Abstract: An arc welding torch having electrode gripping means is located rearward in the torch head and remote from the welding operation which occurs in a carefully formed, unerratic, cooling atmosphere of shielding gas enveloping the electrode and flowing in collimated fashion.

Abstract: An arc welding machine using non-consumable electrode comprises a welding head the body of which accommodates two non-consumable electrodes arranged at an angle to a passage formed therein and intended for a filler wire to extend therethrough. The welding head is operably connected with a mechanism enabling its vertical movement, and with an electrode oscillating mechanism, the former and the latter being electrically connected to an arc length stabilizer and arc length control device, which, in turn, are connected with a sensor means for sensing angular position of the non-consumable electrodes. Electrically connected to the non-consumable electrodes is a mechanism intended for reversing longitudinal motion of the welding head.

Abstract: The disclosure relates to a welding torch with a flexible welding torch head. The head is in the form of a ball and socket with a fluid passage and is biased in position by disc springs which also have fluid passages.

Abstract: A transferred type plasma torch comprises a body containing and rigidly interconnecting; a bushing having an internal constricted surface, a collet attachment mounted in the bushing, an electrode mounted in the collet attachment, a nozzle tip disposed coaxially of the electrode at the tip, and a centrally bored end cap screwed in the end of the bushing and having an internal countersunk surface. The collet attachment is composed of a cylindrical collet having a spherical flanged portion and a collet chuck having a spherical flanged end portion and mounted in the collet, the spherical flanged portion of the collet being received in the internal constricted surface of the bushing, the spherical flanged end portion of the collet chuck being received in the internal countersunk surface of the end cap. The spherical flanged portion of the collet and the spherical flanged end portion of the collet chuck are so designed that they have the same center of curvature.

Abstract: In the body of a plasma arc torch head coolant inlet ducts extend normally to the portions of the nozzle surface subject to maximum heating. The rate of cooling and a permissible power of the plasma arc torch are markedly increased by directing the flow of incoming coolant directly against the surface being cooled. Where the nozzle lateral surface is exposed to the effect of a plasma-forming arc, the coolant inlet ducts are arranged so as to open radially into said lateral surfaces. If electromagnetic coils are provided to allow control over the plasma jet, a coolant is supplied to effect intensive cooling of the nozzle end face.

Abstract: Plasma-MIG welding in which a thermally ionizable gas stream is flowed through a nozzle non-consumable electrode having a central orifice and a surrounding annular opening toward a workpiece and is thereby split into a central gas column enveloped by an annular gas shield. A consumable electrode is fed through the central gas column toward the workpiece, with the establishment of a MIG-arc therebetween. A plasma arc is then spontaneously established by means of the MIG-arc between the nozzle non-consumable electrode and the workpiece. The central plasma gas column is accelerated by constriction of the annular gas shield downstream of the nozzle non-consumable electrode.

Abstract: A plasma-MIG welding system includes establishing a plasma arc between a primary non-consumable electrode and an auxiliary non-consumable nozzle electrode to provide a plasma flow downstream of the primary non-consumable electrode and out through such nozzle electrode. A consumable electrode is fed through the plasma flow out through the nozzle electrode, a MIG-arc being established between the consumable electrode and a workpiece. A gas stream consisting of an inert gas and an oxidizing gas is flowed past the consumable electrode in a manner to completely envelope the same and into admixture with the plasma flow without coming into contact with the non-consumable electrode. A separate gas stream provides a sheath for the resulting plasma flow after its passage through the nozzle electrode.

Abstract: Method and apparatus for modifying the surface properties of a metal part made of a metal which changes its properties with heating to a transformation temperature and subsequent cooling in which method electric current having a frequency of at least 3000 Hz is supplied to a pair of contacts respectively at the opposite ends of the surface area to be modified through a proximity conductor or conductors which are spaced from the surface area by not more than two times the width of the conductor. The duration, frequency and magnitude of the current and the width of the proximity conductor or conductors are chosen so that the metal of such area heats at least to the transformation temperature before the adjacent metal reaches a temperature which would prevent self-quenching of the area metal, by means of conduction of heat from the area metal to the adjacent metal, when the current is discontinued. Apparatus for producing lines of hardening on valve seats is disclosed.

