How to solder brass at home. Brazing

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.

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 and 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. Thus, it is very difficult for electronics engineers who are forced to work with rather fragile microcircuits 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 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.

The division of soldering into low-temperature and high-temperature soldering is, to some extent, conditional. By its physical nature, hard soldering does not differ from soft soldering. Like the latter, it is the process of forming an inseparable connection of two metals with the help of a third (called solder), the melting point of which is lower than the melting point of the metals to be joined.

And yet, despite the fact that low-temperature and high-temperature soldering are phenomena of the same essence, their technology, the materials and equipment used, and the characteristics of the resulting joint differ significantly. What, in fact, was the basis for the separation of these methods. The boundary temperature separating them is 450°C.

Differences between high temperature soldering and low temperature soldering

What distinguishes high-temperature soldering from low-temperature soldering, besides the melting temperature of solders? First of all - a significantly higher strength of the solder joint, due to the greater strength of hard solders in comparison with soft ones.

An important difference between high-temperature soldering and low-temperature soldering is the increased thermal stability of the joint. Since the melting point of hard solders is much higher than the melting point of soft solders, a joint made by high-temperature soldering is able to work at higher temperatures, retaining all its properties. In many cases, when choosing a soldering method, this feature is decisive.

But there is also something in which hard soldering is inferior to soft soldering. Relatively high temperatures can cause structural changes in some metals. This, in particular, is observed in cast iron, in which hardening structures can occur during soldering, leading to increased brittleness of the metal in the weld zone.

The high melting point of solid solders places its own demands on heating sources. They must ensure the melting of solders, the melting point of which sometimes reaches 1000°C. This eliminates the use of handy soldering irons for high-temperature soldering, which are the main tool for soft soldering.

Summarizing the above, we can summarize the comparison of high-temperature and low-temperature soldering. The advantages of the first include the high strength and thermal stability of the connection, the disadvantages are the complexity of the technological process, due to the need to heat the soldered parts to relatively high temperatures.

Application of hard soldering

The field of application of hard soldering is determined by its intermediate position between low-temperature soldering and welding. Wherever it is required to obtain a stronger connection than can be done using soft solders, which is also able to work at high temperatures, and at the same time preserve the structure of the joined metals, prevent their softening and deformation (as is the case with welding), high-temperature soldering is used.

Brazing is the main method in the manufacture of metal-cutting tools with carbide inserts. The soldering of the latter provides sufficient strength of the connection and does not adversely affect the hardness and geometry of the cutting inserts.

The manufacture of all kinds of vessels from non-ferrous metals and stainless steels, the connection of steel and copper pipelines operating under high pressure or elevated temperatures in various systems - refrigeration, heat exchange, etc. - also cannot do without hard soldering.

High-temperature soldering is widely used in the repair of automobiles - radiators, piping systems of the engine and transmission, bodies, various parts - wherever it is impossible or undesirable to use welding.

It is advisable to use high-temperature soldering to connect thin-walled parts operating under significant loads and elastic deformations.

For the repair of copper and brass household items that are exposed to high temperatures during operation, high-temperature soldering is a repair method that has no alternative. Such, for example, as an old samovar, melted by firewood. In this case, soft solders cannot be used due to the inability to withstand high heating temperatures.

Heat sources for brazing

Any equipment that allows you to heat the soldered parts slightly above the melting temperature of the used solders can be used as heating sources for high-temperature soldering. This temperature can vary between 450-1200°C. When using refractory materials such as brass or commercially pure copper, heating in excess of 1000°C is required, when using medium-melting solders, a heating temperature of 700-800°C is required.

The main sources of heat in brazing are gas burners of various types, inductors and furnaces. Electrical resistance heating is also used. In everyday life, most often hard solders are soldered using burners.

Solders

The main merit in the formation of strong and heat-resistant joints during high-temperature soldering belongs to copper. It is not only included in almost all hard solders, but in most of them it plays a major role, being the basis of solders.

Sometimes commercially pure copper is also used as solder. However, much more often soldering is used with copper solders, which are compounds of copper with other metals - zinc, silver, silicon, tin, etc. Each of these elements contributes to the technological properties of solders. Almost all of them reduce the melting point (for pure copper it is 1083°C).

For high-temperature soldering, copper-zinc, copper-phosphorus, silver solders and brass are used.

