Improvements relating to the Welding, Soldering, or Brazing of Metal's, and to Apparátus therefor.
Year: 1889

page_text: [Communicated from abroad by Professor Eu THOMSON, of Lynn, Massachusetts,
United States of America, Electrical Engineer.]
Improvements relating to the Welding, Soldering, or Brazing of
Metal's, and to Apparátus therefor.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, and Co. Patent Agents,
Southampton Buildings, in the County of Middlesex, 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:.
My present invention consists in certain improved methods of, and 'apparatus for,
soldering, brazing or welding metals by the agency of an electric current passed
through the pieces to be joined so as to heat the metals to be joined or to cause
the soldering or brazing material to be. melted..
My invention relates first to the manner of applying the electric-current to bring
the parts that are to be united to the requisite soldering or brazing temperature, and
consists in making either or both of such parts a portion of a continuous electric
circuit formed directly through such part from one clamp or connecting piece to
another, and then passing through said part or parts a heavy electric current of
volume sufficient to gradually bring the part to the desired or requisite welding
or brazing temperature. In this process the path of the electric current through
either part is independent of the other, and the circuit, instead of being formed
across the joint from one piece or part to the other, is formed in the general
direction of the plane of the joint to be established. This process is particularly
applicable to soldering or brazing the longitudinal seam of small tubes of copper,
brass or other like metals. It is also applicable to the joining of strips to bars or
tubes (by lateral seams or junctures) as in the irregular ornamentation of the sides
of strips or tubes as practiced in the manufacture of jewelry and in other small metal
work.
The great advantage of soldering, brazing, etc. by electricity is the facility with
which the exact soldering temperature may be reached or maintained by putting
through the pieces more or less electric current regulated by any suitable means.
In the use of electricity in the manner hereinafter described for soldering or
brazing there is less liability of injury by overheating which is liable to occur in
the ordinary operations. In the electric method the heat may also be distributed
more uniformly, being generated in the body of the metal pieces operated upon and
not communicated from the outside. The liability to damage small projecting portions
by overheating or burning, by flame contact is also overcome, and the operator'
meanwhile secures the greatest comfort in his work, not being required to work over
a furnace or a blow pipe. Besides, in joining delicate pieces by the blow pipe the
blast may easily displace them if resting on another piece, and this may even occur
to the flux or small pieces of solder used, and they are apt to be carried off in the
blast.
My invention consists also in a special process of forming welded, brazed or
soldered joints by passing a heating electric current across the joint and applying
lateral pressure, as will be more particularly hereinafter described.
Informing longitudinal seams or joints it is advisable, when considerable lengths
of material are included in the circuit, to use suitable holders or supports for the
pieces in order to prevent distortion of form owing to their heating, and softening.
In some cases I propose to provide envelopes or jackets surrounding the pieces to
be heated and formed of a material that is a non-conductor of heat so as to prevent
waste of heat in the operation. I prefer to employ for the material of the jacket
I
:

page_text: or envelope some substance of a suitable character for preventing oxidation of the
pieces when they are heated by the passage of the current.
In the accompanying drawings;-
Figure 1 illustrates a tube to which the improved process of forming a
longitudinal seam in the manner first hereinbefore referred to may be applied.
Figure 2 is an end view of the same.
Figure 3 represents in perspective a simple form of apparatus adapted for use in
practising the invention, with the part to be operated upon in place.
Figure 4 is an end view of a clamp or connector such as is shown in
figure 3.
Figures 5, 6 and 7 illustrate in cross section various forms of support and jacket
for the piece to be operated upon.
Figure S is a side elevation of an apparatus provided with the jacket such as is.
shown in figure 5.
Figures 9, 10 11 and 12 illustrate various forms of joint for the longitudinal seam
of a pipe to which my invention may be applied.
Figure 13 shows in cross section a square tube the longitudinal seam or joint of
which may be formed by my improved process.
Figures 14, 15, 16, 17, 18, 18, 19, 21 and 22 show in cross section various
forms of elongated strips or pieces that may be united by my invention.
Figure 20 is a side view of two strips or pieces such as are shown in cross section
in Figures 15 or 16.
Figure 23 illustrates a method of carrying out my invention when the pieces to
be operated upon are of considerable length.
