How to solder an aluminum tube at home: expert advice

Sheva Niva arrived to repair the air conditioner, the fault was found in a broken tube. I had to grind out a nozzle to expand the tube. And learn how to solder aluminum. In the end, everything worked out.

Comments 13

in my youth I tried to solder by tinning with regular solder, under an oil film, I think maybe something is wrong? Now I tried to tin it, dropped some motor oil on the luminaire, scraped off the oxides with a knife, applied it with a solder... it got tinned =)

Did you go to school?

The devil is in the details...)

Soldered with flux solder. Who can tell me the technology for soldering solder separately from flux.

Dmitry, excuse me, but is Russian your native language?

I write on the phone and insert the words myself.

How about editing the words yourself?

Kastolin works wonders

What kind of miracle is “kastolin”?

One of the most famous zinc solders for aluminum, like the popular HTS-2000. In general, there are a lot of them, in “refrigeration” companies they usually have an assortment.

Last year, HTS soldered a rotten low-pressure air conditioner pipe on the bottom of the car - quite simply, even without any experience.

To learn how to connect metal pipes without welding, you need to study in detail the methods for connecting these pipe materials. The thing is that pipelines are a complex structure consisting of a series connection of rolled pipe assortment, measuring equipment, valves and other parts that are provided for in the project.

Docking can be accomplished using various methods. When choosing the optimal solution, they are guided by the purpose of the highway and the conditions of its use. The diameter of the rolled pipe assortment is also taken into account.

When laying a highway, the connection method may be different. Some of them may be permanent, but dismantling and subsequent reassembly of the structure is possible.

And there are monolithic joints that cannot be dismantled without destroying the structure. Welding has gained the most popularity among monolithic joints. But this is far from the only method that allows you to connect sections of the pipeline; there are others.

Despite the high popularity of plastic, steel products are still used. Welded fastening is used very often, but making such a joint is impossible without special knowledge and skills. Therefore, many try to use options that allow you to connect in a different way.

What is the essence of the procedure?

Before soldering an aluminum tube, you should understand what the soldering process is. The formation of connections by soldering occurs in two stages. First, physical contact is created between the surfaces. Next, the physical contact is transformed into a quantum mechanical interaction between the electron shells of atoms. To initiate physical contact between the surfaces and further chemical bonding, the soldered metal is wetted using liquid solder. The feasibility of its use depends on such an indicator as the type of interatomic forces on the contacting surfaces. If physical adsorption is observed, then as a result of wetting with liquid solder a low-strength connection will be obtained. If liquid and solid metals react chemically, a strong bond is formed by wetting.

Causes of breakdowns

It may be that the aluminum tubes in the car's air conditioner are simply clogged. This happens mainly in winter when the air conditioner is not working. As contaminants accumulate between the radiators in the air conditioner and engine, the entire line becomes clogged. As a result, the refrigerant will circulate and mix with moisture no longer fully. Due to the presence of reagents, disturbances in moisture levels and temperature changes, the aluminum from which the tubes are made is destroyed. Thus, their operational life depends on the climate, temperature conditions, characteristics of the road surface, participation in road accidents and general loads on the vehicle. Together, these factors will negatively affect the condition of the cooling system.

Polypropylene

The only widely used method of connecting propylene pipes is socket welding

. For this purpose, a monolithic polypropylene coupling is used.

Diameters: 20-110 mm.

Wall thickness: any.

Advantage: the connection is as strong as a solid pipe.

Disadvantages: requires a special tool (low-temperature soldering iron); The connection is permanent and can only be cut.

Technology:

1. The pipe is cut with a pipe cutter or a regular hacksaw;
2. The outer chamfer is removed;

For PN25 aluminum foil reinforced pipe, stripping of aluminum foil in the welding area is required. For this purpose, a hand shaver or a drill attachment with similar functionality is used.

