Solders and fluxes two in one
In many situations, soldering requires great skill. Combining the functions of solders and flux mixtures in one product greatly simplifies the work.
There are several types of such products, each of which has its own characteristics - these are paste mixtures, ready-made solder with rosin, made in the form of wire, and tubular solder with flux. The choice is determined by the soldering mode, the nature of the part, and the requirements for the seam joint.
Wire with rosin
Combining two consumables in one product significantly simplifies the procedure and improves the efficiency and effectiveness of the work. If rosin as a flux is added separately, there is a high probability of adding an excess amount.
In the finished wire with flux, the ratio is fixed, stipulated by GOST.
Most often, products are supplied in a coil or coil. The version with wire packaging in coils is intended for continuous operation on an industrial scale. The assortment includes products of a wide variety of thicknesses.
Products in the form of coils are used for slightly smaller scales of use.
This option is suitable for both individual craftsmen and repair businesses. The thickness of the wire packaged in coils varies from 0.8 mm to the maximum possible 2 mm.
The solder component is an alloy of 2/5 parts lead and 3/5 parts tin. Each solder granule is surrounded by rosin, the total concentration of which varies from 0.8% to 1.2%.
The convenience of the wire is due to its flexibility . When soldering, such a mixture can be easily introduced into any gap, where it will melt and provide good envelopment of the parts and the formation of a strong seam.
The disadvantage is the low melting point of the mixture . Parts made from refractory alloys cannot be soldered with such consumables.
Working with solder wire containing rosin flux is similar to standard soldering. First, the parts need to be cleaned, then heated to the required temperature and consumables introduced into the work area.
Tube arrangement
The use of materials with dual functions in the form of tubes is economically and technologically beneficial. Consumption is reduced by almost 40%, and there is no need to remove the remaining flux after soldering.
Tubular solder contains 1, 3 or 5 internal channels into which flux is placed. There are several advantages of using this type of consumables:
- simultaneous supply of two trains to the working area;
- improvement of the final result;
- increase in work speed;
- simplification of soldering in hard-to-reach areas;
- reducing losses of funds;
- possibility of strict dosing;
- eliminating the possibility of dirt getting into the flux.
Tubes with one internal cavity can make soldering a little more difficult due to the rapid flow of flux into the work area. When working with multichannel solders containing flux, such troubles are unlikely.
In any case, you need to get used to using tubular products and learn how to properly regulate the solder supply speed. In general, the flow of flux through several channels minimizes the likelihood of disruption of the soldering technology.
Dry work will be completely eliminated. The flux enters the work area evenly through several channels, which leads to improved joint quality.
Solder material composition
The tubes contain both traditional and special solders.
As a solder mass for many metals and alloys, in particular for copper, a common alloy of tin and lead with eutectic properties is used.
The ratio of metals may vary to some extent. Recommendations for the use of such tubes correspond to the instructions for the use of homogeneous solders made of tin and lead.
For surface mounting work, it is better to choose products with a diameter from 0.46 to 1 mm. To solder miniature parts, flux solders containing silver additives are produced. The maximum melting point of the product is 188℃. The diameter of such tubes is 0.46 mm and 0.56 mm.
Solders with tin and copper have higher melting points, reaching 227℃. the tin content in them varies. Tubes are produced with fluxes in which the tin concentration is 95.5% and 99%. Some types of products contain silver additives.
For soldering elements of aluminum lamps, special solders with fluxes containing 80% lead, 18% tin and about 2% silver are supplied. Slight variation in the ratio of components allows you to expand the range of melting temperatures. The minimum is 178, the maximum is 270 ℃.
In most cases, the tubes contain purified rosin as fluxes. Strict dosing almost completely eliminates the possibility of residue formation. If any are discovered after finishing work, they do not need to be deleted.
When choosing consumables, you should pay attention to the manufacturer's information. The technology for producing solders with flux is quite simple, which increases the likelihood of counterfeits.
In low-quality products, the ratio of external and internal components may be disrupted. In professional production, the flux content usually varies from 1% to 4% of the total weight of the tube.
Tips for use
To work with tubular consumables, you can take any soldering iron. It is important that its shape and dimensions provide the required contact with the parts.
If necessary, the tip should be cleaned by tinning using tubular solder with flux. If there is a lot of dirt on the sting, you should first treat it with a special sponge.
To be completely sure that the working part of the soldering iron is clean, you can use special paste-like products.
Do not allow the work area to overheat. To do this, it is important to monitor both the heating temperature of the soldering iron and the duration of soldering.
Soldering printed circuit boards requires special attention. The work area must first be thoroughly cleaned. You can buy specially designed solvents for this.
Each procedure for soldering parts on the board should last no more than 2 s. During this time, one connection must be made. If more time is spent, the wetting capabilities of the fluxes may not be enough. As a result, the strength of the connection between the electronic components and the board will deteriorate.
Handling tubing containing solder and flux takes some getting used to. The end result and convenience in subsequent work justify minor difficulties at the beginning.
Source: https://svaring.com/soldering/pripoj/trubchatyj-s-fljusom
Tin with rosin for soldering
In many situations, soldering requires great skill. Combining the functions of solders and flux mixtures in one product greatly simplifies the work.
There are several types of such products, each of which has its own characteristics - these are paste mixtures, ready-made solder with rosin, made in the form of wire, and tubular solder with flux. The choice is determined by the soldering mode, the nature of the part, and the requirements for the seam joint.
How to solder brass: methods, review of materials, instructions
An alloy of copper and zinc, known since ancient times, is widely used in our time. Brass has high strength, is resistant to corrosion, and is ductile. Thanks to these properties, it is used to make parts of mechanisms and structural elements that are forced to constantly come into contact with aggressive environments.
Despite the reliability of the material, brass products sometimes develop various defects that require repair - breaks, holes, cracks. One way to restore elements is soldering. This process is not very complicated, but it has its own characteristics, so it is extremely important to know how to solder brass.
Familiarity with soldering technology will allow you to successfully carry out such work even at home.
What are the features of the technology?
This method of producing permanent joints is not as popular as welding. The reason is lower solder strength. Seams are formed by melting a filler material called solder. The most important difference between soldering is the melting temperature, which should be lower than that of the elements being connected. They do not change the state of aggregation, which makes it possible to reliably fasten dissimilar materials.