Figures 24, 25, 26, 28, 29 and 30 illustrate other applications of my invention.
Figure 27 is a side view of the apparatus that may be used in the application
of the improved process to the kinds of work illustrated in Figure 26 and other
figures.
Figure 31 is a front elevation of an apparatus suitable for forming a joint by
lateral pressure, as hereinafter described.
Figure 32 is a side view of a part of the same.
Figure 33 is a side view of the clamp or die, shown in Figure 31.
Figure 34 shows a joint formed by the device of Figure 31.
Figures 35 and 36 show the manner of forming the ends or abutting portions of
bars or plates preparatory to the making of a welded butt joint in accordance with
my invention.
Figure 37 shows another form of apparatus suitable for use in practising my
invention.
Figure 38 shows the joint as formed between the plates Figure 36.
Figure 39 shows another form of apparatus similar to Figure 37.
Figure 40 illustrates a special application of the invention and the devices to be
used therein.
Figures 41-50 illustrate a special means to be employed for confining or con-
centrating the current at the joint when the nature of the operation or the work
operated upon is such that a path independent of that through the joint is afforded for
the current, or when the area to be heated is so great that the current would be
dissipated or dispersed if allowed to flow over all parts alike.
In Figures and 2 is shown a tube T, made in the ordinary way by bending
a rectangular sheet fill the edges meet and requiring for completion a longitudinal
sean. To form such a seam by my invention the tube T is electrically connected
at its ends to suitable electric connectors or clamps C. C', to which a heavy electric
current from any source may be delivered, and such current is allowed to pass through
the tube either over its whole cross section or at a part thereof near the joint in
the longitudinal direction of the joint. The clamps C. C are of a good conductor
of electricity and sufficient section to convey a current which will heat T without
heating themselves to any great degree. Underneath the tube T is preferably
placed a non-connecting slab B of fire-brick or other heat-resisting, non-conducting

page_text: substance, which supports the tube T, or other object when heated by the current
and prevents sagging. Before, after or during the passage of the current is applied
a flux, as rosin, tallow or zinc chloride for the case of soft soldering and borax,
carbonate of soda, or other substance for hard soldering or for welding.
The soldering metal or alloy may be laid on in powder or small pieces in the
seam, or a small strip fed into the seam, when heated, or placed in the seain before
heating. S. represents a strip being laid on the seam. The current of electricity
being allowed to pass until all that portion of the tube T, between the clamps C, Ci,
is at a brazing or soldering temperature the joint is easily perfected. In this case
the portion held in the clamps is not brazed or soldered but if the clamps simply
press on the ends of the tube instead of gripping the ends laterally the whole
length may be operated upon at the same time. Clamps so arranged are shown in
Figure 27.
To economize heat it is preferable to employ during the operation a set of blocks. in
addition to the supporting block B, which will form an enclosure or envelope around
the sides of the tube and keep the heat from easily escaping. The covering or envelope
may be variously arranged, all that is needed being a non-conducting mass around the
tube T, which may be easily removed, or from which the tube or piece T may itself
be easily removed.
In Figure 5, side blocks K, K', of fire brick or of loose baked clay, or asbestos
compressed, are shown as resting on the base block B. The pieces B, K. K', forming
the jacket may be made of carbon and will then tend also to prevent oxidation of the
metal when heated. In Figure 6 the support B is shown adapted to receive the
tube T, and to support and protect it from loss by radiation assisted by a block K,
which is carried in a recess in the support B suitably shaped as shown.
In Figure 7 the support is shown' as consisting of a box containing powdered
or granulated charcoal or coal, or powdered or granulated firebrick, ashes, sand.
pumice, or the like non-conductor of heat, leaving the seam portion of T exposed
for brazing, welding or soldering. These provisions against loss of heat and
deformation of the piece T are best used where the temperature needed is high as
in hard, or silver soldering. The relation of the pieces B, K, etc., of the figures 5, 6
and 7, to the clamps is shown in Figure 8, which will be understood at once.
The kind of seam to be made at the meeting parts of the piece T, miakes no difference.
