Soldering copper to brass with hard solder. Proper soldering of brass at home. What are the features of using copper alloys?
Method of strong soldering of products from various metals carried out by heating the parts being soldered gas burner and the use of brass as solder. With the widespread use of copper car radiators, soldering with brass was the only reliable way to eliminate leaks. This type of 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 a cutter or drill string. Soldering with brass allows you to assemble small art products hand forged(chandeliers, fireplace grates, etc.).
Materials and tools
Soldering with brass is carried out using three main components: a gas burner, giving a temperature of at least 1000 degrees.
Brass solder (in the form of wire or tape).
And flux - sodium tetraborate or borax, mixed with powder boric acid.
Modern household gas burners use purified propane, sold in mini cylinders, or special mixtures gases More complex torches with separate gas and oxygen supplies speed up heating and the entire soldering process.
The need for this flux is determined by the zinc content of 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 will need auxiliary tools:
- sandpaper and files for cleaning parts;
- various vices and clamps;
- holding hand tool(pliers, long-nose pliers, etc.);
- liquids for degreasing and washing and removing scale from finished seams (acid solutions);
- fireproof gloves and others individual means protection used during welding work.
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 approximately 5 mm. When soldering two small-diameter tubes end-to-end, you need to make a notch in the end of the soldered tube. This will increase the strength of the connection. Details must be placed in clamping devices and press the joints together. This necessary condition perform high-quality soldering with brass solder, since your hands will be busy with the torch and the supply of solder.
We light the gas burner and begin to heat the soldering area 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 burner flame back and apply flux directly to the junction of the steel tubes. Borax melts quickly and covers the entire soldering area. If you do not remove the flame, the borax will simply blow away from the brass wire.
After this, soldering begins - slow melting brass solder, manually feeding it and filling the joint between the parts.
During work, visual control of the quality of the seam is carried out. If a fistula or an area not covered by solder is found in the lower part. It is better to turn the part over and solder this place again.
After filling the hands, you can solder the “ceiling” joints. The soldered parts must be allowed to cool in air.
Then you need to remove scale by placing the part in a solution of food grade citric acid.
To check the quality of the seam, we bend the product.
Very durable!
Precautions
Soldering with brass is an open hot work. Strict compliance with all measures is necessary fire protection. In addition, working with zinc vapor can cause severe poisoning of the body. Protective measures must be taken. Mini gas cylinders may have leaks in the valve, which leads to explosions and fires. Constant monitoring of the operation of the gas burner is necessary.You can solder brass not only in industrial production, but also at home. In this way you can make a wide variety of things (various decorations and technical devices). In this case, it is necessary to use soldering, connect wires and metal parts. And here it is precisely necessary to be able to solder brass correctly.
To effectively and reliably solder brass at home, you must use a gas torch.
In order for such a process to be completed with maximum efficiency, the following is required:
- Gas burner.
- Silver.
- Graphite crucible.
- Copper.
- Boric acid.
- Asbestos base.
- Bronze may be used.
How is the soldering process carried out on a material such as brass?
For effective soldering of brass, ordinary tin soldering is not suitable. The fact is that such soldering in most cases leaves a fairly noticeable mark. And such an indicator as strength is not up to par here. For soldering brass, it is most advisable to use a different method, which is characterized by increased reliability. To effectively and reliably solder brass parts, you must use a gas torch.
For brass solder, one part copper and two parts silver should be used, all thoroughly mixed and fused together by means of a gas torch in a graphite crucible. The crucible must be lowered into cold water, after which the solder is removed, which is already melted and frozen. After this, it must be flattened, then solder shavings are cut or sharpened; in this regard, it is advisable to use a large file.
Now you need to take 20 g of borax powder and the same amount of boric acid; flux is made from all this. After this, the resulting powder mixture should be filled with 250 ml of water.
Brass parts that need to be soldered should be carefully placed on a base made of asbestos. Now this entire connection of parts should be sprinkled with pieces of solder, which must first be sharpened. And after that, it was time to carefully heat the connection with a gas burner. All this work must be done with the utmost care.
When you solder parts, you need to gradually increase the heating temperature to a certain level. The maximum level that can be tolerated is 700 degrees. You need to clearly know that brass should under no circumstances be overheated, otherwise all parts may be hopelessly damaged. If there is a need to solder large and massive parts, then they must be heated gradually, otherwise the consequences can be very negative.
If small and thin parts are soldered, then you need to be very careful, since they heat up quite quickly.
