How to solder copper to brass. Brass soldering technology. Features of soldering copper alloys

Soldering brass with a gas burner, tin, tin-lead and other similar solders is very common, although many do not dare to pick up the appropriate tool. Below we will consider all the subtleties of this process, areas of application, as well as ways to carry it out on your own at home.

1

Soldering is one of the ways to obtain a permanent connection. It is carried out by introducing molten solder between two elements. This means that the melting point of the latter should be somewhat lower than that of the materials of the main parts. Using this process, dissimilar metals can be joined together, and in some situations this is the only possible method of fastening.

Many identify such a connection of metals with welding, but they have only the end result in common. The essence is completely different. Their most important difference lies in the fact that during welding, the base material is melted. In soldering, only the metal-bond is melted, so that the integrity of the workpieces is fully preserved. Thanks to this, it becomes possible to work with rather small elements without worrying that they are deformed, and the structure with the properties of the soldered materials will remain the same.

However, it should be borne in mind that, compared with the same welding, the connection will be less durable. This is due to the softness of the solder, but if we are talking about brass products, then this material releases zinc when exposed to high temperatures, and the seam is more porous, which also negatively affects the adhesion strength. Moreover, the location of the elements also plays a role, so butt soldering is quite unreliable, it is better to overlap.

Today, it is soldering that occupies one of the leading positions in the creation of permanent joints, giving way only. So, electronics engineers who are forced to work with rather fragile microcircuits find it very difficult to imagine their profession without the participation of this process in it. In addition, solder joints are very relevant in electrics, if you need to build up or simply connect wires.

Also in this way, the connection is made in refrigerators, heat exchangers and other installations. Very often it is used for fastening plates made of hard alloys to a cutting tool. You can also attach thin-walled parts to a thick sheet. In addition, sometimes anti-corrosion treatment is carried out using tinning. In general, the scope is quite extensive.

Soldering can be high or low temperature. In the first case, the connection is more reliable, plus it has increased thermal stability (this is due to the fact that solders for this type of processing have a higher melting point). Thus, parts after such exposure can operate at much higher temperatures compared to parts connected in the second way. However, this type also has its drawbacks, since we are talking about excessively high temperatures, then it will not be possible to carry out this process with a simple soldering iron. It requires special equipment, which greatly complicates the work.

2

Most often, you have to work with a soldering iron on an alloy of copper and zinc, called brass. This material is mainly found in industry and households, as radiators, pipes and many other products are made from this material. Therefore, we will consider the features of working with it. Firstly, it is very important to choose the right flux for soldering brass. After all, ordinary rosin-alcohol is unable to remove the oxide film from its surface well, so it is necessary to use more active components, the basis of which can be zinc chloride.

For soldering elements in salt baths, fluxes containing borax or potassium fluoroborate have found their use. Usually their content in solution is about five percent. They contribute to a better flow of the binder component into the gaps.

Secondly, with special attention should be selected and solder for soldering brass. Silver-plated and copper-phosphorus components are perfect for gaseous media. They are also applicable to work with brasses, where there is a high content of copper. In the latter case, even brass can be used as a solder, just its melting point must be significantly lower than that of the base alloy from which the parts are made. Hard soldering of brass is very common. So, for example, L-CuP6 is used to connect radiators, copper pipes and other elements of heating systems. In general, hard solders are superior to soft solders because the strength of the joint will be greater.

It is also important to consider the situation when the material of the parts to be joined is different, for example, how copper and brass are soldered, at home this process is quite feasible, the main thing is to know some of its features, and what kind of solder should be used. When heated, an oxide film forms on the surface of brass, and excessive heat also contributes to the evaporation of zinc from this alloy, which enters the liquid metal-binder. In this regard, the seams are more porous, which contributes to the deterioration of the adhesive strength.

In addition, because of this property, high-temperature soldering in special furnaces is very rarely used. As for soldering in gaseous media, it is better to do this using flux, but if this is not possible, then a layer of nickel or copper should be applied to the surface of brass parts. Such a solution will avoid the release of zinc and, accordingly, the connections will be more reliable. Some solders contain substances that act as a flux, which makes the job easier as you don't have to juggle multiple components as you work.. An example is copper-phosphorus solder.