In Figure 9 it is simply a plain butt-seam, and in Figure 10 it is a lap, in Figure 11
a rabbeted seam, and in Figure 12 a broad or spread seam. These latter are
suitable also for welding as the projecting or lapping parts. Figure 12 may be
driven together to effect a union, especially if the metal be iron or steel, or other
easily welded metal. Hammering or pressure may be used in this case.
Fig. 13 shows a square tube T, the joint of which is made by placing the solder S
in the interior of the corner which is downward and where the metal edges are.
In Figure 14 the parts to be joined consist of two strips T, T¹, the seam being formed
at S. The current is applied so as to traverse either one or both pieces longitudinally.
In Figure 15 T indicates in cross-section a bar or rod, and S a strip to be joined
edgewise to the same by passing the electric current through the rod and strip or
either of them longitudinally.
In Figure 16 the strip is shown as let into the side of the rod in a groove provided
in the latter for the purpose of giving a firmer joint by the welding or brazing
operation.
In Figure 17 the strip is shown fitted to the side of the rod T.
The rod T may be hollow as indicated in Figure 18, and the strip let into a seam or
groove in the same, or as illustrated in Figure 18. the two may be bent out of one
piece and the seam formed at S, as before.
Figure 19 illustrates the position in which the pieces figures 15 to 18, 'inclusive,
are preferably placed during heating and brazing. In this position the solder may
be more readily applied and retained in position during the operation.
In Figure 20 a strip and rod are shown in side elevation after union.

page_text: The above figures simply exemplify a type of operation to which m
applicable.
Other applications of the invention are as follows:—
Invention is
Thus a flat strip S', may be joined flatwise to a round rod or tube T, as in Figure 21.
In this case it is preferable to have the heating current traverse both pieces longi-
tudinally.
In Figure 22 two round or otherwise formed pieces S¹, S", are shown in position
to be affixed to a bar, T, underneath them, the current passing in T only, if
desired.
It is not necessary that the whole of the tube, strip or other piece be operated on
or heated at once, but the current may be passed through a section of it only at a
time and so progressively the work may be done. This is illustrated in Figure 23,
where the piece T is heated between clamps C and C, so that the part I is operated
upon and the part Q is cold at the time. The piece T is then caused to change position
either by a gradual movement to the left through the clamps C, C¹, fixed in position
or by moving the clamps on the piece, or moving both clamps and piece.
way very long tubes may be brazed with apparatus of moderate capacity.
apparatus, therefore, may serve for the production of great lengths of brazed tubing
in one piece which is very difficult with the ordinary furnace processes.
In this
My
In lateral affixing of light metal pieces as ornamental designs, hooks, chains, etc., to
other heavier pieces forming a base, as in jewelry, my invention may be very
advantageously used.
Thus a light tube St. figures 24 and 25, may easily be soldered or welded to the
Or, as in
upper face of a strip T, which latter is made the path for the current.
Figure 26, light ornamental work St, S¹, may he laid upon a strip T, which is heated
to braze them on, assuming, of course, the proper application in all such cases of the
flux if needed, and the soft or hard solder.
This manner of work is illustrated in Figure 27, the current carrying clamps or
connectors C, C', being caused to press elastically upon, or in any other manner
making connection with the ends of the piece T, resting on a non-conducting slab of
porcelain, fireclay, or the like B. A compression spring Z, between clamps C C', but
insulated from them may be used to effect this elastic pressure and ensure contact so
that current may pass from clamp to clamp through the piece, T.
The current brings the piece T, up to the soldering temperature, and light objects,
as ornamental designs, may then be affixed by hard soldering to its upper surface as
indicated at S₁, si s
In like manner rings, eyes, or hooks R, Figure 28 may be brazed to the piece T, as
bodies of buttons pieces of jewelry &c. The ring R. which may be replaced by
other projecting pieces, may have a cavity made for its reception in the piece T.
Figure 29, whereby it may be very firmly secured by my electric brazing operation.
A series of balls, B. B', may thus be affixed to piece T Figure 30.
One advantage of my invention as applied to such cases of brazing, is that the
joint obtained is apt to be very complete on account of the fact that the heavier piece
is made the hotter by the current and that the heat is higher internally to the joint
on its surface, whereas in ordinary processes by flame or furnace the application of
heat to the surface of the piece may give apparent unions which really are
only limited to the external surfaces which have been most heated during the
operation.