Copper-zinc solders. There are a large number of copper-zinc solders (PMC-35, PMC-39, PMC-50, PMC-54, PMC-57, etc.). The numbers indicate the percentage of copper. They are used for soldering bronze, copper, steel. The disadvantage of purely copper-zinc materials is poor performance under shock, vibration and bending loads. To remove or reduce this disadvantage, alloying them with other metals is used (for example, brass can be considered as alloyed copper-zinc solders). Alloyed copper-zinc solders are used, in particular, when soldering carbide cutters.

Copper-phosphorus solders. Copper-phosphorus solders (PMF-7, PMF-9, PMFOTsr-6-4-0.03) are an alloy of copper and phosphorus. The number following the letters indicates the percentage of phosphorus. Solder PMFOTsr-6-4-0.03, in addition to copper and phosphorus, contains tin and zirconium.

Copper-phosphorus solders are classified as medium-melting (700-850°C), have high fluidity and good corrosion resistance to aggressive environments. Used for soldering copper and its alloys (bronze, brass, cupronickel). They can also be used as a substitute for silver solders when repairing jewelry.

Soldering of steels and cast iron with copper solders containing phosphorus is not used due to the increased fragility of the joint and its inability to withstand shock, vibration and bending loads. This is caused by the formation of a phosphite film along the seam boundary.

A distinctive feature of copper-phosphorus solders is that they are self-fluxing. When soldering copper products with them, the use of flux is not necessary.

Brass. Brass, which is an alloy of copper and zinc, is widely used as solders. Brass L62 and LOK-62-06-04 give strong brazed joints. LOK-62-06-04 differs from L62 in the presence of tin and silicon, which provide higher technological properties of the solder. Tin increases fluidity and lowers the melting point, and silicon compounds protect zinc from oxidation and evaporation. Brass is used for soldering copper, steel, cast iron.

Silver solders. Silver is an excellent material for soldering. Silver solder alloys, which are mainly an alloy of silver with copper and zinc, rank first in terms of spreading, wettability, strength and anti-corrosion. If they were not so expensive, it would be possible to abandon all other solders, using only silver ones. Fortunately, they have versatility and are able to solder almost any metal.

Silver-based solders are designated by the letters PSr (PSr-15, PSr-25, PSr-45, PSr-65, PSr-70). Marks PSr-15 and PSr-25 are used for soldering not very critical parts. If you want to get a particularly high-quality connection, use PSR-45 solder, which has 45% silver, 30% copper and 25% zinc. PSR-45 has excellent qualities - viscosity, ductility, fluidity, corrosion resistance, ability to withstand vibration and shock. Solder PSr-65 is not inferior to PSr-45, but is too expensive.

Almost any metal can be soldered with silver solders - copper and its alloys, silver, steel, etc. However, due to their high cost, soldering with silver solders is used only where it is economically feasible, in particular, for joining stainless steels that are difficult to solder and require solders that have good wettability and avoid corrosion that can occur in the junction.

Fluxes

The main component of fluxes for hard soldering are boron compounds - borax (Na 2 B 4 O 7), boric acid (H 3 BO 3), boric anhydride (B 2 O 3). To enhance the activity of boron fluxes, for example, when brazing stainless and heat-resistant steels, fluorine compounds are added to them - calcium fluoride, potassium fluoride. Special fluxes are used, regulated by GOST 23178-78 - under the brands PV200, PV201, PV209, PV209X, PV284X. The first two include boric acid, borax and calcium fluoride. They are used for brazing stainless and structural steels and high temperature alloys. Flux PV209 consists of potassium fluoride, boric anhydride, potassium tetrafluoroborate. Fluxes PV209X, PV284X consist of boric acid, potassium hydroxide, hydrofluoric acid. Fluxes PV209, PV209X, PV284X can be used for soldering copper and its alloys, stainless and structural steels.

Soldering of copper and its alloys can be done with pure borax, which is a universal flux for high temperature soldering.

Various forms of flux release are used - liquids, powder, pieces (borax crystals, for example). To facilitate their dosing (an excess of flux is as undesirable as a deficiency), they are combined with solder. This is done in different ways - by adding powder to loose solder forms, by coating solder rods or by placing solder tubes inside, by joint pressing of tablet forms.

Brazing Technology

In the above example, parts of a wrench are selected as parts to be soldered. As a solder - a material that is a rod coated with flux. A highly active flux suitable for stainless steels is also required. The heating tool is a gas burner.

Soldering is performed in this sequence. The butt parts of the parts are cleaned mechanically. The operation is necessary to remove the persistent oxide film that covers stainless steels.

Parts are clamped in a vice in the required position.

The soldering area is smeared with flux.

The burner is ignited and the required combustion mode is set. The flame should be reducing, with a slight lack of oxygen (but not to the point of soot and yellow fire). The flame supersaturated with oxygen oxidizes the surface of the metal.

