Methods of welding copper with stainless steel: manual argon arc, electric arc, ultrasonic

Other soldering options: working with copper pipes and various metals

Soldering copper pipes requires some experience in this type of work. Therefore, if a home craftsman takes on such work for the first time, it is worth practicing beforehand so as not to redo a ready-made water supply or heating line several times. Soldering of copper tubes can be done either with hard solder (using a gas torch) or with soft alloys. In the second case, it is appropriate to use a high-power hammer soldering iron for copper pipes.

PHOTO: m-chel.ru Careful and high-quality soldering is the key to the durability of the connection

The nuances of soldering copper pipes: how to do it right

It is best to use rosin as a flux for soldering copper pipes. It is applied in an even layer to the outer surfaces of the pipe, after which the fitting is placed on it. The second part of the line is mounted on its reverse side. Next, the fitting is heated with a gas burner and solder is “laid” along the seams. Under the influence of high temperature it melts, filling the seam and creating a high-quality hermetic connection.

PHOTO: poliasmet.ru Sometimes you have to do without fittings

Soldering copper pipes with your own hands is not too difficult, but this work requires care and precision. Of course, not everything can be explained clearly in words, so we bring to the attention of our dear reader a video on how to solder copper with a gas torch, from which everything will become more clear.

Having dealt with the question of how to solder copper tubes at home, you can move on to the next problem, namely soldering non-identical metals (copper with aluminum, iron or stainless steel).

How to solder copper wire to aluminum

Soldering aluminum and copper is a rather complex process. It should be noted that the same solder is unlikely to be suitable for aluminum as for copper, and vice versa. It is much easier to combine these metals using a steel coupling. Although today the manufacturer offers special solders and fluxes for such purposes, their cost is significant, which makes such work unprofitable.

PHOTO: kak-eto-sdelat.info Soldering copper and aluminum is quite difficult

The whole problem lies in the conflict between copper and aluminum. They have different refractoriness and density. In addition, when interacting with copper, aluminum begins to oxidize strongly. This process is especially accelerated when electric current passes through the connection. Therefore, if it is necessary to connect copper and aluminum wires, it is best to use WAGO self-clamping terminal blocks, which contain Alu Plus contact paste inside. It is this that removes oxide from aluminum, prevents its subsequent appearance and promotes normal contact with copper conductors.

Having figured out how to solder copper to aluminum, you can move on to harder metals.

PHOTO: mastergrad.com Sometimes you can’t do without such a connection

How to solder copper and stainless steel

When soldering copper to stainless steel, it is not the solder material itself that plays a big role, but the tool used, although a lot depends on the consumables. The most acceptable materials in this case are:

copper-phosphorus solder;
tin-silver (Castolin 157);
radio engineering.

Some craftsmen claim that with the right approach to work, even the most common solder based on tin and lead will do. The main thing is the mandatory use of flux (borax, soldering acid), thorough heating and only after this soldering (applying solder).

PHOTO: cusi3.ru Complex soldering of copper and stainless steel

Such connections are rare, and therefore specialized solders for such purposes are quite expensive.

Soldering copper with iron - is it possible?

This option is possible, but subject to certain conditions. For example, a simple propane torch is no longer suitable as a heater. Propane with oxygen must be used. You need to use borax as a flux, but brass will be the solder. Only in this case can we hope for a normal result. It is not difficult to buy solder for soldering copper with iron or stainless steel. The main thing is to understand whether the extra costs will be justified.

PHOTO: svarkavol.ru Soldering copper and iron tubes is also possible

And now we propose to look at how carefully home craftsmen can carry out the work of soldering pipes of mains for various purposes.

Advantages

This method allows solving complex technological operations;
This is one of the few ways to achieve such a connection;
The procedure itself occurs quite quickly and does not require additional tools, since an ordinary burner is sufficient for this;
Modern developments of solders provide relatively high compatibility of metals during soldering;
The process is available for both home and industrial needs.