The low-temperature effect on the surface to be soldered has made soldering indispensable, and in some cases the only possible: for example, when it is necessary to obtain a permanent connection of dissimilar metals. The integrity of the processed parts is the main advantage of such a technological operation, since it allows you to work with the smallest elements without fear of their deformation or change in structure.
Soldering is especially relevant in electronics, where you have to work with miniature, very fragile microcircuits, and in electrical engineering, when there is a need to connect or extend conductors.
Classification of brass alloys
Brass can be double or multi-component. In the first case, the composition includes only copper and zinc, which increases the hardness of the alloy. Other components that improve its physical and chemical characteristics include aluminum, iron, silicon, manganese, nickel, tin, lead and other elements. For this reason, it is necessary to know exactly the composition of brass in advance; this will help determine the method, as well as the specifics of soldering.
Brass is classified according to its chemical composition:
- Two-component (double, simple). It consists only of copper and zinc. The percentage of these components may vary. These compositions are marked with the letter “L” and a number, which always indicates the amount of copper. For example, L90 contains from 88 to 91% copper, zinc accounts for 8.8-12%. There are impurities, but their amount is minimal - about 0.2%.
- Multicomponent (special). This brass has a large number of ingredients that increase the corrosion resistance of the alloy, its strength, and hardness. It is marked differently: another one is added to the letter “L”, meaning the alloying element, and another number appears - the percentage of alloying metal. For example, LA77-2 is aluminum brass, it contains 77% copper, about 2% aluminum, and the rest is zinc. All such alloys are named after the alloying element: ferrous, silicon, nickel, manganese, lead, etc.
Brass is used to make various products. According to the degree of processing, these alloys are divided into:
- deformable, they are used to produce bolts, nuts, car parts, brass strips, sheets, wire, pipes, pipes;
- foundry (fittings, bushings, instrument parts, bearings, car hydraulic system fittings).
Based on the percentage of zinc, brass is divided into:
- Red (tompak), containing 5-10% of this component. Such alloys are ideal for jewelry, figurines and similar artistic products.
- Yellow, here the percentage of zinc is 21-36%.
The reason for the popularity of brass is its durability, reliability, resistance to temperature changes and mechanical stress. Therefore, parts made from this alloy are widely used in water supply systems, sewerage systems, and in mechanical and instrument making. Brass products have a long service life, but this is only true if their operating rules are not violated.
Efficiency and obstacles
There are several technologies that allow you to easily weld parts or products made of brass, but they are not simple, promise significant costs, and require certain work skills from the master. Soldering is an alternative that is technologically simpler, which means this option is also suitable for a home craftsman, since there is no need for a highly qualified performer.
If the zinc content in the alloy is not too high, then there are no insurmountable obstacles on the way to the goal: simple soldering using ordinary rosin can cope with the task. When the percentage of this metal in brass exceeds 15, special fluxes are required.
The reason is strong evaporation during soldering of copper and zinc; it leads to the formation of a strong oxide film on the material, and it is quite difficult to remove it. Therefore, without special solders and neutralizing fluxes, an ideal result cannot be achieved.
Selection of optimal materials
Before looking for the best option for soldering brass, you need to determine its brand. Only in this case can an acceptable result of the operation be guaranteed.
Choosing the right solder
This is the material, usually an alloy, that is used to solder the elements. its peculiarity is its melting point, which must be lower than that of the metals being joined. Typical examples of alloys are tin and lead, pure tin.
However, the quality, mechanical strength of such a clutch and appearance are very far from ideal. The reasons for poor quality are pores that appear as a result of zinc evaporation.
To ensure reliable contact, the melting temperature of the material must be significantly lower than brass, and the solder must have excellent adhesion to this alloy.
- For soldering brass containing a large amount of copper, it is better to take compositions related to copper-zinc solders, since as a result of the addition of zinc, the melting point of these alloys is reduced. For example, PMC54 and PMC-48 solders melt at a temperature of 880°, PMC-36 - at 800-825°.
- For the same alloys, you can use silver solders - grades from PSr12 to PSr72. If brass has a higher zinc content, then similar solders are recommended, but not lower than PSr40.
- Relatively inexpensive copper-phosphorus solders are MF-1, MF-2, MF-3. They are plastic, but have good electrical conductivity. If the mechanical and vibration loads are high, then it is better to purchase solders with silver.
- If it is necessary to guarantee special strength, then hard copper alloys are chosen: for example, the universal L-CuP6.
The latest brand of solder has a temperature range of 710-880. It is designed to work with bronze, red bronze, brass, as well as copper, when installing pipes, radiators, and heating systems. When using silver or phosphorus solders, it must be taken into account that brass dissolves rapidly, so the processing time (heating and soldering) must be reduced.
Fluxes: homemade or ready-made
Fluxes clean the surface of metals from grease and also prevent the formation of an oxide film. They are also selected depending on the composition of the alloys. For copper compounds, rosin alone is sufficient, but for brass a more aggressive agent is already needed. The simplest flux option for soldering brass is a mixture of borax and boric acid (1:1). It is poured with water (5 mm per 1 g), boiled, stirring, then cooled. However, the best characteristics are possessed by “professionals” - purchased compounds.
- Borax flux. He has been known for a very long time, but since then he has not lost his fans. The reason for its popularity is its high-quality work.
- Other brands are no less effective: PV-209 (from 700 to 900°), PV-209X (from 650 to 850°).
Source: https://dom-i-remont.info/posts/obshhie-voprosy/kak-payat-latun-kak-vyibrat-flyus-pripoy-i-podhodyashhiy-instrument/
How to solder correctly with a soldering iron: what is required for soldering using rosin - Machine
In the modern world, saturated with electronics and electrical appliances, you need to know how to use a soldering iron. This skill will save a lot of time and money on repairing broken appliances. Despite the apparent complexity of this process, it is actually very easy to learn how to solder correctly with a soldering iron.
Soldering technology is to use a metal that has a lower melting point to connect more refractory metals.
Soldering irons
Soldering irons have several types, differing from each other in the heating method. According to this criterion, they are divided into electric, hot-air, induction, and hammer. The most popular in everyday life are electric soldering irons with a spiral or ceramic heater.
For each type of work you need to use a soldering iron of a certain power. For example, for soldering electronics, you will need a low-power soldering iron up to 40 W, and for parts with walls up to 1 mm you will need a more powerful device up to 100 W.
To solder together parts with a thickness of more than 2 mm, you will already need an electric hammer soldering iron with a power of 200-550 W. Such a device is unsuitable for everyday use, as it is intended for large-scale work and has a huge price.
