Cold welding for aluminum, its alloys, silumin

Aluminum is considered one of the most common metals at the moment. This metal is used in various industries due to its characteristics. However, it is not always possible to join aluminum parts by welding. A bolted connection will be unreliable for this metal. Because of this, cold welding for aluminum has become very popular.

High-tech joining of aluminum with “Cold Welding” glue

Cold welding of aluminum is the joining of parts using a special adhesive mixture. Thanks to it, a reliable connection is obtained without heating the metal.

An epoxy compound acts as a binding mixture. It is a thick mass, the consistency of which resembles mastic. Cold welding for aluminum consists of epoxy resin saturated with metal powder. Due to its content in the resin, the strength of the hardened composition increases. The glued area can be stronger than the material itself.

In addition to the main component (epoxy resin), the package contains a second component. This is a special hardener that, when mixed with epoxy, reacts and the composition begins to harden. In a period of time from 10 to 30 minutes, the master must have time to apply resin to the parts and connect them. Next, you need to press the individual parts together for 15-20 minutes (in some adhesives, the fixation time for hardening reaches 40 minutes).

Advice! It is advisable to begin further work 2-3 hours after applying the adhesive mixture. As a rule, you need to wait at least a day for the epoxy resin to completely harden.

It is important to remember that both high-temperature and cold welding are harmful processes that require individual protection of the human body. When interacting with adhesives, the room must be well ventilated and there is no open fire nearby. To protect your respiratory system, you should wear a respirator. To avoid irritation of the mucous membrane of the eye, it is advisable to wear safety glasses. If epoxy resin is swallowed, you should go to the hospital immediately.

Adhesive mixtures have a number of serious advantages:

• There is no need to buy additional equipment or look for network connection points.
• Anyone can work with epoxy resin without any skills. The packages contain step-by-step instructions. The same cannot be said about welding using electrical equipment.
• The hardened glue forms a strong seam, which is slightly inferior to welded joints.
• Hardened compounds are resistant to corrosion processes, moisture, oils and fuel.
• After 20-60 minutes, a strong connection is obtained.
• Cold welding is considered an economical option for repairing a variety of equipment.

When using automatic welding machines, the metal being joined is exposed to high temperatures and severe deformation. Cold welding does not have these disadvantages. However, glue cannot be used when repairing high-pressure vessels and containers that are often subject to changes in the environment (humidity, temperature).

Specifications

This product has a number of characteristic features that are determined by its characteristics. Of course, each brand may have its own characteristics, but in most cases the characteristics look like this:

If high-temperature cold welding is used for aluminum, then its upper limit can be above 700-100 degrees Celsius. Some additional substances that are added to the composition can also change the characteristics, but they are often narrowly targeted and not so common.

Cold Welding Selection

Selecting the right brand largely determines the quality of the subsequent repair operation. To do this, you need to pay attention to certain parameters that are important to you. Here you need to find a balance between price and quality, since trusted manufacturers can offer quite expensive products. First of all, you need to pay attention to the temperature conditions in which the material can be used. It must match or exceed the one in which you will work.

Next, you should pay attention to what surfaces you can interact with. After all, there are compounds intended only for aluminum, but there are also universal ones. "Note! Here we should not forget about the presence of a metal filler made of aluminum. The fact is that some universal compositions, which are also suitable for aluminum, may not contain this metal, although they glue it together.

The container capacity matters if you use this substance frequently. Everything is simple here, since the more material there is in it, the relatively cheaper it costs per unit of weight. The packaging should be convenient for storage and transportation, because it is often necessary to use cold welding for repairs on the road and away. If there is often a need for urgent repairs, then the substance should have a quick drying period. This parameter may differ several times between different brands.

Features of application

Full instructions for use of each variety are written on the packaging, but this type has a number of its own features that you need to know, regardless of the brand presented.

• First of all, when cold welding for aluminum is used at home or at work, all procedures should be carried out using special protective gloves. The possibility of skin contact with the material should be avoided as much as possible.
• The surface on which work is being carried out must be degreased and cleaned of debris, plaque and other unnecessary things. Otherwise, the quality of the connection will deteriorate.
• When preparing the mixture, it is advisable to use non-metallic objects, including containers. If the adhesive is intended for adhesion of metal parts, then on such surfaces it will interact less even before direct use.