Flaws

The quality of soldering is inferior to other methods in terms of reliability;
Finding the right solder is difficult;
The flux oxidizes quickly, so the action must be carried out without delaying the start of heat treatment;
Often, low-melting solders are used, which makes the processing process more complex, since you need to carefully regulate the temperature and ensure that nothing spreads.

Methods

There are several ways to make a connection of this kind, and they no longer depend on what kind of solder is used for soldering stainless steel to copper, but on the processing tool. Thus, two main ones stand out: soldering with a soldering iron and a torch.

In the first case, when using a soldering iron, this tool is used for relatively small parts. It is more convenient for them to connect small things, since there is no risk of overcooking them with too much heat. At the same time, the soldering iron itself is inferior in power to the torch and cannot work with hard-melting materials. They are also inconvenient for processing large surfaces, since in this case the process will be too long and the flux may oxidize by then.

The torch is the more commonly used method. It can be used for soldering stainless steel with copper, brass and other solders. Here you can easily process large surfaces and make hermetic connections. The process itself is much faster than with a soldering iron, and it is also possible to heat the workpiece to the desired temperature. The speed of the procedures does not allow the flux to oxidize.

Soldering copper with a stainless steel torch

Solder selection

The final result of the work depends on the correct selection of solder, since it ensures the filling of the joint, which must be completely covered with material that must be well grasped on the surface. One of the simplest options is to solder stainless steel with brass. After all, this is a very common solder, which is also used for soldering stainless steel to stainless steel. In some cases it can be used without flux.

It is inferior in its properties to others, but is more common and accessible, so it is mainly suitable for simple connections that do not bear a lot of responsibility.”

Stainless steel is also soldered with copper-phosphorus solder, which improves the quality of the connection with copper. This is a more expensive material, but is better suited for critical connections.

Tin-silver solder, such as Castolin 157, is an excellent soldering method, but the material cost is higher than others.

In the simplest cases, radio-technical solder can be used, but depending on the production technology, it is better to choose specialized consumables.

Technology of soldering stainless steel with copper

Soldering stainless steel with brass or other solders begins with surface preparation.

The material must be cleaned of all excess and all deposits removed, free of grease and possible rust;
Then prepare the flux, tinning the joints of the workpieces and the solder itself;
After the flux has been applied to the joints, you should place the workpiece in the desired place and lay out the solder;

This process should not be delayed, since the flux tends to oxidize.”

Then you should gradually heat everything with a burner until the solder begins to melt;
You need to ensure that it spreads evenly over the joint surface;
Allow to cool naturally.

Quality control

The quality of soldering is controlled according to GOST 19249-73. There are several basic professional methods which include:

Radioscopic method;
Radiation control;
Technical inspection.

Safety precautions

When working with a burner, you should pay attention to the connection of the gas cylinder and its location, as it poses the greatest danger. You also need to carefully handle hot objects that may not have cooled down after soldering. You should not come into direct contact with the flux, but rather use protective gloves.

Source

How to solder copper with hard and soft solder

Copper products are found everywhere in different areas of life. For example, it is used to create strong and durable heating and water supply systems. But to connect the two elements, experts resort to a special technology - soldering copper pipes. The procedure requires suitable tools and materials, as well as knowledge. Since it has certain features that a beginner may not know about.

To solder copper, the master needs to have with him a composition such as solder. This thermoplastic substance seals the surface of the product and, under the influence of high temperature, melts, spreading over the entire joint. But as soon as it cools, it hardens and securely holds the products together.

The result is one item that has a long service life, withstands high loads, pressure and temperature changes, and is not afraid of ultraviolet radiation.

Distinctive features of copper

Copper can conduct heat six times more than regular iron. Because of this, welding must be performed with increased thermal energy, and in some cases even preheating of the base metal is possible.

