How to solder brass and aluminum

Rod for soldering aluminum at home / Tools / iXBT Live

Hi all! Many people know that aluminum is soldered mainly in an argon atmosphere with a special welding machine, but there is also an option for working with a gas torch, and even a turbo lighter can be used on a small scale.

In general, this is not my first acquaintance with this wire, but the shopping experience is not very good, so I will share not only the test result, but also trusted places to buy so as not to get sample No. 2 , but let’s start in order.

• Characteristics
• Unboxing and appearance
• Testing
• Results

Characteristics

Diameter: 2.0 mm
Length: 500 mm
Soft solder ISO 3677: ~B-Zn98Al 381-400
Approximate composition (weight%): 2.4 Al – rest Zn
Melting point ºС: 360
Tensile strength (MPa): Up to 100 (Al)
Density (g/cm3): 7.0

Unboxing and appearance

The last and most profitable purchase was sample No. 3 from banggood.

Came in a small gray package

The rod is additionally packaged in a transparent zip bag.

5 meters cost me $8 with points, that is $1.6 per meter - go to the store

White powdery flux is visible in the center, the rod is moderately hard, looks like aluminum without oxidation

Comparison

The first one I bought was the leftmost sample No. 1 from Ali. Its properties are absolutely identical to sample No. 3 , but 3 meters cost me $12 , that is, $4 per meter , which is almost three times more expensive. check current price

In the center is sample No. 2 . It costs $5 for 3 meters or $1.7 per meter , like sample No. 3

But as soon as you take the bag in your hand, you realize that this is a POS with not very thick flux inside.

don't buy here

Two more samples at $8 for 3 meters were never delivered, they were probably not even sent.

Testing

Over time, aluminum becomes covered with an oxide film, due to which the surface becomes dull, so, before soldering, the surfaces must be cleaned to a shine, otherwise the solder will simply roll off in balls on the surface, regardless of the degree of its heating. Sample No. 1

 In general, it is correct to heat the part to a temperature of about 400 degrees, and then simply move the rod, which will melt and fill the cracks, but I have little experience, so in order not to overheat the surface, I periodically bring the rod into the burner flame. If the temperature is low, the solder will roll down the surface like a ball; if it is sufficiently high, it will tin it.

 The fracture test shows a good result - the break does not occur along the seam

Sample No. 2 . It melts very well, emits a lot of smoke, and smells like burnt “aspirin.” It sticks to aluminum, but if you overheat it, it burns out pretty quickly.

It is inconvenient to work due to the stench and the need to control the temperature.

Sample No. 3 . I decided to solder the tubes with the outer walls

We try to break the seam. After the tube came out of the vice, I clamped it higher, bringing it out of focus and only noticed this at the stage of creating GIFs

But there is a photo of the result which shows that the seam was not damaged.

And finally, let’s splice the aluminum tube with a piece of duralumin.

 The tear test was also successful.

Results

An interesting wire - aluminum solders perfectly, filling even small gaps, the main thing is that the joints are not dirty. It also sticks well to copper, but experienced people say that it is better to use other alloys to work with it, although this rod is quite suitable for emergency field repairs.

The melting point of aluminum is about 660ºC, it would seem that you can use rods at 450-500 degrees, but you may encounter two problems:
1. A massive part needs to be heated up to 500 degrees with something else
2. You can overheat the soldering area and ruin the part

Sample No. 3 seemed to me the most optimal .
It corresponds to the declared characteristics and costs at least half as much as the others. There are also lots of different lengths to choose from: 1 meter - $2.89
2 meters - $4.39
3 meters - $6.39
5 meters - $9.89

go to the store

Source: https://www.ixbt.com/live/instruments/prutok-dlya-payki-alyuminiya-v-domashnih-usloviyah.html

Soldering duralumin at home - Metalworker's Guide

There is a widespread belief that it is impossible to solder or tin aluminum (as well as alloys based on it) without special equipment for this.

Two factors are cited as an argument:

1. upon contact with air, a chemically resistant and refractory oxide film (AL2O3) is formed on the surface of the aluminum part, resulting in an obstacle to the tinning process;
2. The soldering process is significantly complicated by the fact that aluminum melts at a temperature of 660°C (for alloys this ranges from 500 to 640°C). In addition, the metal loses strength when, during the heating process, its temperature rises to 300°C (for alloys up to 250°C), which can cause a violation of the stability of aluminum structures.

Considering the above factors, it is truly impossible to solder aluminum using conventional means. The use of strong fluxes in combination with the use of special solders will help solve the problem. Let us consider these materials in detail.

Solder

Commonly used low-melting solder bases are tin (Sn), lead (Pb), cadmium (Cd), bismuth (Bi) and zinc (Zn). The problem is that aluminum is practically insoluble in these metals (with the exception of zinc), which makes the connection unreliable.

By using a flux with high activity and properly treating the joints, you can use tin-lead solder, but it is better to avoid such a solution. Moreover, a solder joint based on the Sn-Pb system has low corrosion resistance. Applying a paint coating to the soldering area allows you to get rid of this drawback.

For soldering aluminum parts, it is advisable to use solder based on silicon, copper, aluminum, silver or zinc. For example 34A, which consists of aluminum (66%), copper (28%) and silicon (6%), or the more common TsOP-40 (Sn - 60%, Zn - 40%).

Domestic solder – TsOP-40

Note that the higher the percentage of zinc in the solder, the stronger the connection and the higher its resistance to corrosion.