"Important! After use, you should carefully remove cold welding residues, both from the tools and preparation area, and from places on the parts where excess pieces remain. Otherwise, after drying, it will be quite difficult to get rid of them.”

Application of Cold Welding for Aluminum

Manufacturers and popular brands

It’s worth familiarizing yourself with the types of cold welding on aluminum to make the right choice.

• Mastix (Russia);
• Weicon;
• Permatex;
• Loctite;
• Poxipol;
• Devcon.

How and how to glue aluminum to aluminum. Types of cold welding

Aluminum and its alloys are one of the most common metals in the modern world. It has a lot of advantages, which is why it has gained popularity, but its use is also marked by a number of disadvantages. In particular, the problem of fastening becomes a stumbling block.

This metal does not withstand conventional bolted joints well due to its softness. It can be welded with argon, but this requires sophisticated equipment and a qualified specialist, which may not be at hand.

Therefore, in many cases, especially when the connection does not have special requirements for tensile strength, cold welding for aluminum comes to the rescue.

ASTROhim cold welding for aluminum, Total Bond series

ASTROhim – cold welding for aluminum. Used for various types of repair work. In addition to aluminum, this composition effectively joins wood, steel and ceramic parts in various combinations.

Stages of performing work using ASTROhim cold welding:

1. Clean work surfaces from dirt and dust. Remove rust using sandpaper, degrease and dry.
2. Next, you need to wet your hands under running water, cut off part of the epoxy rod, mix it with the hardener and knead it in your palms.
3. Apply the prepared composition to the surfaces to be bonded. Press them for 15 minutes.

If you need to restore the thread, you need to spread the prepared mixture on the old part of the thread and screw in the bolt. After 20 minutes you need to unscrew the bolt. You can use the finished thread after 90 minutes.

Characteristics:

• The pot life of the mixture after mixing the components is 7 minutes. The room temperature should be about +20° C.
• Setting time: 20 minutes.
• Other work can be carried out after 1.5 hours.
• Retains its properties at temperatures from -60 to +150° C.

The glue hardens faster when heated and slower when the temperature drops.

This series produces “ASTROhim heat-resistant cold welding” - high-temperature cold welding for aluminum and silumin. Reliably repairs parts made of other non-ferrous and ferrous metals, as well as ceramics, operating temperature from -60° C to +250° C.

What is it or types of welding

In fact, the term “cold welding” refers to two different in nature methods of connecting aluminum parts to each other.

The first, often used in factory conditions, is based on the principle of diffusion, that is, the interpenetration of molecules of two solid substances when they come into contact with each other. Diffusion, in principle, is characteristic of many metals, and for some (aluminum, copper and some others) the process occurs faster than for others.

This process is initiated by pressure. Under the influence of pressure, the molecules of two different aluminum parts seem to “mix” with each other, new intermolecular bonds are formed, and a fairly strong seam is formed.

Another way to connect aluminum parts is gluing. It is aluminum glue that most people most often associate with the very concept of cold welding.

How to glue aluminum to aluminum? Basically, various two-component compositions are used, the basis of which is epoxy resin. An additional component that provides strength and adhesion to metals is fine steel powder, which is added to the epoxy base immediately before use.

Such adhesives can be produced in various states of aggregation - both in liquid or semi-liquid form, close to a gel or resin itself, and in the form of mastic - a plasticine-like mass from which rectangular or cylindrical bars are formed.

Each bar consists of two substances not mixed with each other. Mixing, which activates the adhesive properties of the mastic, occurs in the human fingers immediately before application.

Advantages and disadvantages of strain welding

The first method, cold welding under pressure, is more often used when stamping parts at a factory.

Its main advantage is that the seam is formed from the same material as the parts, this reduces the cost of conveyor production and allows the formation of joints that are close in strength to cast parts.

Cold welding of aluminum under pressure is, one might say, high-temperature. It allows the parts to withstand the same level of heat as pure aluminum.

Advantages of deformation welding:

• withstands large temperature changes;
• withstands great pressure (but no more than the metal itself can withstand);
• shows resistance in aggressive environments;
• does not release harmful substances into the environment.

The only disadvantage is the need to use special equipment for such welding.

There are three main methods of such welding:

1. Stykova.
2. Suture.
3. Spot.

In the first case, two parts are connected end-to-end in a press and are strongly compressed along the longitudinal axis.

In this way, it is possible to weld elements with a local joining area (small size). It is necessary to take into account the process of “loss” of material after compression: for example, when welding two pieces of aluminum reinforcement in this way, their total length will be 5-7% less than the total length separately.

