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:-
An aluminium solder of practical value, capable, without the employment of any
flux, but simply by means of a soldering iron, of being successfully applied to
aluminium has hitherto been an unattained desideratum; for the article now known
AS "aluminium solder " an invention of M. Th. Mowny a goldsmith of Paris, is an
alloy or mixture of predetermined quantities of aluminium, copper, and zinc, which,
in the molten condition, has such a heavy flow and sets so quickly that actual
soldering with it is out of the question.
Now by careful experiment, extending over a great many years, during which
the inventor has tested a considerable variety of alloys of aluminium with other
inetals, he has come to the conclusion that the aluminium soldering compound
presently to be described is alone fitted for effective use in practice.
The improved aluminium solder consists of an alloy of aluminium, silver, and
copper in the following proportions,-
9 parts of aluminium,
1 to 3 (or even 4) parts of silver, and
2 to 4 parts of copper (and even 5 parts according to recent experience).
Not only has this solder an easy and uniform flow, but it also offers the material
advantage not realized before-of requiring no flux in soldering aluminium with
the same or other metals, an ordinary soldering tool of any suitable material being
sufficient for the purpose.
It is not impossible to employ brass instead of copper in preparing the alloy; or
a very small proportion of zinc may be added to the ingredients already named
viz. aluminium silver and copper.
An alloy of tin copper and aluminium (tin being employed instead of silver) will
also make a very good aluminium solder, which however is fit only for soldering
comparatively large pieces.

page_text: The zinc contained in the aluminium-tin-and-copper-alloy should not exceed
25 per cent. of the quantity of tin contained therein by weight so that there is
1 part of zinc for every 4 parts of tin. In alloys containing silver the proportion
of zinc is still less.
All trials made with a so-compounded solder have given the most satisfactory
results.
To aluminium solder containing tin or zinc (or tin and zinc) and copper, gold
may be added, say in the proportion of from 0.03 to 0.10 gramme of gold to
15 grammes of the main alloy of copper and aluminium, with or without the
addition of silver. The resulting solder owing to the readiness with which it
liquefies, will be found particularly serviceable for delicate work.
In the silver-tin-copper-and-aluminium-alloy the zinc may be replaced by either
cadmium or bismuth, or by an alloy of from 1 to 3 parts of cadmium and from
4 to 10 parts of bismuth, or again by one of the well-known readily fusible metal
alloys such as what is generally termed "Wood's metal" (1 part of cadmium, 1 of
zinc, 2 of lead, and 4 of bismuth). Of course where the proportions of the other
metals are increased in "Wood's metal" the proportion of the zinc must be corre-
spondingly greater. In adding cadmium or bismuth the boiling point is to be
taken into account. These metals should not be added to the liquid alloy until
after they have practically ceased from being incandescent, and where both bismuth
and cadmium are used the former should be added previously to the latter.
The method of manufacture of this new aluminium solder is as follows,―
In a crucible of the best graphite the copper and silver are first melted together,
while the aluminium is melted separately in a second crucible. The molten
aluminium is then added to the silver-and-copper-alloy, while it is being con-
tinuously stirred with a dry piece of wood.
To obtain an alloy of silver, copper, zinc, and aluminium, the silver and copper
are first melted together, as before stated; molten aluminium melted in a separate
crucible is then added the mixture being stirred, and lastly while the alloy is still
liquid, unmelted zinc is added to it, and, by stirring, caused thoroughly to mix with
the alloy.
To produce an alloy of silver, brass and aluminium, the silver and brass are
melted together, whereupon aluminium, melted separately, is added while the
mixture is being stirred.
Where copper, tin, and aluminium are to form the alloy, the copper and
aluminium are melted each by itself; the aluminium is then added to the copper
which is stirred the while; and lastly unmelted tin is mixed with the liquid alloy,
the stirring being continued. If zinc is to form part of the alloy it is added
previously to tin.
The order in which the metals are melted, as here indicated, is extremely
important where small quantities of a metal, melting with difficulty, are to be
mixed with large quantities of aluminium. And it is necessary that the aluminium,
when added to metal that is not readily fusible, but has been melted previously,
should be in a molten condition also; for if it were added to the molten metal in a
solid state it would absorb so much of the heat inherent to that metal, that it
would cause the latter to solidify, and allow of no thorough mixture, or in other
words prevent the formation of an alloy. Where however the method here.
described is adopted a perfect alloy is obtained, because the respective temperatures
of the metals when they meet are as nearly as possible equal.
In order firmly and reliably to solder together pieces of aluminium, or a piece
of aluminium with one or more of other metal or metals, the solder, broken up
into larger or smaller particles or grains, according to the size of the articles to
be soldered is placed over the soldering surfaces of these articles, and each of the
articles is heated separately. When the solder begins to melt, it is crushed and
spread by means of a soldering iron over the respective surfaces which are then
joined; or the surfaces to be united, after being covered with solder, may first
receive a finishing touch with a file or the like, so as more neatly to fit each other,