Solders
Solder is essentially an alloy of metals with a low melting point. Solder usually contains tin, but due to its high price, a cheaper material, lead, is added to it.
Also, solder often contains auxiliary substances that are used to improve soldering strength or reduce the melting point.
Soft solders marked from POS-18 to POS-90 are very popular. The number in this abbreviation means the percentage of tin in the solder.
Hard solders are rarely used at home. They contain copper and zinc, which allows the solder not to melt until the temperature reaches 450˚C.
You need to know that solders with different compositions are suitable for different types of metals. For steel, POS-41 is better suited, for copper almost any solder is suitable, and for stainless steel - tin solder with cadmium.
It is best to determine what metal will be used for soldering before purchasing solder and, based on this information, purchase the appropriate solder.
Flux
Flux is an auxiliary substance that is used to free parts from oxidation products during soldering. Fluxes also contribute to the spreading of metal during soldering.
There are a huge number of soldering fluxes on sale. There are both neutral and metal-active fluxes to varying degrees.
The most popular base for flux is rosin. It is fusible and begins to boil already when heated to 250 ˚C.
- To learn how to solder with a soldering iron with rosin, you must know that after soldering you must completely remove the remaining rosin from the metal, otherwise oxidation of the metal will occur at this point.
- Also, due to its hydrolyzing properties, rosin increases conductivity at the soldering site, which disrupts the operation of electronic devices.
- It is also best to select the flux for the type of metal with which you plan to work - this will ensure high quality work.
Pastes
Solder pastes or tinol are a mixture of solder and flux. The paste is used for soldering in complex, hard-to-reach places. Tinol is also convenient to use for beginners without experience with a soldering iron.
Tool preparation
Don’t be afraid if the new soldering iron starts to smoke when you first turn it on. This occurs due to the burnout of the oil that preserves the instrument during long-term storage.
Before using a soldering iron, you should prepare its working part - the tip. It can be forged a little or sharpened to the required shape. If the working part of the soldering iron is coated with nickel, then such preparation is strictly prohibited.
The stores have a wide range of tips or tips for soldering irons, differing in sharpening. For large parts, a round tip with an angular sharpening is suitable, and for small parts, a sharp conical one.
If the soldering iron has a tip made of copper, then before work you need to tin it during the first heating. Tinning can be done by rubbing molten solder over a heated tip with a wooden block or by any other method.
The main thing is that upon first use the working part of the soldering iron is covered with a thin layer of solder. Otherwise, the soldering quality will be poor and the working part of the tool will be damaged.
Preparing parts
The preparation of parts does not depend on the metal from which they are made or the method of soldering them. Preparation always follows the same scheme - first the part is cleaned of contaminants and degreased.
For this purpose, use gasoline, acetone or other solvents. Rust must also be removed mechanically.
Temperature
The temperature of the soldering iron is the main parameter when working with it. When working with an insufficiently heated tool, the solder does not melt, but forms a lump.
To determine at what temperature you should solder, you need to know the melting temperature of the metal of the part and the solder. The temperature of the soldered parts should be 40-80 C˚ higher than the melting temperature of the solder, and the temperature of the tool tip should be 20-40 C˚ higher than the soldering temperature.
If the soldering iron does not have a temperature control function, then this parameter can be assessed using rosin. When touched by a soldering iron, it should boil, without instant combustion. Overheating will be indicated by the appearance on the solder, after touching it with a soldering iron, of a dark film consisting of oxidation products.
Soldering technique
- Basically, soldering occurs in two ways: by applying solder to the parts using a soldering iron or by applying solder directly to the parts.
- When using any of the methods, you must first clean and degrease the parts, secure them, heat the tool and treat the soldering area with flux.
If you are using a soldering iron to apply solder, melt a small amount of solder at the tip and transfer it to the soldering pad. Next you should move along the junction of the parts.
- If solder is applied directly to the junction, then the parts are first heated with a soldering iron, and then solder is supplied there later.
- If you plan to solder circuits, then it is better to find high-quality photo instructions on how to solder electronic circuits.
To evaluate the quality of work, you need to evaluate the color and shine of the junction. A high-quality solder has a pronounced shine; if the solder is burned through, it has a matte color and a fragile structure. The spongy structure of the solder indicates a defect.
For the first tests, it is best to use simple and inexpensive materials. The easiest way is to understand how to solder with tin and rosin correctly.
Photo recommendations on how to solder
- We also recommend visiting:
Source: https://regionvtormet.ru/okrashivanie/kak-pravilno-payat-payalnikom-chto-trebuetsya-dlya-pajki-s-ispolzovaniem-kanifoli.html
What is flux solder and how to use it?
Reading time: 6 minutes
Solder and flux for soldering are indispensable tools for many home and professional craftsmen. With their help you can achieve high-quality, even seams. Manufacturers offer many types of fluxes and solders. There is even solder on the market that has flux inside! And all this variety is difficult to understand if you have never used solders and fluxes.
We decided to make your task easier and tell you about the types of solders and fluxes and their applications. You will learn how low-melting solders differ from high-melting solders, what active and passive fluxes are, and how to use these materials in your work.
Types of solders
Solder is a metal rod used to fill joints between two parts. It melts and mixes with the base metal or acts as a base metal altogether. May have different diameters. Made from tin, but with the addition of other metals. For example, lead zinc or copper. Can be low-melting or refractory.
Low-melting
Low melting point solders are most often used for small jobs. For example, when soldering radio equipment. Also, such solder is indispensable if soldering of radio-electronic elements is necessary. In the composition you can most often find a combination of tin with cadmium, bismuth, lead or zinc.
Based on the name, it is not difficult to guess that such solders melt easily. One small soldering iron is enough to melt them. If you need solder for working with radio electronics, then choose rods with a melting point of up to 140 degrees.
There are also special solders for tinning circuit boards. Their melting point does not exceed 100 degrees. Due to these properties, tinning is easier and faster. Solders have their own brands, but we will not focus on this. This is a topic for a separate article.
Let's just say that when soldering modern equipment, it is recommended to use lead-free solder and with a melting point of about 200 degrees. This is due to the peculiarities of foreign technology. It is manufactured in accordance with strict environmental regulations, according to which lead emits harmful fumes when soldering.
Refractory
Refractory solders are the antithesis of low-melting solders. Their melting point starts at 400 degrees. Such solders are used in professional industrial welding, where large parts need to be welded. Refractory solders contain a lot of copper, silver, nickel or magnesium. They are very strong and thick, so they are not used in home soldering. Such solders reveal their potential when welding refractory metals. For example, cast iron or brass.