Under normal conditions, copper is inert, but when heated it reacts with oxygen, hydrogen, phosphorus and sulfur. Oxygen is capable of oxidizing copper at high temperatures, and above 900 °C the oxidation rate increases significantly. This is due to the fact that the initial composition of copper contains oxygen in a bound state. Cuprous oxide forms a eutectic with a lower melting point (1065 °C). The melting point of copper is 1085 oC. Therefore, the oxygen contained in it worsens its positive indicators.

What tools and materials are needed

Soldering is carried out not only at industrial facilities, but also at home. To do this, you need to prepare the following tools and materials:

electric soldering iron or gas burner;
pipe cutter;
solder;
flux;
brush and steel brush.

How exactly to connect the products depends on the convenience and preference of the master. But the power of the device is selected in accordance with the melting temperature of the solder. Flux can be liquid or solid; each type has individual differences that should be taken into account. If the material is used in the form of a thickened mixture, then it is applied to the joint, both before and after the connection. Flux is needed to protect the surface from oxidation, promote solder flow and improve adhesion.

Useful tips

Experts who have had the opportunity to solder stainless steel more than once assure that this process is not so complicated. Here are some recommendations from them when using a soldering iron:

For soldering you need to use a soldering iron with a non-burnable tip;
The power of the tool varies in the range of 60-100 W, optimally 100. You should not use higher than that, overheating of the workpieces means overheating of the solder, which will begin to boil. Below is also not desirable, because molecular bonds will not form between all the metals that participate in the soldering process;
It is recommended to clean the tool tip after each operation. Sometimes you have to sharpen it;
It is better to solder with tin rods or tin-lead rods. The second type is not used for joining food grade stainless steel. Pure tin solder will have to be heated well, at least to the consistency of softened plasticine. In general, the metal must be liquid; it is in this state that it can stick to the steel;
Phosphoric acid is used as a flux. Rosin, due to its neutrality, is not used for stainless steel;

It is imperative to adhere to safety precautions, especially if soldering is carried out at home. It is necessary to use personal protective equipment, as well as organize ventilation of the room.

As you can see, there are many caveats. But taking them into account, we can talk about the high quality of the final result.

Types of fluxes and solders, features of working with them

Craftsmen know a variety of hard and soft substances that ensure high-quality soldering of metal products. 95% use tin, which is a low-temperature composition with slightly worse technical parameters. But it is valued for the fact that work can be carried out at any temperature without reducing the strength of the products being joined.

Connecting elements also include silver, which has excellent technological properties. Craftsmen often use three-component compositions of silver, tin and copper. Often, materials used in low-temperature soldering contain zinc chloride.

The advantage of soft solders is that they cover a larger area when applied to the surface of the part. They provide high strength and reliability.

Soft solders

Soft solder is used in the installation of water supply and heating networks, where the pipe diameter reaches 10 cm and the water temperature does not exceed 130 degrees. These types include:

lead-tin type;
with low tin content;
special and fusible.

How to solder steel: nuances

In order to start soldering steel, you need to choose the appropriate method. This takes into account:

oxide film resistance;
interaction of steel and solder;
change in the characteristics of steel after the thermal soldering process.

Oxides are very easily removed when carbon steel is soldered. It is much more difficult to remove the oxide film when working with alloy steel, which contains chromium, aluminum, titanium and silicon.

Hard soldering diagram.

The fact is that after heating, poorly soluble oxides М203, М203 appear on the surface of the steel.

To solder steel, use solders, which include:

These materials have little effect on the properties of steel; they practically do not dissolve it.

Why do you need solder paste?

Solder paste is a pasty mass consisting of small particles of solder, flux and special additives. Flux paste is used in industry when soldering elements on printed circuit boards. The paste is selected according to certain conditions:

after application there should be easily removable particles;
the substance must maintain viscosity and stickiness;
do not have a negative impact on the surface being treated;
do not leak onto clothing during melting.

How to work with the paste depends on the type and size of solder contained in its composition. The material also differs in the type of flux (rosin, water-washable, no-clean). It is necessary to hold small parts in place and facilitate the joining process.

