What is soldering flux

Why do you need flux when soldering?

The soldering procedure can be carried out independently if you have the required materials and tools. It is used to connect individual metal elements when using solder and flux. The second auxiliary substance can significantly improve the quality of the resulting seam. When considering what a soldering flux is, one should take into account a large number of its varieties; only with the correct selection and application can the required connection reliability be ensured.

What is flux?

Soldering flux is used when joining several materials. Depending on the structure of the substance, the temperature at which soldering can take place varies in the range +50+500°C.

The choice of flux compositions is carried out taking into account the following points:

1. Melting temperature. All materials are characterized by the temperature at which it becomes plastic.
2. The type of material also matters. Some of them may react chemically with the substances used during soldering.
3. Temperature operating conditions. Some resulting products may be exposed to environmental heat.
4. Surface resistance to corrosion. Some of them are susceptible to oxidation. Corrosion causes a decrease in electrical conductivity, strength and other properties.

Some versions are made in hard form, others in soft form. Use involves exposure to high temperature, at which a change in state occurs.

Purpose

When using solders, a change in the basic qualities of the material occurs at temperatures above +500°C. As a result of exposure to heat and certain substances, a high-quality compound is obtained. The disadvantage of this connection method is that there is a high probability of overheating of the material.

Flux is used as an easily alloyable type of substance that is used in the field of radio engineering and other industrial activities. The temperature range is +500°C, so processing when using these fluxes does not lead to damage to the connecting elements and the board. Among the features we note the following:

1. The composition includes lead and tin.
2. Super low-melting materials are used when working with transistors and other electronic equipment. Oxidation temperature is not higher than +150°C.

The use of special solutions allows you to achieve better results. This can be related to the following points:

1. Increased heat transfer and electrical conductivity. Such properties allow you to quickly heat the surfaces being joined without changing the basic characteristics.
2. The strength of the resulting connection increases significantly. Some elements are included in the composition of the metal, making it stronger and more reliable.
3. The degree of surface resistance to corrosion and oxidation increases. Such changes can cause deterioration in strength and conductivity.

There are various flux compounds on sale that can be used for soldering. Recommendations for selection include the following:

1. The heating temperature is determined. Each material melts at its own temperature, which must be taken into account.
2. The type of material that will be joined is taken into account.
3. The basic properties that a connection must have are considered: conductivity, strength, resistance to variable loads.

When repairing radio equipment, one composition is used, and for industrial melting another.

Types of flux compositions

The substances under consideration are divided according to the type of effect on the parts being connected during the soldering process. Flux is capable of removing a thin oxide layer of metal from the surface, thereby reducing the likelihood of corrosion. The most common types of fluxes are:

1. Active. Hydrochloric acid is used in production. Such compositions are suitable for joining iron elements. In some cases, zinc chloride is used in manufacturing. Active flux has increased chemical activity. The increased degree of electrical conductivity allows you to connect large wires. This design option is not recommended for use in radio engineering, since flux residues are practically impossible to remove from the surface of the boards.
2. Acid-free. This substance is created on the basis of glycerin, as well as ethyl alcohol or turpentine. Its use is possible at temperatures up to +150°C. The active composition can remove thin layers of lead, copper, and tin from the surface. Therefore, when using it, the surface can be cleaned. Area of ​​application: surface soldering without metal separation. Craftsmen use the composition to work with small parts and electrical circuits.
3. Activated. A similar substance is made on the basis of aniline hydrochloride and salicylic acid. The area of ​​application is the soldering of all parts that do not need to be cleaned first. It is possible to use activated flux when joining materials that are subject to mechanical stress during operation.
4. Anti-corrosion. The purpose of such compositions is to protect the surface from the occurrence of corrosive deposits. The main component is orthophosphoric acid; it is included in all impregnations with anti-corrosion properties. The substance does not have a destructive effect on the structure of the material; corrosion is removed through a chemical reaction.
5. Protective. The composition of the substance determines that after its application the required level of protection against oxidation is provided. A distinctive feature of this group is that olive oil, wax, petroleum jelly and other oily substances are used in production. The area of ​​application is soldering small microcircuits.
6. Refractory. In the manufacture of such flux options, copper, zinc and phosphorus are used. In some cases, silver is also included.

Classification is also carried out according to other criteria; only a specialist can choose the appropriate version of the substance, based on his experience. The wrong substance will reduce the performance of the resulting compounds.

Application procedure

The substances in question can be distributed in solid and liquid states. The application procedure is characterized by the following features:

Source: https://electrod.biz/payka/zachem-nuzhen-flyus.html

What is soldering flux

24.03.2019

Despite the constant development of the industry, soldering does not lose its popularity in this area. With its help, permanent connections of various materials are obtained, if the need arises. However, to organize a high-quality and responsible process, you need to think in advance about the necessary materials and suitable equipment.

This article will take a closer look at why flux is used for soldering and what it is.

Flux and its features

Flux is an alloy of certain materials. It has a special structure that is easy to melt, which allows the flux to be used for soldering a variety of parts. The alloy can be produced industrially, or you can create it yourself. The article number in stores for such alloys is 040053.

In order to join two materials using flux, you need to maintain a certain temperature while creating the seam. Temperature readings range from 50 to 500 degrees.

It is worth immediately noting that flux has several types, so when choosing a suitable alloy you should pay attention to the following factors:

• type of metal and its melting point;
• strength;
• resistance to rust formation.

Depending on certain points, the possibility of using the selected flux is determined.

Types and classification of fluxes

There are two main classifications of fluxes:

1. Solid. This group includes alloys created at high temperatures.
2. Soft. In this case, the melting temperature is quite low.

As for the first group, the temperature of seam formation can reach 500 degrees and exceed this figure. The advantage of this group of fluxes is the creation of a strong connection. However, a significant disadvantage is the possible overheating of the structure. A problem like this can cause a breakdown.

The second group melts at temperatures from 500C to 4000C. This includes alloys made of lead, tin, and other specially selected impurities. They are used to connect radio components.

If we are talking about thin surfaces, then it is better to resort to soft fluxes. If it is necessary to connect, for example, wires of significant diameter, a solid flux will be required.