1. The pipe is inserted into a soldering iron nozzle of the appropriate diameter heated to 240 degrees. At the same time, the second side of the nozzle is used to melt the coupling;

1. The fitting and pipe are combined with a smooth translational movement and fixed until the polymer melt sets. The fixation, heating and cooling times are predictably determined by the pipe cross-section. For the convenience of the reader, I will collect all the recommended parameters in one table.

Connection methods

You can connect pipes using crabs, couplings, bolts, clamps for square pipes and other connecting elements, including those made by yourself.

Two profile pipes can be connected at an angle of 90° using a steel angle.

To join pipes with the same cross-section, you can make a connecting element with your own hands. For this you will need a welding machine.

It is necessary to take a piece of pipe with a cross-section larger than the cross-section of the elements being connected so that they can be inserted into it. The connecting element is cut into two parts, and a bevel is made at one end of each of them at an angle of 45°. After this, a 90° corner is welded from the two halves of the pipe folded with beveled sides. At the edges of the resulting element, holes are made no larger than half the thickness of the profile wall, and nuts with a diameter corresponding to these holes are attached. The same holes are also made at the ends of the connected pipes.

Main selection criteria

When choosing aluminum pipes for the construction of a particular facility, the following aspects should be taken into account:

• pipe manufacturing method;
• diameter, shape and other dimensions.

Pipe making methods

In modern production, the following methods for manufacturing aluminum pipes are used:

• cold deformation. A pipe with specified parameters is made from an aluminum circle by drawing and subsequent calibration. This method makes it possible to produce pipes with precise dimensions, including minimum diameters and high quality. The main disadvantage is the high cost;

Cold deformation pipe manufacturing technology

• pressing. Heated aluminum billets are passed through a special press with specified parameters. Pressed pipes are characterized by increased resistance to mechanical stress;

Production of pipes by pressing method

• welding An aluminum billet with specified dimensions is bent into the shape of a pipe. The ends of the workpiece are welded together. Pipes made by welding are most susceptible to cracking under high pressure or mechanical stress. Therefore, it is recommended to use them exclusively for domestic purposes and within reach for inspection and repair work.

Pipe production by welding

Selection of basic parameters

Aluminum pipes can be round, square, rectangular:

• round and oval pipes are mainly used in the construction of pipelines and ventilation systems;
• square and rectangular (profile) pipes are used for laying cables, constructing building frames, and constructing various structures.

Polyvinyl chloride

PVC pipes are known, first of all, as the most affordable solution for indoor and outdoor installation. However, pressure socket pipes are also used for installing water pipelines.

O-rings

Connecting PVC pipes using ring seals is practiced both in free-flow sewers and in pressure pipelines. The only difference is the thickness of the pipe walls and the force required to uncouple the socket.

Diameters: 50 - 600 mm.

Wall thickness: any.

Advantages: pipes are supplied completely ready for installation of the connection, with O-ring seals installed. When cutting to size for installation, couplings with two counter-directional sockets are used.

Disadvantages: large force required to assemble the connection with a large pipe diameter; possibility of spontaneous undocking of the connection.

Technology:

1. Factory pipe ends are ready for joining. On pipes cut to size, the burrs are cleared and the outer chamfer is removed;
2. Apply a small amount of liquid soap or silicone grease to the end of the pipe and the O-ring;
3. The pipe is pressed into the socket.

If significant force is required for pressing, the following can be used:

• Clamp and lever systems;
• Loading equipment.

Adhesive joints

They are used when installing pressure pipelines. The glue is a solution of polyvinyl chloride in an organic solvent.

Diameter: up to 110 mm.

Wall thickness: any.

Advantage: the strength of the connection is almost as good as that of a solid section.

Disadvantage: the connection is made permanent.

How to connect PVC pipes with glue?

1. The glue is applied to the inside of the socket and to the end of the pipe with the outer chamfer removed;
2. A smooth section of pipe is inserted into the socket and rotated 90 degrees
   ;
3. The connection is fixed until the glue sets (no more than 1 minute).