Solder with flux
There is a separate category of solders - this is solder with flux inside. It's tubular solder. It is a hollow rod, the core of which contains flux. The rod melts during soldering, allowing flux to be released and perform a protective function. A striking example is Castolin 192 K flux solder and Brazetec Comet 3476U solder.
Such solders are very convenient to use because they perform two functions at once: practical and protective. There is no need to waste time applying flux and choosing it. But you must understand that such solders do not provide sufficient protection for the soldering area. They only slightly improve the quality of the seams. If you need a perfect result, it is better to use solder and flux separately from each other. Like two different materials.
But what flux is and why it is needed, you will find out further.
Types of fluxes
Flux is a substance applied to the soldering or welding site that protects the metal from oxidation and improves the quality of the seam. Flux can radically change the quality, including the evenness of the seam and its aesthetic characteristics. Therefore, you need to approach the choice of flux wisely.
There is a clear connection here with solder. The easier the solder melts, the better the properties of the flux are revealed. The flux should have a melting point slightly lower than the solder. Then you will achieve high-quality results.
Manufacturers offer two types of soldering fluxes: active and passive.
Chemically active
Chemically active fluxes contain acid-containing substances. They, in turn, are ways to destroy any plaque or signs of corrosion. Well-known hydrochloric acid, zinc chloride, etc. can be used as an acid-containing agent. If the soldering area is not cleaned of flux residues, the metal may deteriorate and new corrosion will appear.
The chemical activity of such fluxes is both an advantage and a disadvantage at the same time. If used improperly, such fluxes corrode metal and textolite if used in radio electronics. Do not forget that such fluxes can leave burns on the skin, so it is important to follow safety precautions. But when used correctly, active fluxes remove any plaque and corrosion, allowing you to improve the quality of work.
We do not recommend using chemically active fluxes in everyday soldering. They require attention and experience. And when soldering radio components, it is better not to use this type of flux at all. Because with a high probability it will corrode the textolite, and you will not be able to fix anything.
Chemically passive
Chemically passive fluxes are used very often. They do not have such pronounced oxidizing properties as chemically active ones, so they are easier to work with. Chemically passive fluxes remove grease and light stains, but not corrosion. These fluxes contain organic components, so they can be used when soldering radioelements.
Chemically passive fluxes protect the welding zone from oxidation and improve the quality of work. However, like chemically active ones.
Source: https://svarkaed.ru/rashodnye-materialy/flyus-i-svarochnaya-provoloka/chto-takoe-pripoj-s-flyusom-i-kak-ego-ispolzovat.html
How to make your own solder paste
A soldering iron is the main tool for people who are interested in radio electronics. But to mount SMD elements on a printed circuit board, one soldering iron is not enough. It is necessary to purchase solder paste for it, which will not only hold small parts on the surface of the board, but will also increase the reliability of their fastening. You can buy it ready-made, or you can prepare it yourself. Solder paste is easy to prepare with your own hands, and its properties are not inferior to expensive analogues.
Solder Paste Application
Solder or solder paste is used in the electronics industry for mounting SMD components on printed circuit boards. This substance is used in the installation of water supply systems. It is used to connect pipes and fittings made of copper and brass alloys.
Using homemade solder paste
If the installation of water supply systems requires a special paste, which is difficult to make yourself, radio engineering parts are less finicky. But in order to get a quality product that meets all the necessary requirements, homemade solder paste must meet the following criteria:
- it should not oxidize or quickly delaminate;
- the product must maintain viscosity and deformability for a long time;
- the applied dose of the prepared mass should not spread beyond the application site;
- After soldering there should be no solid residues that cannot be removed.
It is important to pay attention to the adhesive properties of the finished product, since this quality will allow you to securely attach small parts to the board. When heated, metal tends to spatter. The use of high-quality paste is designed to minimize this property.
It is important that applying a paste-like composition to the board does not reduce the technical characteristics of the latter. And product residues could be easily removed using standard solvents.
To understand how to make solder paste at home, you need to know what it contains. This substance is based on solder powder. It is mixed with a binder and some other components.
Advantages of a homemade product
Knowing how to make solder paste is not enough. It is also important to evaluate the merits of a product prepared with your own hands. The use of paste-like substances in radio electronics makes it possible to produce micro-boards with very fine details. In this case, there is no need to use a soldering iron and a set of other standard tools.
Homemade solder paste
However, instead of a traditional soldering iron, you will have to use a special hair dryer, which melts the components of the paste and secures the parts in place.
The main disadvantage of purchased products is their high cost. Making homemade pasta will save you a lot of money. By purchasing all the components of the product separately, you will be able to obtain a similar substance, the final cost of which will be several times lower.
Varieties of compositions for soldering work
To connect elements using soldering, compounds that have a lower melting point are used. Previously, solder was used for these purposes in combination with flux - a substance that helps remove oxides from soldered surfaces and improves the spreading of solder.
Modern electronics manufacturers use special formulations that contain both of these components, as well as various additives that speed up the soldering process.
DIY solder paste for soldering SMD components is prepared from the following components:
- solder (made from lead, tin or silver);
- flux;
- connecting components.
Solder pastes are divided into several types:
- washing;
- no-wash;
- water soluble;
- halogen-containing;
- halogen-free.
The change in composition is influenced by flux. Pastes that cannot be washed off with water are prepared by adding rosin. To wash the composition off the board, you will have to use solvents.
Preparing the base for homemade solder paste
Description of cooking technology
Making solder paste for SMD with your own hands is not difficult at all. Depending on the type of work performed, you can use one of three methods to prepare the composition.
For fine soldering. This composition contains the following components:
- refined vegetable oil – 100 g;
- beef fat (melted and strained) – 300 g;
- rosin – 500 g;
- ammonium chloride – 100 g.
All components except ammonium chloride are placed in a porcelain container and heated in a water bath. During the heating process, they must be carefully mixed until a homogeneous consistency is obtained. Ammonium chloride is poured into the resulting composition and mixed. The paste is transferred to a jar and sealed tightly.
For very fine soldering. This composition is indispensable when performing very delicate work. Palm oil is used for these purposes. It itself has a paste-like consistency.
Its effectiveness can be increased by adding ammonium chloride. In DIY solder paste, the proportions of this substance should be about 5-10%. Instead of ammonium chloride, you can use aniline hydrochloride. The substances are placed in glass containers and ground until a homogeneous consistency is obtained. The jar must be stored tightly closed.