High-temperature solder is considered to be solder consisting of metals such as copper, silicon and aluminum. For example, like the above-mentioned domestic solder 34A, or its foreign analogue “Aluminium-13”, which contains 87% aluminum and 13% silicon, which allows soldering at temperatures from 590 to 600°C.

"Aluminum-13" produced by Chemet

Flux

When choosing a flux, it is necessary to take into account that not all of them can be active towards aluminum. We can recommend using products from a domestic manufacturer for such purposes - F-59A, F-61A, F-64, they consist of ammonium fluoroborates with the addition of triethanolamine. As a rule, the bottle is marked “for aluminum” or “for aluminum soldering.”

Domestic flux

For high-temperature soldering, you should purchase flux produced under the brand 34A. It consists of potassium chloride (50%), lithium chloride (32%), sodium fluoride (10%) and zinc chloride (8%). This composition is most optimal if high-temperature soldering is performed.

Recommended flux for packing at high temperatures

Surface preparation

Before you begin tinning, you must complete the following steps:

• degrease the surface using acetone, gasoline or any other solvent;
• remove the oxide film from the place where soldering will be performed. For cleaning, use sandpaper, an abrasive wheel or a brush with steel wire bristles. As an alternative, etching can be used, but this procedure is not so common due to its specificity.

It should be taken into account that it will not be possible to completely remove the oxide film, since a new formation will immediately appear in the cleaned area. Therefore, stripping is carried out not with the goal of completely removing the film, but to reduce its thickness in order to simplify the task of the flux.

Heating the soldering area

To solder small parts, you can use a soldering iron with a power of at least 100W. Massive items will require a more powerful heating tool.

Soldering iron 300 Watt

The best option for heating is to use a gas burner or blowtorch.

Simple gas burner

When using a burner as a heating tool, the following nuances should be taken into account:

• Do not overheat the base metal, as it may melt. Therefore, it is necessary to regularly monitor the temperature during the process. This can be done by touching the solder to the heated element. Melting the solder will let you know that the required temperature has been reached;
• Oxygen should not be used to enrich the gas mixture, since it promotes strong oxidation of the metal surface.

Soldering instructions

The process of soldering aluminum parts does not have its own distinctive features; it is carried out in the same way as with steel or copper.

The algorithm of actions is as follows:

• the soldering area is degreased and cleaned;
• the parts are fixed in the desired position;
• the connection area heats up;
• touch the solder rod (containing active flux) to the joint. If flux-free solder is used, then flux is applied to destroy the oxide film, after which a solid piece of solder is rubbed over the soldering area.

A brush with steel wire bristles is also used to break down the aluminum oxide film. This simple tool is used to rub molten solder over an aluminum surface.

Soldering aluminum - complete video instructions

Source: https://ssk2121.com/payka-dyuralyuminiya-v-domashnih-usloviyah/

Soldering brass at home step by step instructions

Brass parts, unlike steel, are easy to process, and it is this useful quality of the alloy that makes it possible to solder brass at home, without resorting to industrial methods. To create a wide variety of things, soldering is required - connecting wires and metal parts. To properly solder brass, you must have a gas torch, a graphite crucible, an asbestos base, as well as silver, copper and boric acid.

Soldering brass is much easier than soldering steel, which allows it to be done at home.

Preparation for soldering brass products

To clean the alloy, you can use oxalic acid. If you don’t have it at hand, you can look at various household products. They are applied to brass products, after which it will begin to darken quite quickly. Then you can get rid of the deposits by taking a thin brush and cleaning the parts in plain water.

After this, you will need soda, which is poured into the brass product. After a few minutes, the soda is washed off. If oxalic acid is present, it is diluted in proportions of 20 grams per liter of hot or cold water. It is not recommended to breathe over the solution, and you should also protect your hands with gloves. The container must be plastic to avoid exposure to other metals.

Once the brass part has been processed, it should be wiped down and dried.

Oxalic acid is used to clean the alloy.

To solder brass most effectively, you should not use regular tin soldering, since its use leaves quite noticeable marks. In addition, it cannot boast of great strength. In order to solder brass, it is recommended to use another method that provides increased reliability.

Effective and reliable soldering of brass parts is ensured by the use of a gas torch. To make solder from brass, you should take copper and silver in proportions of 1:2, mix thoroughly and fuse together using a graphite crucible and a gas torch.

The crucible is placed in a container with cold water, and only after this is it possible to remove the molten and solidified solder. It must be flattened and cut or ground into shavings, which can be done with a large file. After this, you will need borax powder and boric acid, each ingredient should weigh 20 grams.

Based on these substances, flux is produced. The resulting powder mixture is poured with a quarter liter of water.

Solders for soldering brass parts

Soldering with a gas torch must be done extremely carefully, at a maximum temperature of 700 degrees.

Brass parts that require soldering are placed on an asbestos base. The connected parts are sprinkled with solder, cut into small pieces and pre-sharpened. The joint is then gently heated using a gas torch. This work must be done as carefully as possible. When soldering parts, the temperature should gradually approach a certain level.

The maximum permissible level is 700 degrees, but if you exceed it, you may encounter hopeless damage to all parts. When it is necessary to solder large and massive parts, their heating should be gradual in order to avoid negative consequences. When soldering small and thin parts, the heating process occurs in a very short time, so it is important to be careful about it.

Of course, conventional soldering with tin is much simpler than a similar method, but it is thanks to it that the reliability and strength of the soldering of brass parts will be much higher. It is important to remember some features of brass soldering, such as the evaporation of zinc when it is very hot. In addition, the surface of the alloy is covered with an oxide film.