In Figure 31 I have shown devices that may be employed in forming welded.
brazed or soldered joints by my modified process involving the application of lateral
pressure. In this process I pass the heating electric current from any desired source
through the material from one side to the other of the joint and then when the
material is properly heated, subject the joint itself to pressure by suitable tools forced
upon it in a lateral or transverse direction, that is to say, in a direction transverse to
the general common line or plane in which the joint and the part or portions of part
adjacent to the joint and on either side thereof lie. The means for effecting pressure

page_text: may be dies, clamps, rollers or other instrumentalities forced against the hot metal to
consolidate and perfect the weld or brazing. In Figure 31, C, C₁, are clamps or
holders of any desired character mounted on a plate or base M, and insulated from
one another. The clamps are connected by heavy cables or large gauge electric
conductors with some source of electric energy capable of delivering current of great
volume or strength, but of comparatively small electro-motive force.
The clamps serve to hold the bars or pieces to be welded and to convey current.
thereto. In the present case the bars B, B in the clamps are shown as arranged to
be united by a lap welded joint where their ends match.
The clamps C, C are good conductors, and are kept clean, making such good
contact with the piece or pieces B, B1; that current passes so as to heat that part
of B, 131 between the clamps to the welding or brazing heat.
A pressure clamp or die press G is arranged to be used to press laterally upon the
bars at the lap joint and to force the two intimately into contact.
Brass and borax
may be applied where the joint is wanted to braze the pieces while pressed and held
by the clamps.
The view Figure 32 shows how the clamp C may be constructed to permit easy
insertion and removal of pieces operated upon. S is a screw which bears on an
extension of the clamp pillar P, and forces the clamp C pivoted at
upon the piece B.
down hard
The clamp G may be made as shown in figure 33, in the ordinary way or in any
other way to give the pressure. It may carry flat or curved die faces F, F, if it
be desired to modify the shape at that part of the metal B, B operated upon. The
die surfaces F, F should be faced with carbon, soapstone or other nonconductor of
heat of refractory nature.
The ends of bars, formed as in Figures 34, 35 and 36, may be placed together and
united by pressure applied by G, laterally, so as to make a perfect weld when heated
by the current.
In forming a butt welded joint by the application of lateral pressure it is desirable
that there should be an enlargement of the blank at the abutting edges, in order that,
on the application of the lateral pressure, material may be present in sufficient
quantity to form a
good union between the pieces without reducing the thickness at
This enlargement may be given to the pieces or object in any desired manner, but
is conveniently formed by upsetting the material preparatory to the welding
operation.
the finished joint
In cases where an extended seam or joint is to be formed the stationary pressure
clamp G may be replaced by rollers as K K', Figure 37, connected to opposite sides
of the circuit so as to form electrodes between which the current passes through the
metal to be operated upon.
Thus in the case of flat plates, as in Figure 36 to be welded edge to edge, to form
a longitudinal seam or joint, it is well to roll the joint by pressure rolls during its
formation and in this case the rollers may be made massive and of good conductor of
electricity, not too easily melted, and may be used to press the sheet or plate and
convey current thereto for heating the joint for welding successive portions of the
seam or joint, as the strips or plates, passing through the rollers.
In Figure 37, the plates B B', whose edges where the joint is to be made, have
been previously upset, are firmly pressed together edgewise, and the roller K, K¹.
caused to press on each side oppositely while the plates progress through the rollers
slowly. A very heavy current passing at the same time from roller to roller through
the upset jointing edge softens the metal and causes welding. A flux, as 'borax, is
sometimes applied to the joint.
The effect or result, as shown in Figure 38, is a single plate.
In Figure 39 the rolls K K¹, are arranged to be adjusted as to proximity by
screws SS, as usual in rolling mills, and are kept insulated at I, I, but driven by
gearing D so as to move together.
Guiding rolls H, H, H, insulated from K and K' are suitably placed according to

page_text: the work to be guided or fed: Very heavy cables connect rolls K, K², to the "source
of current G¹..