Adding Flux to Homemade Solder Paste
DIY solder paste for copper soldering and tinning. To prepare such a composition you will need the following components:
- tin-lead solder rod;
- solder fat.
Using a file, a needle file and a mechanical attachment on a drill, you need to grind the rod into fine crumbs and mix it in equal proportions with solder fat, heating it in a water bath. When the mixture reaches a uniform consistency, it is transferred to a large medical syringe.
Conclusion
Any thrifty owner will have the ingredients to prepare solder paste with his own hands. And with a little effort, you can prepare a product whose characteristics are superior to expensive analogues.
Do-it-yourself quality solder paste (subtitles available)
Source: https://svarkaipayka.ru/material/flyus-dlya-payki/kak-izgotovit-payalnuyu-pastu-svoimi-rukami.html
Brands of soft solders and fluxes for soldering with a soldering iron
For soldering with a soldering iron, solder is used, and in order for the solder to spread well over the surface of the parts being connected by soldering, a substance called flux is used. Depending on the metal of the parts and their size, the strength and tightness of the soldering, it is necessary to choose a specific brand of solder and flux. The information in the tables will help you select the required solder and flux for soldering.
Brands of soft solders for soldering with a soldering iron
The main component when soldering with an electric soldering iron is tin-lead solder. It is available in the form of wire or tube of different diameters. The tubular solder inside is filled with rosin. This type of solder is very convenient when working, since it does not require additional flux to the soldering iron tip.
Solder is an alloy of low-melting metals. As a rule, solder contains tin. You can solder with pure tin, but it is expensive and therefore cheap lead is added to the tin. Tin is an environmentally friendly metal and can be used as solder for soldering food utensils and medical instruments in its pure form. If you bend or squeeze a tube made of pure tin, it crunches. The more lead in the solder, the darker the surface of the solder.
Solders are marked with letters and numbers. For example, POS-61, which means P - solder, O - tin, S - lead, 61 - % tin content. POS-61 is the most common, as it is suitable for soldering in most cases. Popularly, POS-61 is often called a tertiary, since it contains a third of lead (Pb).
Solders can be soft or hard. The melting point of soft solders is below 450˚C. Hard solders melt when heated above 450˚C and are not used for soldering with an electric soldering iron.
Main technical characteristics of soft solders
for soldering with an electric soldering iron
The electrical resistivity of tin-lead solder (conductivity) is 0.1-0.2 Ohm/meter, aluminum 0.0271, and copper 0.0175. As you can see, solder conducts current ten times less than copper or aluminum.
The most common solder is POS-61, also called tertiary. It is excellent for soldering and tinning of live parts made of copper, brass and bronze with a sealed seam and is not expensive. Suitable for almost all household soldering situations.
Flux is an auxiliary substance necessary for freeing the surfaces of parts being soldered from oxides and for better spreading of solder over the metal surface during soldering. Without using flux, it is almost impossible to perform high-quality soldering with a soldering iron.
When preparing the most popular fluxes for soldering with an electric soldering iron, rosin is used. It is obtained from the wood of coniferous trees, mainly pine. At a temperature of about 50°C, rosin softens, and at 250°C it begins to boil.
Rosin is not resistant to atmospheric moisture - it hydrolyzes. It consists of 85-90% abietic acid. If you do not remove the remaining rosin after soldering, oxidation of the soldering area occurs. Many people do not know this and believe that rosin is harmless to metal. In addition, by absorbing water from the atmosphere, rosin increases its conductivity and can disrupt the operation of electronic devices, especially their high-voltage circuits.
Popular fluxes for soldering with an electric soldering iron
Flux based on alcohol and solvents must be stored in an airtight container, otherwise the liquid will quickly evaporate. A bottle of manicure polish is very convenient for this purpose. Always have a brush at hand, which is convenient for applying flux to the soldering area.
You can find such a bottle in almost any home. Another advantage is that the brush and twist are not dissolved by alcohol and solvent. Before filling with flux, be sure to thoroughly wash the bottle and varnish brush. If the varnish has hardened too much, pour in acetone and leave.
After a while the varnish will dissolve.
I prepare alcohol-rosin flux in a bottle. First, I pour rosin powder through a paper funnel and then fill it with alcohol. It is easy to pour alcohol into the narrow neck of the bottle if you touch the neck of the bottle with alcohol to a brush previously soaked in alcohol. You need to pour it very slowly and you won’t spill a single drop. Over time, the alcohol evaporates and the flux becomes thick. Then you need to dilute it with alcohol to the required consistency.
As a flux, I often use the undocumented flux of aspirin (acetyl salicylic acid), which is used as a medicine. With its help, you can tin copper and steel surfaces without prior preparation. Liquid flux for soldering with a soldering iron can easily be prepared on the basis of aspirin; just dissolve the tablet in a small amount of alcohol, acetone or water.
Solder pastes (tinol) for soldering
Solder paste (tinol) is a composition of solder and flux. The paste is irreplaceable when soldering with a soldering iron in hard-to-reach places, and when installing unframed radio components. The paste is applied with a spatula in the required amount to the soldering area and then heated with an electric soldering iron. The result is a beautiful and high-quality soldering. Its use is especially convenient if you have no experience working with a soldering iron.
You can make your own pasta. To do this, you need to select a brand of solder suitable for soldering the required metal. Next, use a file with a large notch to cut sawdust from the rod. Then add the liquid soldering flux selected from the table, mixing the sawdust until a paste-like composition is obtained. The paste should be stored in an airtight container. The shelf life of the paste is no more than six months, since solder filings oxidize over time.
Source: https://YDoma.info/tehnologii-remonta/kak-payat/kak-payat-pripoi-flyusy.html
How to solder with flux and solder
Before you solder with a soldering iron, you need to get everything you need. The main tools and materials without which soldering is impossible include the soldering iron itself, solder and flux.
Fluxes
Choosing the right flux for soldering means solving the main problem of soldering. It is the quality of the flux that primarily determines the solderability of a particular metal, the ease or difficulty of the soldering process itself, and the strength of the connection. The flux must correspond to the material of the products being soldered - in its ability to destroy its oxide film.
Effective fluxes for soldering steel are an aqueous solution of zinc chloride, soldering acids based on it, and LTI-120 flux. You can use other, stronger fluxes, of which there are plenty on the market.