Using the suture method, two parts with a long seam length are fastened together, for example, two sides of one sheet, forming a pipe. They are overlapped and placed under a pressure roller. Rotating, the roller compresses the aluminum sheets and presses them against the support shoe, pressing them into each other. This way a uniform seam is formed.

The disadvantage of this technology is that this seam itself is a weak point in the design. Therefore, where it is necessary to withstand high loads, the point-suture method is used, in which the roller is not smooth, but protected. The protectors are working ridges that provide localized pressure so that the seam appears not as a line, but as a uniform chain of dots. It is stronger than a “smooth” seam.

And finally, the point method itself - two overlapped sheets or plates of aluminum are subjected to force at several local points by superhard objects - punches.

When they are pressed into aluminum and then removed, a weld point is formed. With the correct calculation of the geometry of these points and the magnitude of the deforming effect, it is possible to achieve a very high quality connection with minimal metal loss.

Please note: during butt welding, antioxidant treatment, that is, abrasion of the surface oxidized layer, occurs simultaneously with the welding process; in all others, it is necessary to first clean the surfaces of the parts being welded from oxides.

Advantages and disadvantages of glue welding

The main advantage of any adhesive composition is ease of use at home, for personal needs, including when carrying out work with tightness requirements. You can select an adhesive composition with special additives for high-temperature welding. This method of joining aluminum parts is very simple and cheap.

How to glue aluminum to aluminum? If you are using a bar of two-component mastic, then simply cut off the required amount from it and knead it in your fingers until the mixture is mixed and softened.

Degrease the surfaces you are going to glue with acetone or another solvent, wipe dry and apply the compound. The plastic mass will take any shape and fill any hole, so it can be used for sealing cracks in aluminum parts, installing plumbing elements and other needs in almost any area.

If you are using a composition with a liquid base, then, following the instructions, simply mix the metal powder with the epoxy mass until a plastic mass is obtained, and proceed as described above.

If the advantage of such welding is ease of use and low prices for compounds, then there are many more disadvantages.

Parts cold welded using mastic or glue should not be subjected to heavy loads, especially tensile loads. The glue provides a tight seal, but is not able to withstand strong pressure, although there are certain compounds that form a very strong connection. Their prices are naturally higher.

Not every composition can tolerate high temperatures, and especially temperature changes. You should be very careful when processing the parts to be glued, especially when degreasing - any fats reduce the adhesive properties of the glue.

The time for complete hardening of the glue is usually 2 - 2.5 hours. It is necessary to prepare exactly as much glue at a time as you are going to use, otherwise (this is especially typical for liquid glues), it will harden tightly, and the container in which it was prepared will have to be thrown away. In addition, to avoid vapor poisoning, it is recommended to use a respirator during work.

Cold welding of aluminum

A light metal, one of the most used in the history of civilization (although on an industrial scale for only a century and a half), resistant to corrosion, malleable in machining, ductile, with excellent thermal conductivity. This is aluminum.

Complex aluminum products can be produced by casting and using welding (manual, semi-automatic, argon-arc).

An alternative to classical welding methods is cold welding of aluminum. This method is actively used in industry (for welding housings of electronic and other devices, cables, repair and restoration of surfaces, manufacturing frames, stands, household products) and in home workshops. For motorists, this is an irreplaceable thing (repair of radiators, cylinder heads, batteries, cracks and holes in parts bodies).

Advantages of cold welding:

• the ability to repair products that cannot be heated;
• reducing the cost of work by reducing the amount of material waste up to 10 times;
• possibility of welding without the use of fluxes;
• work in fire hazardous areas becomes available;
• the ability to connect wires without breaking or melting the insulating coating;
• the ability to obtain a welded joint with steel and other ductile metals.

Cold welding equipment:

• mechanisms for the necessary fastening of parts;
• hydraulic or mechanical drive to create the required pressure at the welding sites;
• mechanisms and machines for performing work.

Sealant (cold welding) Anles Uniplast-universal 20g aluminum

Epoxy plasticine, supercompound. Anles Uniplast-universal is a cold welding based on aluminum. Used for fastening workpieces made of various metals (non-ferrous and ferrous), restoring threads, repairing plumbing pipes and fuel storage tanks. This is a two-component composition, which consists of a hardener and epoxy resin. The base is further strengthened with aluminum or bronze dust.

