Abstract: The present invention provides a titanium-made plate-type heat exchanger comprising first-fluid flow paths and second-fluid flow paths arranged alternately, which is formed by joining titanium-made constituting members, wherein: a titanium-zirconium based brazing solder containing 20 to 40 wt. % of titanium and 20 to 40 wt. % of zirconium, which melts under 880° C., is coated over positions to be connected of the constituting members, and brazing solder coated constituting members are heated under 880° C. in an vacuum and/or inert gas atmosphere. The present invention also provides a production method of the heat exchanger, which can prevent titanium-made constituting members of the heat exchanger from being deteriorated due to over-heating.

Abstract: A first plate and a second plate have brazing paste on the surface thereof. When the first plate is combined with the second plate while an inner fin is disposed therein, a protrusion forms a clearance there between. Heat is added to evaporate the organic substances in the brazing paste. The organic substances vapor is discharged into outside of the tube through the clearance. After that, heat is added furthermore to melt the brazing paste. The first plate and the second plate are brazed together to form the tube and the inner fin is brazed to the inside of the tube.

Abstract: The invention relates to a soldered heat exchanger, especially a capacitor for a motor vehicle ventilation system, comprising a heat exchanger network made of tubes and ribs and at least one collector pipe made of a base (2) and a cover (3) and separating walls (8), whereby the base (2) and the cover (3) have edges (4, 5, 6, 7) which overlap on the longitudinal sides thereof. The base (2) receives the ends of the tubes and the separating walls (8) are fixed in relation to the cover (3) by means of a first and second shoulder (8b, 8c and a lug (8a). According to the invention, groove-shaped recesses (3b, 3c) are arranged in the edges (6, 7) of the cover (3) in the region of the separating walls (8), wherein the shoulders (8b, 8c) of the separating walls (8) engage. A secure positioning of the separating walls in the collector pipe is obtained in addition to a leakage-free soldering of the capacitor.

Abstract: A mounting bracket for securing a component, including a unitary first bracket member including a first plate portion having a first section for securing to the component, a second plate portion having a second section for securing to the component, and an intermediate plate portion, the first and second plate portions being spaced apart from each other with the intermediate plate portion extending there between, the first, second and intermediate plate portions defining a central space there between; and a separately formed second bracket member mounted to the first bracket member and having a central portion extending at least partially across the central space, the bracket member including engagement members extending outward from the central portion and engaging the first bracket member thereby securing the second bracket member to the first bracket member, the central portion defining a mounting opening there through.

Abstract: The invention relates to a method of manufacturing and coating heat transfer parts for a heat exchanger such as tubes in an automobile radiator. The tubes are coated with brazing material by thermal spraying, such as plasma deposition or wire-arc deposition. The coating is then melted by application of heat to braze the tubes to the fins and to the headers to complete the formation of the heat exchanger.

Abstract: An apparatus for brazing a heat exchanger, in particular a flat-tube heat exchanger, comprising a block of flat tubes and corrugated fins. The apparatus comprises a brazing frame that accommodates a tube-fin block within itself and which has two brazing bars arranged parallel to each other which are connected by tie rods. The brazing bars have a plurality of openings that are open toward one side, e.g., notches.

Abstract: The invention relates to a method of manufacturing and coating heat transfer parts for a heat exchanger such as tubes in an automobile radiator. The tubes are coated with brazing material by thermal spraying, such as plasma deposition or wire-arc deposition. The coating is then melted by application of heat to braze the tubes to the fins and to the headers to complete the formation of the heat exchanger.

Abstract: A method for producing a plate heat exchanger with multiple plates made of a solderable material. The plated define circuits for fluid circulation and are assembled together by soldering. The soldering is done after a soldering material is applied to the regions to be soldered. The soldering material is deposited on the plates with an electrolytic solution.

Abstract: A high temperature prime surface heat exchanger is created using adjacent pairs of plates having braze cladding on a first surface thereof that are formed to create fluid flow passages for coolant and fluid flow passages for hot gas when assembled into a core by stacking the plates. The coolant passages are adjacent the first or clad surface of each formed plate to avoid direct contact with the high temperature gas flowing in the hot gas passages. The adjacent plate pairs are joined by brazing of a contacting portion of the first surface on each plate to form sealed coolant passages the core.