NAME OF WORKS

1. Refueling of air conditioners of cars and trucks (on-site possible) – from 2000 rubles *
2. Manufacturing (replacement with a rubber hose) of air conditioning system pipes – from 1,500 rubles *
3. Replacement of the rear circuit line with rubber hoses from RUB 20,000 *
4. Replacement of car air conditioning compressor pulley bearings from RUB 3,000*
5. Replacement of electromagnets of a car air conditioning compressor from 500 rubles

Cars

1. Repair of an aluminum car radiator (soldering of tubes) 1500 – 3000 rubles *
2. Repair of an aluminum car radiator (replacement of a plastic tank with aluminum) 4500 – 7500 rubles *
3. Repair of a copper car radiator (soldering of tubes) 1000 – 3500 rubles*
4. Repair of “GAZelle” copper radiator (soldering of tubes) 1000 – 3000 RUR*
5. Repair of heater radiator (stove) (soldering of tubes) 500 – 1500 rubles *
6. Repair of an aluminum air conditioner radiator (soldering of tubes) 1500 – 3500 rubles*
7. Car intercooler repair from RUB 2,500

Trucks

1. Repair of an aluminum car cooling radiator (soldering core tubes) 2500-5000 rubles *(if the base of the radiator is required to be filled with a special compound - additionally 1000-1500 rubles)*
2. Repair of an aluminum cooling radiator (replacement of a plastic tank with an aluminum one) from RUB 12,000 (1 side)*
3. Repair of a copper car cooling radiator (soldering of tubes) 3500 – 5000 rubles
4. Repair of a copper car cooling radiator (with opening and cleaning with a cleaning rod) 7500 – 500 rubles
5. Soldering one side around a copper radiator tank – 2000 – 2500 rubles
6. Re-soldering of copper radiator pipes – from RUB 2,500
7. Repair of aluminum intercoolers from RUB 2,500

Argon arc welding

1. Repair of aluminum fuel tanks (welding cracks, installing patches) from – RUB 3,500
2. Repair of fuel tanks (straightening of dents, restoration of partitions, opening) from RUB 8,000
3. Increasing and decreasing the volume of the fuel tank (cutting, welding) from RUR 6,000
4. Repair of pallets (replacement of cracked drain plugs, turning, welding) from – RUB 1,500
5. Repair of all aluminum parts and assemblies of cars from – 500 rub.
6. Repair of aluminum tubes (welding, replacement of sections) from – 800 rub.
7. Welding (repair of stainless steel products)
8. Repair of copper tubes (soldering, replacement of sections) from 500 rubles
9. Soldering of copper, brass, bronze parts.
10. Repair of frames of semi-trailers, cement tankers and other equipment.
11. Repair of aluminum engine cylinder blocks (installation of patches, welding, soldering of cracks) dog.
12. Repair of cast iron cylinder blocks of dog engines.
13. Repair of excavator buckets, snow removal equipment dumps.
14. Repair of aluminum car rims from 1000 rubles
15. Surfacing of shafts followed by turning from mast.

1. Repair of starters and generators with removal and installation (passenger cars)
2. Repair of starters and generators without removal (trucks)
3. Replacing the core of cooling radiators, intercoolers, etc.
4. Manufacturing of radiators (copper, aluminum, selection of “donor” according to customer sizes)
5. Repair of aluminum boats, boats (manufacturing of attachments)
6. Manufacturing of containers (stainless steel tanks)
7. Repair of radiators of special equipment, buses, truck cranes

Tips for choosing

The choice of necessary connecting elements depends on the type and function of the structure:

1. The crab system is used in the construction of structures from pipe profiles with a small cross-section - gazebos, partitions, pergolas, arches, greenhouses and other garden and park buildings that are easy to assemble and disassemble.
2. Flange fasteners are used for buildings that are subject to periodic disassembly and reassembly during operation.
3. Coupling fastening is most often used when installing pressure-type pipelines, since it can withstand high pressure and ensure its tightness.
4. Simple fittings are widely used in the assembly of pipelines with branches and turns. This type of fastening may require additional welding reinforcement.