It will be understood that the current need not be passed from roll to roll as it
would be clearly within my invention to pass the current, as in Figure 31, between
clamping supports or otherwise so that the part to be operated upon by the rolls is
heated by the electric current during the manipulation. Thus when a tube is to be
welded either by a lap or buttweld, current may be caused to traverse it, as in
Figure 31; to heat the portion to be operated upon and an external roll K Figure 40,
applied to shape the exterior and assist the union while an internal mandrel M,
prevents collapse.
The roll K may be caused to traverse around the circumference of the tube T, or
the tube T may be revolved and K pressed against its side, while the heat is maintained
by the current..
In the case of a bent bar to be formed into a ring by a welding or soldering
current passed: across the joint as in the case of the bar R. Figure 41, a considerable
fraction of the current would, in the absence of any special provision to avoid it.
pass around the ring R from one clamp C to the other C through the continuous
portion of the ring R, avoiding the part J where the joint is to be formed.
In very heavy and small diameter rings or links, the current so shunted will be a
large fraction of the total current. I have devised a way of preventing this by
causing, through any suitable means, a counter-electro-motive force to be set in the
part through which the current is liable to be shunted. In this kind of work it is
necessary to use an alternating current.
A convenient means of establishing such counter-electro-motive force tendency or
opposition is an iron sheath, S Figures 41 and 42, partially or entirely surrounding
that part of the piece R, below the clamps C, C. This sheath is preferably made of
laminated iron wire and divided into two parts so that it may be put on or taken off
by separating the parts. The parts may be hinged together as at H, Figure 42. The
iron sheath S gives a magnetic circuit around the piece R, which sets up a strong
counter-electro-motive force to the currents which attempt to thread themselves
through the sheath in rapidly alternating directions. The practical effect is to
virtually convert the lower part of the bar or piece R into a non-conductor of
alternating currents. Instead of one such sheath $, several smaller may, of course,
be provided. As shown in Figure 43, the sheath S may have its portions wound
with insulated wire and connected to the source of alternating currents such as the
mains m, m which supply current to a transformer, whose primary coil P or the
currents therein, induce welding or heavy currents in a secondary bar Q, which latter
supplies the current for the work. If the currents in Q are sent through the work R
by the clamps C, C, and the sheath S, Figure 43, so wound and connected be applied.
the direction of currents may be such that the winding on the sheath actually develops
counter currents in the part of the ring R, Figure 41, passing through it, which
current will be in proper direction not only to prevent the working current supplied
to the clamps from being shunted, but also to assist the welding currents in developing
heat at joint J, by adding themselves thereto, the ring R itself becoming a secondary
-coil, as it were.
In Figure 44, a means for adjusting the magnetic conductivity of the sheath is
shown, being a screw A separating the two parts more or less. This varies the
counter-electro-motive force, which may be developed by the application of the sheath.
In fact the sheath, so constructed, may be applied to surround any circuit or portion
of a dirauit conveying alternating impulses for modifying them directly by generation
outer-electro-motive force.
of
In Figures 45 and 46 a welding induction coil T has the secondary bar or circuit Q
thereof extended, and around it and between the coil T and the welding clamps C, C¹,
the sheath S of adjustable character may be applied to vary the counter-electro-motive
force set up in the secondary circuit, or its self-induction, and so to modify the
strengths of current delivered by it to the work.
The process is likewise applicable to localizing the passage of current in metal

page_text: masses of some width, as when two plates are abutted endwise or edgewise and there
s not power of current enough to heat the whole joint at one time. In this case the
im is to so localize the current that its passage may be effected through any part of
he joint to heat the same, even though the other parts possess high conduction and
much larger extent and are also at the same time in electrical connection with the
clamps or other devices.
In Figures 47, S1 and S2, the sheaths or conductors of magnetism are wound with
copper wire and utilized like the sheath S, in Figure 43, not only to set up a counter-
electro-motive force opposing the current which tends to avoid the part of the work
selected for welding, but to actually add to or enhance the flow of current taking place
at the point J, of the line of union a, a, to be formed, by setting up between their
limbs counter currents which return as in Figure 48, along with the main currents
This is done by connecting the
from the main source and clamps by the path J.
coils on S1 and S2, as in Figure 43, with the source of current supplying the main
welding currents m, m, Figure 43.