Abstract: A plurality of parts are brazed using an iron/chromium filler metal. The parts are preferably composed of stainless steel. The brazed assembly forms a heat exchanger characterized by good corrosion resistance and low rates of leaching of Ni, which are further improved by a post-brazing conditioning step in an oxygen-containing atmosphere at a temperature of about 150° to 600° C. The preferred brazing filler metal consists essentially of a composition having the formula FeaCrbCocNidMoeWfBgSih wherein the subscripts are in atom percent and total 100%, “b” is about 5 to 20, “c” ranges from 0 to about 30, “d” is 0 to about 20, “e” is 0 to about 5, “f” is 0 to about 5, “g” is about 8 to 15, “h” is about 8 to 15, the balance being incidental impurities of up to about 1 percent by weight of the total composition.

Abstract: In a method of applying a brazing material to braze a joining portion between a first member and a second member, a relationship between an amount of the brazing material and an expanding dimension of the brazing material is determined. Then, a position to apply the brazing material or a necessary amount of the brazing material is decided based on the relationship. After the first member and the second member are joined, the brazing material is applied. The position is defined by a distance from the joining portion. The distance is set smaller than one-half the expanding dimension of the brazing material on an applying surface.

Abstract: A method of establishing a leak tight and structural connection between a core tube and an accommodating header plate in a tubular heat exchanger, including the steps of positioning the core tube into bores of the header plate and a braze foil, installing a ferrule inside the core tube end, radially expanding the ferrule in the core tube end, thus expanding the core tube end into intimate contact with the header plate in which it is received, deforming a ferrule into pinching contact with the braze foil plate, directing the flow of the braze material towards the contact surface area, and brazing the tubular heat exchanger in order to form a seal at the intimate contact area. A leak tight connection and a tubular heat exchanger having a leak tight connection produced via the noted method are also set forth.

Abstract: Objects of the present invention are to provide a laminated heat resistant alloy plate has a large area, and to provide a manufacturing method therefor. The laminated heat resistant alloy plate according to the present invention is obtained by brazing a Ni alloy plate having plural striae formed thereon at a predetermined interval and a plate which is made of a material the same as or different from that of the Ni alloy plate with a sheet of Ni solder which is amorphous and does not contain organic binder.

Abstract: In a method of making finned tubes as components of air-cooled systems or condensers, a sheet metal strip of aluminum is first shaped into a waved finned structure with plural fins in parallel relationship and arched ends for connecting the fins, thereby defining crests on opposite ends of the finned structure. A fluxing agent of cesium-aluminum tetrafluoride is applied in lines onto the crests on at least one of the ends of the finned structure. The finned structure is then placed upon a broad side of a flat steel tube coated with a zinc/aluminum alloy. The finned structure and the flat tube are subsequently joined in a brazing furnace in the presence of an inert gas at a temperature between 370° C. and 470° C. to produce a unitary structure which is then allowed to cool down at room temperature.

Abstract: An annular recuperator for use with an annular combustor. The annular recuperator includes a frame and an enclosure provided about its frame that defines a recuperator chamber. A plurality of involute shaped sealed and open recuperators are received in the recuperator chamber.

Abstract: A method for manufacturing a metallic component comprises the steps of assembling different metallic parts of said component, and subsequently fixing the assembled parts by heat treatment. According to the invention, said heat treatment includes the steps of placing the assembled parts in an adapted enclosure, associating heater means with said assembled parts, and subsequently switching on said heating means within said enclosure in order to heat said assembled parts to a predetermined temperature at which mechanical fixing of said assembled parts occurs. The method is preferably used in the manufacturing of heat exchangers.

Abstract: A method for manufacturing a metal structure in which the metal structure has separate walls forming channels through which a fluid can flow includes at least partially wetting the walls inside the channels with an adhesive, bringing the metal structure into contact with a solder that adheres to the adhesive, and carrying out a heat treatment to form soldered connections between the separate walls. The method is distinguished by the fact that the dosed delivery of the adhesive is performed by at least one dosing element having a honeycomb configuration and having an inlet side (8) and an outlet side, the element being connected to the adhesive. The adhesive enters the dosing element through the inlet side and is uniformly distributed into the channels through the outlet side. The invention also includes a device for wetting the metal structure with the adhesive.