As for the material used as solder, it is usually:

• rods;
• wire;
• tubes filled or covered with colophonium.

Tin rods are considered the most popular solder. The optimal diameter of such similar elements should not exceed 5 cm, the minimum value is 1 cm.

Features of low-melting alloys

Special attention should be paid to the features of each of the available groups of fluxes. When it comes to soldering with soft flux, the main feature is the formation of a strong but elastic seam. In turn, light fluxes are divided into categories such as:

• special;
• fusible;
• tin-lead.

Tin is considered one of the most famous and sought-after metals, but the pure version of this type is a rather expensive material, and various impurities are often used in fluxes. Lead acts as an additional element.

Special fluxes are used to combine several characteristics of two materials by soldering them. Nickel, aluminum, tungsten, steel, cast iron, and iron are used as soldering compounds.

For example, to solder structures made of aluminum, you will need an alloy consisting only of tin.

Features of refractory alloys

Hard alloys are also divided into certain categories:

1. Copper-zinc alloys.
2. Silver.
3. Phosphorus-copper.

Zinc and copper are used quite rarely, as they have two main disadvantages - low weld strength and high cost. Silver is also used quite rarely. Usually it is replaced with brass or zinc. It is also possible to use bronze.

Using copper and phosphorus compounds, elements that consist of the same materials are connected. It is very important that the subsequently formed structure does not experience heavy loads in order to avoid deformation and breakage.

Alternative types of solder

Additionally, alternative types of fluxes are distinguished. Among them are alloys:

• With increased resistance to corrosion. The advantage of such alloys is that there is no need to use various liquids or cleaning agents.
• Liquid type. They are made using Vaseline, alcohol, and gold. Salicylic acid is also added to the composition. This type of flux is used to connect electrical enameled wires. The process is distinguished by its purity.
• Rosin and air. It is considered a neutral type of flux, used for almost all electrical appliances;
• Borax and rosin. Using this mixture, pipes through which water or other liquids flow are connected. The compound can withstand fairly high temperatures, and the alloy has no toxic properties.
• Rosin and alcohol. The mixture is an active alloy, after use of which you have to thoroughly clean the device board.

Important! Flux residues lead to short circuits in electrical circuits and damage to the device. Therefore, it is recommended to clean the surface on time.

There are also separate homemade fluxes that can be prepared at home. This will be discussed in more detail below.

Review of popular brands

Below is a table that details the most popular brands, their advantages and disadvantages.

Flux brandProsCons

Phosphoric acid agent	Quickly solders almost any materials. It's inexpensive.	Toxicity. Formation of burns upon contact with skin.
Borax	Used to form alloys when exposed to high temperatures.	As a result, it is necessary to wash off the flux, otherwise it will corrode the burner.
Soldering fat	It evaporates from the surface of the soldering iron for a long time, which indicates its economical use. It also leaves virtually no residue. Cheap.	Solid consistency. It is difficult to apply and also to remove if residue is found.
LTI 120, TAGS, ZIL, flux-gel TT, F64	The ability to use different materials for soldering at different temperatures is inexpensive.	Active fluxes, they need to be washed after use.
Rosin	Inactive flux. The alloy cannot be washed off after use. Emits a pleasant smell when heating.	A huge amount of smoke is released if the quality of the product is low enough.
SKF 64	Availability, popularity, almost complete absence of smoke.	It evaporates strongly during heating and begins to make a characteristic hissing sound.
Amtech RMA-223	It is easy to apply, bonds materials well, and is considered an inactive agent - no-clean.	There are many fakes, the use of which produces smoke.
EFD NC-D500 6-412-A Flux- OFF Rexant	Inactive substance, does not produce smoke, can be easily soldered.	High price.
Unispa -3	A solution of orthophosphoric acid, in the form of a paste, used for stainless steels.	It is quite expensive and fakes are possible.
Interflux fluxes	It has different fluidity, viscosity, characteristics, which allows it to be used almost everywhere.	High price.
KINGBO RMA-218	A good product, available in the form of a gel or paste.	High price.

Thus, based on the table, it can be understood that there are quite a lot of means for organizing high-quality fusion of materials.

How to use

To properly solder simple connections, you need to become familiar with how to use flux. To do this, you need to take into account a few fairly simple rules presented below:

1. All tools for organizing the soldering process must be laid out on the table. These include a soldering iron, sponge, solder, wire cutters or tweezers.
2. It is recommended to carefully connect the soldering iron to the mains to start working. First of all, try to melt the solder.
3. If this happens, then you need to cover the end of the soldering iron tip with molten solder, and remove the insulation from the ends of the wires using wire cutters. So, for example, these could be wires from LEDs.
4. It is necessary to remove the remains of old tin with a sponge in time so as not to cause deterioration of the process or breakage of the soldering iron
5. The process can be started only after the ends of the wires are clamped with tweezers. Then they usually start soldering.

At the end of the connection process, for example, the wires of an LED strip, you need to check the seam for strength, and then remove the remaining flux using a cotton swab soaked in acetone. A good product would be REXANT FLUX OFF 85-0003. It is primarily used as a PCB cleaner to remove flux residues after work.

Important! If you don't have a soldering iron at hand, you can use a hairdryer.

How to make flux with your own hands

You can make your own flux at home. For this you will need:

• Vessel or other container. It is advisable to make a hole at the bottom of the container.
• Tin sheet. A container will be placed on it. Sometimes the sheet is replaced with a metal plate;
• Thin lead or tin rods. From them, in fact, solder will be made.

The sequence of steps for preparing the alloy is presented below:

1. The required number of rods is weighed on the scales.
2. The metal is placed in a previously prepared container. It is placed on the fire to melt.
3. During heating, pieces of metal are mixed using a rod made of steel.
4. When it is melted, remove a thin film from the surface.
5. The resulting alloy is poured into special molds.

Regardless of the type of flux being made (it can be a glycerin alloy or alcohol-rosin), it is necessary to wipe the soldering with a cloth after finishing work. It is advisable to moisten the fabric in acetone before doing this. The seam can be cleaned using a stiff brush coated with a layer of solvent.