Soldering technology

The process is quite simple, therefore, when it is necessary to connect something at home, the owner does the soldering with his own hands and without the involvement of specialists. But still, you can’t do without the preparatory stage.

It determines how high-quality and reliable the connection will be. First of all, you should pay attention to the cut of the part, which should be strictly vertical, without burrs, with even and smooth edges. If you find the slightest defects, you should take sandpaper and rub it over the surface until the defects disappear.

If two copper pipes are connected, then, having brought the cut to an ideal state, it is necessary to insert it into the fitting and then remove it. The part that came into contact with the fitting must be cleaned of oxidation. The next step is applying flux. There is nothing complicated about this, you just need to run the brush over the entire part, paying special attention to the joint.

Then the elements are connected to each other and firmly fixed. Further actions depend on what is being used for soldering - a gas torch or a soldering iron. Considering that the parts must be stationary, an assistant will be required. He will be the one to hold them, but if one is not found, you need to manage and do it yourself.

When something needs to be soldered at home, a solid compound is most often used. But the master can purchase special pastes. With the correct choice of compositions, it is possible to connect two pipelines or radio components as accurately and firmly as possible.

Soldering is performed at either high or low temperature. In the first case, the process is distinguished by high strength of the seam, and the connected area also gains heat resistance. Which is very important if it later serves as part of various communications. But high-temperature soldering is not allowed on threaded connections. Most often this process is performed with a propane-filled torch.

When low-temperature soldering is used, a soft compound, paste or gel is used. It is most suitable for a beginner master because it is simple and easy. In this type of process, the temperature does not rise above 425 degrees, so it is even possible to use a soldering iron, which is found in almost every home.

Working with a soldering iron

Every person has seen a soldering iron at least once in their life, and many constantly work with it. Therefore, they will not see anything complicated in soldering copper products with this tool. The whole essence of the process is that the solder located between the two parts is heated with a soldering iron until it begins to melt.

When it hardens, the two parts will be securely fastened into one. To solder efficiently, it is necessary to distribute the substance evenly over the entire surface, filling every gap. It is important to choose exactly the material that can withstand the high temperature of the soldering iron.

Working with the burner

The tool is turned on when the two parts are already connected to each other. You should not hold it near the joint for too long, since the combustion temperature is several thousand degrees. While you only need to heat a certain place to 250-300 degrees.

This will take 20-30 seconds. As soon as the flux changes color to dark, the compound to be joined is introduced. Important! The burner or hair dryer should be placed in the middle to cover the entire joint area.

Copper welding – technologies, electrodes, devices

Sometimes brazing stainless steel is preferable to welding. Soldering is used for thin-walled products that are not subject to heavy loads, and in cases where they do not want to experience warping from heating.

It should be taken into account that some types of stainless steel require a certain approach, taking into account their composition and manufacturing technology. For example, cold-worked stainless alloys crack at high temperatures, so their soldering is carried out without loads, after first annealing the metal. There are other subtleties.

Soldering with silver solder

When you need to solder parts at home, silver solder is often used. It is beneficial because you can create it yourself. But it should not be used alone, in combination with zinc and copper.

Treated with this solder, the seam will be very strong and neat. The percentage of components is controlled by GOST 19746 74. But you can find out exactly what types of substances to use from the instructions of experienced craftsmen or those included with the products being connected.

How to solder copper and stainless steel

If you need to solder copper to another metal, such as steel, you will have to work hard. This process is not easy, but it is quite feasible. This is explained by the fact that stainless steel interacts poorly with other metals and is difficult to heat treat.

When two different products are combined, you need to find an average composition that suits both at the same time. In such cases, you have to sacrifice quality and it is not even necessary to use flux. But it is important to carry out preparation, tinning and other soldering steps.