Abstract: The aim of the present invention is a manufacturing process for assembly parts (101, 102, 111, 112) for the manufacture of elements of chemical devices (100), comprising the fixation of an anticorrosion metallic coating (31, 32) on an unprocessed assembly part (21, 22), by means of an operation comprising a brazing operation under a controlled atmosphere and, possibly, the shaping of the coated part (101, 102), by plastic deformation. The brazing temperature is preferentially less than approximately 750° C., and more preferentially between 600° C. and 720° C. The process according to the invention makes it possible to fix solidly on a steel plate an anticorrosion coating with a thickness less than 1 mm.

Abstract: A folded fin heat sink assembly and a method of fabricating a folded fin heat sink assembly for use as a cooling solution in micro-electronics and/or telecommunication applications. The heat sink assembly is formed by placing a sheet or paste of Sn—Zn solder upon a copper base plate, placing one or more aluminum folded fin assemblies on the solder sheet or paste, heating the base plate, the folded fin assembly and the solder to a temperature exceeding the liquidus temperature of the solder and allowing the solder to flow, and cooling the solder to form a soldered joint between the base plate and the folded fin assembly.

Abstract: A method for producing a metallic honeycomb body, according to which at least partly structured metal sheet is coiled, laminated or looped to form a matrix. The matrix is oscillated by an external excitation and during or after the external excitation is introduced into a casing tube.

Abstract: Fluoride-based flux is uniformly dispersed in and mixed with synthetic resin, which has fluidity at room temperature and sublimes at a temperature lower than a brazing temperature, so as to constitute 40 to 70 wt. % of the mixture, thereby producing coating material. This coating material is applied to coating belts which undergo rotation and is transferred from the coating belts to the surface of the aluminum material. The coating material has high viscosity and stably adheres to the transferred areas.

Abstract: A phosphorus-copper brazing material formed of a phosphorus-copper brazing alloy which can easily be cold-worked into a thin sheet, a brazing sheet having a brazing layer of the phosphorus-copper brazing alloy, and a flow path structure for heat exchangers constructed by brazing with the alloy, are such that the phosphorus-copper brazing material includes a phosphorus-copper brazing alloy containing Cu as a major component and phosphorus of not less than about 2.0 mass % to not more than about 3.2 mass %. The brazing sheet includes a metal sheet, and a brazing material layer that is integral with the metal sheet on at least one side of the metal sheet, the brazing material layer being formed of the phosphorus-copper brazing alloy. The metal sheet may be formed of copper or a copper alloy containing Cu as a major component.

Abstract: A condenser that is to be brazed in a radiant energy oven has a significant, localized mass differential which would, without further treatment, create a significant temperature differential across the condenser in the braze oven. This is compensated for, in the method of the invention, by thermally spraying onto the surface of the higher mass portion a rough surface layer of a compatible material that increases the emissivity of that portion sufficiently, relative to the rest of the condenser, to decrease the temperature differential that would otherwise occur.

Abstract: Methods for the manufacture of assemblies which included brazed components and in which nickel/chromium-based filler metals are used wherein the manufactured assemblies are characterized by low leaching rates of nickel in water and water-based fluids, are disclosed. More specifically, there are disclosed methods for the manufacture of a heat exchanger or other assembly which method includes a brazing step, as well as a post-brazing conditioning step for treating the heat exchanger or other assembly. The manufactured heat exchangers and other assemblies are particularly useful in the handling of materials intended for human consumption such as water, beverages or food as the manufactured heat exchangers or other assemblies are characterized by reduced leaching rates of nickel into fluids passed through the heat exchanger. Brazing compositions useful in such manufactured assemblies are also described.

Abstract: A plurality of parts are brazed using an iron/chromium brazing filler metal. The parts are preferably composed of stainless steel and the brazed assembly forms a heat exchanger characterized by good corrosion resistance and low rates of leaching of Ni into fluids passing therethrough. The heat exchanger is especially suited for use in processing items intended to be ingested by humans or animals. Leaching rates and corrosion resistance are further enhanced by a post-brazing conditioning step wherein the assembly is heated in an oxygen-containing atmosphere to a temperature ranging from about 150° to 600° C.