We must not forget that this soldering method is no different in simplicity when compared with conventional tin soldering. But the time is undoubtedly not wasted: this soldering method is characterized by an increased degree of reliability and strength when connecting to brass parts.
We must not forget that brass soldering has some peculiarities due to the evaporation of hot zinc. In addition, an oxide film forms on the metal surface. We must not forget that you can start mixing the components of tinol using wire only after the silver and copper are completely melted.
As for the graphite crucible, it can be easily made from graphite coals. There is no need to buy such material in a store, since it can be easily found at electric transport stops. As for its size, it should be approximately 20 by 20 millimeters. Doing this yourself is not at all difficult, and the workflow is greatly simplified.
- It is recommended to carry out soldering on some heat-resistant material.
- The resulting seam must have an identical, pronounced color to the parts being soldered.
- At the end of the work process, it is necessary to thoroughly rinse the products from flux. Washing is best done in hot sulfuric acid (it should be 3 percent).
If everything is done in this way, then there is no doubt that the results will be the most positive. And there is no need to resort to the services of specialists, who are sometimes very expensive. Everything can be done independently and in short terms. After this, you can even give master classes to your friends and acquaintances; they will be very grateful for the useful lessons.
Soldering brass, which allows you to obtain high-quality and reliable connections, is a technological process that involves the use of a gas torch, as well as special solder. The latter is wire, the material of which can be tin or an alloy of this metal with lead. If you thoroughly study the features of such a process, and also prepare everything necessary equipment And consumables, then you can successfully perform it even at home.
Conditions and scope of soldering
Before understanding the question of how to solder brass, you should thoroughly study all the features of such a technological process. When performing soldering, which is one of the methods for producing permanent connections, molten solder is introduced into the gap located between the parts being connected, which acts as a fastening element.
An important condition for soldering is that the solder, which is melted using a gas burner, must melt at a lower temperature than the material used to make the parts being joined. This technology (in some cases it is the only possible way obtaining a permanent connection) allows even dissimilar metals to be reliably soldered together.
It is completely wrong to compare soldering with this technological process, like welding, which assumes that not only the special solder wire will melt, but also the metal of the parts being connected. It is precisely due to the fact that when performing soldering, the solder is exposed to the main temperature effect, the characteristics of the parts being connected and their integrity remain unchanged. This feature makes it possible to successfully use this technique for joining metal parts that are even very small in size.
Meanwhile, it should be borne in mind that to perform soldering, more solder is used. soft materials, when compared with those used to form the weld. This leads to the fact that connections created by soldering are initially less strong and reliable than welded seams. And in cases where brass is soldered, zinc evaporates from the solder during intense heating, which leads to porosity of the formed seam. Such metal porosity significantly impairs the quality and reliability of the connection. When soldering parts made of brass, great value has their mutual arrangement. It is better to connect such parts not end-to-end, but overlapping.
Metal soldering as a technology that makes it possible to obtain permanent connections occupies one of the leading positions, second only to welding in popularity. This technology is practically indispensable in the electronics industry, where it is used to create electrically conductive connections between elements of various instruments and devices. It is with the help of soldering that wires are most often connected and extended, through which electric current will subsequently pass.
If we talk about the most common areas of application of soldering, then these include:
- formation of hermetic connections of pipes made of copper and its alloys, including brass (such pipes are used primarily for completing refrigeration and heat exchange units);
- fastening carbide plates to the load-bearing part cutting tool;
- connection between parts that differ significantly in thickness.
The photo shows the result of soldering brass tube and jet. We used P14 fluxed solder and an imported pure propane burner.
Using soldering equipment and solder, they also perform a technological operation such as tinning, which allows you to create a reliable anti-corrosion coating on metal surfaces.
Depending on the type of solder used for soldering, it can be high- or low-temperature. The use of a more refractory material when performing soldering allows you to create connections that can be used at higher temperatures. high temperatures. However, this is associated with some difficulties, which are associated with the need to turn to special equipment allowing the solder to melt. The use of such an alloy, in particular, is quite problematic at home, where a conventional blowtorch is most often used for soldering.
Features of the technology
Both in industrial and at home conditions, one has to face the need to connect products made of brass by soldering. This is due to the fact that this product is actively used for the production of plumbing and plumbing elements. heating systems, as well as many other products.
