Features of joining aluminum using cold welding

Aluminum is a widespread metal, it is used in most industries in its pure form and in alloys. Despite the mass of advantages, the material has drawbacks, in particular, there is a problem of connecting parts. Due to its softness, the method of bolt bonding of products is not suitable, and argon welding is time consuming and expensive. Cold welding comes to the aid of the craftsmen - this method will be ideal for aluminum, especially if there are no high tensile and impact requirements for the joint.

Content:

• Types of cold welding aluminum
• Cold welding application
• Deformation Welding Methods
• Spot welding
• Seam welding
• Butt welding
• Cold glue welding
• The choice of glue for welding
• Step-by-step cold welding process
• Precautionary measures
• Advantages and disadvantages of the adhesive technique
• Manufacturers and popular brands

Types of cold welding aluminum

Three joining methods are suitable for aluminum parts, all of which may be referred to as “cold welding”. The first is used in factories and other large-scale industries and is based on a diffusion mechanism. The mutual penetration of metal particles into each other is not only inherent in aluminum, but it is in this material that the process occurs faster. Diffusion of metals is achieved by applying pressure with special rods (punches), as a result, new molecular bonds are formed, a strong seam appears.

Another method of joining components is shear welding. Here, the pressure on the workpieces will be not point, but continuous with displacement in the horizontal plane. In this case, a connection is created on a large surface. For work, machines with high strength and clamping ability are used.

At home, you can weld the products in the above ways, but there is a simpler technology. This is cold welding or gluing of aluminum with special chemical compounds. They are based on epoxy resin. Also, the products contain metal powder, sulfur, other mineral components and additives. In appearance, they resemble mastic, plasticine or are liquid. The resin is capable of, as it were, melting the surface of parts, providing molecules with mutual penetration. The result is a reliable, sturdy seam.

Cold welding application

Repair and gluing of parts by cold welding is used in industry and everyday life. The method is indispensable in an emergency when you need to urgently repair a pipe break, a breakdown in the fastening. Most often, such a measure will be temporary, as far as possible remove the patch and weld the defect with argon or change the part. Adhesives based on epoxy are also suitable for car repairs: they close bumpers, interior elements, and reconstruct other details. Welding is well attached to the car body, after which it is polished and painted.

There are high-temperature products on sale, they are applied in the same way, during operation they can withstand temperatures up to +1000 degrees. Such materials after contact with fire become even more durable.

Deformation Welding Methods

Can I make aluminum parts with my own hands? To create an integral connection, it is necessary to destroy the oxide film that is present on the metal surface, as well as firmly press the products to each other.This will help create new crystal lattices between the molecules in the compounds. It is worth considering in more detail three possible methods of welding by deformation in order to choose the best.

Spot welding

Spot cold welding is the most popular, it does not need clamps. The quality of the finished joint will depend on the severity of the deformation of the metal at the weld point. Standards for the ratio of the depth of indentation to the thickness of the product are as follows:

• pure aluminum - 60-70%;
• aluminum alloys - 75-90%.

This technique is suitable only for parts no more than 1.5 cm thick, but they can be quite dimensional. The sheets are overlapped, squeezed punches pointwise, with a certain interval. The disadvantage of this technique is leakage of the joint.

Seam welding

To perform this method of joining parts, special equipment is needed - an annular punch or a rotating roller. By applying alternating pressure, the joint becomes continuous. If one-sided welding is required, the roller may be stationary. For two-sided welding, two movable devices are used. The mechanism helps to squeeze the details to the desired depth and get a high-quality seam.

The lack of technology is serious. Due to the strong continuous compression, the strength of the structure itself decreases. Therefore, the technique was improved and combined the elements of a suture and spot technique. The joint is created during the rotation of the roller with protrusions, which exerts pressure on the parts pointwise. The finished joint is an intermittent chain of welded sections, because the design remains strong.

Butt welding

The method involves the use of clamping devices (jaws), and their dimensions determine the maximum length of the parts, which impose certain restrictions on the process. Products are compressed by their end parts and the zone in contact with the sponge. Next, axial pressure is directed to the support, which contributes to the formation of a durable seam. The disadvantage of the technique can be called the complexity of removing the device from the jaws.