Abstract: The invention relates to a method and an apparatus for positioning solder or braze material on the fin material to be used in a heat exchanger, as a radiator for vehicle, in which method the fin material, as a corrugated strip, is partly covered with solder or braze material. According to the invention the fin material (8) is transferred to the vicinity of a cladding device (1,2) so that when the fin material (8) is passed by the cladding device (1,2), the fin material (8) is cladded by solder or braze material (11) at least in one side of the fin material (8) essentially at the curved parts (10) of the fin material (8).

Abstract: A method for the production of a sealing element with a backing 1 and a honeycomb structure 2 attached to this backing 1, in which the cellular arrangement of the honeycomb structure 2 is formed by individual, profiled layers 3 to 7 made of a thin, foil-like, metallic material, and in which the layers 3 to 7 are bonded to each other and the honeycomb structure 2 is bonded to the backing 1, wherein the bonding of the individual layers 3 to 7 of the honeycomb structure 2 and the bonding of the honeycomb structure 2 to the backing 1 is effected by means of a brazing process in which pure aluminum or an aluminum alloy is used as the brazing filler material.

Abstract: Novel methods of making laminated, microchannel devices are described. Examples include: assembly from thin strips rather than sheets; and hot isostatic pressing (HIPing) to form devices with a hermetically sealed wall. Laminated microchannel articles having novel features are also described. The invention includes processes conducted using any of the articles described.

Abstract: In a method of manufacturing a plate type titanium heat exchanger in which a plurality of titanium herringbone plates are laminated and flow paths are formed between the respective herringbone plates, after brazing materials are charged or coated to the joints between the herringbone plates, respectively, the herringbone plates are placed in a vacuum heating furnace, subjected to vacuum degas processing while being gradually heated, and joined to each other by brazing by being more heated after a prescribed vacuum pressure has been obtained.

Abstract: In a method for joining a steel tube with an aluminum rib, a zinc-aluminum alloy layer, having an aluminum content of 0.5% by wt. to 20% by wt., is applied to the surface of the steel tube or the aluminum rib, and then a fluxing agent in the form of cesium-aluminum tetrafluoride is applied between the steel tube and the aluminum rib at room temperature before or during the mechanical contact of the aluminum rib with the steel tube. The steel tube provided with the aluminum rib is then heated to a soldering temperature of between 370° C. and 470° C. and subjected to room temperature to cool down.

Abstract: An internal channel in a metal body for use in applications where internal fluid flow within a metal body is desired, as in a heat exchanger. The internal channel is formed in the metal body by frictionally stirring with a pin plunged into the metal body, and traversing the metal body with the pin.

Abstract: An iron based brazing material for joining of objects by brazing represents an alloy, which apart from iron contains maximum 40% Cr, maximum 16% Mn, maximum 40% Ni and maximum 7% Mo, all stated in weight percent and 6-40% Si, which Si-addition lowers the liquidus temperature, that is the temperature at which the brazing material is completely melted. A brazed product is manufactured by brazing of iron based objects with an iron based brazing material which is alloyed with a liquidus lowering element as Si, possibly also with B or P.

Abstract: A heat exchanger, characterized in that Al or Al alloy tubes, each having a thermally Zn-sprayed layer formed on the surface of it, and having a brazing filler metal layer formed on said thermally Zn-sprayed layer using a powdery brazing filler Al alloy composed of 5 to 60 weight % of Si and the balance of Al and unavoidable impurities, are combined with and brazed to an Al or Al alloy header having a brazing filler metal layer formed using a powdery brazing filler Al alloy composed of 5 to 60 weight % of Si and the balance of Al and unavoidable impurities. The tubes and the header are strongly bonded to each other, and Zn is uniformly diffused and distributed. So, the heat exchanger shows good corrosion resistance.

Abstract: A process of brazing an end portion of a heat exchanger tube to a manifold, and a tube therefor comprising at least one fluid passage having an opening in the end portion. The process involves depositing a stop-off containing coating on at least part of the end portion of the tube, assembling the tube to the manifold by inserting the end portion of the tube through an opening in a wall of the manifold, and then brazing the tube to the manifold wall. The coating inhibits brazing material from entering the opening of the tube fluid passage.