Abstract: A method of treating electrodes intended for operation in argon as electric arc cathodes. Each of the electrodes being treated consists of a holder with an active insert. The active insert comprises elements selected from the series of rare-earth elements, yttrium, alkali-earth elements, elements of Group IV A of the periodic system and compounds thereof, taken separately or in combination. The electrodes are treated in an electric arc burning in an atmosphere of argon and an active gas, such as nitrogen or oxygen. During the course of treatment the electrode functions as a cathode. A mixture of argon and oxygen or argon and nitrogen is fed to the cathode area of the arc. The duration of the electrode treatment cycle is at least 100 times less than that of the electrode operation time in an argon arc. Treatment is conducted by currents that do not exceed the maximum operating current values of the treated electrode. The volume concentration of the active gas in the mixture varies from 0.1 to 100%.

Abstract: A class of age hardenable nickel base alloys for use as filler wires in fusion welding superalloys is described. The alloys contain manganese in levels of from about 0.5 to 3 percent to greatly reduce the incidence of heat-affected zone cracking in the metal being welded. The weld filler alloys also contain significant amounts of aluminum, titanium, tantalum, and columbium, and therefore the resultant welds can be age hardened to relatively high strength levels.

Abstract: A plasma-MIG welding system in which the power for establishing the MIG-arc is supplied to the consumable electrode at a point downstream of the non-consumable electrode.

Abstract: A machine and method whereby a metallic stick is pressed into a mold which is moved along two axes substantially perpendicularly to the stick so as to make the end of the stick follow the mold while it is softened by heat produced by passage of an electric current between the mold and the stick, the stick only being moved in its axial direction while the mold is only moved in the two substantially perpendicular directions to this axial direction.

Abstract: A hard surface on reactive metal such as a titanium member is weld deposited in an inert gas atmosphere using a welding rod tubing made of the same metal as the member and filled with tungsten carbide particles.

Abstract: A welding electrode for a TIG welding torch has a short disposable electrode tip attached to a holder. The holder, which is solid and made of a highly conductive material such as copper, carbon, steel, or graphite, is mounted in the chuck or collet of a conventional torch. The tip is made from a standard electrode material, such as tungsten, and is preground to a precise point angle. In the preferred form of the invention, the holder includes a collet assembly in which the electrode tip is removably held. In other forms of the invention, the tip may be permanently attached to the holder by mechanical engagement of the tip in an end of the holder or by cementing, welding or brazing the tip to the end of the solid conductive holder. In this form, tips may be attached on both ends of the holder. The holder with the attached prepoint tip reduces unnecessary wastage of the electrode material, eliminates the grinding of points in the electrode and the resulting electrode contamination, and redcuces I.sup.

Abstract: A conventional plasma arc cutting torch in which the plasma gas passageway of a cutting tip is flared about 90 degrees outwardly, the cutting torch angle-to-work is about 45 degrees, the torch stand-off from the work is about 3/16 inch, and the torch travel speed is about 60 inches/minute to obtain metal preparation of consistent width and depth dependent on the work metal and its thickness. Changes in these characteristics, when limited to established parameters, varies the width and depth of the resulting metal preparation which remains constant for each combination of changes.

Abstract: A TIG pipe welding method which employs two sets of machine guide surfaces on the pipe ends. First radially inner guide surfaces cooperate with a sensor coupled to the welding torch to continuously monitor the arc gap between the welding electrode and the weld puddle as the welding electrode moves around the circumference of the pipe. The second set of radially outer surfaces cooperate with a welding carriage to guide the carriage and welding modules around the pipe joint. The carriage is constructed to provide a sealed welding chamber surrounding the electrode. An additional flow of shielding gas is provided around the torch electrode of a TIG or hot wire TIG welding module to augment the normal gas shield.

Abstract: A method of forming a through-the-partition intercell connection between adjacent cell groups in a multicell, lead-acid storage battery. Plate strap lugs are positioned on either side of an aperture in a partition between adjacent cells. One of the lugs has a substantially flat face thereon abutting the partition while the other and opposing lug has a cavity formed in its partition-abutting face, which cavity is substantially axially aligned with the aperture during positioning. The battery is rotated 90.degree. such that the cavity-bearing lug lies beneath the flat-faced lug. The flat-faced lug is then arc welded through its center backside such that the melt formed flows by gravity through the aperture in the partition and into the cavity in the opposing lug. After the battery is inverted and the center backside of the cavity-bearing lug arc welded to fuse the lugs together, cold pressing the lugs together completes the connector forming process.