3

Having studied all the features of the process and familiarized yourself with all the possible components, attention should be paid directly to the question of how to solder brass. After all, it is very common in our everyday life, and the budget does not always allow hiring specialists, so you have to cope on your own. Moreover, all we need is:

• gas burner (sometimes you can get by with a simple soldering iron),
• solder,
• flux,
• borax.

Without the last two elements, the seam, of course, will work out, but it will be rather weak, white and the folds, if any, can very quickly disperse.

So, let's start collecting everything you need. This list includes: gas burner, asbestos base, graphite crucible, borax, solder and boric acid. Solder is prepared as follows: one part of copper and two silver are taken, then they are placed in a crucible and melted, heated on a gas burner, while not forgetting to stir. After the mixture has turned out to be homogeneous, place the container in cold water so that the contents cool down. Then it can either be cut or used in the form of shavings.

To make a flux, you will need a drill for soldering with brass and boric acid, which are taken in a 1: 1 ratio and filled with water. So, taking 20 grams of each component, you will need 250 ml of liquid. Now we proceed directly to the process. We take the parts, treat their surface with flux and sprinkle with solder shavings. Then we bring it to a gas burner and heat it up to about 700 ° C. Beware of overheating, because thin brass parts heat up very quickly and can be deformed. Massive elements must be warmed up gradually. The soldering can be considered complete. Of course, this procedure is much easier to do with a soldering iron, but it is more reliable with a burner.

Brass soldering is used when small metal parts are to be joined. For example, it is used in artistic forging when assembling a general composition or in a home workshop. In this case, ornamental steel with a flat or square section is most suitable, where the contact area is larger than that of round rods. In addition to the fact that brass can be used as a solder to solder parts from this material, there are also some tricks to get a quality seam.

How to use brass solder

Before starting soldering, the product must be assembled. To do this, individual parts are fastened together with a metal wire (bindry). When the preparation is over, everything is placed together in a gorg, where heating takes place until the metal is heated to redness. When laying, you need to exercise extreme caution. To clear the place in the coals under the product, a poker is used, the fuel remains on the grate in a sufficiently large and even layer. When working with coal, it is important to ensure that it does not fall on the forging, even in the smallest pieces. The blowing of the hearth should not be strong in order to obtain uniform ignition.

As a flux, as a rule, borax acts. Before application, it is wetted over the entire surface with water, after which they proceed to soldering. Leaving the flux in place, take a twig of brass and run it where the connections should be. At this moment, the flame in the forge changes its color to green. During the soldering process, the workpiece of the product should not move and move from its original place. This will help to avoid accidental displacement of parts relative to each other, so as not to spoil the seam, both in terms of visual appeal and the reliability of the seam.

If the composition contains many elements, then welding occurs in a different way. In those places where soldering will be carried out, from the very beginning the brass is laid out in pieces, in the expectation that when heated it will begin to spread, as a result of which the parts will be fastened together.

Brass can be used in separate pieces, shavings or sawdust, filled in at the welding points. At the same time, they must comply with the purity requirements so that there are no impurities and foreign inclusions. Iron chips and other small metal parts are removed by means of a magnet.

To solder smaller parts, clay with salt added to it is used as a bonding material. But when assembling individual parts for fastening, wire is used not from iron, but from brass. After that, the product is sprinkled with brown, coated with clay and carefully placed on a sheet of metal, which is sent to the forge. It is also necessary to blow weakly, the heating of the clay should occur evenly. After it dries, the air supply is more active. Clay that has begun to crack indicates that the fastening of parts is reliable. The soldering of individual parts takes place by means of brass wire, which at this point melts and holds the parts together. At the end of the process, the hearth is turned off, the finished forged product must cool. The final step is the removal of clay and flux, excess solder is cleaned with a file.

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Soldering brass with a gas torch

Quite often, craftsmen wonder how to solder brass. If it is necessary to fasten brass parts, a slightly different technology is used. Brass parts lend themselves well to processing, soldering, after which they are specially blackened. Many people use tin as solder in this case: it is available in almost every workshop and is easily melted with an ordinary soldering iron.