There are several criteria that should be followed when choosing connecting elements for profiled pipes:

1. First of all, you need to decide what fasteners you will need and in what quantities.
2. When choosing steel crabs, you need to pay attention to the thickness of its profile. It must be at least 1.5 mm. Crabs with a smaller thickness are not able to provide the required strength and rigidity.
3. Parts must be inspected for visible damage - cracks, chips, dents, and rust. These are all defective products.

Cast iron

Currently, cast iron pipes are used primarily for laying sewers, and even then to a very limited extent: they have been seriously replaced by cheaper and lighter products made of PVC and polypropylene.

Pressure cast iron pipes are even less popular: they are used for laying water pipelines with a slight depth under conditions of significant load on the ground.

Socket connection with embossing

When installing a free-flow sewer system, the connection of cast iron pipes is performed as follows:

The above diagram needs a few comments:

• Instead of a caulk (oil- or bitumen-impregnated organic fiber), a more durable graphite gland can be used;
• Embossing is easy to make by flattening one end of a steel tube with a diameter of 10 - 12 mm and bending its end into the shape of a club;

Personally, I always used a wide, strong screwdriver to make joints. It's less convenient, but it takes up less space in your toolbox and is useful for many other plumbing jobs.

• To seal the socket, you can use pure cement, diluted with water to the consistency of very thick sour cream;
• The socket must be firmly fixed during operation
  . Otherwise it will become loose and leak.

Flare connection with rubber ring

This type of connection is typical for ductile iron pipes (made of high-strength nodular cast iron). Thanks to the combination of corrosion resistance and the ductility characteristic of steel, the material is in demand, among other things, for the installation of water pipes.

The instructions for assembling the connection are extremely simple: the smooth end of the pipe with the chamfer removed is pressed into a socket with a rubber seal. Since, with large pipe diameters, assembling the connection requires a lot of effort, and the mass of the pipes amounts to tens and hundreds of kilograms, loading equipment is often used for installation.

Previously, gray cast iron pipes with hammered sockets were often used for the installation of water pipelines. However, they were sealed not with cement, but with lead.

Areas of use of aluminum pipes

Pipes made of aluminum have the following positive qualities:

• resistance to corrosion. This factor significantly increases the scope of use of pipes and their service life;
• light weight, which is reflected in the ease of delivery of pipes and their installation;
• resistance to chemicals and aggressive environments. Thanks to this factor, pipes can be used for laying underground pipelines;
• high cross-country ability. Due to the smooth internal surface, aluminum pipes can pass more liquid than pipes made from other materials of the same diameter;
• processing capability. Pipes can be painted, sewn up with any materials, mounted in a wall, and so on. Any method will not have a negative impact and will not reduce the period of their use.

The positive characteristics of aluminum products determine the scope of their application. Pipes made of this metal can be used:

• for the construction of water supply, drainage, heating, ventilation systems, both for domestic and industrial purposes;
• for the construction of drainage systems;
• for the construction of a storm sewer network;
• for laying pipelines for the oil production and oil processing industries;
• for electrical cable insulation;
• for the construction of building frames;
• for the construction of gazebos, benches, greenhouses and other small architectural forms.

Greenhouse frame made of aluminum pipes

Steel

Despite the abundance of polymer pipes, black and galvanized steel still remains in demand in the housing and communal services sector and for the installation of high-pressure lines. The methods used for connecting elements of steel pipelines largely depend on the cross-section of the pipe.

Electric welding

Diameters: any, pipe wall thickness: from 0.5 mm.