Abstract: A method of plasma MIG welding in which an arc is maintained between a workpiece and a welding wire in a thermally ionized gas (auxiliary plasma) which is generated by an electric gas-discharge between two non-consumable electrodes; neither the welding wire nor the workpiece acts as a single electrode for generating the thermally ionized gas.

Abstract: Disclosure is made of an inductor for working metals by the pressure of a pulsating magnetic field, which comprises a magnetic field concentrator with an insulating slot. The concentrator has a cylindrical surface, whereon there is arranged a winding which induces eddy currents in the concentrator, and a surface, whereon there are concentrated eddy currents which induce eddy currents in the workpiece. The concentrator is provided with a conducting compensation rod overlapping the insulating slot, which rod is insulated from the concentrator and received in an opening extending along the slot in immediate proximity to that surface of the concentrator where there are induced eddy currents which induce eddy currents in the workpiece. The proposed inductor design makes it possible to produce a uniform magnetic field which, in turn, produces electrodynamic forces that work a blank so as to improve the quality of products, as compared to conventional working techniques.

Abstract: The disclosure of the present application relates to an improved method of open-arc welding. According to the present method, the outer shield of a double-shield welding system consists of a stream of gas formed in a shield concentric with the inner shield. This method is distinguished by the fact that atmospheric air may be used as the outer shield gas because the outer-shield velocity is so regulated and so positioned as to prevent the air from being drawn into the weld area, the outer shield gas velocity nearly approximating the inner shield gas velocity.

Abstract: An active gas plasma arc torch and a method of operating the same, said torch including a rod-shaped cathode, a first gas passage formed around said cathode to feed a protecting gas or shielding gas, a second gas passage formed around said first gas passage to feed a plasma gas and a constricted port for discharging the plasma gas, characterized in that at least a part of the shielding gas which flows out from the first gas passage is removed from the inside of the torch at the position short of said constricted port of the torch, whereby the working quality and the working speed are substantially improved while the rod-shaped cathode is satisfactorily protected by the shielding gas.

Abstract: In a welding apparatus for overlaying on a base metal, a reverse polarity soft plasma arc is formed between an electrode and the base metal and a welding rod is fed into the arc to weld the base metal by melting the welding rod and the feeding speed of the welding rod is controlled corresponding to the arc current to form a bead having low penetration.The electrode is oscillated and an active gas such as CO.sub.2 or O.sub.2 is incorporated in a shield gas at a rate controlled corresponding to the oscillation of the electrode.

Abstract: An arc welding apparatus and method is described which includes a guide nozzle surrounding a non-consumable electrode and a shielding nozzle disposed outside the guide nozzle so as to feed a protecting inert gas about the electrode from a position within the guide nozzle and to feed a shielding carbon dioxide gas or a mixture of carbon dioxide gas and oxygen or other inert gas from a position within the shielding nozzle, whereby the electrode is protected by means of the guide nozzle and the protecting gas supplied therethrough and the outer portion of the arc is cooled to restrict the radial extent thereof by the shielding gas, while a deoxidizing reaction with the melted metal may be performed by means of the carbon dioxide gas and a deoxidizing agent within a welding rod when the latter is employed between the electrode and a base metal, or in the vicinity of the welding arc.

Abstract: A filler material such as in wire form is applied to the work surface of a workpiece through a method and apparatus which moves the wire in a reciprocating motion, alternatively to withdraw from and then reinsert the end of the wire into a molten weld pool generated such as from an electric arc between an electrode and the workpiece, a plasma arc or other heating torch means.

Abstract: Plasma-MIG welding involving the use of two parallel consumable electrodes axially introduced into a plasma arc initiated by a non-consumable electrode and out through a nozzle. All three electrodes are maintained at a positive polarity whereby a substantial increase of the deposition rate is achieved, without rotation of the MIG-arcs and without exceeding the critical current intensity.

Abstract: A compact plasma-MIG welding torch in which the non-consumable electrode and the contact tube for the consumable electrode are accommodated in separate passages in the housing whereby the distance between the non-consumable electrode and the contact tube becomes comparatively small, the distance between the contact tube and the nozzle is short, and the extension of the consumable electrode is small during welding.