The need for a connection often arises at home. Joining stainless steel and copper requires little time and a conventional gas torch is sufficient. Therefore, having decided on the tool and solder, you should clean the surface of both joints and prepare flux. Then tinning the bonding area and applying flux. After which the two parts are connected, and the resulting seam is coated with solder.

The next stage is its uniform heating with a burner. Once the solder has spread, the product is left to cool naturally.

Advantages

This method allows solving complex technological operations;
This is one of the few ways to achieve such a connection;
The procedure itself occurs quite quickly and does not require additional tools, since an ordinary burner is sufficient for this;
Modern developments of solders provide relatively high compatibility of metals during soldering;
The process is available for both home and industrial needs.

Flaws

The quality of soldering is inferior to other methods in terms of reliability;
Finding the right solder is difficult;
The flux oxidizes quickly, so the action must be carried out without delaying the start of heat treatment;
Often, low-melting solders are used, which makes the processing process more complex, since you need to carefully regulate the temperature and ensure that nothing spreads.

Methods

Solder selection

It is inferior in its properties to others, but is more common and accessible, so it is mainly suitable for simple connections that do not bear a lot of responsibility.”

Tin-silver solder, such as Castolin 157, is an excellent soldering method, but the material cost is higher than others.

In the simplest cases, radio-technical solder can be used, but depending on the production technology, it is better to choose specialized consumables.

Basic mistakes when soldering yourself

Most often, it is haste that leads to the fact that the connection of two elements is unsuccessful. Because they forget to inspect the surface of the parts being connected. The first action aimed at correcting an error is checking for the absence of defects. They could appear when cutting parts.

How reliable the seam will be depends on the cleanliness of the surface. Therefore, it is still worth brushing off even invisible specks of dust. One of the most basic mistakes is made when applying flux. The master may forget to process a small area of the product. And it will cause the proper connection to fail.

It is also important to monitor the temperature of the torch or soldering iron, since overheating of the element being processed leads to combustion of the flux. But insufficient melting point is also harmful. In this case, the connecting compounds do not soften or stick.

How to solder correctly

To reliably solder copper wires, you need to prepare a soldering iron. If you do not tin the tip before work, the solder will not stick, but will roll off the rod in balls. This happens because the tip is covered with a layer of copper oxide and carbon deposits formed during previous soldering.

Preparing the soldering iron

For ease of work, some specialists sharpen the tip with a flat file to give it the shape of a spatula or flat screwdriver. The sharpening angle should be 45-60 degrees.

A non-burning tip (eternal) cannot be sharpened under any circumstances; special sponges are used for it.

The mechanically cleaned tip must be heated and then tinned. To do this, it is coated with flux.

If the flux is solid (rosin), simply immerse the tip in it. The rosin will melt and cover the heated surface. After this, you need to touch the solder bar with a soldering iron and heat it up. The molten solder will coat the tip, protecting it from further oxidation.

The procedure for tinning a soldering iron must be repeated as carbon deposits form on it. This happens because the temperature of the tip is much higher than the melting point of the solder, and over time it begins to burn. To reduce the likelihood of this happening, it is recommended to use a soldering iron with temperature control.

Preparing the wires

The copper wires to be connected also need to be prepared for soldering. First, remove the insulation from the ends at a distance of about 4 cm, strip them, twist them together and tinning them. Copper wires can be tinned as follows:

heat the twist with a soldering iron;
coat with flux;
Apply a small amount of solder, spreading it over the surface of the wire.

The actions are similar to those performed when tinning a soldering iron tip. If you are going to solder stranded copper wires, then you must stock up on liquid flux, since it will be very difficult to cover the entire surface of the copper “hairs” with molten solid rosin. To get a quality connection, you need to heat the stranded wire and then dip it in liquid flux, which will wet the entire surface intended for soldering.

Further, soldering of stranded and single-core copper wires is carried out in the same way. The two or more conductors being joined are heated together and solder is applied to them. After applying it, it is necessary to ensure that the joint remains motionless while it cools. It is not allowed to accelerate cooling by wetting it or blowing air on it.