The soldered zone is heated until the part begins to change color (when touched, the flux on the bar should begin to melt). You need to warm up the entire connection, moving the flame in different directions.

The joint is fluxed with flux from the rod - by rubbing the latter over the joint. If an unfluxed rod is used, after the tip has warmed up, it must be dipped in flux to coat it.

Brass is used to make taps, hardware, pipes, decorative interior items and many other products. This material is obtained by alloying copper, zinc (in different proportions) and various additives.

Soldering brass provides a reliable and high-quality connection of parts. Soldering involves the use of a special tool in the form of a gas burner, as well as solder from a mixture of tin and lead. In some cases, in the manufacture of hard solder for brass, one tin is used.

If you have the necessary tools and materials, as well as after learning the basic methods of handling brass, you can do the soldering of this material yourself.

Soldering brass products has several features. This technology involves the use of a specially prepared solder, which is introduced into the gap between the parts and plays the role of a "grasping" element. In addition, the equipment by which the solder material is melted is essential.

Usually, a gas torch is used for soldering, providing a melt of solder wire at temperatures lower than the melting point of the brass itself. Using this technology, it is possible to reliably solder individual workpieces of similar in structure or dissimilar materials.

In some cases, the use of brass soldering is the only possible way to obtain one-piece contacts.

It is unacceptable to compare brazing with welding procedures in which each of the alloyed metals is subject to melt. In this case, only hard solder with tin is subjected to thermal impact, and the state of the parts to be joined remains unchanged.

This feature allows you to process brass products of a very small size and mass without causing any damage to them.

When carrying out soldering, it must be taken into account that this process involves the use of softer consumables than when welding consumables. As a result, the joints obtained by soldering are considered to be less durable compared to welds.

In cases of working with brass, zinc completely evaporates from the body of the solder (due to its strong heating), as a result of which the seam becomes porous, which significantly reduces the quality of the joint formed.

In addition, when brazing brass parts, it is important to choose their relative position correctly (in this case, overlap joints are preferred).

Application

Modern technologies for processing copper and zinc alloys are widely demanded in such industries as:

electronics and electrical engineering;
instrument making and tool production;
production of refrigeration and ventilation equipment.

If you have everything you need (solder of the required quality, flux and soldering torch), you can tin brass surfaces in order to protect them from corrosive destruction. The tinning procedure is also in demand in the repair of heating and plumbing systems made on the basis of brass.

Depending on the type of solder used for soldering, the joints are divided into high and low temperature. This division allows the use of more refractory joints for soldering workpieces operated at high temperatures.

Use is not possible at home, as this situation requires special equipment.

Features of soldering homogeneous workpieces

In domestic conditions, there is often a need to solder two brass blanks of the same structure. In this case, the correct choice of the flux composition, which differs from the traditional combination of rosin with alcohol, is of paramount importance.

The usual composition, due to the low activity of the components, will not be able to dissolve the oxide film formed on the surface of the brass. So for the soldering option under consideration, a more active flux, prepared on the basis of chlorine and zinc, will be required.

All the details of its preparation can be found in the table, which shows several varieties of zinc chloride mixtures.

In addition to the types of flux considered, when soldering brass, compositions based on borax and potassium fluoride-boron salt can be used. The mixtures prepared from them occupy no more than 5% of the total volume of the solder bath and have excellent activity indicators.

Activity refers to the ability to create ideal conditions for the penetration of molten solder into the gaps between parts during soldering.

Along with the considered problem, one should not forget about a competent approach to the choice of solder coming to the junction in the form of a calibrated wire of one composition or another.

In the case when brazed brass products are supposed to be used in a gaseous environment, it is desirable to use special types of solders made on the basis of copper phosphate and silver alloys. They are also suitable for brazing red brass with a high percentage of copper content.

Sometimes a wire made from brass itself is used as solder. However, in this case, it is possible to solder a brass part only if the melting temperature of the brass wire is lower than the same indicator for the workpieces being processed.

General procedure

Before you start self-soldering brass parts, you should carefully clean them from extraneous deposits and contaminants. Next, you need to place them on a fire-resistant substrate, the function of which can be performed by river pebbles poured into an old bucket.

The general procedure for soldering brass can be represented as follows.

During the soldering process, overheating of the workpieces is unacceptable, which can cause their deformation. In general, independent soldering of brass is not something absolutely inaccessible.

To master this technology, it is enough to correctly select all the necessary consumables and follow the recommendations given exactly.

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 rather 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.