Abstract: This disclosure describes a method for metallurgically bonding a complete leak-tight enclosure to a matrix-type fuel element penetrated longitudinally by a multiplicity of coolant channels. Coolant tubes containing solid filler pins are disposed in the coolant channels. A leak-tight metal enclosure is then formed about the entire assembly of fuel matrix, coolant tubes and pins. The completely enclosed and sealed assembly is exposed to a high temperature and pressure gas environment to effect a metallurgical bond between all contacting surfaces therein. The ends of the assembly are then machined away to expose the pin ends which are chemically leached from the coolant tubes to leave the coolant tubes with internal coolant passageways. The invention described herein was made in the course of, or under, a contract with the U.S. Atomic Energy Commission.

Abstract: The invention relates to a heat exchanger comprising two manifolds (10). Profiled pipe sections (11) are accommodated with a lamella configuration (12) between said manifolds. According to the invention, an obstructing means (13) for preventing the flow of solder is provided on the exterior of the profiled pipe section (11) between the manifold (10) and the lamella configuration (12). The invention also relates to a method for producing a heat exchanger. The invention provides that the obstructing means (13) is formed on the profiled pipe sections (11) before the sections are cut from a profiled pipe billet.

Abstract: The present invention provides a heat exchanger including a tank, a plurality of tubes in fluid communication with the tank, and a plurality of fins extending between the tubes. The tank includes a header member and a cover member, each of which is formed from a single sheet of aluminum. The header member includes an elongate generally planar base section having first and second ends and a middle portion disposed between the first and second ends. The header member also includes a flange section that extends along one edge of the base section and a wall section that extends along the opposite edge of the base section. The cover member has a central section that is spaced apart from the middle portion of the header member and a periphery that is joined to the first and second ends of the base section, the flange section, and the wall section.

Abstract: A module is formed in which semiconductor components are soldered to an electrically conductive heat sink. The electrically conductive heat sink is formed so that it will serve as an electrical bus in an electronic device. The chips of the semiconductor component are metallurgically bonded to the surface of the heat sink. The heat sink uses a heat transfer fluid that flows through an interior of the heat sink, the interior containing an internal element. In the preferred embodiment, the internal element is a plurality of silver plated copper balls. The copper balls are brazed to each other and to the walls of the heat sinks in an assembly process. The heat sink housing will typically be made from copper, with one surface made from molybdenum so that the expansion and contraction of the heat sink housing molybdenum surface will be similar to that of the silicon substrate of the chips, thereby avoiding the problem of the chip substrate cracking and breaking due to thermal flexing.

Abstract: A heat exchanger for enabling the flow of a heat exchanging medium disclosed. The heat exchanger comprises a collecting box having a peripheral edge; a tube bottom having a peripheral edge and a plurality of openings, the peripheral edge of the tube bottom being coupled to a peripheral edge of the collecting box; an intermediate bottom having a plurality of openings and a peripheral edge, the peripheral edge coupled to the peripheral edge of the tube bottom; and a plurality of flat tubes coupled to the plurality of openings in the intermediate bottom. A method of manufacturing a heat exchanger is also disclosed. The method comprising the steps of coupling a collecting box to a tube bottom; coupling an intermediate bottom to the tube bottom; and coupling a plurality of flat tubes to the intermediate bottom.

Abstract: The present invention relates a method of manufacturing a high fin density heat sink comprising the steps of: aligning a plurality of length sections side by side in a mutual parallel arrangement, said length sections having a cross-section comprising a first end portion, a second end portion and a web portion connecting said first and second end portions, said first and second end portions having a width wider then the width of the web portion; clamping the parallelly arranged length sections together, such that said first and second end portions of adjacent parallel length sections are abutting against each other; and bonding the length sections together by applying at least one friction stir welding (FSW) seam across the end portions of the parallelly arranged length sections.

Abstract: A method for applying a brazing medium to a configuration, which is formed of a honeycomb body and a jacket pipe is described. First, the honeycomb body is configured by stacking and/or winding of sheet metal layers, at least some of which are structured sheet metals layers such that the honeycomb body has channels for conducting a fluid flow. The honeycomb body is partially placed in the jacket pipe. A section of the honeycomb body that projects out from the jacket pipe is brought by its end face into contact with an adhesive medium. The honeycomb body is further introduced into the jacket pipe. Subsequently, a brazing medium is introduced into the honeycomb body.