The method is quite simple, but has significant drawbacks:

• the finished seam stands out against the background of brass in white, while not everyone immediately comes out thin and neat;
• the seam is fragile, does not withstand bends;
• in the process of blackening, both metals behave differently, the tin seam differs from the brass part in color, they have different shades.

Soldering with special solder for brass and flux will help to avoid such problems. As a result, the seam is difficult to distinguish from the base metal of the product by color, it is highly durable, and in terms of chemical composition it is much more similar to brass than tin.

Working with brass is more like welding because of the high temperatures for which an ordinary soldering iron is not suitable, but it is called soldering mainly due to the fact that solder is used.

First of all, the solder is prepared.

It consists of silver and copper in a ratio of 2: 1, which must be fused together on a gas burner. Copper is more refractory, so you can start with it and then pour in molten silver and mix it with a wire bent in the form of a hook. The finished solder is cooled, rolled out in rollers or on an anvil, and then cut into pieces. There is a more accessible way: using a coarse file, go through the casting to form chips.

Next, the flux is prepared. Borax powder is mixed with powdered boric acid in equal parts of 20 g, after which it is poured with a glass of water. In order for the ingredients to dissolve well, all this must be boiled. As one of the options for use, it can be advised to evaporate the water, ignite the solid finished flux and grind it into a powder, which is subsequently mixed with solder.

Brass is an alloy, the essential components of which are copper and tin. Possessing high strength, ductility and corrosion resistance, it is well suited for the manufacture of both heavily loaded parts of various mechanisms and structural elements operating in aggressive environments. Its main disadvantage is its high cost. But there are other problems associated with the use of this material.

To date, various technologies have been developed that allow welding brass products. But all of them are quite complex, costly, and require that the specialist who performs the work has certain skills. An alternative to welding is often brass brazing. It is somewhat simpler technologically and imposes other requirements on the qualifications of the performer.

Encountering Obstacles

If the zinc content in the alloy is low, then there are no special problems. It is possible to cope with the task with the help of ordinary rosin. But in the case when the amount of zinc exceeds 15%, the use of special fluxes is mandatory. This is due to the fact that evaporating when heated, zinc and copper form a strong oxide film on the surface of the part, which is very difficult to remove.

Choose ready-made or make your own?

The simplest flux for soldering brass is easy to make yourself. To do this, you need to mix borax and boric acid powder in a one-to-one ratio, pour the resulting amount of water at the rate of 5 ml per gram of the powder mixture, gently stir, boil, and then cool. But ready-made formulations that go on sale have the best characteristics.

• One of the most common is the "Bura" flux. Invented a long time ago, this recipe has received the approval of many jewelers involved in soldering various metals, including brass. It belongs to the category of high-temperature mixtures that are activated when reaching 700 - 900 degrees Celsius. Despite his advanced age, he performs his work qualitatively.
• Fluxes of the PV-209 and PV-209X brands do their job well. The first is based on fluorosalts, and the second is made using hydrofluoric acid. Both of them also work at temperatures approaching a thousand degrees.
• Somewhat less heating will be required by the German-made Chemet FLISIL-NS-Pulver (powdered) and Chemet FLISIL-NS-Paste (paste) formulations. For them, 550 - 800 degrees Celsius will be enough. They work best when using silver-containing solders.

The brands listed are examples only. There are many options on the market for this essential product for brazing brass.

What kind of solder to take

Just as important as the choice of flux is determining the right solder composition.

• For soldering brass with a copper content, PMC-48 solder is well suited, the melting of which occurs at 870 - 880 degrees. PMC-36 has a slightly lower melting point. Both compositions belong to the group of copper-zinc solders.
• Marks MF-1, MF-2 and MF-3 belong to the group of copper-phosphorus solders. They are relatively inexpensive, ductile, but have high electrical conductivity and resist shock and vibration loads worse than compositions containing silver.
• Silver solders have the best mechanical properties. Among them are PSr-10, PSr-12m, PSr-25 and beyond, up to PSr-72. All of them have some differences, consisting in the chemical composition and melting point. They also react differently to the percentage of copper and tin in the metal being joined.

From the foregoing, it is clear how important it is to decide on the brand of brass before proceeding with the choice of flux and solder. Only then will it be possible to achieve an acceptable soldering result.