Stages of working with Anles Uniplast-universal:

1. The working surface is cleaned of dirt and rust. Processed with sandpaper. Then the surface is degreased and dried.
2. The hardener and base must be cut in equal parts, mixed until a homogeneous mass is obtained and applied to the parts to be glued.
3. Secure the gluing area with a rope or place it under a weight.

It is recommended to continue work after 24 hours. Has high electrical insulating properties.

Characteristics:

• The viability of the finished composition is about 25 minutes. Temperature +20° C.
• The maximum strength of the connection occurs after a day.
• Cold welding is resistant to prolonged exposure to water, gasoline and oils.
• Withstands temperatures from -40 to +120° C.

You need to work with this glue in a well-ventilated area and away from sources of fire.

Step by step process

To perform cold welding on aluminum or its alloys, you must follow the recommendations indicated on the packaging of the product. They often boil down to the following:

1. Print cold seal packaging.
2. The polymer has a two-color structure, the components of which are either in different containers or wrapped in one another. It is necessary to cast or cut the required portion of the substance, visually sufficient to cover the crack or hole.
3. The product is mixed together until smooth. It is best to do this with gloves to prevent skin irritation. The mixed composition is suitable for use for 30 minutes, with constant kneading, which maintains its temperature and plasticity.
4. The sides to be welded must be degreased with acetone.
5. Cold welding is applied to the future joint and the surfaces are tightly pressed together. A wait of 40 minutes is required until the material hardens.
6. After this, excess particles of the substance are removed from the sides. This can be done with sandpaper.
7. The product is left alone for another two hours until the materials are completely bonded.

Weicon Repair Stick ST Aluminum. Repair rod

Weicon Repair Stick ST Aluminum is a repair stick that is used to repair plumbing pipes, repair visual damage to the trim of ships, boats, cars and window frames. The rod consists of epoxy resin with copper filler. Refers to repair sticks.

Weicon Repair Stick ST Aluminum Cold Welding Steps:

1. The surface of the parts to be joined is cleaned of dirt, treated with sandpaper, and degreased.
2. Using a stationery knife, you need to cut off the required part from the rod, wet your hands and knead the glue in your fingers.
3. Apply to the broken part and press for 20 minutes.

It is advisable to continue working with the glued product after a day.

Characteristics:

• At 20 degrees, the pot life of the composition is 4 minutes.
• Resistant to temperatures from -50 to +120° C.
• Total curing time is 24 hours.

You can work with the adhesive from +10 to +35° C.

Preparation and more preparation

Aluminum welding diagram.
Preparing aluminum for welding is a responsible and mandatory task. The conditions and requirements for the preliminary stages of working with this metal are much stricter than with other metals. Particular attention is paid to processing the edges of the parts being welded.

The preparatory stages are as follows:

• All metal surfaces of the workpieces being welded, including the filler wire, are thoroughly cleaned of any contaminants, oils or grease. This also includes degreasing surfaces using acetone, aviation gasoline or other solvents.
• When necessary, you need to cut the edges of the metal workpieces being welded. If the method does not include the use of coated electrodes, edge cutting is required for parts with a thickness greater than 4 mm. In the case of using coated electrodes, such cutting is necessary only when the thickness of the parts is over 20 mm. When welding thin aluminum sheets with a thickness of less than 1.5 mm, special flanging of the ends of the parts is used.
• Removing the oxide film from the surface of workpieces using a file or a metal brush made of stainless steel. The film must be removed at a width of at least 25 - 30 mm.
• If aluminum welding is done at home, the oxide film can be removed using chemicals such as benzene

Cold welding “Fast steel” METALFIX LAVR 60g

“Fast steel” METALFIX LAVR is a two-component mixture that is used to join ferrous and non-ferrous metals, concrete, wood, plastic, granite and various polymer materials. This cold welding is also used to repair plumbing pipes, repair cars and industrial equipment.

Application:

1. The surfaces of the parts to be glued are cleaned of dust and rust. Next, it is processed using coarse sandpaper.
2. Surfaces need to be degreased and dried.
3. Cut off a piece of epoxy resin and knead it thoroughly in your palms.
4. Apply the mixture to the surfaces to be glued, rub it to the desired shape with any flat object.

To continue work, you only need to wait 1.5 hours. Not inferior in strength to a welded seam. Eliminates leaks in gas tanks, radiators, engine crankcases and gearboxes.

