Solder and flux for brass. Features of soldering brass at home: solder and equipment. Features of soldering homogeneous workpieces
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 joined parts themselves 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.
When repairing them, the owners have to resort to soldering technology. Since this method of joining metals has specific features, beginners may experience difficulties in the course of work. Therefore, they are interested in how to solder brass. If you know the technology and follow the recommendations of specialists, everyone can handle this procedure. You will find information on how to solder brass at home in this article.
About the composition of alloys
In everyday life there are many different parts containing brass and bronze. Despite the outward similarity of these copper alloys, they have different compositions. Brass is in which tin, aluminum and other metals are added during production. Bronze is a combination of tin, aluminum, lead and other substances with copper. The composition of brass with the addition of tin is close to bronze, but zinc predominates in the base of the metal.
What are the features of using copper alloys
Many beginners ask the question of how to solder bronze and brass. Interest is due to the fact that soldering is associated with some difficulties. During thermal exposure, active evaporation from the zinc alloy occurs, resulting in the formation of a dense film of zinc and copper oxides. It's pretty hard to destroy it. According to experts, rosin will not cope with this task either.
The master will have to use special fluxes. If tin-lead solder is used, there is a risk that the joint will have low mechanical strength. Unlike copper soldering, in this case, the strength indicator will be one and a half times lower. The reason for this is evaporating zinc. The choice of method for soldering bronze parts will depend on its composition. Bronze with a high content of tin and nickel should be soldered using tin-lead solders. Bronze containing aluminum and beryllium is best joined with special solders and fluxes.
About fluxes
Their task is to remove the formed film from the surface of the joined metals and prevent its further appearance. According to experts, rosin is suitable for soldering copper products. The situation is different with brass. How to solder this alloy? What flux to choose? These questions are often asked by beginners. Experienced craftsmen advise using a more "aggressive" flux than rosin. Since metals are used as additives in the production of brass, fluxes with different compositions should be taken for soldering. Flux containing zinc chloride and boric acid is designed to work with the most common brands of brass L63 and LS59. For LKS80 with lead and silicon, the best option would be a borax-based flux containing boron, potassium and fluorine. On the shelves of specialized stores there are ready-made compositions. Experts recommend paying attention to fluxes PV-209, PV-209X and Bura. Anyone who wants to save money can prepare the flux at home.
About artisanal flux
According to numerous consumer reviews, this composition can work with different brands of brass. Cooking a flux is not very difficult. You need to take 20 g of borax powder and mix with boric acid, which will also require no more than 20 g. The dry composition of the substance is thoroughly mixed. Then the mixture must be filled with water (200 ml). Before use, the mixture should be boiled and cooled.
About solder
With the help of this molten metal soldering is carried out. In a liquid state, it penetrates into the soldered metals, and then cools down, as a result of which the connection occurs. The melting point of the solder must necessarily be lower than the melting point of the metals themselves. For those who are interested in whether it is possible to solder brass with tin, experienced craftsmen recommend using solder with good adhesion. Conventional alloys containing tin and lead are best used in cases where high mechanical strength is not required. Also, solder is suitable when the appearance of the junction is not important.
About solder compositions
The choice of solder depends on the brand of brass. PSR12-PSr72, brass PMTs36-PMTs54 and copper-phosphorus are recommended for brass with a predominance of copper in its composition. If there is more zinc in the metal, then you need to work with silver solders from PSr40 not lower. With phosphorus compounds, fragile phosphorus zinc compounds are formed, which reduces the mechanical strength of the solder joint. For parts that are not subjected to shock and vibration during their operation, MOC brass solders are suitable. Note that brass can dissolve easily, so crafters using silver and phosphorus solders should reduce the heating and soldering time.
To work with permanently fixed parts (radiators and pipes), experienced craftsmen recommend using special hard solders with complex compositions. According to numerous consumer reviews, L-CuP6, which melts at a temperature of 730 degrees, is very popular. You can also prepare solder at home.
How to do it
For soldering brass, it is best to use silver solder. It is desirable that the place of melting be a special crucible adapted for significant thermal effects. As a material for crucibles, contact carbon elements for a trolleybus can be used. In a heated state, they are of no value, and a home craftsman can adapt them for making solder. In this product, a recess of 20 x 20 mm should be made. Next, a groove should be made to it. It will be easier to remove the solder if its width is 0.5 cm.