When welding with high currents, it is easy to burn through the walls of a thin-walled pipe; a decrease in current leads to sticking of the electrode. Therefore, electric welding of thin metal requires a certain skill.

Advantage: arc welding is the only way to connect large-diameter pipes with significant wall thickness that provides acceptable weld strength. Automated welding is used in the production of seam pipes and in the installation of pipelines.

Disadvantage: a sealed seam is almost impossible for a beginner. Pipeline welding requires the highest qualifications.

Technology:

As usual, there are a number of nuances:

• The chamfer can be removed only from the outside of the pipe or from the outside and from the inside. Thick-walled pipes of large diameters are welded on both sides;
• When welding pipes of small diameters, the braids must first be grabbed at two or three points and aligned along a common axis, then begin welding the seam along the entire circumference. Due to uneven heating, the seam area leads noticeably;
• Welding can be performed with a continuous supply of argon to the arc area. Inert gas completely eliminates oxidation of the seam.

Minor leaks in cold water supply lines can be eliminated by rubbing the hot seam with a piece of bitumen. Thanks to the capillary effect, it instantly fills the pores with melt. This instruction is useless in hot water: when reheated, the bitumen will melt again and be forced out of the pores.

Gas welding

Diameters: up to 100 - 150 mm.

Pipe wall thickness: up to 3-4 mm.

Advantage: undemanding welder experience. I was able to achieve a sealed seam after just a few hours of practice.

Disadvantage: inability to cook thick-walled pipes with gas. The burner is simply unable to heat their walls until the edges melt.

Technology:

1. The pipe is cut perpendicular to the longitudinal axis;
2. The outer chamfer is removed from thick-walled pipes (more than 2 mm);
3. The edges of the future seam are heated with an acetylene torch until they glow red and the edges melt
   ;
4. A welding wire is inserted into the torch flame, the melt of which fills the seam. The melt bath should not freeze: only in this case will the seam be airtight.

A special case

Fixed sutures are welded with a mirror or using a surgical suture. In the latter case, a window is cut in the pipe, then the seam is welded from the inside, after which the window is welded again.

coupling

Diameters: up to 50 mm.

Wall thickness: any.

Advantage: the simplest threaded connection of pipes that can be connected in series and rotate around the longitudinal axis.

Disadvantage: the coupling assembly of a long string eliminates the disassembly of a separate connection. The pipes have to be unscrewed from the couplings sequentially.

Technology:

1. The pipes end at right angles to the longitudinal axis;
2. On a lathe or with your own hands, using a die, cut a short (five threads) thread on both pipes being connected;
3. A threaded pipe is screwed onto one of the pipes, into which the second pipe is screwed. For sealing, plumbing flax is used (preferably impregnated with paint or sealant) or polymer sealing thread.

Couplings, in particular, were installed in houses with steel water supply connections and served to connect them with eccentrics when installing a wall-mounted mixer.

Sgon

Diameters: up to 50 mm.

Wall thickness: any.

Advantage: makes the connection of fixed pipes dismountable.

Disadvantage: long threaded threads are most vulnerable to corrosion

due to the minimum wall thickness and the absence of a protective paint coating. Once applied, it is broken upon the first disassembly.

Technology:

1. A short thread (5 threads) is cut on one pipe, a long thread (12-15 threads) is cut on the other;
2. A locknut and coupling are screwed sequentially onto a long thread;
3. The coupling is pushed all the way onto the wound short thread;
4. Following it, a lock nut is driven in, clamping the thread winding in front of the coupling.

Flanges

Diameter: 76 mm or more.

Wall thickness: from 3 mm.

Advantages:

• The connection remains collapsible, including on non-rotating lashes;
• The force required for installation or dismantling is not tied to the diameter of the pipe. As the diameter increases, the number of bolts holding the flanges increases;
• Flanges can be used to connect to shut-off valves or to install retaining washers. In particular, it is the washers that ensure circulation in the hot water risers of most houses built in the 80s and newer.