Of great importance for obtaining high-quality and reliable connections of brass products using soldering is right choice flux. To successfully carry out this process, ordinary flux, which contains alcohol and rosin, is not suitable. Due to the rather low activity of its constituent components, such a flux is not capable of dissolving the oxide film that is necessarily present on the surface. That is why for soldering brass products it is necessary to use a more active flux, which is often used as zinc chloride.
Quite popular fluxes that are used for soldering brass in salt baths are borax and potassium fluoroborate. Such fluxes, the amount of which in the bath solution, as a rule, does not exceed 5%, ensure good flow of molten solder into the gap between the parts being connected.
The correct choice of solder wire is another important task that must be solved in order to obtain a high-quality connection of brass parts. For soldering brass products that will later be used in a gas environment, you can use popular types of solders based on silver and phosphorus copper alloys. Such solders are also ideal for joining brass products containing a significant amount of copper.
Brass itself is often used as solder, but it is necessary to ensure that the melting temperature of the filler wire does not exceed the same parameter of the parts being connected. In cases where it is necessary to form a connection of increased reliability using soldering, hard solders are used, which, when compared with filler materials soft type, have higher strength.
Particular attention should be paid to the selection of solder and the soldering technology itself in cases where dissimilar materials need to be soldered together. It should be taken into account that such materials have different melting points and can also behave completely differently when heated. In particular, when intensely heated, zinc begins to evaporate from brass, which negatively affects both the decorative and strength characteristics of the joint being formed (it acquires a porous structure).
Certain technological techniques allow you to avoid active evaporation of zinc from the material subjected to heating during the soldering process. The most effective of these techniques is the use of flux, which will perform protective function, preventing the evaporation of zinc from the brass structure. The use of combined solder for soldering, which includes not only filler material, but also flux, is another effective way, which avoids the evaporation of zinc from brass.
By choosing the right solder and soldering technology, you can even connect parts made of such a complex material as stainless steel at home. It should be borne in mind that brass solder is not suitable for this; completely different materials are intended for this.
Brief instructions
In order to perform high-quality brass soldering at home, it is not enough to simply study the theoretical basis; it is also advisable to watch a video on this topic. The need to independently carry out such a process often arises, because almost every home has brass products that are not insured against breakdowns. Considering the fact that the services of qualified specialists are not cheap, it makes sense to study this process using both the recommendations presented below and videos that are easy to find on the Internet.
Brass is an alloy whose essential components 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, developed various technologies allowing welding of brass products. But all of them are quite complex, costly, and require the specialist performing the work to have certain skills. An alternative to welding is often brass soldering. It is somewhat simpler technologically and imposes different requirements on the qualifications of the performer.
Obstacles encountered
If the zinc content in the alloy is low, then no special problems arise. You can cope with the task using ordinary rosin. But in the case when the amount of zinc exceeds 15%, in mandatory requires the use of special fluxes. This is due to the fact that when zinc and copper evaporate when heated, they form a strong oxide film on the surface of the part, which is very difficult to remove.
Choose a ready-made one or make it yourself?
The simplest flux for soldering brass is easy to make yourself. To do this, you will need to mix borax and boric acid powder in a one-to-one ratio, pour the resulting amount with water at the rate of 5 ml for each gram of powder mixture, boil with gentle stirring, and then cool. But best characteristics ready-made formulations available for sale have.
- One of the most common is Borax flux. Invented a long time ago, this recipe has received the approval of many jewelers who solder various metals, including brass. It belongs to the category of high-temperature mixtures, activated when reaching 700 - 900 degrees Celsius. Despite his advanced age, he performs his work efficiently.
- 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 also operate at temperatures approaching a thousand degrees.
- The compositions Chemet FLISIL-NS-Pulver (powdery) and Chemet FLISIL-NS-Paste (paste) produced in Germany will require slightly less heating. For them, 550 - 800 degrees Celsius will be enough. They work best when using silver-containing solders.
The brands listed are provided as an example only. There are many options on the market for these brass soldering essentials.
Which solder should I take?
No less important than the choice of flux is the determination the required composition solder.
- For soldering brass with copper content, PMC-48 solder is well suited, melting at 870 - 880 degrees. PMC-36 has a slightly lower melting point. Both compositions belong to the group of copper-zinc solders.
- Grades 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 further, up to PSr-72. They all have some differences, which are chemical composition and melting temperature. They react differently to percentage copper and tin in the metal being joined.
From the above, it is clear how important it is to decide on the brand of brass before choosing flux and solder. Only then will it be possible to achieve an acceptable soldering result.