Abstract: Plasma-MIG welding in which a thermally ionizable inert gas is flowed past a starter non-consumable electrode through a nozzle non-consumable electrode toward a workpiece, firstly a plasma arc is established between such starter non-consumable electrode and such workpiece to initiate and sustain a plasma flow, a consumable electrode is fed through such plasma flow toward the workpiece, secondly a MIG-arc is separately established between such consumable electrode and the workpiece, and finally the nozzle non-consumable electrode is electrically connected to the starter non-consumable electrode so that the plasma arc is taken over by the nozzle non-consumable electrode and extends solely from the nozzle non-consumable electrode to the workpiece.

Abstract: A gas-shielded arc-welding torch constituted by a holder section having a barrel adapted to retain a tungsten electrode and a handle section which supplies electric current to the holder section as well as an inert gas thereto, the holder section being bendable relative to the handle to assume any desired angular working position. Included in the handle section is a conductive metal helix of solid wire, one end of which is connected by a tubular metal coupler to the barrel of the holder section, the other end being connected by a pipe to a hollow electrical connector to define a current-supply line extending from the connector to the barrel.

Abstract: A multi-electrode welding apparatus is provided which includes a torch body and a least two electrodes, preferably of the non-consumable type, which are adjustably mounted in the torch body so as to be vertically positionable with respect to a workpiece and a nozzle mounted in the torch body. Interchangeable nozzles are provided for the electrodes, each nozzle being removably and interchangeably mounted in the torch body and adapted to be employed in conjunction with either of the electrodes so that one of the nozzles in conjunction with one electrode provides an open arc between such electrode and the workpiece, and another of the nozzles employed in conjunction with the other electrode provides a constricted arc between such electrode and the workpiece.

Abstract: Apparatus for thermal spraying powdered material onto a substrate. The apparatus consists of an elongated conductive tube, an electrode positioned coaxially within one end of the tube. Inert gas such as helium is mixed with a powdered material such as a ceramic or a metal and a controlled amount is injected evenly into the tube. A high energy pulse is applied between the electrode and the conductive tube to produce current sheets which move from one end of the electrode to the other forming a high temperature and velocity plasma for melting and discharging the powdered material at a high velocity from the other end of the tube.

Abstract: Welding torch comprises a combination collet body which functions interchangeably for electric arc welding, of the open arc type using a consumable electrode, or for inert gas shielded welding using a non-consumable electrode. The collet body has a screw-threaded collar at one end which is screwed into the welding head. At the other end, it has a slitted or splined chuck. The slightly enlarged central body portion between the collar and the chuck includes a plurality of gas vents. For open arc welding, a consumable electrode, interposed into the chuck, is secured in place by a constricting metal adapter sleeve which also serves to close the gas vents. For inert gas shielded welding, the consumable electrode and the metal adapter are replaced by a nonconsumable electrode and a ceramic shield open at one end. The open vents permit inert gas to escape under the ceramic shield and surround the nonconsumable electrode during the welding process.

Abstract: A plasma-arc spraying torch is disclosed which comprises a cathode unit and a separable anode unit which units are connected to each other approximately at a section of the torch in which the cathode of the torch is mounted on a cathode supporting member. The connection of the units and the mounting of their parts are all self-centering. Each unit has its own separate cooling circuit. Cooling of the anode nozzle is provided by a helical water duct within a nozzle holder member surrounding the anode nozzle. The nozzle holder and cathode supporting members are each at least laterally embedded in body parts of insulating material.

Abstract: A method for TIG welding by using a plurality of nonconsumable electrodes extending frm the tip of a TIG welding torch and one filler wire fed through a space between the electrodes, each electrode being independently supplied with power. A molten pool is formed by melting both the base metal to be welded and the filler wire by means of arcs generated between respective electrodes and the base metal. Melting of the base metal is mainly controlled by the arc produced by one of the plurality of electrodes while melting of the filler wire is mainly controlled by the arc generated by the other electrode.

Abstract: An electrical plasma jet torch has front and back electrodes mounted in a torch body and means for maintaining a high current electric arc between the electrodes. The front electrode is the anode and is formed with a passage that provides a nozzle through which high velocity, high temperature plasma is ejected. The anode includes an improved arrangement of concentric rows of coolant passages extending to the front of the anode. A single annulus formed in the anode provides communication with all passages of the outer row. Passages of both rows are arranged in mutually spaced groups to provide space for a number of powder bores which extend substantially radially through the anode. The powder bores are enlarged to receive a sleeve which is readily replaced when eroded by highly abrasive powders. An annular grooved boss of the front of the anode is received in a groove in a cover plate and sealed thereto by means of O-rings to provide a coolant flow reversing annulus at the front end of the anode.