In conclusion, it should be said that soldering is rightfully considered one of the best methods of joining metal. With its help, not only the strength of the seam is ensured, but also the tightness. In addition, the process of joining two materials takes less time than, for example, welding.

Source: https://svarkaspec.ru/pajka/instrumenty-i-prinadlzhenosti/flyus-dlya-pajki.html

Flux for soldering metal parts: what it is, its purpose and types

In many industries and in everyday life, soldering is used to connect metal parts and repair any equipment. In order for the work to be of high quality, you need special tools and consumables in the form of solder and flux. And while everything is relatively clear with tools and solder, few people know about flux. Therefore, before the soldering process, you need to understand what flux is and why is it needed?

Fluxes - definition, purpose

Fluxes are chemical active substances with the help of which soldered surfaces are cleaned of grease and oxide films. Surface tension on parts treated with flux is reduced, resulting in improved solder flow. In addition, this chemical can protect joints from environmental influences.

Without flux treatment, solder may not adhere to the surface of the workpiece. Therefore, the material should be selected carefully, guided by the following requirements:

1. The flux must have a melting point lower than that of the solder.
2. It should not react chemically with the solder. That is, when these two materials melt, two immiscible layers should form.
3. In the gaseous state, the material should allow the solder to flow.
4. In a liquid state, it should spread well, wetting the products being connected and flowing between them.
5. The material must destroy and remove non-metallic films formed on them from surfaces.
6. It must be minimally active or chemically inert with respect to soldered alloys and metals.

What types of fluxes are there for soldering?

Most often, soldering material is prepared from 10 grams of ammonium chloride and 30 grams of zinc chloride , dissolving them in 60 milliliters of water.

"Soldering acid" or "soldering fluid" is also used. They can be prepared from preserved hydrochloric acid and zinc metal:

• pour the acid into a porcelain or glass container and add zinc in portions;
• as a result of dissolving zinc in acid, oxygen should begin to be released and zinc chloride should form;
• after the release of oxygen slows down, the container should be placed in warm water;
• at the end of the reaction, the liquid is drained and only undissolved zinc remains, to which ammonia must be added (2 grams of ammonium per 3 grams of metallic zinc).

The liquid can not be drained, but evaporated to dryness. Then, immediately before soldering, the resulting mixture is dissolved in water (1:2).

However, fluxes prepared in this way are not suitable for all metals. According to the degree of effectiveness, they are divided into three groups:

1. Due to their weak activity, protective or non-corrosive materials They are mainly used for joining copper, its alloys and cadmium-, tin- or silver-plated steel products. In this case, solders should only be low-melting. Protective fluxes include rosin and its various solutions, petroleum jelly, stearin, wax, and wood resins.

2. Slightly corrosive substances are more active than non-corrosive substances.

   Most often these are mineral oils, animal fats, organic acids (oxalic, benzene, stearic, oleic, citric, lactic, etc.) dissolved in alcohol, water or organic acid derivatives.

   In order to weaken the corrosive effect of such substances, rosin or other substances that do not cause corrosion are added to them. Slightly corrosive substances are used when soldering only with low-melting solders, since they easily decompose, burn and evaporate.

3. Corrosive soldering fluxes consist of metal fluorides and chlorides and inorganic acids. They are capable of destroying any resistant films of non-ferrous and ferrous metals, therefore they are effective when soldering by any method. Corrosive materials are used in the form of aqueous solutions in paste and solid states.

Materials for soldering aluminum

It is difficult to connect aluminum products by soldering under normal conditions, since an oxide film forms instantly on its surface. Therefore, it should be poured with molten rosin immediately after stripping .

To solder aluminum, you need a powerful soldering iron, as well as special solder and flux.

In most cases, connections of aluminum parts are made with tin-lead and multicomponent solders, which include bismuth, cadmium, zinc and other materials. They can also be applied to aluminum alloys. Such solders contribute to durable and excellent joining of aluminum products.

For soldering aluminum, concentrated orthophosphoric acid or “binary” flux is most often chosen. The no-clean material must be applied to the part in a thin layer until the surface turns white.

You can also use an active no-clean flux, after which no cleaning of surfaces is required. It can be used to solder copper and stainless steel .

How to clean stainless steel

In most cases, phosphoric acid is used for stainless steel. This substance of inorganic origin of medium strength is hygroscopic colorless crystals. When brought to 213C, it turns into pyrophosphoric acid.

As a rule, flux in the form of an 85% aqueous solution of phosphoric acid is used for stainless steel. However, other solvents, such as ethanol, can also be used.

The acid is applied to the surface of the steel in a thin layer, thereby cleaning it from dirt and rust and forming a film protective against corrosion.

Flux for brass

This material requires a special flux. However, you can also use a universal one, which is suitable for soldering galvanized iron, aluminum, copper, corrosion-resistant alloys, and bronze.

The flux special for brass must be shaken . With its help, a strong connection will be obtained and an anti-corrosion coating will be formed.

Silver processing material

For soldering silver, it is recommended to choose a specialized flux. This material will neutralize the soldering area and prevent the appearance of an oxide film. Before using it, the surface of silver products must be slightly heated using a gas burner.

The operating temperature range of flux for silver is 520-820C. Thanks to it, an excellent strong connection of silver parts is achieved.

Flux for ferrous metals

For soldering ferrous metals, zinc chloride is used, which is an active flux. In addition, you can choose materials of low or medium activity, for example, ammonium chloride. A similar flux is also used for enameled metal baths .

Active flux can be in the form of a solution, powder or paste. The most popular solder paste. A worthy alternative to it is a solder tube, which contains a flux filler.

Fluxes for processing microcircuits

Previously, only rosin, which is an active flux, was used for soldering circuit boards and other various parts. However, it is not recommended to use an alcohol rosin solution for repairing microcircuits, as it has several significant disadvantages:

1. At high temperatures, rosin removes not only metal oxide, but also the metal itself.
2. Cleaning the soldering after using rosin becomes a big problem. Its remains are washed off only with solvents or alcohol. It is impossible to leave excess flux on the board, since various short circuits caused by contamination are possible.