Training

Before starting work, it is necessary to properly clean the junction from contamination. To do this, you can use a variety of tools - metal brushes, special nozzles, files or sandpaper. After that, the treated metal must be degreased. If you do not do this, you will make your work more difficult, and the soldering, if it can be done, will not have sufficient strength.

The parts to be soldered must be laid on a thermally insulating lining. Strange, but many sources still recommend sheet asbestos, recognized as a carcinogen, for this purpose. Undoubtedly, it is worth finding a replacement that is not harmful to health. For example, based on fiberglass or carbon fiber.

Soldering iron or torch?

The use of an electric soldering iron is acceptable when flux and solder with a melting point of about 500 degrees Celsius are used. But even in these cases, the power of the device must be at least 100 watts. It is better if this figure is 0.5 kW and above. After all, the soldering place must be preheated well.

Joining massive parts or soldering thick brass is more convenient with a gas burner. In this case, it is possible to heat the metal so that the use of high-temperature components becomes possible. The connection zone is treated with a flux, and sprinkled with crushed solder on top. Only after that proceed to the heating of the metal. This must be done with extreme caution. First, preheating is performed, allowing the flux to become more active, and the solder to grab onto the surface. Gradually, the temperature is increased until the brass acquires a characteristic redness. It is at this moment that the solder spreads, filling all the small pores in order to securely connect the parts when cooling. If everything is done correctly, then after a gradual cooling, you will get a neat seam, the color of which will be close to the color of brass.

Application area

It is quite obvious that brass soldering is easier than welding, not only at home, but also in production. The resulting connection will have sufficient strength. However, it is still not worth counting on the fact that it will withstand very high loads. Based on this, the scope of the technology is also determined.

• Manufacture of electrical and electronic components. Mechanical loads in this case are low, and electrical conductivity comes to the fore. We should not forget how difficult it is to use welding to connect small parts.
• Connection of elements subjected to small and medium loads. This includes parts of small mechanisms like clocks, or components of pipelines operating at pressures not exceeding a few atmospheres.
• Jewelry production. Of course, the cost of brass is much lower than that of silver or gold. And yet, it is quite often used to make inexpensive rings, brooches and other jewelry, becoming, if not their main part, then at least a component of frames and clasps.
• Do not forget the restoration work. Sometimes soldering brass is the only way to restore a thing that was made many years ago.

There was an application of such a technique in mechanical engineering. Making a new one with it, or soldering a damaged brass radiator is much easier than using welding. The efficiency and durability of the resulting part will be significantly higher than that of cheaper aluminum counterparts.

Brass is a widely used alloy for creating various products, so the question of how to work with it is relevant for many craftsmen. The process has certain features and difficulties; it can be performed both at home and by industrial methods. Subject to the rules, soldering brass will be within the power of any person.

Technology nuances

Brass is an alloy in which the main components are copper and zinc, and the additional elements are tin and aluminum. Metal products are always used in everyday life. When you need to connect two different objects, they resort to soldering. The method has some nuances that you should be aware of before proceeding with the work.

The main feature of the process is the active evaporation of zinc due to exposure to very high temperatures. As a result, a dense film is quickly formed, especially if the percentage of zinc in the alloy is more than 15%. It is not possible to destroy it even with the help of rosin with alcohol. Therefore, when brazing brass, it is important to use special fluxes.

It is also required to carefully study all the stages of the process, since this is the only possible option to firmly combine two different objects into one. The essence of soldering is that molten solder is introduced between the two parts to be joined, which holds them together. The main condition of the process is that the heating temperature of the connecting element must be less than the melting temperature of the connected objects.

Hard soldering allows you to get stronger and more heat-resistant seams. The technology is carried out according to standard rules. The advantage of the method is that it is possible to connect objects from different materials. At the same time, their surface, structure and properties do not change, as is the case with welding.

Preparatory process

Before you connect brass products, you need to prepare them. To achieve the most effective result, you need to use special equipment - a gas burner. Then the soldering will turn out to be reliable, and the junction will not be conspicuous.

For the treatment of brass parts, oxalic acid or various household products are used. When working with acid, you should wear gloves and do not breathe over the solution, which is obtained in the following proportion: 20 grams per liter of hot or cold water. A solution is prepared in a plastic container to avoid exposure to other metals. It is needed to clean the alloy, after processing the product is wiped off and left to dry.