Figure 48 shows the courses taken by the currents in Figure 47, a crowding taking
place at J, composed of the main transverse current flow and the current eddies set
up inductively between the limbs of poles $1 and S2. The heat being as the squares
of the current, it will be seen that most of the heating effect is given out at J, for
any desired purpose and a true localization of the heating effects of the currents
takes place thereat.
I sometimes construct the magnetic sheet as a part of a sort of tongs, as in
Figures 49 and 50, with handles D, for separating and approaching the parts of the
sheath proper S, jointed as shown. A. means for quick application of the sheath to
enclose a conductor, or bundle of conductors, is thus provided for in cases in
which it is desired to produce and very the counter-electro-motive force in the
conductor.
Any means of supplying a current of large volume but low electro-motive force to
the clamps or holders of the various devices before described may be employed.
One device suitable for this purpose consists of a transformer or induction coil
having a very coarse secondary conductor of a few number of turns connected with
the clamps and having a primary conductor of a comparatively large number of turns
connected to an alternating current dynamo. The current may be regulated by varying
the resistance in the primary circuit.
The clamps through which the welding and soldering or brazing current passes might
also be connected directly with a dynamo-electric machine having an armature provided
with a conductor of very large gauge so that the current delivered from the same
will be of great volume and large heating effect. The construction of the devices for
giving the current of large volume is immaterial.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed as communicated to me by my
foreign correspondent I declare that what I claim is :-
First. The herein described method of electric welding, brazing or soldering,
consisting in passing through one or both of the parts or pieces to be operated upon a
heavy electric current in the general direction of the line or plane of the joint and of
a volume sufficient to bring the piece or pieces to the requisite temperature.
Second. The herein described process of forming longitudinal seams or joints in or
between elongated metal pieces, consisting in passing a heavy electric current through
the piece or pieces longitudinally, and of a volume sufficient to heat the same to the
desired welding or brazing temperature, as and for the purpose described.
Third. The herein described improvement, in affixing light metal pieces to a
heavier or base piece, consisting in passing an electric current through the latter,
of a volume sufficient to heat the same to the requisite welding, soldering or brazing
temperature.
Fourth. The herein described improvement in forming longitudinal seam metal

page_text: tubing, which consists in passing a heavy electric. current through the tube longi
tudinally and of a volume sufficient to heat the parts at the joint to the requisite
welding or brazing temperature..
Fifth. The herein, described improvement in forming elongated longitudinal seams
or joints which consists in heating portions of the material in successive lengths
by the agency of an electric current, passing longitudinally and producing the seam
or joint of each section, while such section is included in. the electric circuit, as and for
the purpose described.
Sixth. The herein described improvement in electric welding, brazing, or soldering,
which consists in surrounding the parts acted upon by the electric current by a
supporting and heat retaining jacket or envelope, as and for the purpose described.
Seventh. The combination with the clamps or connections of the intermediate bed-
plate, arranged as described to support the body through which the heating electric
current passes, as and for the purpose described.'
Eighth. The herein described method of forming a
consisting in passing an electric current through the material from one side to the
welded. or brazed joint,
other of the joint, and then applying lateral pressure directly to the material at the
part where the joint or weld is to be formed.
Ninth. The herein described process of forming a butt welded joint, consisting in
forming or providing the metal with an enlargement at the point of abutment, passing
a heating electric current through the material, and then applying lateral pressure to
the material directly at the joint, as and for the purpose described.
1
Tenth. The herein described improvement in electric welding, soldering and the
like, consisting in setting up or establishing a counter-electro-motive force or
tendency, in those parts of the work which form a shunt to the part to be
heated for the purpose of confining or Iocalizing the heating current at the part to
be operated upon.
Eleventh. The herein described improvement in electrical ring welding, etc., con-
sisting in establishing in the continuous portion of the blank, a counter-electro motive
force or tendency opposing the flow of current therethrough from one to the other of
the clamps by which the heating current is supplied.
Twelfth. The herein described improvement in electric welding, soldering and the
like by alternating currents which consists in establishing, in the part of the work
forming a shunt to the portion to be heated, a series of alternating currents derived
from the same source as the main beating currents, and tending to
main heating current in the shunt while at the same time assisting such main currents
oppose the
in heating the work.
D11.*. 111