Cold glue welding

For the master, the use of adhesives is the most affordable method of welding aluminum. Such compositions are sold in any construction, hardware stores. It is better to immediately buy a tool from a trusted manufacturer, not the cheapest, otherwise the weld will not last long.

The choice of glue for welding

When buying, you should carefully study the instructions, considering the following parameters:

• Operating temperature range;
• degree of adhesion;
• resistance to aggressive conditions.

With regard to aluminum, it is more convenient to use plasticine-based products, especially if repairs are carried out in an emergency. All formulations are two-component, therefore, before use, they require mixing of the components with strict observance of proportions. Most welds work at temperatures up to +130 degrees, some up to +260 degrees. If necessary, you can buy a high-temperature tool, which costs much more.

Step-by-step cold welding process

Metal tools cannot be used to knead the mass, otherwise it will react with them ahead of time. Before work, you need to wear personal protective equipment: gloves, a respirator, since epoxy resins are unhealthy before solidification.

The procedure for working with glue for welding is as follows:

1. Degrease the surface. Otherwise, the grip quality will suffer greatly. For this stage, it is better to use alcohol, acetone. Dry the surface immediately before gluing.
2. Prepare the material. Take out a two-layer whetstone from the packaging, cut a piece of the required size strictly perpendicularly.Knead the mass with your fingers, after wetting the gloves with cold water. Use the product for 15-20 minutes, depending on the brand.
3. Apply glue to the place of the future joint. After carefully applying the parts, they are firmly fixed for 40-50 minutes, until the welding hardens. It is better not to touch the products for 2-3 hours, but to use them only after a day, although many manufacturers indicate a shorter period.
4. Remove excess adhesive mass. Until the material has finally solidified, it is necessary to remove the glue that has come out from the sides with the help of sandpaper, a sharp knife.

If it is necessary to fill a deep defect, layers up to 0.5 cm thick are successively applied to it, and wait for complete drying. Then repeat the process as many times as necessary.

Precautionary measures

When working with cold welding, the use of work clothing is mandatory, especially when work is carried out in such conditions:

• in aggressive environments, places with high temperature or environmentally hazardous areas;
• with a regular change of conditions;
• with vessels under pressure.

Gloves are used even when working with small pieces of glue for welding. It strongly irritates the skin, therefore, in case of accidental contact, it should be washed well with soap. When the product penetrates the eyes, despite the use of goggles, they are washed, and then consult a doctor. In the room you need to equip an exhaust hood or provide an influx of fresh air in another way, otherwise you can get poisoning with fumes of epoxy resin and solvents.

Advantages and disadvantages of the adhesive technique

Glue for cold welding is a convenient device, with it you can quickly repair aluminum and other household products. If you create a continuous seam, it will be airtight, moisture resistant, practically not subject to destruction even with vibration (due to elasticity). High temperature formulations allow bonded parts to work under the most severe conditions.

Other advantages of the glue welding method:

• simplicity, lack of need for work experience;
• low cost of repair;
• short time before the start of operation of products;
• lack of waste and energy costs;
• the ability to create seams, seal holes, chips, scratches;
• the ability to weld aluminum with any other materials.

The disadvantage is that welding cannot be used on dishes and other accessories that come in contact with food. It is also better to immediately weld parts that are subjected to shock loads daily with argon - the strength of the adhesive joint will quickly decrease. Cheap formulations usually do not tolerate strong pressure, although there are remedies that prevent even tensile stress.

Manufacturers and popular brands

You should not buy compounds for welding by unknown manufacturers; it is better to glue aluminum parts with reliable materials. The choice of brands is great, the following have proven themselves well:

• Diamond;
• Mastix;
• Zollex;
• Abro;
• Poxipol;
• Loctite;
• Weicon.

For auto parts made of aluminum, duralumin, you can use the Polirem-Aluminum welding (it is also suitable for domestic needs). The tool is designed specifically for aluminum and its alloys, allows for high-quality repairs without a welding machine. Cold welding is suitable for auto radiators, bodywork, panels, cylinder heads, pipelines. In any case, the quality of the seam will depend on preliminary preparation, compliance with the instructions and the reliability of fixation, which should be given close attention.