To solder two different items, you will need solder and flux, which are made by hand. For example, to obtain solder from brass, you need to stock up on 20 grams of copper and silver, which are mixed and fused with a gas burner and a graphite crucible. After that, the substance is placed in cold water and pulled out when the solder has cooled.

The flux is created from borax and boric acid, taking 20 grams of each powder, and diluting them with 250 ml of water.

Tools Used

To connect two dissimilar products, either a gas burner or soldering irons are used. As the latter, conventional electrical tools are most often used. What power it should be depends on the nature of the work. If, for example, parts up to 1 mm thick are connected, then a tool with a power of 80-100 watts is suitable.

When brazing is performed with brass, a porous weld is obtained due to the evaporation of zinc. This degrades the reliability and quality of the connection. Therefore, it is recommended to overlap the products. Using a soldering iron, the preparation is carried out in several stages:

They plug it in for the first time and wait until the tool stops smoking. That is, until all the substances used in the last time of use burn out in it.
After waiting for the tool to cool, sharpen the sting.
If the tip does not have a protective coating, then a thin layer of tin is applied to the tip.
During connection, the tool must have a temperature of at least 500 degrees Celsius.

Solders and fluxes

For high-quality bonding, you need to reasonably consider the choice of flux and solder. This matters when the work is done either with a gas burner or a soldering iron. Experienced craftsmen say that it is necessary to use a more active solder, which includes zinc chloride. It is he who is able to clean the surface of objects from the emerging films of zinc oxide during heating.

Therefore, it is better to purchase a special flux, which can be borax. If you have to work with an alloy containing a large amount of copper, then it is better to use silver or copper-phosphorus components.

When the objects to be joined differ in the material of manufacture, it is especially important to know which solder is suitable. Solder for soldering brass must be compatible with the surfaces of the products and have a temperature much lower. If there are no strict requirements for strength and appearance, the connection is possible with tin.

How to solder at home

Go to the direct implementation of soldering should be after the features of the technology have been studied. First you need to prepare the following equipment and materials:

• gas burner or soldering iron;
• flux and solder;
• borax.

The task is feasible without a drill with flux, but then the seams will turn out to be visible, the junction will not be particularly strong.

Fastening of products is carried out in the following way:

• the surface of the parts is treated with flux and sprinkled with solder shavings;
• then they are brought to a gas burner and heated to 700 degrees.

Very large products must be heated gradually.

Soldering with a gas torch

When you need to solder brass of any brand, a gas burner will help out. First, the parts are placed on an asbestos base and connected. The seam is wiped with a flux based on borax, the solder is sprinkled on top.

The flame of the gas burner should fall exactly on this place. When soldering copper with brass, a special agent should be prepared in advance to remove the oxide film.

Soldering with a soldering iron

The soldering iron also manages to achieve a strong connection between the two products. In this case, a flux such as soldering or phosphoric acid is used.

Having previously processed the surface of the products, after which a soldering iron with solder is brought. In soldered products, defects can be hidden in this way. Soldering is performed with a well-heated tool.

At home, very often you may be faced with the need to connect brass products. For example, elements of plumbing and heating systems.

With your own hands, you will be able to fulfill the required when there are two soldering irons at home - low-power - 40-60 W and powerful - from 100 W.

Mistakes to avoid

With a lack of experience with a soldering iron, some craftsmen do not warm it up to the required temperature. In order to qualitatively solder brass, it is necessary to clean the tool and the surface of the parts to be joined.

Quality control

When soldering brass at home, you should be responsible and prepare the materials in advance. If there is no gas burner, you can get by with a soldering iron. But in both cases, it is important to thoroughly understand the instruction manual.

How well it was possible to solder brass products can be understood by the appearance of the seam, structure and mechanical strength.

Safety

The torch and soldering iron are dangerous tools, so while working, you should pay attention to the angle of the tool or flame. It does not hurt to verify the integrity of the wiring and plug. During soldering, do not be distracted or leave a hot soldering iron in the reach of children. Some fluxes release harmful substances during melting, so you need to either work in a respirator or ventilate the room more often.