Brass, which contains less than 15% zinc, is oxidized and becomes coated with a film containing interlocking particles of copper oxide and zinc oxide. Copper alloys, which contain much larger quantities of zinc, oxidize to form a film consisting mainly of zinc oxide.

The problem with such alloys is that copper oxide is removed more easily and quickly than zinc oxide.

The finished product is washed with hot 3% sulfuric acid.

If conventional low-temperature soldering is carried out using solder containing lead and tin or other tinols, the oxide film must be removed from the metal surfaces. Here it is possible to use rosin-alcohol or more active fluxes.

To process brass with a high zinc content, for example, L63, it is necessary to use a flux that contains zinc chloride. It is important to remember that brass has some of the worst melting properties with tin-lead solders. This feature leads to the fact that intermetallic layers slowly begin to grow during the soldering process.

They have a positive effect on the weld, and an improvement in the mechanical properties of metals can be expected.

You should not hope that soldering, which uses tin-lead solders of L63 brass, will lead to high-quality connections. Their adhesive strength and quality will be inferior to copper if the conditions are the same.

The tensile strength indicator for copper parts soldered with tin will reach 90 MPa, and for brass parts it will not reach 60 MPa. Soldering of brass parts, which contain a high copper content, can be carried out using PSR 72, 45, 25 and 12 solders.

Sometimes in such cases it is permissible to use copper-phosphorus brass or a brass alloy that melts at a low temperature. This is mainly applicable to gas soldering.

With a high level of zinc, it is possible to use PSR 40 solder. The use of phosphorous solders is completely unsuitable, because there is a high probability of developing a solder joint that has low ductility.

This is explained by the formation of zinc phosphides, which are distinguished by their fragility. Hard solder is also very common, used when joining large products, for example, for working with brass and copper pipes and heating systems in general.

The advantage of hard solders is the high strength of the resulting joints.

Additional recommendations

It is recommended to mix solder paste components using wire only after the silver and copper have completely melted.

https://www.youtube.com/watch?v=qTDDAng7shE

You can create a graphite crucible yourself using graphite coals. The fact is that graphite coals are used as contact elements in trolleybuses, and they are quite easy to find: the final stops of electric transport are suitable for this. The dimensions of the crucible are quite small - 2x2 cm. Creating it manually is quite easy, and this will significantly simplify the work process.

Source: https://MyTooling.ru/instrumenty/pajka-latuni-v-domashnih-uslovijah-poshagovaja

How to attach a gas burner to a cylinder?

Both among people who carry out repairs professionally and among home craftsmen, a manual gas burner with a cylinder is very popular. The scope of their application is very wide, there are several varieties. This article tells you how to choose the right gas burner for a cylinder and learn how to use this device, which is not the most intricate design, but extremely useful in many cases when a room is being renovated.

Gas burners for a cartridge with a collet connection represent a separate class of tools. They are used in conditions of high fire safety where serious construction equipment is involved, and the risk of damage to the apparatus is minimized.

The main parameters are temperature and flame shape. In the simplest devices, the combustion temperature is close to the minimum - 700−1000°C. Air comes naturally and there is never enough of it. More expensive products have a special shape of air supply channels, which increases air flow and the flame temperature increases to 1200°C.

The flame has an even higher temperature in ejector burners, in which air is supplied to the hearth due to rarefaction, and the flow force is directly proportional to the operating gas pressure. Thanks to this, the temperature can be increased to 1500−1600°C and relatively smoothly adjusted with the flame length just by turning the tap. There may be several sources of combustion in the apparatus. This tool does not perform delicate work, but it successfully heats large areas.

The threshold temperature of the burners is 2000−2400°C, and it is achieved by concentrating the injected air into the combustion chamber, as well as using methyl acetylene propadiene gas (MAPP). A high-temperature cone is formed in the flame, whose power and temperature can be compared with oxy-fuel welding.

In addition, any type of product can be equipped with a flexible or rotary tube, piezo ignition and a highly sensitive control valve. There is a wide selection of devices based on power and gas consumption .

Travel lamps

Low-temperature devices are used to perform a wide range of work, suitable for both domestic use and professional construction. These blowtorches often replace electric hair dryers where only autonomous operation is possible.

The main disadvantage of burners without an injector is the low flame stability, especially noticeable during sharp tilts and turns. The splashing of liquefied gas does not have a significant effect in more expensive devices that have a special gearbox and heating circuit.

Typically, such devices are not used for soldering. They are mainly used to light firewood and coals or to heat materials that allow the use of an open flame. The lamp is indispensable for thawing pipes, heating car engines, burning paint to remove it, unpacking strips on tow, and other rough work.

The design and purpose of ejector blowtorches is more specific. These devices are used for processing non-ferrous metals. Due to their high temperature and ability to regulate the flame, these devices are excellent for soldering and hardening of metals, and other heat treatments that require high temperature accuracy and a strictly defined cone.

The specifics of the application seriously adjust the size of the nozzles and burners. Miniature devices are used for soldering thin metal and jewelry. Mid-class torches have a cone thickness of 3-9 mm; they are more suitable than others for electrical soldering of cable joints, aluminum and copper tubes.

Due to their high power, larger products can be used in the following areas:

• artistic forging;
• precision stamping and bending of metal.

It is these tools that home craftsmen use as the basis for homemade hardening furnaces and gas forges.

In the case of ejector options, the concept of flame instability is purely figurative, although there is a possibility of periodic flashes of gas, in the core the temperature remains relatively stable. The gas preheating circuit is used more to increase the efficiency of burners, speed them up to operating power, and more accurately control the temperature.