But there is a way out for radio amateurs. Modern materials markets offer a large selection of different fluxes, which ensure high quality soldering, do not destroy the soldering iron tip, and are easily washed off with water. Such materials are most often sold in convenient-for-use packaging - syringes.

In some cases, instead of rosin, you can use its substitutes:

1. You can prepare spruce or pine resin yourself. To do this, the resin collected from the trees should be melted in a tin can and poured into small boxes. The fire on which the resin will be heated must be low, otherwise it may ignite.
2. An aspirin tablet can also be used instead of rosin. When melted, aspirin emits an unpleasant odor, which is its significant drawback.
3. Rosin varnish is sold in hardware stores and is used instead of rosin in alcohol. In addition, it can be used for anti-corrosion coating of metals.

After using flux, the finished soldering should be cleaned with a hard brush or brush soaked in solvent, and also wiped with a cloth soaked in rectified alcohol.

Nowadays, fluxes are produced that do not contain components that cause corrosion and oxidation and do not conduct electric current . Therefore, it is not necessary to wash the board after using them. You just need to remove the excess.

In order to apply liquid flux to the board, you can use a cotton swab, brush or a special convenient “flux applicator”. Such a device is quite expensive, so it’s cheaper to make it yourself:

• cut the disposable medical syringe into two parts;
• insert the cut parts of the syringe into a rubber tube with an internal diameter of 5-6 millimeters;
• shorten the needle and bend it slightly.

The flux applicator is ready, now you can use it to process the board. To do this, lightly press the hose and squeeze out a drop of flux. To prevent the needle from drying out, you need to insert a piece of wire into it.

Fluxes in the form of a paste or gel can be applied to the parts to be joined using a disposable syringe with a thick needle .

Having understood what flux is and starting to use it to solder metal parts, it is important to do this in accordance with safety precautions. When working with chemically active substances, the room must be ventilated, and soldering must be carried out wearing glasses and protective gloves.

Source: https://stanok.guru/oborudovanie/raznoe/flyus-dlya-payki-metallov-chto-eto-takoe.html

What is soldering flux used for and its features? classification: low-melting and high-melting fluxes for soldering

Today, soldering is common in almost all industrial areas. It is used to obtain a permanent connection between solid metals. But not everything is as simple as it seems. In order for the work to be of high quality, you must have consumables, equipment and the right set of tools. Soldering flux refers specifically to such materials.

Soldering flux is a metal alloy that has a low-melting structure. It is used to solder two different types of materials. If you know exactly what the characteristics of the connection during heat treatment are for two different materials, then you can make such a flux yourself.

It will be possible to join two different materials using flux when the required temperature is maintained at the seam level. The temperature can fluctuate , depending on the type of materials, within 50−500 degrees. The temperature regime for solder melting must be much higher than the temperature regime of the material being processed.

Soldering flux is divided into several types. It is chosen based on the following factors:

1. Material resistance to corrosion.
2. Strength of materials.
3. Temperature parameters of the work surface.
4. Flux temperature.
5. Soldering temperature.
6. Type of metal.

Soldering flux is divided into two groups:

1. Soft . The melting temperature is low.
2. Solid . The temperature threshold is high.

Refractory solder has a melting point of more than 500 degrees. With its help, a strong connection is created. The disadvantage is that in some cases, increased temperature conditions can cause overheating of a key structural element and cause it to fail.

Low-melting solders have a melting temperature in the range of 50−400 degrees. These solders include components such as:

1. Tin.
2. Lead.
3. Other impurities.

This type of flux is used for soldering radio equipment during installation. There are also ultra-low-melting solders used for connecting and soldering transistors. The maximum melting temperature can be 150 degrees.

To solder thin surfaces, it is necessary to use soft fluxes, and for large-diameter wires - hard ones with a high temperature threshold. The flux must have the following characteristic features:

1. Temperature differences when melting the base material and solder.
2. Corrosion resistance.
3. Stretching ability.
4. Structural strength.
5. Ability to conduct current and heat normally.

The following materials can be used as solder:

1. Tubes with colophonium.
2. Wire reels.
3. Ribbons.
4. Rods.
5. Other fluxes.

The most common form is a tin rod with a cross-sectional diameter of 1-5 meters.

There are also multi-channel types of fluxes that have several sources of solder in order to create a more durable connection. They can be sold in flasks or skeins, contained in reels or in a spiral shape. To use a disposable one, it is recommended to take a small piece of wire , the size of which will not exceed a match.

In order to solder electrical circuits, you should use tube fluxes that contain colophonium. This is a resin that acts as solder. This filler material can easily join metals such as brass, silver and copper.

Features of low-melting fluxes

Soft soldering fluxes can melt up to 400 degrees. Thanks to them, the seam becomes elastic, soft and durable. Low-melting fluxes can be divided into the following categories:

1. Ultra-low-melting.
2. Special.
3. Lead-tin.
4. With a minimum amount of tin.

Tin can be considered the best option for solder, but due to the high cost of the material, it is practically not used in its pure form. Lead and tin compounds are mainly . They make strong connections.

The markings indicate what percentage of tin is contained in the solder. This solder contains antimony in small quantities. Therefore, this type of solder can be used for connections that will not be subject to vibration or stress.

Low-tin, lead-free flux is used for soldering contacts at temperatures up to 300 degrees on small electrical circuits.

At temperatures of 60−145 degrees, ultra-low-melting fluxes can turn into a liquid state and be used for manual soldering of delicate products. But the connection is not very strong .

Special solders are required if the characteristics of the solder and the base material need to be compatible. For this purpose, compounds that cannot be soldered are used. These include:

1. Cast iron.
2. Low carbon steel.
3. Nickel.
4. Aluminum.

In order to solder a part made of aluminum, it is necessary to make a solder consisting almost entirely of tin. And in order for diffusion to be better, a small amount of cadmium, borax and zinc is added to it.

Hard solders are used to connect those seams that are subject to various temperature changes, vibrations, shocks and loads.

They begin to melt at temperatures above 400 degrees . They have the following varieties:

1. Pure copper.
2. Silver.
3. Phosphorus-copper alloys.
4. Copper-zinc alloys.

It should be noted that alloys of copper and zinc are not used very often. This is due to the fact that their cost is high, and the quality of the seam is not very reliable. This type of solder can be replaced with a bronze-zinc alloy or brass.