Abstract: A method of plasma multiarc welding by permanently burning direct-current arcs of different polarities makes use of a plasma forming gas and shielding mediums and the arcs are located so that the adjacent arcs have opposite polarities, consisting, according to the invention, in that all arcs are started between nonconsumable electrodes and a workpiece or some arcs are started between nonconsumable electrodes and a workpiece and other arcs are started between consumable electrodes and a workpiece, the currents of all arcs and the distance between the arcs being set so that the ratio of the product of the currents of two adjacent arcs to the distance therebetween is equal or more than 6.10.sup.3 A.sup.2 /cm.

Abstract: An electrode structure for use in an electric discharge device includes a fluid-permeable discharge chamber; a flow of gas seeded with actively emissive elements is delivered to the interior surface of said discharge chamber for a distributed electric discharge to be maintained thereat. The discharge chamber is fitted with an opening providing for a discharge channel outlet. Service life of the proposed electrode structure reaches several thousands of hours, which is possible due to erosion inhibition at the discharge surface. Simplicity of design, reasonable weight and dimensions of the electrode structure renders it suitable for use as an electrode in plasmatrons employed in chemical industry and metallurgy, as well as an electrode for electric arc melting furnaces. The electrode structure can also be used as a welding electrode, and as an electrode for MHD generators and other electric discharge devices with electric arc heating process being used therein.

Abstract: An orifice tip for a plasma arc welding and cutting torch is described wherein the tip is comprised of an isotropic graphite of substantially uniform thermal conductivity and with a very small particle and pore size, thereby providing substantially superior operating life.

Abstract: Welding apparatus for inert gas shielded arc welding comprising a welding gun for holding and controlling a non-consumable electrode and including means for supplying inert gas to the welding arc region by way of a gas cup surrounding but spaced from such an electrode when positioned in the gun, the welding gun being further provided with an extended gas shielding wall arrangement protruding a substantial distance beyond the gas cup and capable, either by itself or in combination with a narrow gap weld preparation, of substantially enclosing an electrode in the gun, except for its tip, when the electrode is protruding for a similar distance beyond the gas cup.

Abstract: A high frequency oscillator is pulsed on and off to create at least a first and second pulse to be applied by inductive heating to a steel tool which has not previously been heat treated. The pulse width, amplitude and interval between pulses are adjusted for a given alloy and then kept constant during the production run. A Hartley oscillator with a frequency above 10 MHz is utilized and the pulses have pulse widths of less than 100 milliseconds.

Abstract: A torch for welding, cutting or heating comprises a torch head having at least one outlet nozzle, a torch housing spaced from the torch head, connecting means connecting the torch head with the torch housing and provided with passages therethrough to be flown through by a cooling medium, and elongated hermetically sealed heat-transmitting means extending through the connecting means for automatically transporting heat from a heat receiving zone adjacent the torch head to a heat releasing zone adjacent the torch housing for cooling the torch head, in which the heat releasing zone is cooled by the cooling medium passing through the aforementioned passages.

Abstract: Arc heater apparatus and method for producing acetylene from heavy hydrocarbons characterized by arc heater means for producing arc heated plasma gas forming a downstream reaction zone, wall means forming a plenum chamber having a substantially vertical axis and surrounding the reaction zone, inlet means upstream of the arc heated plasma gas for introducing heavy hydrocarbons into the chamber, and the walls of the chamber flaring downwardly outwardly to minimize the deposit of solid reaction products on the walls.

Abstract: An arc welding torch terminates in a gas cup open at one end through which an electrode projects. Inert gas is introduced under pressure at the other end of the gas cup and flows past and through a gas diffuser disposed in said gas cup. The diffuser is spaced from the inner wall of the gas cup, and a portion of the gas flows axially parallel to the central axis of the gas cup. The diffuser has a set of passageways to form and direct columns of gas in an outward direction, and another set of passageways to form and direct columns of gas in an inward direction. The diffuser is axially and angularly adjustable to vary the pattern of gas discharge with relation to the arc and to control the contour of the weld bead.BACKGROUND OF THE INVENTIONThe present invention relates to inert-gas arc welding, and more particularly, to a method and apparatus for applying a shielding gas in the welding operation.

Abstract: A method is disclosed in which gas shield arc welding is carried out while applying a gas at a higher pressure than the shield gas to the rear part of the surface of molten metal during welding. By this method, welding proceeds while the molten pool is being maintained in the desirable shape, and the welding can be performed at high currents and speeds without causing bead defects such as undercut formation or humping.