Solder is made from silver and copper (2:1). After taking the required amount of metals, they should be placed in a crucible. Their heat treatment is carried out by a gas burner. Some craftsmen pre-crush consumables. In this case, the melting procedure is much simpler. Next, a steel or ceramic (porcelain) rod is added to the composition. Brass can be soldered when the handicraft solder has completely hardened.
How to solder with a gas torch
How to solder brass? The procedure is as follows:
- Before starting the process, you need to heat the metals. This work is carried out on heat-resistant materials. Experts advise using an asbestos plate.
- The parts to be soldered must be aligned with each other.
- Thoroughly wipe the surfaces at the place of soldering with flux.
- Make a cut of silver solder. Ultimately, it should be a shaving, which should be poured into the junction of the metals.
- Adjust the flame on the gas burner. To seize the solder with metal surfaces, the junction is first warmed up with a weak fire.
- Set the gas burner to 750 degrees for the main heating. A red tint should form on the brass surface. Solder fills all the gaps, then it spreads over the entire junction.
- Turn off the burner and allow the product to cool down. The procedure is considered to be performed correctly if a seam is obtained that differs little from metal.
- Rinse the joint to remove residual flux.
How to solder brass with a soldering iron
This method is the most common because it is the easiest to perform. For those who do not know how to solder brass with a soldering iron at home, experts recommend adhering to the following algorithm of actions:
- At the very beginning, you need to clean the connected parts. On metal surfaces there should be no various extraneous layers and contamination.
- Place the parts on a special refractory stand. You can make it at home from improvised means.
- To remove all defects in the brass surface, treat the joint with flux.
- Sprinkle crumbs on top.
- Perform heating with a soldering iron.
Very often, beginners ask the question of how to solder copper with brass with hard solder. Experts advise using low-temperature soldering, which is able to provide a high-quality connection. For this purpose, you will need a soldering iron, the power of which is not more than 100 W, and phosphoric acid. Before work, the surface of the product is thoroughly degreased, the oxide film is removed from it. It is better to join metals using POS60 tin-lead solder. To start soldering brass, the tool should be warmed up well.
To work with silver solders, you will need a soldering iron, the power of which varies from 0.5 to 1 kW. Degreasing is carried out by flux - concentrated phosphoric acid. Borax-based flux is also considered quite effective. In the soldering zone, a temperature of at least 500 degrees is formed.
Works with stainless steel
According to numerous reviews, home craftsmen often have to solder stainless steel with brass. Since the presence of nickel and chromium in the compositions of steel alloys does not exceed 25%, working with such materials is less laborious. In addition, this composition provides a reliable connection of stainless steel parts with other metals.
The exceptions are magnesium and aluminum. If a stainless steel with a significant nickel content, then as a result of its heating to 700 degrees, the formation of carbide compounds occurs. The longer the heating, the more intense they are formed. For this reason, soldering should be done as quickly as possible. The risk of formation of these compounds will be minimal if titanium is added to the alloy during soldering. According to experienced craftsmen, you should be especially careful with riveted stainless steel. This is due to the fact that cracks may appear on the surface of the metal. To prevent their formation, soldering is performed after preliminary annealing of the parts.
Working process
Soldering stainless steel is performed as follows:
- First, the surface is carefully cleaned with sandpaper or a file.
- Next, the place of soldering is treated with a flux, namely soldering acid.
- Then the surfaces need to be tinned - apply a thin layer of solder containing tin and lead to them. It happens that it is not possible to apply solder the first time. In this case, you will have to use a brush containing metal veins. They will be much more convenient to remove the oxide film that prevents tinning.
- Using a soldering iron and solder, solder the parts.
Finally
The soldering process may seem complicated only at first glance. There will be no problems if you master the technology and work with well-chosen consumables.
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.
The method of strong soldering of products from various metals is carried out by heating the parts to be soldered with a gas burner and using brass as a solder. With the mass distribution of copper car radiators, soldering with brass was the only reliable way to fix a leak. Such soldering is widely used in the manufacture and repair of household and industrial equipment, air conditioners. In addition, brass soldering allows you to securely fasten refractory cutting parts to the body of the cutter or drill string. Soldering with brass allows you to assemble small hand-forged art products (chandeliers, fireplace grates, etc.).