High temperature lamps

• There are devices where MAPP gas is used instead of a propane-butane mixture. The flame temperature in these devices is 2200−2400°C. The main energy is concentrated in a cone, which is quite stable and has a pronounced boundary.
• Such products are used for heating, bending and forging massive parts and high-carbon steels. High temperature allows for better tempering and hardening of metal.
• As for welding and soldering, MAPP gas devices do an excellent job with stainless steel, and even thin parts do not overheat. Another advantage of MAPP is its low boiling point, which allows it to be used at temperatures of -20°C even in products without a heating circuit.

When choosing a gas burner, do not forget about the nuances.

1. The simplest, naturally aspirated torch burners are well suited for tourism. Even cheap Chinese products that you don’t really mind breaking or losing will help you light a fire or heat up food.
2. For everyday use and minor repairs, amateur series tools are preferred. The design of semi-professional burners is more complex, and there are no shortcomings in it, such as, for example, melting of the plastic lining of the mouthpiece or failure of piezo ignition.
3. An additional argument against average prices is the almost universal absence of a normal control valve, which can also be important in the case of rough work.
4. If you plan to use the device for delicate work, soldering or welding, additional attention should be paid to balancing and ergonomics. These jobs involve frequent switching on and off of the burner; therefore, the shape of the housing and the placement of the controls should allow one-handed ignition and adjustment.
5. The choice of power is dictated by the thickness and material of the parts being processed. Burners with a power of 500-700 W are quite suitable for soldering copper wires or burning paint. Steel products and tubes made of non-ferrous metals up to 3 mm thick can be heated well with a burner with a power of about 1200-1500 W. 2-3 kW burners are used for heating and bending reinforcement up to 14 mm thick.
6. And about one more feature: the flame of high-quality, powerful burners can be adjusted for more delicate work, but it will not be possible to heat a massive part with a low-power burner.

Source: https://rem-serv.com/flyus-dlya-payki-latuni-i-medi/

Soldering aluminum at home with a soldering iron and gas torch: solder and flux

Soldering aluminum is a rather difficult task. Basically, soldering aluminum parts becomes more difficult due to the appearance of a chemically resistant oxide on the metal surface.

In addition, due to the relatively low melting point and low temperature of loss of strength, it is quite difficult to heat aluminum without causing destruction of the entire product. Therefore, soldering aluminum parts is difficult if conventional consumables are used.

At the moment, soldering of aluminum products is carried out using specialized fluxes and solders.

Process Features

The key problems of soldering aluminum with traditional solders and fluxes are related to:

• the formation of an oxide film with a high melting point and good chemical resistance, preventing interaction with tin or lead solders;
• low melting point of pure metal, making high-quality soldering difficult.

To solder aluminum parts, specialists must clean the surface of the material from the oxide film or use specialized aggressive solders and fluxes.

Soldering aluminum with a soldering iron should be done using zinc solders. This option for low-temperature soldering of aluminum, unlike cadmium, bismuth, tin or indium, interacts well with pure metal and forms a strong seam.

Melting temperature of aluminum products for soldering.

The basic rules for soldering aluminum at home in the absence of zinc or aluminum solder include the following points:

1. Pre-cleaning of the surface.
   The area where soldering work needs to be performed should be carefully cleaned of paint, dirt and particles of other metals.
2. Grinding.
   For better adhesion between the solder and aluminum, the area of ​​the intended connection should be sanded.
3. You should not take a long break between cleaning aluminum and directly applying flux.
   Due to the high rate of oxide formation on the surface, the cleaning process for aluminum may need to be repeated.
4. The correct choice of device for heating the soldering area.
   Electric soldering irons with adjustable tip temperatures are ideal for this work.
5. Monitoring the temperature of the connection point.
   Due to the good thermal conductivity of the metal, the temperature will quickly spread over the entire area of ​​the product, and therefore the soldered area will quickly cool down.
6. A prerequisite for successful soldering of aluminum is tinning the area of ​​the intended contact.
   If a drop of solder is applied to the cleaned area of ​​aluminum in time, an oxide film will not be able to form.

There are several secrets that can be used to solder aluminum without specialized solder:

1. Destruction of the oxide film by intense friction of the joint with a brick.
   After a certain amount of dust has peeled off the stone, you should put the required amount of rosin or flux on the soldering iron tip and fill the soldering area. After this, you should make strong pressure movements with the flat cut of the soldering iron at the place of the planned soldering. With this simple action, brick dust will destroy the thin oxide film, and the solder on the soldering iron will tin the cleaned metal.
2. Destruction of the oxide film using iron particles.
   To do this, grind off a thick nail with a file, apply a large amount of liquid rosin or flux to the soldering area, and then add metal filings. After the soldering agent has hardened, you should put solder on the tip of the soldering iron and press it firmly into the soldering area.
3. Use of transformer oil.
   To implement this method, remove the top layer of the part with sandpaper, and then pour oil onto the cleaned area. After this, you can rub in the heated solder and get good adhesion between the tin and aluminum.

Necessary materials and available tools

Soldering of aluminum products with proper surface preparation can be performed with all types of solders. For example, soldering aluminum with tin is possible by removing the oxide film.

Materials required for soldering aluminum.

However, in most cases, aluminum joints obtained by soldering with tin solder have low reliability due to the poor solubility of the materials.

The most optimal solders for soldering aluminum are:

• zinc;
• copper;
• silicic;
• aluminum.

There are a large number of solders on the market based on the above materials. One of the most common zinc solders is TsOP40, which contains 40% zinc and 60% tin. In addition, 34A solder remains popular, consisting of 66% aluminum, 28% copper and 6% silicon.