The main difference between soldering stainless steels with a soldering iron and soldering carbon and low-alloy steels is the need to use more active fluxes, which are required to destroy the chemically resistant oxides with which stainless steels are coated. As for cast iron, it needs to be soldered with high-temperature soldering, and, therefore, an electric soldering iron is not suitable for this purpose.
For stainless steel, phosphoric acid is used. Specialized fluxes, such as F-38, also cope well with chemically resistant oxide films.
For galvanized iron, you can use a composition containing rosin, ethyl alcohol, zinc chloride and ammonium chloride (LK-2 flux).
Auxiliary materials and devices
The soldering iron stand is used to ensure that the heated soldering iron does not touch the table or other objects. If it does not come with a soldering iron, you can purchase it separately or make it yourself. The simplest stand can be made from a thin sheet of tin, cutting grooves in it for storing tools.
soldering iron with a damp viscose or foam sponge placed in the socket to prevent it from falling out than with a regular cloth. Brass shavings can also serve for the same purposes.
Excess solder can be removed from the surface of parts using a special suction or braid. The first one, in appearance and design, resembles a syringe equipped with a spring. Before use, it must be cocked by recessing the rod head. By bringing the nose to the molten solder, the spring is released by pressing the release button. As a result, excess solder is drawn into the removal head.
Desoldering braid is a braid of flux-fluxed thin copper wires. By placing its end on the solder and pressing it on top with a soldering iron, thanks to capillary forces you can collect all the excess solder in it like a blotter. The tip of the braid, saturated with solder, is simply cut off.
A very useful tool is called Hand Tool. When working with a soldering iron, sometimes there are catastrophically “not enough hands” - one is occupied with the soldering iron itself, the other with the solder, but you still need to hold the soldered parts in a certain position. The “third hand” is convenient because its clamps can be easily installed in any position relative to each other.
The parts being soldered are heated to high temperatures; touching them can cause you to get burned. Therefore, it is advisable to have various clamping devices that allow you to manipulate heated parts - pliers , tweezers , clamps .
Preparing the soldering iron for use
Before using a soldering iron, you need to prepare its tip. Preparation depends on its original form. If the tip is made of bare copper, the tip can be forged into a screwdriver shape, this will seal the copper and make it more resistant to wear.
You can simply sharpen it with sandpaper or a file, giving it the required shape - in the form of a sharp or truncated cone with different angles, a tetrahedral pyramid, an angular bevel on one side. Nickel metal coatings are used to protect copper from oxidation.
If the soldering iron has such a coating, then it cannot be forged or sharpened to avoid damaging the coating layer.
There is a standardized range of tip shapes, but you can, of course, use any shape suitable for the particular job.
When soldering massive parts, the contact area between the soldering iron and the part should be maximum to ensure better heat transfer. In this case, angular sharpening of a round rod (2 in the photo above) is considered the best. If you plan to solder small parts, then a sharp cone (4), knife or other shapes with small angles are suitable.
Instructions for working with a soldering iron that has an uncoated copper tip contain one mandatory requirement - tinning the “tip” of the new soldering iron in order to protect it from oxidation and wear. Moreover, this should be done during the first heating, without delay. Otherwise, the “tip” will be covered with a thin layer of scale, and the solder will not want to stick to it. This can be done in different ways.
Heat the soldering iron to operating temperature, touch the “tip” to the rosin, melt the solder on it and rub the solder on a piece of wood. Or wipe the heated tip with a rag moistened with a solution of zinc chloride, melt solder on it and rub it over the tip with a piece of ammonia or rock table salt.
The main thing is that as a result of these operations, the working part of the tip is completely covered with a thin layer of solder.
The need to tin the tip is caused by the fact that the flux gradually corrodes, and the solder dissolves the tip. Due to loss of shape, the tip has to be sharpened regularly, and the more active the flux, the more often, sometimes several times a day. For nickel-plated tips, nickel blocks access to copper, protecting it, but such tips require careful handling, they are afraid of overheating, and it is not a fact that the manufacturer has made a sufficiently high-quality coating, for which they require an overpayment.
Preparing parts for soldering
First of all, this is cleaning the part from dirt and degreasing. There are no special subtleties here - you need to use solvents (gasoline, acetone or others) to clean the part from oils, fats, and dirt.
If there is rust, it must be removed by any suitable mechanical method - using an emery wheel, wire brush or sandpaper.
In the case of high-alloy and stainless steels, it is advisable to treat the edges being joined with an abrasive tool, since the oxide film of these metals is particularly strong.
Soldering temperature
The soldering temperature (temperature of the parts being soldered) should be 40-80°C higher than the melting temperature of the solder, and the heating temperature of the tip should be 20-40°C higher than the soldering temperature. The last requirement is due to the fact that when it comes into contact with the parts being soldered, the temperature of the soldering iron will decrease due to heat dissipation.
Thus, the heating temperature of the tip should exceed the melting temperature of the solder by 60-120°C. If a soldering station is used, the required temperature is simply set by the regulator. When using a soldering iron without temperature control, its actual value, when using rosin as a flux, can be assessed by the behavior of the rosin when touched by the soldering iron.
It should boil and release abundant steam, but not burn instantly, but remain on the tip in the form of boiling drops.
Source: https://crast.ru/instrumenty/kak-pajat-s-fljusom-i-pripoem
Solder with rosin: a few secrets of soldering
Every radio amateur or DIY repairman will sooner or later be forced to pick up a soldering iron and try it. The quality of the work performed and even the performance of the product will directly depend on many factors, which you must know about before starting work.
Proper use of a soldering iron
Despite the apparent simplicity of working with a soldering iron, it is very desirable to have initial skills in high-quality work and be able to correctly use solder with rosin.
Soldering is done using a variety of solders. The so-called solder in a rosin reel is perhaps the most popular. When performing work related to soldering, solder is used. The amount of tin and lead it contains is 60 and 40%, respectively. This alloy melts at 180 degrees.
What is needed to work with a soldering iron:
- the soldering iron itself;
- solder;
- rosin.
Heated solder will create a sufficient internal bond with metals such as copper, brass, silver, etc., if the following conditions are met:
- The surfaces of the parts must be cleaned of oxides.
- The part at the soldering site is heated above the melting point of the solder itself.
- During operation, the soldering area must be protected from exposure to oxygen; various fluxes are used for this purpose. They create a protective film directly above the soldering area.
A book on how to solder can be read and understood, but soldering skills can only be learned through practice.