Materials and tools
Soldering with brass is carried out using three main components: a gas burner that gives a temperature of at least 1000 degrees.
Brass solder (in the form of wire or tape).
And flux - sodium tetraborate or borax, mixed with boric acid powder.
Modern household gas burners use purified propane, sold in mini cylinders, or special mixtures of gases. More complex burners with separate gas and oxygen supply speed up heating and the entire soldering process.
The need for this flux is due to the zinc content in brass. Zinc, when melting brass wire without borax, causes the solder to boil, which affects the quality of the seam and its strength properties.
In addition to the main components, we need auxiliary tools:
- sandpaper and files for cleaning parts;
- various vise and clamps;
- holding hand tools (pliers, long nose pliers, etc.);
- liquids for degreasing and washing and removing scale from finished seams (acid solutions);
- refractory gloves and other personal protective equipment used in welding.
Brass soldering process
It is necessary to prepare the parts to be soldered. Let's say we need to make a small frame structure from thin-walled steel tubes with a diameter of about 5 mm. When soldering two tubes of small diameter end-to-end, you need to make a notch at the end of the tube to be soldered. This will increase the strength of the connection. The parts must be placed in the clamping devices and the connections pressed together. This is a necessary condition for performing high-quality soldering with brass solder, since the hands will be busy with the torch and solder supply.
We light the gas burner and begin to heat up the place of soldering until a red color appears.
We also heat the brass wire (solder) and lower the heated end of the solder into the borax. Borax sticks to the solder wire.
We briefly move the flame of the burner aside and apply the flux directly to the junction of the steel pipes. Borax quickly melts and covers the entire soldering area. If you do not remove the flame, then the borax will simply be blown off the brass wire.
After that, soldering begins - the slow melting of brass solder, its manual supply and filling the joint between the parts with it.
During the work, visual control over the quality of the seam is carried out. If a fistula is found in the lower part or an area not covered by solder. It is better to turn the part over and solder this place again.
After stuffing the hand, you can also solder the "ceiling" joints. Soldered parts must cool in the air.
Then you need to remove the scale by placing the part in a solution of edible citric acid.
To check the quality of the seam, bend the product.
Very durable!
Precautionary measures
Soldering with brass refers to open fire work. All fire protection measures must be strictly observed. In addition, work with zinc vapor can cause severe poisoning of the body. Protective measures must be taken. Mini gas cylinders can have valve leaks, causing explosions and fires. It is necessary to constantly monitor the operation of the gas burner.It can be quite simply done at home, although many craftsmen do not dare to do such work, being afraid of certain difficulties that may arise in the process of its implementation.
Meanwhile, the brass soldering technique is quite simple and does not require any special training.
Most often, brass soldering is performed with an ordinary gas burner, and for these purposes, tin, brown or other similar material can be used as solder, which can replace traditional flux.
It should be noted that this work can also be done with a special graphite electrode or a soldering iron, using the appropriate solder.
At its core, the soldering of this material is somewhat reminiscent of the soldering of steel, copper or cast iron, however, it has some features and subtleties that must be taken into account without fail.
It should be noted that brass parts are easier to machine than steel, copper or cast iron parts.
A feature of soldering brass, cast iron or copper at home, unlike steel, is that an oxide film forms on their surface, which affects the quality of the connection being made.
Despite this, at home, with the right approach to business, it is possible to solder brass blanks with a drill, as well as copper parts, not only with a gas burner, but also with a soldering iron, unlike cast iron or steel, which are welded exclusively with an electrode.
Soldering, in its essence, is the most optimal way to obtain a sufficiently strong and permanent connection, both for parts made of brass and blanks made of other materials, including cast iron. Welding with a graphite electrode, in turn, requires certain skills and training.
When making a connection between the elements, molten solder is necessarily introduced, and for this you can use tin or borax.
The solder should have a melting point slightly below the melting point of the base material.
With the help of soldering, a variety of materials can be firmly connected to each other, including parts made of cast iron or copper.
Very often this is the only way to bond metal surfaces of various types.
Of course, soldering in some way can be compared in a certain way with welding, when the surfaces are joined by an electrode, but in this case only the final result is common.