Disadvantages: flange installation is carried out only by electric welding, which is not always convenient in field conditions.

Technology:

1. The pipes end perpendicular to the longitudinal axis;
2. The external (and, if the diameter is large, internal) chamfers are removed from them;
3. The flanges are welded;
4. After cooling and cleaning the seam, the flanges are tightened through a rubber, silicone or paronite gasket. The bolts are tightened alternately, crosswise, one turn at a time. The price of violating this simple rule is uneven compression of the gasket and a high probability of leaks during pressure surges.

Compression fittings

Diameters: up to 32 mm.

Wall thickness: any.

Advantages: extremely simple installation using available tools, possibility of installation on corroded pipes.

Disadvantage: low tensile strength of the connection.

Technology:

1. The edges of the pipes are cleaned of paint and rust;
2. They are then inserted into the fitting with the nuts loosened;
3. The nuts are tightened. At the same time, they compress the pipe with rubber O-rings, sealing the connection.

A special case

Compression fittings are also used for installing corrugated stainless steel pipes. However, in this case, the strength of the connection is not inferior to the strength of the pipe itself: it can withstand pressure up to 50-65 atmospheres. The secret is simple: the silicone seal of the fitting does not compress the smooth surface, but the crest of the corrugation, so it is almost impossible to tear it out of the tightened fitting.

Many fittings use additional comb fixation with a split retaining ring.

American

Diameter: up to 32 mm.

These are the exact sizes of American women I saw on sale. Perhaps they are also produced for diameters of 40 - 50 mm, but I have not seen such offers in the assortment of local construction and online stores.

Wall thickness: any.

Advantages: extremely quick disassembly of the connection

. To open the pipeline, you just need to unscrew the union nut.

Disadvantage: connecting pipes using an American method requires preliminary threading.

Technology: the halves of a disassembled American fitting are screwed onto the wound threads of adjacent pipes, and then tightened together with a union nut. Sealing is ensured by an annular rubber gasket.

Crabs

The so-called crabs are steel plates that allow you to connect round and profile pipes with bolts. They are used in assembling frames of greenhouses, shelving (commercial, for tools, etc.) and other structures that do not require special strength or tightness of connections.

Pipe sizes: diameter up to 25 mm; sections of profile pipes up to 20x40 and 25x25.

Wall thickness: any.

Advantages: allow quick assembly and disassembly using a pair of open-end or ring wrenches; allow repeated reuse of fasteners and pipes.

Disadvantage: limited strength.

Technology: the ends of the pipe are clamped between the halves of the “crab”, after which they are tightened with bolts and nuts.

A greenhouse assembled on “crabs”.

Metal-plastic

Metal-plastic is two layers of cross-linked (reinforced by cross-links between polymer molecules) polyethylene with a thin aluminum tube between them. During installation, three connection methods are used.

Compression fittings

Diameters: any.

Wall thickness: any.

Advantage: the use of simple hand tools. a couple of adjustable wrenches to assemble the fitting.

.

Disadvantage: the quality of the connection depends on the correct assembly technology. If the pipe is not calibrated, the displacement of the rubber O-rings along the fitting will lead to a leak after several heating and cooling cycles.

Technology:

1. We cut the pipe with pipe cutter scissors;
2. We calibrate it and remove the internal chamfer
   ;
3. We put a union nut and a split ring on the pipe;
4. Apply silicone grease to the fitting fitting;
5. Carefully, so as not to displace the o-rings, put the pipe onto the fitting;
6. We move the split ring and nut towards the fitting until it stops;

1. Tighten the nut until you feel resistance.

Press fittings

Their only difference from the previous solution is that instead of a union nut and a split ring, the pipe is crimped onto the fitting using a stainless steel sleeve.

Diameter: any.

Wall thickness: any.

Advantage: a correctly made connection does not leak under any temperature changes.