Characteristics:

• The glue partially sets in 15 minutes.
• Resistant to prolonged exposure to moisture and oils.
• Complete hardening is achieved after a day.
• Withstands temperatures from -60 to +150° C.
• It is advisable to have time to apply cold welding within 10 minutes.

Precautionary measures

Despite the simplicity and versatility of using polymer materials made of resin and metal filler, a number of rules must be followed so that the product does not harm health. Firstly, mixing a plastic substance or mastic should only be done while wearing gloves. The composition can cause skin allergies. Metal particles penetrate the pores and promote inflammation.

Secondly, when materials are mixed, a chemical reaction begins. In contact with metal, the product begins to destroy the oxide film and mix with the structure of the base material (aluminum). This contributes to the release of certain chemical components into the air. If you inhale them, you may feel dizzy. Therefore, it is recommended to perform such work in a respirator or in the open air. The room must be ventilated after welding is completed.

Mix the ingredients carefully until smooth. Especially when working with a liquid product. Contact with the eyes may cause severe irritation and inflammation of the membrane. In such cases, you need to rinse your eyes with plenty of clean water and consult an ophthalmologist.

Aluminum Putty F (Devcon F), metal polymer filled with aluminum

Aluminum Putty F (Devcon F) is a two-component composition that is saturated with aluminum powder. Used for joining non-ferrous metals, as well as plastic and concrete. With this cold welding it is possible to create aluminum surfaces that are resistant to corrosive processes.

Application:

1. Initially, the surfaces of the parts to be glued are cleaned of paint, dirt and rust. Remaining oil and grease must be removed using a solvent. When working with aluminum products, you need to clean it before applying cold welding.
2. If work is carried out at a temperature less than +10° C, the surfaces are heated to +40° C.
3. On a flat board, mix the base and hardener using a spatula. They also apply the finished glue to the parts.
4. Treat the finished product with wet sandpaper.

When applying glue, you need to press it into the voids and cracks of the material. This type of cold welding can be used to repair containers that will contain gasoline or oil.

Characteristics:

• Start mechanical work on the glued product after curing no earlier than 4 hours later. After 16 hours at room temperature, it reaches 75% readiness for use.
• Resistant to corrosive processes. Protects metal.
• When fully prepared, it retains its properties at temperatures up to +120° C.
• The glue can be applied within 60 minutes.

Devcon F compounds are chemically resistant to water, salt solutions, gasoline, petroleum products, oil and propylene glycol. Not suitable for prolonged contact with concentrated acids and organic solvents.

Why is he such a difficult character?

If we translate the saying “a big ship has a long voyage” into an aluminum version, it will sound like this: “unique properties mean unique difficulties.” Aluminum has more than enough uniqueness. Accordingly, there are also difficulties.

Welding aluminum in argon.
It’s better to describe and explain point by point:

• The main physico-chemical nuance consists of a combination of two very unpleasant factors for work: the constant presence of a surface oxide film and the very high melting point of this very film - from 20500°C. It should be noted that aluminum itself is ready to melt at a ridiculous temperature - only 660°C.
• This point is already a consequence of the first: drops of molten liquid aluminum are instantly covered with an oxide film, which directly interferes with the formation of a continuous weld. A solution to this problem has long been found: to isolate the working area from air, the process is carried out under the protection of inert gases.
• The formation of a weld pool is also difficult. The high fluidity of molten aluminum plays a role here. And this problem has been solved technically: by using special linings that remove heat.
• In addition to all these troubles, aluminum contains hydrogen, which tends to escape when the metal cools at the end of the process. This affects the welding seam - pores and cracks form in it. Cracks have another explanation: aluminum alloys always contain a lot of silicon, and it contributes to their formation.
• The high coefficient of linear expansion of aluminum contributes to its expansion at high temperatures and, accordingly, shrinkage upon cooling. This leads to significant deformation of the long-suffering weld.
• The high thermal conductivity of aluminum makes it necessary to use fairly high welding currents when working with it.
• There are many grades of pure metal and its alloys. It often happens that it is difficult to determine a specific brand, which leads to additional difficulties in choosing a mode and consumables.

Cold welding - epoxy multi-purpose compound Permatex GOLD WELD

“Permatex GOLD WELD” is a multi-purpose compound, an epoxy-based mixture. Used for joining various metals, plastics, ceramics, glass, wood, rubber and various polymers. Apply using a tube. The application process is similar to applying instant glue. Recommended for rigid connections and pouring forms.