Special mention should be made of special solder for low-temperature soldering of aluminum parts. One of the most common consumables for such an operation is HTS-200 solder.

Of course, we should not forget about the mandatory use of a special flux for low-temperature soldering of aluminum.

The flux for trouble-free soldering of aluminum must contain at least one of the following elements:

• triethanolamine;
• zinc fluoroborate;
• ammonium fluoroborate.

One of the brands of fluxes for welding aluminum with a gas torch is F64. The popularity of this flux is due to its high activity. Even aluminum parts can be soldered with F64 flux without first stripping the oxide film.

The F64 flux composition includes:

• 50% potassium chloride;
• 32% lithium chloride;
• 10% sodium fluoride;
• 8% zinc chloride.

Preparing parts

Soldering aluminum at home involves careful preparation of the part.

As a rule, qualified craftsmen perform the following procedures before soldering aluminum with their own hands:

1. Degreasing the surface.
   The most suitable substances for high-quality degreasing of the soldering area are acetone, gasoline and solvent.
2. Removing the oxide film.
   This procedure is carried out using a grinding machine or a homemade wire sponge. In rare cases, specialists use film etching using chemicals, such as acid.

After completing all the preparatory procedures, you can proceed to direct soldering of aluminum at home.

Technological approaches for aluminum soldering

The technology for soldering aluminum with flux is practically no different from joining other metals.

The entire process of soldering aluminum with solder can be divided into the following stages:

1. Surface preparation.
   Before soldering aluminum, the parts to be joined should be cleaned and degreased.
2. Installing the product into working position.
   This step may require a vice or a third hand.
3. Applying flux to the soldering area.
4. Warming up the product using an electric soldering iron or gas torch.
5. Apply solder or solder paste to the required areas.
   Zinc or copper solders are suitable for this role. Sometimes high-temperature solders may be needed to ensure good mechanical fixation of the product.

Scheme for soldering aluminum pipes.

It is important to remember that when soldering with flux-free solder, you should make striking movements with the soldering iron in order to ensure interaction between the components of the solder and the metal.

Carrying out work using a special soldering iron with a scraper will give good results in the following cases:

• soldering of aluminum utensils;
• soldering aluminum wires;
• seal surfaces not subject to strong mechanical loads;
• connection of small parts.

Soldering of massive aluminum parts and thick rods should be carried out using welding or a torch. Welding is not always suitable due to the high temperature of the arc, which melts the metal. Therefore, most specialists prefer to use burners.

The best effect is achieved with continuous soldering with a torch. If, for some reason, the soldering process had to be stopped, the entire seam should be completely heated in order to ensure uniform distribution of the solder and get rid of unsoldered areas.

The process of soldering aluminum rods using a torch is divided into the following stages:

1. Cleaning metal from dirt and preparing the surface by grinding.
2. Heating the entire surface of massive products using a burner.
3. Remove all flammable materials from the work area.
4. Turn on the hood to neutralize the caustic fumes of solder.
5. Preparation of solder wire.
6. Preparation of flux grades F-59A, F-61A or F-64A.

It is allowed to heat the metal to a bright orange color. In this form, the metal does not melt, and the solder is applied as evenly as possible.

The most complex and at the same time high-quality method of joining aluminum products is welding. This method is difficult due to the low melting point of the metal.

Qualified specialists most often weld aluminum products using the following methods:

• welding using coated electrodes;
• welding using shielding gas.

The first welding option has the following disadvantages:

• low weld strength;
• strong splashing of metal during cooking;
• poor separation of slag from the seam.

Welding in an inert gas atmosphere has no noticeable disadvantages and is considered the best method for joining aluminum parts.

Heating an aluminum product

The heating method for aluminum parts is selected individually. Products of relatively small sizes can be heated with an electric soldering iron and tinned with solder and flux for soldering copper. For more massive parts, it makes sense to use another method of soldering aluminum using a gas torch or blowtorch.

Table of solder brands for aluminum soldering.

When warming up the part, you should:

1. Control the temperature of the heated product.
   You can find out the current surface temperature of a part by touching it with a solder rod. When the aluminum solder wire begins to melt, reduce the heat and begin direct soldering using active flux.
2. Watch the burner flame.
   The burner jet contains a mixture of natural gas and oxygen, and therefore should be bright blue. The correct composition of the burner flame allows the aluminum part to oxidize less and not overheat.

The key advantages of heating massive aluminum products with a gas burner are presented:

1. Low cost of equipment.
   A gas burner consumes a small amount of fuel and is sold at any hardware store.
2. Absence of uneven heating and stress inside the product.
   Parts heated by a gas burner have an even seam and do not change geometry due to overheating.
3. Easy control of operating temperatures.
   If the metal heats up too much, reduce the intensity of the burner flame.
4. Possibility of soldering work at home.
   When the metal is heated with a burner, there is no pungent odor, there is no ultraviolet irradiation of the skin and no sparks fly.

Conclusion

Soldering aluminum with flux is a rather non-trivial task. When connecting aluminum products, certain standards must be observed, and the surface of the part must meet numerous requirements. If the technological process is not followed, the welded or soldered seam will crack and fall apart.

Aluminum welding technology depends on the massiveness of the product. Small parts, such as wires or dishes, can be easily repaired with an electric soldering iron, but large rods or pipes should be heated with a gas torch or blowtorch.

Source: https://tutsvarka.ru/vidy/pajka-alyuminiya

Soldering aluminum at home: features of the process, types of flux and solders, how to solder a pipe

Aluminum and its alloys have very good characteristics, such as high thermal and electrical conductivity, ease of processing, low weight, and environmental safety. But this beautiful metal has one very big drawback: it is extremely difficult to solder. A properly selected flux for soldering aluminum helps solve this serious problem.