I suspect that press fittings do not leak only because, when installing them, professionals are not lazy in calibrating the pipes and chamfering them. According to my observations, a connection assembled according to all the rules using compression fittings is not inferior in reliability to a press fitting.

The photo shows a plastic tee with two push-couplings and an adapter for pipe threads.

Diameter: any.

Wall thickness: any.

Advantage: easy assembly without tools.

Disadvantages: high cost of fittings, moderate tensile strength of the connection.

Technology: the end of the pipe is inserted into the fitting with a previously loosened nut, after which it is tightened. The pipe is fixed with a metal ring with legs directed inward. Tightness is ensured by an o-ring rubber seal.

Due to its qualities, aluminum pipe is a fairly common building material. It can be used in the construction of various pipelines, drainage and ventilation systems, as well as for the manufacture of various structures. How to choose the right pipes, join and lay pipes, read on.

Attention

In fact, this is certainly not welding. This method can perhaps be called soldering. Despite this, this method is quite suitable in the case when the parts being connected will not experience strong loads, and not strong ones either. For example, for the manufacture of decorative items and souvenirs.

So, if you need to weld aluminum parts, use the services of professionals. Or buy a welding machine and become a professional yourself. Good luck!

With copper it’s clear, everything solders well, everything works fine if you use normal flux. But what about aluminum? No matter what flux I tried, it’s impossible to take it with anything(. The solder seems to stick in places, but generally the quality of work is no good(Probably some kind of special solder is needed for aluminum? Who has come across this, please share the information? I think the topic is relevant!

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Sergey N wrote: With copper it’s clear, everything is soldered well, everything works fine if you use normal flux. But what about aluminum? No matter what flux I tried, it’s impossible to take it with anything(. The solder seems to stick in places, but generally the quality of work is no good(Probably some kind of special solder is needed for aluminum? Who has come across this, please share the information? I think the topic is relevant!

There are several methods for soldering aluminum with lead-tin solders. But in ordinary home refrigerators, they often use a connection of copper tubes with aluminum evaporators. And Odessa residents solder dissimilar metals and demonstrate this process...

About flame soldering

In this case, you will need a special burner that runs on household gas, propane or acetylene. It is used for heating parts whose thickness does not exceed 1 cm. In addition to aluminum, acetylene torches are used for heating and soldering carbon and low-alloy steels, gray cast iron, copper, nickel, copper-nickel alloys, silver and gold. It is necessary to determine the temperature at which soldering will be carried out. It is important that this indicator is 50 degrees higher than the melting point of the solder used. For flame soldering, tin-lead, tin-zinc, copper, silver, aluminum and gold solders are suitable. The procedure lasts for three minutes. Propane is supplied under pressure up to 400 kPa (not lower than 100), acetylene from 60 to 80, household gas - 30 kPa. When choosing a flux, you will have to proceed from the temperature indicators and properties of the solder. You can also use gaseous fluxes.

Features and characteristics

Crabs are staples with a fastening system. They are made of galvanized sheet metal, the thickness of which must be at least 1.5 mm. They mainly found their application in the installation of rolled pipes with a cross-section of 20x20, 20x30, 40x40 and 20x40 mm. Fastening is carried out using clamping force. The bolts are tightened on the crab itself, and not on the pipes being connected. Because of this, this design has low tensile strength, that is, the fixed pipe, with some effort, can be removed from the connecting element.

An outdoor metal structure constructed using fastening crabs is continuously exposed to adverse conditions (wind, precipitation, temperature changes, frost). Gradually this will lead to loosening and loss of stability of the structure. Therefore, fasteners must be periodically checked, tightened and, if necessary, repaired.

Precipitation will definitely accumulate at the fastening joints, which can cause rust over time. Therefore, it is important that the entire structure has an anti-corrosion coating. Its integrity must also be periodically checked and, if damaged, corrected.

This type of fastener allows you to create a frame structure that can be assembled and disassembled when necessary.