page_text: and then brought together and soldered to each other by means of the hot soldering
iron.
By such means the solder is caused to form an actual alloy with the articles
soldered and fulfils all the requirements of a perfect solder.
To solder iron with aluminium it is advisable to cover the iron at the contact
surface first with a layer of brass and then with one of an alloy of ("fine" or
ordinary) gold or silver, whereupon the iron is soldered with the alumiinium in the
same manner as explained above in reference to the soldering of two pieces of
aluminium.
The same applies to the joining of aluminium bronze with aluminium or of
platina with aluminium. The platina however should first be treated with fine
gold or with a suitable alloy of gold or silver, previously to the application of the
aluminium solder. Where pieces made of alloys of silver or gold are to be
soldered together the aluminium solder is employed in the same manner as if two
pieces of aluminium were to be joined. Other metals are similarly prepared
before soldering, and if required covered with a layer of tin first. Tin, itself, in
order to be so soldered, should be pure.
The pieces of solder to be used may according to the size of the pieces to be
joined be a little larger or smaller though in all cases they must be small. Should
the pieces of solder be too large in relation to the articles to be soldered the
consequence will be that they will not attain red-heat at the same time as the said
articles, and will therefore be too slow in melting, while the articles to be joined
will be liable to be burnt in the process.
The tool used for soldering may, as desired, be made of aluminium, copper, or
iron, being equally serviceable in each case, though an aluminium tool is to be
preferred because, when the solder, melts, some of the aluminium of the tool is
absorbed by the solder as it is rubbed in. An iron soldering tool offers the
advantage that it can more readily be made in a tapering or pointed shape and so
prove of better service in cases where the solder is applied in recesses or angles.
Aluminium-bronze tools, however, will generally be found most advantageous.
The performance of this method of soldering with aluminium obviously requires
some skill or practice; but when this is acquired the joints obtained by means of
this solder will be found so tight and secure, that if the parts joined together were
to be broken asunder by main force and without the employment of heat, the
fracture will show no particles of broken solder, or in other words the piece will
be found to have been broken not at the soldered joint, but at some other part.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is,-
1. An "aluminium" solder mainly consisting of 9 parts of aluminium 1 to 4
parts of silver and 2 to 4 parts of copper and with or without 1 part of zinc
substantially as described.
2. The solder as described in Claim 1 but with the complete or partial
substitution of tin for the silver the said tin being if desired alloyed with zinc to
an extent not exceeding 25 % substantially as described.
3. The addition to the solder described in Claim 1 of a very small amount of
gold say 003 to 0.1 of one gramme of gold to 15 grammes of alloy substantially as
described.
4. As a substitute for the zinc in aluminium solders containing in combination
silver tin copper and aluminium or tin zinc copper and aluminium the employment
of cadmium or bismuth or of an alloy of from 1 to 3 parts of cadmium and 2
to 16 parts of bismuth or of alloys similar to what is known as "Wood's metal" in
combination with the zinc contained in the original alloy with or without a small
percentage of gold (from 0.03 to 0.1 gramme) substantially as described.
5. The method of preparing solder described in Claims 1 to 3 consisting in
melting together in a separate batch small quantities of slowly melting metals

page_text: such as silver copper and the like and melting aluminium alone in a separate
crucible and theu mixing together the molten aluminium with the molten copper
and silver or the like stirring the mixture the while for the purpose of obtaining
one alloy the component metals of which are thoroughly mixed substantially as
described.
6. The process of soldering pieces or articles of aluminium with pieces of
aluminium and other metals by means of a soldering "iron". or tool and without
the employment of a flux in the solder according to which the pieces or parts to
be soldered together are first heated each separately with a piece of solder placed
upon the surface to be joined which solder by the time that the said piece is
brought to red-heat will be molten so that by means of the soldering tool which
may be made of aluminium copper iron or any other metal it may be spread or
rubbed in whereupon the parts to be soldered are joined and the joint after a
further addition of solder finished by means of the soldering tool whereby a
thorough adhesion of the solder to the parts with which it is in contact and
consequently a strong and reliable connection of these parts is ensured substantially
as described.
Dated this 6th day of February 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
1