Copper-phosphorus alloy can be used for soldering elements made of brass, bronze or copper, which are not subject to much stress. This composition also replaces expensive silver solder.

Solid fluxes cannot be used when soldering low-carbon steels and cast iron, since when iron is heated with phosphorus or copper, brittle elements are formed, as a result of which the seam is destroyed.

The optimal, but very expensive option for soldering iron is silver. But thanks to it, the materials are connected very firmly. Silver solder is used to solder complex silver-based circuit boards and wires.

Classification of alternative types of solder

There are other alternative types of solder:

1. Based on rosin with alcohol . This flux is active, but at elevated temperatures not only the oxide is removed, but also the metal. After soldering with this solder, you need to clean the board thoroughly.
2. Activated homemade flux . Used for soldering connections that are often subject to shock and other stress. To prepare it, you need to mix salicylic acid, diathylamine, anhydride, aniline rosin.
3. Borax mixed with rosin . This mixture is used for soldering copper water pipes. This mixture is highly active and does not require cleaning of materials. Borax can melt at a temperature of 70 degrees. No harmful substances are released.
4. Combination of rosin with air . This flux is neutral and is used for high-precision electrical devices (mobile phone circuits, switches, relays, etc.). Rosin should be used on pre-cleaned and tinned metals. And for high-quality cleaning of diamond contacts, you can use a laser.
5. Liquid fluxes based on ethyl alcohol, salicylic acid, gold or petroleum jelly are used for soldering radiators or electrical wires. At the same time, the seams are clean and neat.
6. With increased anti-corrosion characteristics based on solvent, phosphorus and acids. There is no need to use additional cleaning agents after soldering.

Residues of flux must not be left. In addition to the fact that they spoil the appearance of the product, they are also harmful. They can cause short circuits in electrical circuits if the surface is not cleaned promptly.

Fluxes are also classified according to the following principle:

1. Protective . These include substances that are inert to metal. They are intended to protect cleaned elements from oxide formation. These include powdered sugar, mineral and olive oils, wax and petroleum jelly.
2. Anti-corrosion . Their task is to free the surface that needs to be soldered from corrosion and further protect it from the formation of oxides. An essential component is phosphoric acid.
3. Active (acidic) . These compositions are prepared on the basis of hydrochloric acid. It is used in its pure form. Iron products are soldered with it. Zinc chloride is another component of hydrochloric acid flux. This flux is known to many as “soldering acid”. Its scope of application is the soldering of silver, iron alloys and copper. Since acid flux is a reagent with high chemical activity, it destroys various films more effectively on the surfaces being treated. But it also interacts vigorously with the metal itself.

To solder the product with tubes of rosin, you must perform the following steps:

1. The surfaces to be joined must be thoroughly cleaned of dirt and oxidation.
2. At the weld site, it is necessary to heat the part to a value that will exceed the melting temperature of the flux.
3. After this, the soldering process is carried out.

For large surfaces that have good thermal conductivity, this method should not be practiced, since the power of the soldering iron will be insufficient to heat the metal in sufficient quantities.

To solder radio wires, solders are used in the form of thin rods that have a diameter of 2 millimeters. They are easy to make with your own hands.

In order to make them you will need to take a vessel. Make a hole at its bottom. And after that you will need to pour molten tin-lead solder into it. In this case, the vessel will have to be located above a metal plate or tin sheet. After hardening, the rods are cut into pieces of the required length.

You can pour this mixture into molds:

1. Plaster.
2. Duralumin containers.
3. Tin gutters.

This is all done as follows:

1. You need to weigh the required amount of tin and lead on the scales.
2. Melt the metal in a metal crucible over a gas burner. It should be mixed using a steel rod.
3. It is necessary to remove the film from the molten surface using a steel plate.
4. The alloy should be poured into molds.

Regardless of what type of flux you use, wipe the finished soldering with a cloth, after moistening it in rectified or acetone. To clean the seam, use a stiff brush, first dipping it in solvent.

Today you can buy gel and liquid fluxes on the market, which have the following advantages:

1. No cleaning required after soldering.
2. This flux does not conduct current.
3. There are no components that provoke corrosion and oxidation.

Liquid flux is applied using a brush or cotton swab. You can make your own device for applying it using a silicone hose and an ordinary syringe. It is the hose that will be filled with liquid flux.

Soldering is one of the best ways to join metals. With its help, a high level of tightness and strength is ensured, and the process, compared to welding, does not take much time and is simple.

But during the soldering process, harmful gases are released. That is why when working, do not forget about such protective equipment as an apron made of thick fabric, glasses and gloves. And the risk of poisoning will be minimal if you use fluxes from good manufacturers.

Source: https://tokar.guru/instrumenty/payalniki/flyus-dlya-payki-opisanie-i-osobennosti.html

Do-it-yourself flux for soldering aluminum, iron, copper, steel - Asutpp

The joining of two or more non-metallic or metallic materials and substances by means of an added metal is called soldering. We propose to consider what soldering flux is, how you can make it yourself, and also consider the characteristics and how to make solder for copper, silver, tin, and stainless steel.

Soldering and its features

To obtain a truly high-quality connection, you need to maintain a special temperature in the seam area. On average, this indicator varies between 50-100 degrees. It is also taken into account that the temperature threshold required for the solder to melt is much higher than simply for melting the metal being processed. Positive qualities of soldering:

• complete tightness of the connected parts;
• high strength of connections;
• significant savings in time and effort compared to welding processes;
• At the soldering sites, a special film layer is formed that resists corrosion and oxidation of metals.

Types of solder

Solders are a fairly specific series of substances that must meet the following conditions:

1. High thermal conductivity and electrical conductivity;
2. Good strength and high elongation coefficient;
3. Corrosion resistance;
4. Transformation into a liquid medium when exposed to welding temperature;
5. Contrasting magnitude of cooling of solder metal and crystallization of solder.

These substances vary depending on the temperature of the soldering process, and are soft and hard.