Welding aluminum is not an easy task

The high electrical and thermal conductivity of aluminum, very low weight, combined with the excellent mechanical properties of its alloys, have made this material simply irreplaceable in many areas of production. But for all its unique properties, this metal is very difficult to weld. The ability to weld aluminum with high quality is what distinguishes a highly qualified welder from an amateur welder.

There are two main methods of welding aluminum parts:

• MIG welding of aluminum semi-automatically
• Argon arc TIG welding of aluminum

Sometimes there is a need to connect aluminum parts to each other, but there is no suitable welding machine or professional welder at hand, and the strength of the connection does not play a special role. In this case, the method described in our video instructions will come to the rescue.

You will need:

• Propane torch
• Aluminum soldering rods
• Surface degreasing liquid
• Clamps for holding parts together

Heating of surfaces

For those who do not know how to solder an aluminum tube and where to start, experts recommend pre-preparing the surfaces of the parts to be joined. They are heated with a sheaf of flame. It is advisable that it be at a distance of 1 cm from the surface. If you need to connect massive parts, it is better to use multi-nozzle burners with soft and uniform heating. Copper-zinc solders are melted using an oxidizing flame, in which the evaporation of zinc is reduced.

Stainless steels are heated with a normal flame. The main thing is that chromium carbides, which can initiate intergranular corrosion, are not formed. If you need to solder dissimilar parts that have different thicknesses, then the flame must be directed to a surface with greater thermal conductivity and mass.

Where to begin?

First of all, you need to diagnose the device. According to experts, it will be difficult to do this by eye. The fact is that the tube may have microcracks through which freon leaks. Since the refrigerant is colorless, its leakage is detected using special equipment. They start with an external inspection, then measure the refrigerant pressure, and then use ultraviolet diagnostics and a leak detector to determine the location of the freon leak. If you do not want to waste your time troubleshooting, immediately use the services of specialists. For example, in the southeast of Moscow you can solder an aluminum tube in several car repair shops. For example, at Red Hot Service, in addition to soldering the pipes of the cooling device, they will also perform other work, namely, they will change the oil, refill the air conditioner, and repair electrical equipment.

Polyethylene

Polyethylene pipes are used:

• For laying pressure sewerage;
• As a material for cold water supply lines;
• When organizing country water supply systems;
• When installing a non-pressure sewer system.

When installing a polyethylene sewer system, the connection of HDPE pipes is no different from that for socketed PVC pipes with ring seals.

The black sewer pipe is polyethylene.

For pressure water pipes, two fundamentally different installation methods are used.

Butt welding

Diameter: from 40 to 2400 mm.

Wall thickness: from 4 to 70 mm.

Advantage: the strength of the seam reaches 80% of the strength of a monolithic pipe.

Disadvantage: when joining large diameter pipelines, expensive equipment and mechanical or hydraulic devices for centering and clamping are required.

The pipe clamping force during butt welding should reach 1.5 kgf/cm. In this case, the cross-sectional area of ​​the pipe cut can amount to thousands of square centimeters.

Technology:

1. The pipe ends only at right angles to the longitudinal axis;
2. The ends to be welded are centered;
3. A heater mirror is inserted between them;
4. After melting, the mirror is removed, and the ends of the pipes are pressed against each other;
5. After the joint has completely cooled, the flash (extruded polymer melt) is mechanically cleaned off on the inside of the pipe.

Compression fittings

How to connect HDPE pipes with a small diameter and insignificant wall thickness?

In this case, the already familiar compression fittings are used.

Diameter: 16 - 32 mm.

Wall thickness: any.

Advantages: simple installation without tools, quick disassembly.

Disadvantage: relatively low tensile strength.

Technology:

1. A union nut, a locking ring and a rubber or polyethylene seal are sequentially put on the pipe;
2. Its end is inserted into the fitting;
3. The nut is tightened, compressing the pipe with a seal.