Safety precautions

Soldering copper products is a rather dangerous process, so it is very important to comply with all standards and regulations for safety. The process involves open flames and hazardous substances, so DIYers and professionals alike must wear protective equipment. We are talking about mittens, glasses and special clothing.

Before you take up the tool, you need to carefully study the rules of technology.

We also recommend reading:

Theory

Copper is one of the oldest metals, which is used by people to create various decorations, devices and communications. It is characterized by high plasticity and pinkish-red color, sometimes with a golden tint. In the household, copper is most often used in water pipes and heating, because it does not corrode and is resistant to temperature changes.

Photo - copper connections

There are many types of soldering; capillary soldering is used for copper. It allows you to connect two parts of a pipeline or radio components as accurately and firmly as possible. This thermal effect is also divided into:

High-temperature soldering is characterized by higher weld strength. In addition, it allows the connection to be thermally stable, which is very important for various communications. But at the same time, this type of work is not used on threaded connections. To carry out such soldering, special equipment is required - a burner with piezo ignition and acetyl, propane.

Photo - copper elements

Low temperature is used when working with soft solders (pastes, gels). The main advantage of this technique is the simplicity and ease of work. It is carried out at a temperature lower than 425 degrees, so soldering can even be done with a soldering iron. It lies in the fact that, under the influence of a certain temperature, the solder applied to the gap between the part and the area being connected expands, closing the gap.

The essence of the process

The essence of the soldering process is that metals are joined together using an alloy that has a melting point lower than the melting point of the substances being joined.

During soldering, materials are heated to the melting temperature of the solder. This ensures very strong adhesion (sticking) - the property of materials to adhere to each other at the molecular level.

However, the main parts do not melt and mix with the solder material, as happens when welding using filler material.

Soldering tools

Before starting work, you need to prepare special tools and devices for soldering copper connections. You will need:

Gas or oxygen torch for soldering copper (with nitrogen, acetate, etc.);
Solder (for capillary soldering according to GOST R 52955-2008);
A brush (hard, but not metal) and abrasive paper for stripping copper connections;
Fittings or other connected elements;
Soldering flux.

It should be noted that if the work is done on pipe connections, then you may also need a chamfer, an expander, or a special cutting device. All of these fixtures can be found at a professional plumber so you don't have to buy them.

Photo - burner

Burners for copper are: professional (for working with hard solders), for heating pipes and soldering with soft pastes, semi-professional or combined. There are also special hair dryers that are used for soft soldering. They allow you to quickly heat the joint at temperatures up to 650 degrees.

Solid. They are represented by rods of a certain diameter, which is selected based on a certain gap when connecting. It is used when connecting copper and iron in water supply systems, gas supply and air conditioning systems. This solder can be with phosphorus or silver;

Photo - hard solder
Soft ones can be either in the form of paste or thin wire up to 3 mm in diameter. They are produced with lead and tin. Also sometimes the process is carried out with orthophosphoric acid.

Also, to join copper alloys, it is necessary to use flux. It performs several useful functions: it promotes better spreading of solder over the metal, protects the processing area from an oxygen film, and cleans the seam from oxide. Fluxes come with borax (for various high-temperature solders), used for medium-melting compounds of gold, copper, bronze, cast iron, and stainless steel. Outwardly, they look like a paste and are applied with a special brush.

Photo - flux paste

Brushes and abrasive sheets (sandpaper) are needed to remove solder residues from the seam after finishing work. Fittings are selected based on the required connections (they can be branching, corner, curved, etc.).

Photo - soldering iron

Copper Welding Machine

Quality welding machines for copper:

– semi-automatic and automatic machines;
– TIG – devices;
– inverters.

Popular models are produced by TESLA, SPETSELECTROMASH, ESAB.
BUDDY TIG 160 from ESAB (pictured on the right) has two and four stroke torch firing modes.
It can be used to join stainless steel and most other types of metals. It is compatible with almost any generator. RENEGADE ES 300i ESAB inverter stores several welding parameters in its memory. Automatically sets the best starting parameters based on the configured current. It is lightweight but has high power.