The problem with soldering aluminum is due to its chemical structure. This metal itself is chemically very active; it reacts with almost all chemicals.

This causes pure aluminum to instantly react with oxygen in air. As a result, a very thin and at the same time extremely strong oxide film is formed on the metal surface: Al2O3.

In terms of their properties, aluminum and its oxide represent two extreme opposites combined into a single whole. For example :

• The melting point of pure aluminum is 660 degrees. Aluminum oxide, or corundum as it is also called, melts at a temperature of 2600 degrees. Refractory corundum is used in industry as a refractory material.
• Aluminum is a very soft and ductile metal. Corundum has extremely high mechanical strength, which makes it possible to produce all kinds of abrasive materials from it.

Aluminum oxide turns ordinary soldering into a rather complex process. For its successful implementation, it is necessary to use specific methods and special aluminum solders and fluxes.

Metal soldering

The meaning of soldering any metal is that a special substance called solder is introduced into the space between the parts being soldered in a molten state. After hardening, the solder reliably binds two metal parts into a single whole.

When soldering aluminum, the oxide film on its surface prevents the molten solder from connecting to the metal. In other words, adhesion is impaired, and therefore the solder cannot spread over the surface of the metal and stick to it . This makes soldering aluminum almost impossible without the use of special means that partially remove the oxide from the metal surface and promote normal adhesion.

Removing oxide film

Removing oxide from the surface of aluminum is a complex process and never leads to a final result. That is, the oxide film is practically impossible to remove, since instead of the one just removed, a new one is instantly formed. It is possible only with the help of specific means to weaken its effect. This can be done using two different methods :

• Chemical method. With the help of special aluminum fluxes, the film is destroyed as a result of exposure to active acids.
• Mechanical method. Through the use of abrasive tools, the integrity of the film is damaged.

In practice, both of these methods are most often combined to achieve the maximum possible effect.

Fluxes for aluminum

Flux is used to remove oxide from the metal surface and subsequently prevent the formation of a new film. It must be remembered that during the soldering process, the flux should not interact with the solder and enter into chemical reactions with it. Fluxes can be in different states :

• Liquid.
• Paste.
• Powder.

For aluminum, liquid fluxes based on orthophosphoric acid are most often used . There are so-called no-clean fluxes, the use of which does not require subsequent washing of the soldered surfaces under running water.

However, most often aluminum fluxes contain highly toxic substances that are unsafe and, from an environmental point of view, can severely corrode the metal at the soldering site. Therefore, the use of fluxes requires thorough washing of the soldering area under running water.

The industry produces a larger number of aluminum fluxes, among which the following can be distinguished::

• F-64. Highly active flux for aluminum and its alloys. It is considered the best flux for this metal. High activity is determined by the high content of active fluorine in its composition, about 40%. When heated, fluorine destroys the oxide film on the surface of aluminum. The use of this flux requires thorough washing of the welded surfaces after the process is completed.
• F-34A. Special aluminum flux for refractory solders. Ingredients: potassium chloride 50%, lithium chloride 32%, sodium fluoride 10%, zinc chloride 8%.
• F-61A. It is used with conventional lead-tin solders, melting at a temperature of 150−350 degrees. Composition: zinc fluoroborate 10%, ammonium fluoroborate 8%, triethanolamine 82%. Used for soldering dissimilar metals, such as aluminum and copper. Therefore, when the question arises of how to solder aluminum to copper, this flux will be the answer.
• NITI-18 (F-380). Suitable for refractory solders with a melting point of 390 - 620 degrees. The peculiarity of this flux is that, while dissolving the oxide film well, it has virtually no effect on the base metal. After finishing soldering, flux residues must be removed immediately. To do this, the soldering area is first washed with hot running water, then with cold water. And finally, incubate for 15 minutes in an aqueous solution of phosphoric anhydride.
• A-214. Universal no-clean flux of medium activity. Application temperature 150−400 degrees. It does not contain harmful salts of aniline, phenol or carboxylic acids, therefore, thorough rinsing is not required after use. Residues can be easily removed with a paper towel soaked in alcohol.

Mechanical oxide removal

To facilitate the dissolution of the film using flux, it is first partially removed using mechanical methods. These techniques make it possible to only slightly weaken the effect of the oxide, since it was experimentally established that the newly formed film is somewhat inferior in strength characteristics to the old one. For these purposes the following devices are used :

• Sandpaper.
• Files and rasps.
• Hard metal brushes.

The process of mechanical removal of surface oxide can be optimized using brick dust. The soldering area is first sprinkled with fine brick chips . Then:

• A large amount of dry rosin is poured onto the brick crumbs.
• With a preheated soldering iron tip, the rosin is melted and distributed over the metal surface in an even layer.
• With the tinned tip of the soldering iron, they begin to vigorously rub the soldering area. In this case, the brick chips peel off the oxide film, and the molten rosin prevents the penetration of oxygen instead of soldering and therefore a new oxide film does not form.
• The result is a well-tinned aluminum surface.

As an abrasive, with the same effect, you can use sifted river sand or metal filings.

Soldering aluminum

The basis of any soldering is the so-called tinning or tinning. In this process, solder is distributed evenly over the surface of the metal. In order for tinning to go well, two important components are needed: a special flux and properly selected solder. We have already looked at fluxes, now it’s the turn for solders.