Tricks and secrets of working with a soldering iron
After the solder has begun to melt, it can already be used for soldering. To do this, you need to cover the soldering iron tip with a thin layer of solder, and then wipe it thoroughly on a damp sponge. This is how the solder and rosin remaining from work are removed. It won’t hurt to get into the habit of wiping the tip with a wet sponge every time after soldering.
Before you start soldering a radio component, you need to prepare it. Its leads should be bent so that the part fits freely into the holes intended for it.
Beginners without experience often touch the soldering area with the tip of the soldering iron tip. And you need to hold the soldering iron so that the contact area between it and the place of soldering is as large as possible, otherwise the place where you need to solder does not heat up enough to hold the parts together.
How to clean a soldering iron tip
When soldering, carbon deposits often appear on the soldering iron. It can be removed with plain water. If you run a soldering iron over a damp cloth, the scale will remain on it, and the tip will become clean again. You need to do this periodically while working with a soldering iron. If the cloth doesn't help, you can use a stiff sponge.
- The tips are removable and coated with nickel.
- Copper stings.
First-class soldering tips are usually used in complex soldering irons, in which it is possible to regulate the temperature.
The stings of the second are the most common.
Types of nickel-plated soldering tips
- The needle-shaped tip is used to solder very small radio components, such as SMD. When repairing phones, such a tip is indispensable. It is used on boards with a high density of mounted parts.
- Tip-spatula - used for desoldering and in cases of installation of large radio components. They work with multi-pin microcircuits.
- The tip is in the shape of a drop - it is convenient for them to transfer solder with rosin to the place of soldering, which leads to improved quality of work.
- A tip with a curved shape - most often it is used to solder radio components that are in a copper shell, so that no excess solder remains on the board. It can also be used for regular soldering. The soldering iron heats up to a temperature of 290-300 C.
When working with a soldering iron, you must always keep it perfectly clean. New soldering tips are usually hammered to create fine nicks on the surface.
Subsequently, they are carefully trimmed with a file to give the tip the most correct shape.
Then the tip should be tinned using solder with rosin. That is, cover with a thin layer of solder, dipping it in rosin.
How to cool a soldering area
The metal tweezers used to hold the radio component also work as a heat sink during the soldering process. You can also use a special alligator clip for this purpose.
Secrets of soldering with a soldering iron
To obtain a good result when soldering, you must correctly use solder with rosin and flux. This is a low-melting alloy of a special metal that is used to solder the leads of parts and wires.
- The best solder is pure tin. But such metal is too expensive to be used for soldering. Therefore, when working with radio components, so-called lead-tin solders are used.
- Lead with tin. In terms of soldering strength, these solders are no worse than pure tin. They melt at a temperature of 170-190 degrees. It is customary to denote such solders by the abbreviation “POS” - tin-lead solder. The number after these letters in the designation means the share of tin, expressed as a percentage. It is better to use POS-6O solder.
- Fluxes are substances that have antioxidant properties. They are used to prevent oxidation of the soldering area. If you don't use flux, the solder simply won't stick to the metal surface.
Types of fluxes
When working with radio components, fluxes that do not contain acid are used. For example, rosin. Bow rosin for lubricating musical instruments is also sold in stores. It can also be used for soldering. But metal utensils are soldered using solder without rosin. To repair it you will need “soldering acid”. This is zinc dissolved in hydrochloric acid. It is also impossible to solder radio components with such solder, since over time it will destroy the soldering.
If you need to solder in hard-to-reach places, you need to have liquid flux. You can make it yourself. Rosin is crushed into powder and poured into acetone or ethyl alcohol.
After mixing the solution, you need to add more rosin until you obtain a thick, mushy mass. Such liquid rosin should be applied to soldering areas with a brush or stick. However, there is a nuance - to work with printed circuit boards, the flux must be more liquid.
For hard-to-reach places, you can also use wire solder with rosin, which is much more convenient.
When working with various fluxes, it is necessary to take into account that those that contain acetone are very toxic. Therefore, when working with them, it is necessary to avoid getting vapors into the respiratory tract. It is better to solder near a window if it is summer, and in winter it is better to ventilate the room in which the work is being carried out. After finishing work, be sure to wash your hands with soap and warm water.
How to solder with rosin
An important condition for successful soldering is maintaining the cleanliness of the surfaces that need to be soldered. Be sure to clean the soldering areas until they shine. Then the parts need to be placed on a piece of rosin and warmed up. The melted rosin will help the solder spread evenly over the conductor or part that needs to be soldered. You can carefully rotate the part while moving the soldering iron tip over it so that the solder spreads in an even layer over the surface.
If you need to tin a conductor that is soldered into a board, then after cleaning the soldering area with sanding paper or a knife, you need to bring a piece of rosin, and then smoothly distribute the solder as evenly as possible, using a soldering iron.
The quality of soldering is also affected by how correctly the wires or contacts of the parts are connected during soldering. They should be pressed tightly together and then bring the soldering iron to the prepared conductors, touching it. After the heated solder has spread over the surface, filling even small gaps between them, the soldering iron should be removed.
Continuous soldering time should be no more than five seconds. After this period of time, the solder will harden and the parts will be firmly connected. However, to prevent the soldering from breaking, the parts should not be moved for 10-15 seconds after soldering is completed. Otherwise the connection will not be strong.
If work is done with transistors, then their terminals must be protected so as not to overheat. It is better to hold them either with pliers or tweezers, thereby dissipating heat.
When soldering radio components, you should never twist the ends of the parts. If you need to resolder parts or replace conductors, you need to think about this in advance, before starting installation. It is best to solder the ends of the parts at a short distance from each other, and not in one place.
Source: https://FB.ru/article/280254/pripoy-s-kanifolyu-neskolko-sekretov-payki
How to properly solder with a soldering iron with solder and rosin
If in Soviet times there was a game for schoolchildren, the essence of which was to solder a radio-electronic microcircuit on their own, which they successfully did, but now the question of how to properly use a soldering iron puts many in a difficult position. Although learning how to solder with a soldering iron is not so difficult, and having mastered the basics for “dummies”, you will be able to carry out simple work on your own without turning to specialists.
Soldering with a soldering iron
In order to start soldering, you need to prepare a workplace and the necessary tools. Regardless of the type of proposed work, the following requirements are imposed on the workplace:
- The presence of good lighting will allow you not only to work comfortably, but also to notice small flaws in the soldered parts, which is difficult if there is a lack of light;
- No flammable items;
- Free working space on which you can easily place the part to be soldered;
- The presence of ventilation will make work not only more comfortable, but also safer; inhaling molten rosin has a negative effect on the respiratory system;
- A magnifying glass makes it possible to work even with small parts and thin wires;
- A simple stand solves the problem of placing a heated soldering iron.