Inverter machines allow you to weld copper rods; they generate a current of 60-110 amperes. For them you need to buy copper/carbon electrodes. HUNTER company produces semi-professional models, for example, MMA 257D, designed for continuous operation for two hours.

TESLA is known for reliable devices such as MMA 265, 275, 255. They have a non-contact arc excitation function. They connect to a regular household network without any problems. They are convenient for welding copper and its alloys, non-ferrous metals.

For welding with electrodes

Pulse-arc welding of copper plates is possible with tungsten electrodes in an argon atmosphere using an Orion 150s or 250s . They are lightweight and allow you to weld copper efficiently and reliably. The inverter welding device Resanta SAI-220 PN can be connected to a network with a voltage of 140-220 volts. It is easy to move with, it is equipped with a forced cooling system, so it does not overheat.

For wire welding

To perform copper wire welding work, the semi-automatic inverter Energomash SA-97PA20 is used.
It has a light weight of 13 kilograms. It allows you to work with wire of different thicknesses 0.6-0.9 mm. Smooth material feeding is ensured by the Shyuan MIG/MMA-290 model at a speed of 2.5-13 meters per minute. The device makes it possible to use 1-5 kilogram cassettes and allows you to work with electrodes.

The inverter semi-automatic welding machine Soyuz SAS-97PA195 is characterized by the presence of a 60 Volt idle speed function. It has an operating voltage adjustment range of 15-23 volts. A wire of 0.8-1 mm is suitable for it. It has a light weight of 10 kilograms, it is comfortable and reliable.

Welding

Let's look at how copper pipe soldering is done with your own hands:

Any technology involves pipe preparation. You will need to cut the communication to the desired size and trim the ends with a bevel gun. This is necessary so that the next element is not damaged during connection and the maximum rigid adhesion of the parts is obtained;
Soldering flux is applied to the edge of the copper pipe, and it is also applied to the fitting or other pipe. Afterwards you need to carefully insert the communications into each other. If soldering is done with self-fluxing solder or an electrode, then flux does not need to be used;
The selected solder is inserted into the joint. It should be noted that if a paste is used, it must be applied after the flux. Under the influence of a certain temperature, the substance will begin to melt, filling the free space in the pipe. A very important point: the solder cannot be exposed to direct fire, it should melt only from the heat of the heated pipe;

Photo - soldering with solder
If tinning is used, then the flux and solder are applied in a very thin layer, otherwise an unsightly volumetric seam will form at the soldering site. If locks or radio components (usb, contacts) are repaired, this may disrupt the operation of the element;
After heating is completed, the tool is removed. At this moment, the pipe cannot be moved - the connection is still too plastic, and turning the metal bends can damage the fastening. Copper pipes cool naturally;
All that remains is to remove the remaining solder or flux with a brush, abrasive paper or brush. It is not recommended to overcool the joint during the first 24 hours, when the metal solidification process is not completed.

Photo - after cleaning

You can buy all the necessary tools used to solder bronze or copper at any electrical store; the price depends on the category. Burners cost from 3 dollars to several dozen, the cost of solder starts from 5 cu. e., flux - from 3.

Flux selection

As for flux for soldering stainless steel, the best option here is borax. It can be used in paste or powder form. Borax powder is poured into the soldering zone of two workpieces and heated to a temperature of +850 ℃. This is the so-called light red heat temperature.

Once the flux has melted, solder is added to the area. If you follow the standards, then to work with silver solders, use flux No. 209 or 284 according to GOST, and for solders containing copper and nickel - No. 200 or 201.

Remains of flux after soldering are removed with water (cold or hot) or blown with sand. It is not recommended to use hydrochloric or nitric acid for this. This is a potent material that corrodes the solder layer and the stainless steel itself.