Abstract: In a manufacturing method of a heat exchanger including a core portion having a plurality of tubes and a plurality of radiation fins connected to surfaces of the tubes, and a tank portion communicating with the tubes, a preheating step, a brazing step, a gradual cooling step and a cooling step are performed in this order. In the preheating step, temperature of the tank portion having a large heat capacity is increased earlier than that of the core portion having a small heat capacity. Therefore, the temperature of the tank portion is rapidly increased, and the temperature of the core portion is obediently increased in accordance with the temperature increase of the tank portion.

Abstract: A process is disclosed for brazing plate/plate and plate/fin multi-channeled structures using an amorphous brazing foil as a brazing filler metal between the parts in order to form uniform joints having optimal dimensions, shape and strength. The parts are assembled in an unconstrained stack, and a controlled load is applied to the top of the stack. The stack is then heated to a temperature at which the interlayer melts and reacts with the base metal to form the joints. The stack is cooled resulting in a brazed structure having the desired characteristics, wherein the brazed joints are optimally formed and the strength of the structure is equal to the underlying strength of the base metal.

Abstract: Manifold for a heat exchanger intended to be joined by brazing or soldering to heat transfer tubes. A portion of a surface of the manifold that will be joined to the tubes is proved with at least one recess in which a brazing material is mechanically locked.

Abstract: In a method of applying a brazing material to braze a joining portion between a first member and a second member, a relationship between an amount of the brazing material and an expanding dimension of the brazing material is determined. Then, a position to apply the brazing material or a necessary amount of the brazing material is decided based on the relationship. After the first member and the second member are joined, the brazing material is applied. The position is defined by a distance from the joining portion. The distance is set smaller than one-half the expanding dimension of the brazing material on an applying surface.

Abstract: A method of establishing a leak tight and structural connection between a core tube and an accommodating header plate in a tubular heat exchanger, including the steps of positioning the core tube into bores of the header plate and a braze foil, installing a ferrule inside the core tube end, radially expanding the ferrule in the core tube end, thus expanding the core tube end into intimate contact with the header plate in which it is received, deforming a ferrule into pinching contact with the braze foil plate, directing the flow of the braze material towards the contact surface area, and brazing the tubular heat exchanger in order to form a seal at the intimate contact area. A leak tight connection and a tubular heat exchanger having a leak tight connection produced via the noted method are also set forth.

Abstract: The invention relates to a brazing sheet product comprising a core sheet made of an aluminum alloy, an aluminum clad layer cladding at least one of the surfaces of said core sheet, and a layer comprising nickel on the outersurface of one or both said clad layer or layers, and wherein the brazing sheet product is devoid of a layer comprising zinc or tin as a bonding layer between said outersurface of said aluminum clad layer or layers and said layer comprising nickel, and wherein the aluminum clad alloy layer comprises, in weight percent: Si 2 to 18, Mg up to 8.0, Zn up to 5.0, Cu up to 5.0, Mn up to 0.30, In up to 0.30, Fe up to 0.80, Sr up to 0.20, at least one element selected from the group consisting of: (Bi 0.01 to 1.0, Pb 0.01 to 1.0, Li 0.01 to 1.0, Sb 0.01 to 1.0), impurities each up to 0.05, total up to 0.20, balance aluminum.

Abstract: The present invention provides a heat exchanger including a tank, a plurality of tubes in fluid communication with the tank, and a plurality of fins extending between the tubes. The tank includes a header member and a cover member, each of which is formed from a single sheet of aluminum. The header member includes an elongate generally planar base section having first and second ends and a middle portion disposed between the first and second ends. The header member also includes a flange section that extends along one edge of the base section and a wall section that extends along the opposite edge of the base section. The cover member has a central section that is spaced apart from the middle portion of the header member and a periphery that is joined to the first and second ends of the base section, the flange section, and the wall section. The cover member is preferably joined to the header member by brazing.

Abstract: The invention concerns a method whereby a soldering joint is applied on one of the surfaces of a collector plate (2, 3) before inserting the ends of the tube to be assembled thereto, in the form of a flexible adhesive previously perforated to correspond to the holes (20) of the plate.

Abstract: The invention relates to a method of manufacturing heat transfer tubes for a heat exchanger such as an automobile radiator. The tubes are preferably formed of copper or a copper alloy. A sheet of the material is folded into a shape that resembles a B and is brazed together with a brazing material that is free from flux. The brazing material is in the form of a foil or paste. The paste typically includes a powder filler, a binder, and a carrier, which may be a liquid or a wax.