Flux table

Soft soldering

Soft soldering can only be carried out to temperatures lower than 400 degrees Celsius. These substances make it possible to ensure the formation of a truly strong and at the same time soft seam, which will not only be relatively flexible but also have good resistance to corrosion and physical influences.

Soft solders include:

1. Lead-tin
2. Low tin solders
3. Special and easy to melt

Solder, whose operating temperature is 185 ÷ 267˚С, combines tin and lead. Antimony is also added in small quantities. Before purchasing, be sure to check GOST, all information on solder is indicated there.

For example, POS 40 - the last digit means that this substance contains 40% tin, on average 3 to 5 percent of antimony is added, the rest is lead. These solders are used for joining seams that do not require resiliency, i.e.

not loaded, not subject to beating or constant vibration.

Lead-free flux is also used for soldering. They are also called low-tin compounds. They are mainly used for connecting small circuit boards, contacts on delicate electrical circuits, etc. The maximum permissible melting temperature is 330 degrees Celsius.

The most common ones are low-melting type solders, temperatures from 60 degrees to 145. They are purchased for low-temperature soldering or very careful manual welding. In particular, they cannot be called basic solders, because they have very little strength and elasticity. They are more often used for re-soldering or step soldering.

In some cases, it is necessary to produce a special composition; its properties are adjusted directly for materials that cannot be soldered (this is a flux for nickel, low-carbon steel, aluminum, tungsten and cast iron).

Consider the most popular mixtures:

1. Fluxes for soldering aluminum must be tin-based; they also contain borax, zinc, cadmium, but they still contain more than 99% tin. Zinc and cadmium are necessary for increased diffusion, which can penetrate even deep layers of aluminum.
2. Flux paste or gel for soldering microcircuits; such solders are also used for printed circuit boards.

Flux gel

For such alloys, solders are supplied in a variety of relatively thick compositions, rods, strips and wire spools (as for welding). There are also ingots that are half filled with rosin flux.

Brazing alloys for soldering

The composition of fluxes for hard soldering is used to connect problem areas that are constantly susceptible to the negative effects of the environment (vibrations, temperature changes, shocks, etc.). These are mainly compounds for high-temperature soldering, from 400 degrees Celsius and above. These include:

1. Solder for copper and zinc hard alloy (up to 1000);
2. Phosphorus and copper (up to 900 degrees);
3. Pure copper is used for the soldering process of high-carbon iron;
4. No-clean flux, for silver soldering (up to 800 degrees inclusive).

Hard-melting solders also have their own distribution; they are refractory, with a melting temperature of 850 degrees, and low-melting - with a temperature above this temperature range.

It should be noted that a mixture of copper (grades M21, M11 and others are used) and zinc is not widespread enough; due to its low strength and relatively expensive cost, in most cases it can be successfully replaced by solder made of bronze with zinc or brass.

Copper-phosphorus type solders are substitutes for very expensive silver fluxes. They are indispensable when joining copper metals, bronze, brass and other metal compounds that should not be subject to bending or shock loads. By the way, this alloy is also called solder for flux-free soldering (but not for copper).

It is strictly forbidden to use these alloys for soldering iron, ferrous metals, low-carbon steels, because when exposed to temperature and combined with copper or phosphorus, a very fragile chemical element is formed - iron phosphides, which will cause the seam to come apart.

Due to metal-phosphorous solders, iron phosphides are formed, which are too brittle compounds and contribute to a decrease in the quality of the metal; they are not recommended for soldering iron.

Making your own soldering flux

The best option for such soldering processes is silver solders. They are the most expensive. And they are also used to connect wires, capillary mesh of wires, and very complex circuit boards made of silver components.

Other types of flux

1. Fluxes with pronounced anti-corrosion properties. These are compounds based on phosphorus acid and a solvent, which when interacting form organic compounds. They are very beneficial to use because after the soldering process there is no need to use special cleaners;
2. Liquid fluxes made from salicylic acid, petroleum jelly, gold and ethyl alcohol. This is the most convenient connection for radiators and soldering electrical wires.

   This flux ensures high seam cleanliness and neatness;

3. In order to produce neutral flux for electrical devices with high precision requirements (time relays, switches, for connecting mobile phone contacts, etc.) you will need rosin-air connections.

   Rosin is very low-active and should only be used on prepared metals, previously cleaned and tinned; Rosin

4. Activated fluxes are borax and rosin. In most cases it is used for plumbing connections and soldering of copper pipes. The main difference is the fact that borax melts at a temperature of 70 degrees, without releasing absolutely any harmful compounds.

   This is only one variety; Borax

5. In order to prepare activated fluxes, you can use the following recipe: mix rosin, aniline, add a little anhydride, salicylic acid and diethylamine. This is a good option for making soldering for assembly fasteners.

General tips on fluxes

Homemade flux for soldering is not always a profitable option; sometimes it is actually more profitable to buy it, especially since in most cases the price allows, say, smd or bga. At the moment, more than a hundred domestic companies produce fluxes and mixtures for soldering and welding, among which we can recommend LTI 120, Brazetec, Harris, RMA, Sanha, Welco (average cost from 80 rubles).

Sales are carried out in any electrical appliance store and market in all cities: Yekaterinburg, Minsk, Moscow, Novosibirsk, Kharkov, Chelyabinsk, Rostov-on-Don.

It should be noted that in any case, during the welding or soldering process, gases are released that can harm the body, but if you use professional mixtures, this harm will be much lower, so opt for well-known brands.

Source: https://www.asutpp.ru/flyus-dlya-pajki.html

Fluxes: these are devices for soldering, why are such accessories needed and what types are they?

Soldering today is widely used in various industrial fields; it is used to obtain permanent connections between solid materials. However, in order for the work to be done efficiently, you need to have the necessary set of tools and equipment, as well as consumables.

Among such materials is flux. And today we will talk about what it is and what this item represents.

What is flux and its key features

So, flux is a metal alloy with a low-melting structure that is used for soldering two different materials. This alloy can be made with your own hands if you know the peculiarities of joining two different materials during heat treatment.

The joining of two materials using flux can only be achieved if a certain temperature is maintained at the seam level. Depending on what material is taken, the temperature varies from 50 to 500 degrees . The melting temperature of the solder must be much higher than the melting temperature of the material you are processing.