The essence of the soldering process itself is completely different.
The main difference between welding and soldering is that when connecting surfaces with an electrode, the base material melts, while when working with a soldering iron, only the bond metal melts.
In addition, a flux must be present in the soldering, which can be a borax.
Of course, soldering provides a less durable connection of aluminum, copper or cast iron surfaces than, for example, welding, but it allows you to work even with small workpieces.
This can be explained by the fact that the flux used in soldering, which can be a drill, under the influence of relatively high temperatures, releases certain chemical elements, which reduce the strength of the main joint, in addition, the seam itself turns out to be porous.
Soldering aluminum, like, for example, welding cast iron, is best done with an overlap rather than a butt.
Despite the fact that soldering is somewhat inferior to electrode welding in terms of joint strength, it is currently actively used in various industries.
With the help of it, the necessary fastening is carried out not only of brass blanks, but also of copper and even cast iron products.
Most often, various types of metals are soldered with a soldering iron, but if necessary, a gas burner can also be used for these purposes.
To perform soldering, including brass blanks, solder or flux is required without fail, which very often acts as a drill.
It should be noted that welding can be both high-temperature and low-temperature. At home, the first soldering option is used.
In the video above, you can see how brass blanks are soldered.
Material characteristics
In general, brass is an alloy of copper and zinc. Especially often it is used for the production of various household utensils, pipes, radiators and many other devices.
The home craftsman very often has to deal with the need to carry out the appropriate surface treatment of brass, and therefore it is necessary to know all the features of this specific metal.
To perform soldering of a brass surface, it is very important to choose the right flux, and in this case, a drill is best suited, which can effectively remove the formed oxide film from the surface.
You can buy this flux, the role of which is played by the drill, in almost any hardware store at an affordable cost. The borax-based flux allows for better flow of the main binding component into the formed gaps.
Also with special care should be selected and solder for brass.
So, if this work will be performed in a gaseous environment, then in this case it is best to use silver or copper-phosphorus solders.
Such solder is also excellent for working with brass, which has a high copper content. In this case, you can use a solder based on brass itself with a lower melting point.
With special care and caution, solder and flux should be selected when it is necessary to connect parts from completely different materials.
So, for example, the quality of soldering brass and copper directly depends largely on the type of solder that will be used, as well as flux (borax).
It is these components that mainly affect the quality of the weld and its porosity.
When soldering brass in a gas environment at home, it is recommended to use a specific flux, which in some cases can be replaced with a thin layer of materials such as nickel or copper.
This will avoid the release of zinc contained there from the brass surface, respectively, and the connection itself will turn out to be more durable and of high quality.
Currently, you can buy solders, which in their composition contain elements that replace ordinary flux.
This makes it possible to significantly simplify the work, make it better and faster.
Copper-phosphorus composition can act as such a universal solder.
Operating procedure
After all the properties of the materials used in the process of soldering brass are analyzed and studied in detail, you can proceed directly to the process itself.
First you need to prepare all the required tools and material. A gas torch or soldering iron should be on hand, as well as the appropriate solder and flux.
These materials should be selected as carefully as possible, so that in the end the seam is of the highest quality and dense.
In some cases, solder for brass can be prepared independently and for this it will be necessary to take copper and technical silver in certain proportions, melt them in a special crucible and mix thoroughly.
When the molten mixture becomes completely homogeneous, the container with it will need to be placed in cold water until it cools completely.
When preparing solder with your own hands, special attention should be paid to the uniformity of its structure, since the quality and strength of the future connection will largely depend on this.
In this case, you should not save on consumables and opt for cheaper and lower quality components.
In turn, soldering flux is prepared from borax and boric acid, which can also be freely purchased at any hardware store.
These components are taken in equal proportions and filled with ordinary water.
After all the necessary components are ready for soldering brass, you can proceed directly to the work itself.
For this, a brass billet is taken, previously cleaned of dirt and various oil stains, and gently sprinkled with crushed solder.
After that, a gas burner is activated, with the help of which the working surfaces are heated to a certain temperature.
The main thing here is not to overheat the brass part so that it does not burst and deform.
If the brass surfaces are thick, then they must be warmed up gradually.
For more information on how to solder brass without assistance at home, see the video in our article in detail.