Preparation
Before starting work, it is necessary to thoroughly clean the connection area from dirt. To do this, you can use a variety of tools - metal brushes, special attachments, files or sandpaper. After this, the treated metal must be degreased. Without doing this, you will complicate your work, and the soldering, even if it can be done, will not have sufficient strength.
The parts to be soldered must be placed on a thermally insulating pad. It’s strange, but many sources still recommend sheet asbestos, recognized as a carcinogen, for these purposes. There is no doubt that it is worth finding a replacement that is not harmful to health. For example, based on fiberglass or carbon fiber.
Soldering iron or torch?
Usage electric soldering iron it is permissible 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 higher. After all, the soldering area must be well heated beforehand.
It is more convenient to connect massive parts or solder thick brass using a gas torch. In this case, you can heat the metal so that it becomes possible use high temperature components. The connection area is treated with flux and sprinkled with crushed solder on top. Only after this they proceed to heating the metal. This must be done extremely carefully. First, preheating is performed to activate the flux and allow the solder to adhere to the surface. The temperature is gradually increased until the brass acquires its characteristic redness. It is at this moment that the solder spreads, filling all the small pores in order to reliably connect the parts when cooling. If everything is done correctly, then after gradual cooling you will get a neat seam, the color of which will be close to the color of brass.
Scope of application
It is quite obvious that soldering brass is easier than welding, not only at home, but also in production. The resulting connection will have sufficient strength. However, you still shouldn’t count on it to withstand very high loads. Based on this, the scope of application of the technology is determined.
- Manufacturing of electrical and electronic components. Mechanical loads in this case are low, and electrical conductivity comes to the fore. Don't forget how difficult it is to use welding to connect small parts.
- Connection of elements subjected to light and medium loads. This may include parts of small mechanisms such as watches, or components of pipelines operating at a pressure not exceeding several atmospheres.
- Jewelry production. Of course, the cost of brass is much lower than 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.
- Don't forget the restoration work. Sometimes soldering brass is the only way to restore something made many years ago.
This technique has also been used in mechanical engineering. Using it, making a new one 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 analogues.
Brass soldering has own characteristics due to the evaporation of hot zinc, as well as the formation of an oxide film on the metal surface. Brasses containing up to 15% zinc are oxidized by a film, which consists of interlocked particles of CuO and ZnO. In copper alloys containing sufficient large number zinc, the oxide film consists mainly of ZnO, which is much more problematic to remove than in the case of a copper oxide film.
The following tools and materials are useful for soldering:
- Asbestos base;
- Gas burner;
- Graphite crucible;
- Copper, silver, borax, boric acid.
Preparing solder
First you will need to make tinol at home, which will consist of silver and copper in a ratio of 2:1, respectively. To do this, you need to fuse silver and copper using a gas burner. Next, you need to weigh out the required amount of silver and copper, after which they must be placed in a crucible and heated with a gas burner.
A graphite crucible can be produced from graphite coals (contact trolleybus elements), which are not difficult to find at the final stops of electric transport. Regarding the size of the crucible, it should be approximately 20x20 millimeters.
Then we select a 5x40 millimeter semicircular groove to make it easier to remove the solder bead (the hot crucible is lowered into the water). Once the copper and silver are melted, you can begin mixing the tinol components using a wire.
Preparing gumboil
Thus, the solder is ready for use, but it still needs to be cooled, rolled out in a roller, and also cut into small pieces. Now you need to start preparing the flux. To do this, take 20 grams of borax (powder), as well as an equal proportion of boric acid (powder), then thoroughly mix the ingredients and pour a glass of water. Next, boil and cool the finished flux.
We work as follows:
- You need to solder on some heat-resistant material. If you are soldering radiators, do the work thoroughly. For this purpose, we stocked up with asbestos plate. Thus, we place it on non-soldered parts, then moisten it with flux and sprinkle it with solder. Next, we begin to warm it up little by little.
- First, we heat it a little so that the solder adheres to the parts, after which we complete the procedure until a red tint appears.
- The solder quite simply flows into the gap between the parts, soldering them together very tightly. It is worth paying attention to the fact that the difference between the melting point of brass and solder is about 50 degrees. C, and therefore the material should not be overheated.
- The resulting seam has one distinct color with the part being soldered.
- This is followed by washing the product from flux: we wash the product in hot sulfur acid (3%).
Thus, we get excellent adhesion of brass products that will last for many years.