Special solders

Conventional solders used for soldering non-ferrous metals contain tin and lead. The question of how to solder aluminum with tin is not relevant, since such solders are not recommended for aluminum, because it is practically insoluble in these metals. Special solders are used that contain a fair amount of aluminum itself, as well as silicon, copper, silver and zinc.

• 34-A. Special refractory solder for aluminum. Melting point 530−550 degrees. Composition: aluminum 66%, copper 28%, silicon 6%. It is recommended to use it together with the corresponding flux F-34A.
• TsOP-40. Belongs to the category of tin-zinc solders. Composition: zinc 63%, tin 36%. Melting occurs within 300−320 degrees.
• HTS 2000. Special solder for aluminum made in the USA. Main components: zinc 97% and copper 3%. Melting point 300 degrees. Provides a very strong connection, comparable in strength to a weld seam.

The presence of a metal such as zinc in the solder provides it with high strength characteristics and good resistance to corrosion. The presence of copper and aluminum increases the melting point and makes the solder refractory.

The use of one or another solder is determined by the tasks facing the parts being soldered. Thus, for soldering large-sized and massive aluminum parts, which will subsequently be subjected to heavy loads, it is better to use refractory solders; their melting temperature is comparable to the melting temperature of aluminum itself.

When the question arises of how to solder an aluminum tube, you need to understand exactly what this tube will be used for in the future. Refractory solders are characterized by high strength, and the large mass of the part allows for good heat dissipation during the soldering process, which will prevent the destruction of the aluminum structure due to its melting.

How to Solder Copper to Brass

Taps, hardware, pipes, decorative interior items and many other products are made from brass. This material is obtained by fusing copper, zinc (in different proportions) and various additives.

Soldering brass ensures a reliable and high-quality connection of parts.

Soldering involves the use of a special tool in the form of a gas torch, as well as solder made from a mixture of tin and lead.

In some cases, tin alone is used to make brass solder.

Advantages and disadvantages

If you have the necessary tools and materials, and after learning the basic techniques for handling brass, you can solder this material yourself.

Soldering brass products has several features.

This technology involves the use of specially prepared solder, which is introduced into the gap between the parts and plays the role of a “grasping” element.

In addition, the equipment through which the solder material is melted is essential.

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

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

It is unacceptable to compare soldering with welding procedures in which each of the metals being fused is subject to melting.

In this case, only hard solder with tin is exposed to thermal effects, and the condition of the parts being connected remains unchanged.

This feature allows you to process brass products of very small size and weight 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. As a result, the joints obtained by soldering are considered less strong compared to welded seams.

In cases of working with brass, zinc completely evaporates from the solder body (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 soldering brass parts, it is important to correctly select their relative position (in this case, preference is given to “overlapping” joints).

Application

Modern technologies for processing copper and zinc alloys are widely in demand 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 the brass surfaces in order to protect them from corrosive destruction. The tinning procedure is also in demand when repairing heating and plumbing systems made on a brass basis.

Depending on the type of solder used for soldering, connections are divided into high- and low-temperature.

This division allows the use of more refractory joints for soldering workpieces operated at high temperatures.

Using high-temperature soldering is impossible at home, since this situation requires special equipment.

Features of soldering homogeneous workpieces

In everyday life, there is often a need to solder two brass blanks that are identical in structure.

In this case, the correct choice of flux composition, which differs from the traditional combination of rosin and alcohol, becomes of paramount importance.

Due to the low activity of the components, a conventional composition will not be able to dissolve the oxide film that forms on the surface of brass. So for the soldering option under consideration, a more active flux based on chlorine and zinc will be required.

All the details of its preparation can be found in the table, which shows several types 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.

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 problem considered, we should not forget about a competent approach to the selection of solder supplied to the joint in the form of calibrated wire of one composition or another.

In the case where soldered brass products are intended to be used in a gas environment, it is advisable to use special types of solders made on the basis of copper phosphate and silver alloys. They are also suitable for soldering red brass with a high percentage of copper content.

Sometimes 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 point of the brass wire is lower than the same indicator for the workpieces being processed.

General procedure

Before you start soldering brass parts yourself, you should thoroughly clean them of foreign 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.

• first, the place of the intended connection of two parts is treated with a flux of suitable composition, after which finely planed crumbs of solder material are poured onto it;
• after this, you can start heating the brass (only at the joint!) using a previously prepared burner;
• After melting the solder material and filling the gaps between the parts with liquid composition, turn off the burner and wait for the joint to cool down.

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

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

Source: https://steelfactoryrus.com/kak-pripayat-med-k-latuni/

How to solder brass at home - Metals, equipment, instructions

Brass as a material has been known for quite a long time. Good physical and chemical properties have allowed it to become widespread. Brass parts also periodically develop defects (cracks, holes, breaks).

  These problems can be solved by soldering.

In order for the result to be of high quality, it is necessary to have a good knowledge of the composition of brass, its physical and chemical characteristics, how to carry out soldering, what solders and fluxes are used for such work.

Soldering brass

Basic information about brass

Brass can be double or multi-component in composition. It is always based on two metals: copper and zinc. In this alloy, zinc serves as the main alloying component.

To impart different properties, various metals are added to its composition: tin, lead, manganese. Therefore, it is very important to know what composition of brass you have to work with.

This is necessary to determine the conditions and specifics of soldering.

Brass

Modern brass is classified according to the following indicators:

Depending on the chemical composition:

• Two-component alloys. It contains only two metals, zinc and copper. The percentage of each may vary. This type is marked with the capital letter of the Russian alphabet “L” and a number. The number indicates what percentage of copper is contained in the alloy. For example, grade L85 - this alloy contains 85% copper and the remaining 15% is zinc.
• Multicomponent. They are also called special. Such alloys contain a large number of additives. They are marked with two capital letters and numbers. For example, brand LA77-2. She indicates that the composition includes 77% copper, 21% zinc and 2% aluminum. Therefore, very often special brasses get their name depending on the name of the alloying element with the highest percentage (aluminum, tin, nickel, manganese, and so on).