Such a thing as soldering flux has several varieties; it must be selected depending on the following factors:

• metal;
• soldering temperature.
• temperature of the flux itself;
• work surface parameters;
• material strength;
• its resistance to corrosion.

There are two groups of fluxes:

• solids that have a high temperature threshold;
• soft, such flux has a low melting point.

Refractory solder has a melting point of 500 degrees or more ; it creates a fairly strong type of connection. But its disadvantage is that sometimes high temperature can cause a key part of the structure to overheat and fail.

And the melting temperature of low-melting solders ranges from 50 to 400 degrees . This type of flux includes the following components:

• lead;
• tin;
• other impurities.

Such fluxes are mainly used for soldering radio equipment during installation.

There are also ultra-low-melting solders that are used for soldering and connecting transistors. The melting temperature of these fluxes can reach a maximum of 150 degrees .

To solder thin surfaces, soft fluxes should be used, and to solder large-diameter wires, you need to use hard solder, which has a high temperature threshold.

The required flux characteristics are:

• ability to conduct heat and current normally;
• structural strength;
• stretching ability;
• corrosion resistance;
• differences in temperature indicators when melting solder and base materials.

The following materials are used in the form of solder:

• rods;
• ribbons;
• wire spools;
• colophonium tubes;
• other flux.

The most common form is a tin rod, the cross-sectional diameter of which is 1-5 meters.

There are also multi-channel types of fluxes that have multiple sources of solder to create stronger connections. They may be sold in skeins or flasks , have a spiral shape and are contained in reels . For one-time use, it is best to take a small piece of wire the size of a match.

To solder electrical circuits, it is necessary to use tube fluxes that contain colophonium. This is a resin that acts as solder. This filler material is excellent at joining types of metals such as:

Features of low-melting fluxes for soldering

Fluxes for soft soldering are capable of melting at temperatures up to 400 degrees. With their help, the seam becomes strong, soft and elastic.

Low-melting fluxes are divided into the following categories:

• with a minimum amount of tin;
• lead-tin;
• special;
• ultra-low-melting.

The best option for solder is tin, but in its pure form it is practically not used, since this material is too expensive in itself. The most commonly used solders are tin and lead, which produce strong connections.

The marking of such flux contains the percentage of tin it contains. Also, such solders contain small amounts of antimony and can be used for non-critical types of connections that are not subject to load or vibration.

Lead-free, low-tin flux is used for soldering contacts on small electrical circuits at temperatures up to 300 degrees.

At temperatures from 60 to 145 degrees, ultra-low-melting fluxes are capable of turning into a liquid state and are used for manual soldering of delicate parts. The connection is not very strong.

And special solders are needed when it is necessary to obtain compatibility of characteristics with the main type of material. For this purpose, compositions are taken that cannot be soldered, including:

• aluminum;
• nickel;
• low carbon steel;
• cast iron.

So, to solder aluminum parts, you need to make solder, which consists almost entirely of tin, and for better diffusion, you need to add a small amount of zinc, borax and cadmium to it.

Description of refractory fluxes for soldering

Hard solder is used to join seams that are subject to various loads, shocks, vibrations and temperature changes. These fluxes are capable of melting at temperatures from 400 degrees .

Hard solders are divided into the following categories:

• copper-zinc alloys;
• phosphorus-copper alloys;
• silver flux;
• pure copper.

It is worth noting that alloys made of copper and zinc are not used very often, since the strength of the weld is not too high, and their cost is unreasonably high.

This solder can be replaced with brass or a bronze-zinc alloy.

An alloy based on copper with phosphorus can be used when soldering parts made of copper, bronze and brass that are not subject to heavy loads, and it is also used instead of more expensive silver solder.

Solid fluxes cannot be used when soldering cast iron and low-carbon steel, since when iron is heated with copper or phosphorus, brittle elements are formed, which then destroy the seam.

The best solder option for iron is silver, but it is very expensive. However, with its help, the materials are connected quite firmly. Silver solder is used for soldering wires and complex silver-based circuit boards.

How to assemble flux for soldering yourself

For the purpose of soldering radio wires, you can use solders in the form of thin rods with a diameter of 2 mm, which are easily made with your own hands.

To make them, you will need a vessel with a hole made at the bottom, and then molten tin-lead solder will need to be poured into it. In this case, the vessel should be located above a tin sheet or above a metal plate. After the rods have hardened, they can be cut into pieces of the required length.

This mixture can also be poured into molds:

• tin gutters;
• duralumin containers;
• plaster.

This is all done in the following way:

• weigh the required amount of lead and tin on the scales;
• melt the metal in a metal crucible over a gas burner, while stirring it with a steel rod;
• remove a thin film from the molten surface using a steel plate;
• pour the alloy into molds.

Regardless of what type of flux you use, wipe the finished soldering with a cloth pre-moistened in acetone or rectified solution. The seam is cleaned with a stiff brush, which must first be dipped in a solvent.

You can buy liquid and gel-like no-clean fluxes , which have the following advantages:

• absence of components that provoke oxidation and corrosion;
• This type of flux does not conduct current;
• no cleaning required after soldering.

Liquid flux of this type must be applied using a cotton swab or brush. You can also make devices for applying it yourself using a regular syringe and a silicone hose, which will be filled with liquid flux.

Soldering is one of the best methods of joining metals. It provides a high level of strength, tightness, the process itself is simple and does not take much time compared to welding.

However, soldering is harmful because harmful gases are released during it, so you should not forget about protective gloves, glasses and an apron made of thick fabric.

In addition, the risk of poisoning can be significantly reduced by using mixtures from good manufacturers.

Source: https://elektro.guru/osnovy-elektrotehniki/flyusy-dlya-payki-chto-eto-takoe-i-zachem-oni-nuzhny.html

Soldering flux - what is it?

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. 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://rem-serv.com/flyus-dlya-payki-chto-eto-takoe/

Types and features of using flux for soldering

Situations often occur when something electronic breaks down at home and the only way to fix the situation, other than buying a new household appliance, is to solder the broken contacts. This procedure is also in demand in production, in car services and in their own workshops. However, it is impossible to solder the contacts without additional substances. One of them is soldering flux.