Advantages and disadvantages of doing it yourself

When you need to join brass products, soldering is the best solution. It is necessary to study how the process is carried out, since each time it will be expensive to call a specialist for the family budget. But it is the master who can perform work of any complexity with high quality and for a long time. When soldering pipes in the water supply or electrical wires is required, then it is better to entrust the soldering to the master. Therefore, due to inexperience, you can be left without light or arrange a mini-flood.

In our practice, we often have to deal with brass parts. They are well processed, soldered and then blackened. Most solder brass with a soldering iron with ordinary tin solder. This method, along with its simplicity, has three serious drawbacks: the seam turns out to be white, noticeable and few people manage to immediately make this seam thin; the seam is relatively weak; when bent, it can easily disperse; when blackened, tin may behave differently than brass and the seam will turn out to be a completely different color or shade. This article will tell you about the method of soldering brass using a gas burner with special solder and flux. The resulting seam is practically indistinguishable in color from the main parts, very durable and chemically much closer to brass than tin.

For soldering you need:
- gas-burner;
- asbestos base;
- graphite crucible (bath);
- silver;
- copper;
- borax;
- boric acid.

First you need to make solder. It will consist of 2 parts silver and 1 part copper. It is necessary to alloy silver and copper (where to get silver? - do you know silver spoons? ideal). This can be done using the same gas burner. We weigh out the amount of silver and copper we need, place them in a graphite crucible and heat it with a burner. The crucible can be made from trolleybus contacts, there are a lot of them lying around at the final stops. The size of the crucible is approximately 20x50mm. A 5x40mm semicircular groove is selected to make it easier to remove the resulting solder bead; for this, lower the hot crucible into water. When both metals are melted, mix them with a steel wire - a hook. In principle, you can first melt copper (as a more refractory metal), and then add silver to the melt. Or vice versa - as you like.

The arrow shows the graphite bath. She is in a brick "blast furnace".

Everything, the solder is ready. We cool it, roll it in rollers or flatten it on an anvil, then cut it into small pieces. You can simply grind the casting with a coarse file into chips.

Now flux. We take about 20 grams of borax (powder), the same amount of boric acid (powder), mix and pour a glass of water. Boil (for better dissolution of the ingredients). Everything, the flux is ready. This amount of flux is enough for the rest of your life. Don't worry about it being chemically hazardous. Boric acid is quite passive and does not threaten your fingers and tools. In principle, you can evaporate the water, ignite the already solid flux, crush it into powder and mix it with solder. Get a dry mixture of solder with flux. But this is an amateur.

soldering process. You need to solder on something heat-resistant. The best for this are plates from the skin of the "Buran". But if the Buran does not fly over you, then you can get by with an asbestos plate. We place our parts to be soldered on it, moisten it with flux, sprinkle with solder shavings (it needs quite a bit) and begin to slowly warm up. First, a little, so that the solder grabs the soldered parts a little, then until red (about 700 degrees for this type of solder). Solder easily flows into the gaps between the parts and solders them tightly. At this stage, there are the following dangers: since the difference in the melting temperature of the solder and brass parts is only about 50 degrees, care must be taken not to overheat them. Otherwise, you will just get one big ingot. It must be remembered that small parts (for example, brass wire) heat up much faster than massive ones. Therefore, be careful. In this case, it is necessary to heat the entire structure slowly so that the large part has time to warm up.

Details warmed up to red.

The resulting seam has almost the same color as the soldered parts. This is due to the diffusion of the base metal into the solder as a result of soldering. Therefore, the same solder can be used when soldering silver - the seam will be white.

The last stage is washing the product from the flux residues, which remain on the product in the form of vitreous drops and sagging. To get rid of them, you need to wash the finished product in hot 3% sulfuric acid (or 15% when soldering gold). You can do this on a gas stove by placing a quartz glass tube with dilute acid on it. The product is simply lowered into it for a short time (it must first be tied to something that does not interact with acid) and then washed with running water.

I foresee the question: "Why can't you use a soldering iron?" The answer is very simple: the melting temperature of the solder is about 700 degrees, and the soldering iron can give only 200-250 degrees.
Those who have not used a gas burner before may ask how long does a gas bottle last? In normal use, the consumption can be calculated at the rate of 1 liter per year.