By degree and quality of processing:

• Deformable. These include brass in the form of wire, round tube, sheet and tape.
• Foundries. These are fittings, finished products made of brass.

According to the zinc content in the alloy:

• If the zinc content is in the range from 5 to 20%, then such an alloy is called red brass (tompak).
• If this percentage ranges from 21% to 36%, the brass is called yellow.

All brands of brass have similar properties. They are easy to process, have high anti-corrosion characteristics, and have sufficient strength. With a significant decrease in temperature, they retain their plasticity.

These properties have determined the wide range of uses of brass.

Application of brass

In addition to the listed positive properties, brass is a very durable and reliable alloy. Brass is used in the following areas:

• Manufacturing of pipeline fittings (adapters, valves, pipes).
• Plumbing fixtures (taps, mixers, washbasins)
• Furniture fittings (handles, latches, locks, decorative overlays).
• Production of electrical parts.
• Production of souvenirs.
• Production of tableware.
• Art casting.
• Jewelry production. Jewelers mainly use two-component alloys. It can be: yellow, red, green or golden brass.

Soldering brass pipes

Solders and fluxes: classification and selection methods

To obtain good soldering results, additives in the form of fluxes and various solders must be used.

Solder is a specific metal that, after melting, penetrates into metals prepared for soldering.

To achieve reliable contact, the brand of solder must have a melting point that will be significantly lower than the melting point of the brass itself. At the same time, it must have good adhesion to brass. Therefore, special solders are used for soldering brass.

Only as a last resort, if parts are soldered that do not bear much responsibility for the entire unit, and there are no high requirements for strength, ordinary tin-lead alloys are used.

Modern solders are classified as follows:

• By melting point. They are soft with a melting point reaching 400°C; semi-solid with the melting point of tin and solid. The melting point of hard solders exceeds 500 °C.
• By type of melting. Solders that melt completely or partially during the soldering process.
• According to the method of obtaining solder. We produce ready-made solders, and solders that are formed during the soldering process. This type of soldering is called contact reactive soldering.
• According to the list of chemical elements added to the composition. A fairly large number of such elements are used. From common metals zinc, tin, aluminum, to rare earth metals gallium, indium, palladium.
• According to solder manufacturing technology. They are: wire, stamped, rolled, cast crushed.
• By type of solder. They are produced in the form of wire, ready-made powder, in the form of tape and individual sheets, in the form of tablets and ready-to-use embedded parts.
• According to the method of flux formation. Solders are divided into two large categories: fluxed and so-called self-fluxing.

Solders, like brass, are marked with capital letters and numbers. By the marking you can determine which brass a particular solder is intended for. For example, if it is necessary to solder a part made of brass, in which there is a large percentage of copper, then it is proposed to use solder of the PSr12 or PSr72 brand.

This solder contains a large percentage of silver. If there is a large percentage of zinc in brass, then it is advisable to use PSr40 solder. Therefore, in order to obtain a reliable connection after soldering, it is necessary to understand what loads are placed on the part being repaired.

If the part is stationary and does not bear large vibration loads (for example, plumbing elements), you can safely use PMC solder. If it is necessary to ensure a strong connection, special hard solders are used, such as L-CuP6.

This solder has a very high melting point - 730 ° C.

Solders for brass

To choose the right brand of solder, you can use the following method:

• Determine the melting temperature of the parts that are planned to be soldered.
• Determine the coefficient of thermal expansion. For brass that you plan to solder and the solder it should be very close.
• After soldering, the solder should not reduce the mechanical characteristics of the repaired part.
• The solder must form a galvanic couple with the main brass part. If this is not ensured, the corrosion process will quickly occur.
• The properties of the solder must comply with all technical and operational characteristics.
• The solder must ensure good wettability of the main part during the soldering process.

Flux is a special substance that allows you to prepare the surface of the metal, that is, remove the resulting oxide deposits, grease and water stains from it. Without the use of flux, it is impossible to qualitatively solder a brass part. Fluxes are selected depending on the chemical composition of brass.

Experience shows that in order to qualitatively solder parts made from common brands of brass LS59 and L63, it is enough to have a flux consisting of zinc chloride dissolved in boric acid.

If you need to solder brass, which contains lead and silicon (for example, LKS80 brand), then you need a flux containing fluorine and potassium compounds. They are also dissolved in boric acid, or borax.

A similar flux for soldering can be prepared at home, using the appropriate elements in the required percentage.

Flux paste for soldering brass

Today, the industry offers ready-made fluxes for brass soldering. These include: Borax flux; fluxes PV-209 and PV-209X.

Soldering methods

The brass soldering process has certain specifics. The brass heats up and the hot zinc elements evaporate. At this moment, an oxide film is formed, which is quite difficult to remove from the surface of the part and thereby deteriorates the quality of soldering. Usually brass is soldered in two ways: using a soldering iron and using a special torch.

Soldering with a soldering iron

To successfully solder brass, a soldering iron must have a power of at least 1000 W. Such a soldering iron will provide the required heating temperature for the parts themselves and the solder. It should be 500ºС and above. Low temperature soldering of brass is only possible if it has a high percentage of copper content.

Source: https://spb-metalloobrabotka.com/kak-zapayat-latun-v-domashnih-usloviyah/