The next stage of preparation will be the choice of tool, and a beginner is always faced with the question of what is needed for soldering with a soldering iron.
Soldering iron selection
The basis of high-quality soldering is heating metal parts to the soldering temperature; accordingly, for each type of work it is recommended to use soldering irons of different capacities:
- For soldering radio components and microcircuits, it is best to use a soldering iron with a power of no more than 60 Watts, otherwise you can overheat the part or simply melt it;
- Parts up to 1 mm thick will warm up better when using a tool with a power of 80-100 Watts;
- Parts with a wall thickness of up to 2 mm require greater power and some experience in operation, so soldering of such parts will not be considered in this article.
Source: https://pochini.guru/sovety-mastera/kak-pravilno-payat-payalnikom
Flux for soldering: purpose, method of application - Welding
In many industries, soldering is used to join solid materials. High-quality work depends on the availability of tools, equipment and consumables, one of which is flux. Those who attended an amateur radio club as a child or loved to solder at home know what flux is and why it is needed.
Flux is a special alloy of materials with a light structure and is used to join two different materials. In this case, it is more advisable to use a substance suitable for a specific material. That is, a certain composition for enameled metals, and a completely different one for joining copper objects.
But those who first encountered the procedure do not quite understand why rosin is needed when soldering. Amber pieces, familiar from childhood, are the most common flux. Their use results in better and faster soldering. Thanks to rosin, the solder has better contact with the surfaces of both materials.
The tasks of flux during soldering are as follows:
- prepare the surfaces of two products;
- clean the surface of various films and fats;
- Reduce surface tension in the solder.
When using an alloy, the contact area of the objects being connected increases, which promotes strong contact. The substance also extends the service life of soldered elements, because it prevents the formation of new oxidation processes at the joints. This is why rosin and other types are needed. Having learned what it is, you should understand the classification of the alloy.
Types and characteristics
Joining alloys are classified by how they act on the components before, during and after soldering. The same rosin, like many compounds based on it, belongs to the group of low-active fluxes.
If such a flux is needed for anything, it is for soldering microcircuits, where the capabilities of the composition are fully realized. The alloy removes thin oxide films well from copper, brass and other surfaces.
But it does not cause corrosion due to minimal activity. If it is necessary to improve the properties of rosin, the substance is combined with turpentine or alcohol. As a result, acid-free or neutral species are obtained.
This type is often used during the repair of radio electronics, as well as in its production. For such purposes, this particular alloy is chosen because the flux is a dielectric and does not generate current leaks.
If acid is added to rosin, a third type is obtained – activated. Most often, the alloy includes organic acids and amine compounds in small doses. With its help, it is possible to connect copper parts, as well as silver, iron and nickel.
Active fluxes, which include hydrochloric acid, are used to join iron products. But if you add zinc chloride to it, you get “soldering flux.” This composition is produced not only in industry, but also at home.
It is suitable for soldering silver, copper and iron components. But flux is strictly prohibited for use in radio electronics. Because the alloy has high electrical conductivity and chemical reactivity.
Fluxes are also anti-corrosion and protective. The first type is designed to remove corrosion from the surface of the element, and the second does not allow the formation of oxides on an already treated surface. Corrosive fluxes are recommended if the surfaces of both products are susceptible to rust. They include substances such as:
- salicylic acid;
- technical petroleum jelly;
- ethanol;
- triethanoamine
Protective fluxes are the familiar Vaseline, wax, powdered sugar and olive oil.
Differences between alloys
Solders and fluxes also differ in physical state into liquid, solid and paste. Thanks to this diversity, the methods of application are significantly expanded. For example, treat hard-to-reach areas of products with liquid glory to protect them from oxidation. But the amount of paste flux supplied is easier to control when soldering.
Another factor by which alloys are distinguished is temperature. There are substances that are active at high temperatures, and there is another group that melts at sub-zero temperatures. The refractory composition binds products more firmly. But there is one caveat: due to the high melting point, the composition can damage the part itself and render it unusable.
Fluxes that melt at temperatures from 50 to 400 degrees belong to the low-melting group. They are used in radio electronics. Fluxes contain lead, tin and other elements. Each type of alloy has its own purpose, taking into account which you need to choose a flux for a specific job.
Thus, hard flux should be used for soldering products with large diameters, and soft alloys are suitable for joining thin surfaces. If you need to repair metal utensils, it is better to give preference to “soldering flux” - a solution of zinc with hydrochloric acid.
The advantages of alloys are the protection of previously cleaned metal surfaces from oxidation, as well as the connection of solder to the prepared surface. You can check whether flux is really necessary if you try once to solder two different products without auxiliary material.
The best substitutes
Compositions used in industry or by professional craftsmen can rarely be found in an ordinary person’s apartment. But what to do if the need for soldering arises.
https://www.youtube.com/watch?v=MKZBAqnGoZ4
How to replace flux? One of the most common substances is aspirin dissolved in water. The composition is easy to prepare at home - just crush one tablet and pour the powder into a container with water.
The resulting solution is used as a regular liquid flux.
Another substitute is acetic or citric acid. The effectiveness of fluxes prepared at home is lower than the original ones, but certain indicators can be achieved with them.
Using concentrated hydrochloric acid is what will improve the performance. It is only important to handle acid carefully, as it is hazardous to health. Products soldered using this composition should not be thin.
You can prepare flux at home from phosphoric acid, which is sold in stores and has good performance. It perfectly removes oxides, fat deposits and various films.
Based on what characteristics should you choose a composition?
The fluxes used are selected in accordance with the following requirements:
- stretching abilities;
- strength;
- ability to conduct current and heat.
The substance for soldering is selected based on the type of metal being joined, the temperature of both the alloy itself and that achieved during the procedure. It is also necessary to take into account the strength and resistance of elements to corrosion. When choosing solder alloys, you should use those with a lower specific gravity. Then the solder will displace the flux onto the surface of the product when applied.
If soldering fluxes are selected for transistors, then ultra-low-melting compounds are used. The maximum temperature at which they are activated is 150 degrees.
Source: https://svarkaman.ru/metall/flyus-dlya-pajki-naznachenie-sposob-primeneniya.html