Characteristic:

• The hardened composition is resistant to the destructive effects of alkalis and acids.
• Resistant to corrosive processes.
• Hardens in 4 minutes. Partial curing time is 10 minutes.
• The finished product can withstand temperatures up to +177° C for a short time.

This cold welding is resistant to physical impact and vibration. Because of this, it is used to repair industrial equipment. Main applications: aluminum, steel, brass, bronze and copper. The product is resistant to most automotive, industrial and cleaning fluids.

Deformation welding technology features

When aluminum pieces are joined at room temperature, this method is called “cold welding.” In addition to the use of adhesive compositions, which were described above, there is the principle of deformation. This technology consists of several key stages:

1. Aluminum surfaces are initially degreased.
2. Next, the workpieces are brought as close as possible and compressed under pressure.

During the compression process, the outer oxidized layer is destroyed. Intermolecular bonds are formed between the crystal lattices of the metal. This ensures a reliable connection.

Hydraulic Cold Welding Machine for Aluminum and Copper

This technology can be used to bond other non-ferrous metals. Pressure can be applied uniformly or vibration can be added. Based on deformation technology, three connection methods can be distinguished, which will be described in more detail below.

Welding methods for aluminum and its alloys

There are several such methods; they require a variety of consumables and equipment such as granular flux mixtures, inert gases or specialized electrodes.

The most popular aluminum welding methods are as follows:

1. AG TIG – argon arc welding of aluminum in a protective cloud of inert gases using non-consumable tungsten electrodes.
2. DC MIG is a semi-automatic method with automatic feed of filler wire in an inert gas environment.
3. MMA – the use of special electrodes with various coatings.

According to technical comparative characteristics, the most optimal method is cold welding for aluminum TIP TIG. Compared to other methods, TIP TIG has excellent performance on almost all points:

• high speed of the process;
• high level of productivity of the surfacing process – up to 3.6 kg/hour;
• the ability to weld metal with an edge thickness of over 2.5 mm;
• unnecessary costly process of cleaning from slag and metal splashes;
• low gas pollution of the process;
• no highly qualified welder is required; cold welding of aluminum is very democratic.

When choosing the most effective method for joining aluminum, you need to remember that you will have to deal with the unfortunate surface oxide film: in any case, it must be destroyed. To perform this mandatory task, only direct current of reverse polarity must be used.

In this case, the effect of the so-called cathode sputtering works, which is a formidable killer of our refractory oxide film.

Direct current of straight polarity does not work in aluminum welding: with this combination, cathode sputtering does not form.

Butt method

This technique is one of the most reliable in terms of cold welding of aluminum. Suitable for connecting parts through their ends. This way you can combine the plates into one large shield. The process of metal bonding occurs in several stages:

1. First of all, the ends of the parts are cleaned. Paint, rust and dirt are removed from them. Next they are degreased.
2. After cleaning, the parts are clamped in a special vice located opposite each other. Only the ends and 1 cm of metal should stick out.
3. When the workpieces are securely fastened in a vice, end pressure is transmitted through them to the ends. With its help, a reliable connection is obtained.

Technologically, this is a simple and low-cost process that is accessible to any craftsman working with metal. However, it has significant drawbacks.

Firstly, the size of the holding vice does not allow the use of large parts for joining. Secondly, part of the metal clamped in a vice is also subject to deformation. Thirdly, after cold butt welding is completed, it is difficult to remove the finished part from the clamps.

Point technology

With this cold welding method, aluminum sheets can be overlapped. It is considered the most popular technology of the three presented. Bonding process:

1. The parts are placed on top of each other and pressed on both sides with special clamps.
2. The punches are located at a certain interval, to which the precision pressure will be transferred.
3. A force is transmitted to the punches, which presses them into the metal.

The strength of the connection will depend on how hard the punch is pressed into the metal and what material these point elements are made of. Also important is the number of points in the connecting line.

The main advantage of spot cold welding is low deformation of the part. It occurs only at the points of contact of the elements through which pressure is transmitted to the aluminum.

Connecting parts with special glue

So we get to the term “cold welding”. What is it?

IMPORTANT TO KNOW: Methods and methods of welding aluminum

This method does not require any special devices or mechanisms; very often it is used as a temporary remedy to eliminate an emergency situation when troubleshooting occurs literally in the field.