Abstract: This invention relates to welding, brazing or the like utilizing a mixture of hydrogen and oxygen generated in substantially stoichiometric proportions in an electrolytic cell by electrical dissociation of water, the mixture so generated being passed from the generator through a flashback arrestor and thence to a burner where the gases are ignited. The invention also relates to atomic welding in which the above mentioned mixture is passed through an arc causing dissociation of both the hydrogen and oxygen into atomic hydrogen and oxygen which on recombination generate an intensely hot flame.

Abstract: A welding device capable of providing a blanket of nonreactive gas to isolate atmospheric gases from a weld zone to prevent weld contamination and capable of providing a stream of suppression gas across the path of a welding beam to suppress the formation of a beam absorbing plasma is disclosed. The device comprises a housing having a welding beam entrance port, a structure wall cooperating with the housing to form a first cavity therein and having an exit port aligned with the entrance port, means for supplying suppression gas to the first cavity, means for exhausting the suppression gas from the first cavity, a base cooperating with the housing and the structure wall to form a second cavity within the housing, means for providing a nonreactive gas to the second cavity, and means for passing the nonreactive gas from the second cavity to the weld zone.

Abstract: A device is disclosed for producing an electrical arc which is stabilized by a stream of metastable argon, or some other stabilizing gas. The arc may be employed to vaporize a sample material so as to produce light for spectroscopic analysis. The vaporization is rapid so that the constituents of the sample material can be determined very quickly and accurately. The arc is highly stable so that it operates without sputtering, dancing or showing other signs of instability. Thus, the results obtained with the arc are highly accurate and repeatable. The arc is produced between a cathode in one end of an arc chamber and an anode outside the opposite end of the chamber. The arc passes out of the chamber through an orifice in a gas shaping nozzle. Argon gas is supplied to the chamber through a plurality of gas inlets, which preferably are directed at angles having peripheral components so that a whirling motion is imparted to the gas as it enters the chamber.

Abstract: A gas shielded arc welding torch with a working nozzle end including a nozzle seat having first a conically shaped outer surface decreasing towards the working end, a push on gas nozzle adapted to be received on the nozzle seat from the working end thereof and projecting beyond the working end thereof, the nozzle having an expandible section adapted to overlie the nozzle seat in tight engagement therewith, and constricting means resisting expansion of the nozzle.

Abstract: A method of removing surface defects from the surface of a steel product, such as a slab designed for rolling, wherein the defects are melted by an arc generated by an arc welding apparatus having a non-consumable electrode, a guide nozzle about the electrode to maintain an inert gas atmosphere immediately thereabout, and a shield nozzle about the guide nozzle to inject a mainly carbon dioxide gas therefrom, and a deoxidizer is applied to the molten pool formed in the welding operation so as to cover the surface thereof with a slag formed by the deoxidizer which is oxidized.

Abstract: Disclosure is made of an inductor for working metals by the pressure of a pulsating magnetic field, wherein on the outer surface of a concentrator, which has a working opening to receive an article to be worked and a radial slot, there are provided annular grooves, the spacings between the annular grooves forming stiffening ribs of the concentrator; laid in said annular grooves are flat helical sections of a winding, the beginning of each section enveloping an electrically conducting rod arranged in a bore extending through the concentrator, being parallel with the axis of the working opening and being next to said annular grooves; the ends of each flat helical section are interconnected in parallel by means of a bus; in said concentrator ribs, there are provided threaded holes to receive screws whose butt ends press upon the electrically conducting rod.

Abstract: A holder for a consumable electrode used to cut metal by means of an electric arc is disclosed. The holder has an elongated barrel for containing the electrode and a pistol grip depending from the barrel for supplying electrical energy to the electrode. The exposed length of the electrode can be adjusted by a ram which slides in the barrel behind the electrode and which cooperates with clamping means actuated by a trigger on the pistol grip to secure the electrode at any adjusted length. Compressed air and electrical energy are supplied to the base of the pistol grip and are respectively communicated to a nozzle at the front end of the barrel and to the electrode. The nozzle is mounted for rotation relative to the electrode and has orifices for ejecting the air along any desired side of the electrode. Manifold means in the nozzle insures a continuous supply of compressed air to the orifices irrespective of the angular position of the nozzle.