This is a two-component adhesive in the form of a liquid or mastic based on epoxy resin with the addition of steel powder.

The development of the chemical industry has discovered new properties of some elements, so special additives are now added to the traditional welding “recipe”, which improve adhesion, temperature characteristics, resistance to aggressive environments, and so on.

It can be said that modern glue often surpasses the parts being joined in its strength characteristics.

You can find cold welding in almost any hardware store - many domestic and foreign manufacturers produce such compositions, differing only in external design.

Liquid welding is always available in a package of two tubes or bottles, the contents of which are mixed in one container immediately before use.

Video:

Mastic is more often found in the form of a two-layer bar, reminiscent of plasticine, glue, or placed for convenience in a cylindrical package.

Before welding, the required amount is cut off from the piece strictly perpendicularly. The welding components are connected by kneading between fingers and quickly applied to the area to be glued.

It is better to degrease the gluing areas first, since oiling under the glue reduces the adhesive properties to 15-20%

Let me draw your attention to the fact that freshly prepared glue has working properties within 20-30 minutes after mixing, sometimes less (detailed information is indicated on the packaging).

It is during this period that glue can be applied to the objects being glued, which then need to be pressed together for 40-45 minutes at room temperature.

The complete hardening time of this “welding” is about 2.5 hours, after which the product can be used.

The places where glue was used can be subjected to almost any load, except tensile deformation.

IMPORTANT TO KNOW: Definition and types of welding

“Cold welding” can not only connect various aluminum parts, it is also used to seal holes in aluminum radiators, holes and cracks in cars, as it fills various holes well, taking any shape.

Video:

The glue has high adhesion, a short drying time, after hardening it acquires increased strength, and is very difficult to break down, which determines its wide popularity.

But there are a number of restrictions for its use; the composition cannot be used:

• in places of increased environmental danger;
• in places with high temperatures;
• in places with sudden changes in operating conditions;
• in vessels under high pressure;
• in places with an aggressive environment.

When performing cold welding of aluminum blanks using this method, it is better to take care of protective equipment - gloves and a respirator, since the glue contains substances that irritate the skin and respiratory tract.

In case of contact with eyes, rinse them immediately with running water and immediately consult an ophthalmologist.

Attention! The use of epoxy resin-based adhesives for items in direct contact with drinking water and food is strictly prohibited.

I would also like to note that the price of such welding for aluminum is very low, and it can be used almost anywhere.

Glue, unlike gas welding, does not provoke oxidation of the metal, does not cause it to melt, which means your product will last much longer.

Thanks to all this, more and more people are choosing “cold welding” for repair work, and high-temperature welding is being used less and less at home.

Suture method

An effective cold welding technique that involves creating a continuous seam using special equipment.

It consists of two rollers, between which parts are secured. The rollers are located parallel to each other. Punches or a special ring are attached to their working part. These elements form the joining seam. Seam welding can be divided into two types:

• One-sided - one roller rotates, the other is firmly fixed in one position.
• Double-sided - two rollers are driven by electric motors.

The process of fastening metal sheets:

1. The area that will be fastened is initially degreased and cleaned of dirt and rust.
2. The parts are pressed between the rollers.
3. After the engine starts, they begin to rotate and drive parts through the working part. This results in a smooth, uniform seam.

Metallurgists often join large sheets of aluminum and other non-ferrous metals in this way. However, it must be remembered that continuous seams reduce the strength of the overall part. Because of this, the suture technique has been modernized over time. In the process of technology development, the point-suture connection method appeared. It involves installing punches on rollers, which make the seam divided into many points. This way it turns out much stronger.

Choice of product

When choosing the type of cold welding for aluminum, it is advisable to use special mixtures. Additives in the form of metal or aluminum powders are introduced into such mixtures, which make the fastening more durable.

A peculiarity of aluminum parts is the formation of a film of oxides on their surfaces. Because of this, such parts do not have sufficient adhesion (adhesion). Therefore, to connect aluminum parts, it is necessary to select products that have special additives that prevent the formation of oxides. For example, preparations with an additive in the form of steel powder can be used for welding.

In the case of joining aluminum parts and parts made of other materials, it is better to use universal welding.

There are a number of cold welding methods available on the market that allow you to reliably connect aluminum parts with other parts made of the same material or a different type of material. Some brands are shown in the table.