What is flux and its key features

Not many beginners know what flux is and how it is used in the soldering process. This is a connecting mixture. It contains materials that melt easily. Before purchasing flux, you need to pay attention to several factors:

• operating temperature of additional composition;
• the type of metal to be worked with;
• temperature at which the soldering process begins;
• the presence of additional surfaces that surround the adhesion site;
• the presence of an anti-corrosion film on the metal surface.

There are two types of additional compounds used for soldering. Some are hard and melt at high temperatures. Others are soft and you can start working with them at low temperatures.

Purpose

To work with additional substances, you need to know what flux is used for when soldering. To connect the contacts on the board, it is necessary to heat them to a temperature of over 500 degrees. This can damage important components of the board. To prevent permanent breakdown of electronics, low-melting compounds are used, in which lead and tin predominate. They melt at temperatures up to 500 degrees and help connect broken contacts.

To connect light parts, it is enough to use light alloy solder, which can be worked with at minimum temperatures. To connect large parts, it is necessary to use hard types of solder.

Application of flux

Before using solder and flux for soldering, you need to pay attention to certain characteristics:

• resistance of the composition to corrosion processes;
• working size of the connecting seam;
• connection strength;
• melting temperature.

Very often, a tin rod is used as solder.
How flux works - using flux to solder SMDs under a microscope.

Storage

For simple repair work at home, it is enough to purchase a tube of flux. It must be stored in a tightly closed container. The liquid composition must not be allowed to come into contact with moisture.

Also, do not store fusible compounds near heating devices and open flames. The temperature in the room where the flux is stored should not be allowed to rise above 25 degrees.

It is advisable to dispose of compositions that were stored in packages that were not sealed properly and purchase a new one.

Types of fluxes for soldering

Soldering fluxes come in several varieties, depending on the effect of these compounds on the contacts being connected during heating. Before purchasing a fusible substance, you need to familiarize yourself with its main types.

Active fluxes

These are fluxes containing predominantly hydrochloric acid. They are used to work with iron parts. During the soldering process, these compounds exhibit a powerful chemical reaction. They are not used when working with radio equipment, as they quickly corrode the board.

Acid-free fluxes

These are liquid fluxes that are made on the basis of turpentine, glycerin and ethyl alcohol. Such compositions melt up to 150 degrees. Acid-free fluxes are used for soldering small parts.

Activated fluxes

Compositions made on the basis of salicylic acid. Used when connecting elements that do not require initial stripping.

Anti-corrosion fluxes

These are special substances that clean parts from deposits that appear during the corrosion process. They protect the connection point from destruction during operation. Manufactured on the basis of orthophosphoric acid.

Protective fluxes

The peculiarity of such compositions is the absence of a chemical reaction. Protects parts from corrosive processes. They are made from wax, olive oil or petroleum jelly. Such compositions begin to melt at 70 degrees. During heat treatment they do not emit harmful substances. Also, when working with protective fluxes, there is no need to pre-clean the parts.

How to choose the right flux

Even with knowledge of the varieties and technical characteristics, not every person knows how to choose a flux. It is important to understand which composition is better. For safe soldering, neutral fluxes should be chosen. They are suitable for working with various parts. However, when soldering large components, the work will be slow.

To speed up the process, you can use medium-active fluxes.
Such compositions are suitable for working with various metals. For working with large parts, silver solders are ideal. Which flux should I choose for soldering? Review of fluxes from my workshop.

The best substitutes

It is not always possible to find solder at home to solder broken contacts or wires. In such situations, repairs can be carried out without purchased compounds. You can replace flux with several substances:

• amber;
• fat;
• "Aspirin";
• resin.

Before starting work, Aspirin must be dissolved in a small amount of liquid.

Application procedure

Before you start soldering with flux, you need to understand how to use it. The application process will depend on what type of low-melting composition is used:

1. When using hard solders (tin rod), you need to dip the soldering iron into the reagent body and hook a small amount of solder.
2. If a liquid ready-mix is ​​used, it can be applied with a brush.
3. When working with paste, you need to apply it to the joint with a stick or toothpick.

Also, we must not forget about cleaning the surface from oxidation.

The entire process of using a low-melting substance can be divided into several stages:

1. Initially, the surfaces are cleaned.
2. After cleaning, a layer of flux is applied.
3. Using a soldering station, the joining compound and parts are heated.

Next, you need to wait for the seam to harden and further process it.

Without a special composition it will not be possible to connect the contacts.
Experienced craftsmen suggest that beginners do the work without flux and see the result - the work will take much longer, the shock will quickly fall off. Pure tin is considered the best additional material for soldering. However, this is not a cheap metal and is used in combination with lead. Soldering technique with soldering flux

How to prepare flux for soldering yourself

To connect radio electronics elements, you can make your own soldering flux. Fat or resin can be used as improvised means to replace rosin. In order not to buy a composition for work, you need to know how to make flux for soldering:

1. You need to prepare equal amounts of lead and tin in advance.
2. Melt two metals in a crucible.
3. Remove the film of side deposits that forms on the top of the cooled metal mixture.
4. Pour the mixture of tin and lead into prepared molds.

It must be remembered that after soldering any contacts or parts, it is necessary to process the finished shock. For this, acetone or alcohol is used. However, solders have appeared in stores that do not require additional processing after completion of the work. They have some advantages:

• are dielectrics;
• not susceptible to corrosive processes;
• no additional cleaning required.

Due to the fact that such solders do not conduct current, they are not used to connect contacts and wires.
How to make a soldering flux with your own hands / Liquid rosin / SKF You can also make your own solder paste. To do this, grind the solid flux using a coarse file.

The powder obtained after grinding must be mixed with alcohol and rosin. Next, you need to pour the resulting paste into an airtight container and close tightly. It deteriorates when exposed to moisture and requires compliance with storage rules. Experienced professionals recommend applying the paste using a syringe.

How to easily and quickly make flux gel. Soldering flux is a must-have substance when repairing electronics and radio equipment. It is important to know what types of these compositions there are and how to work with them correctly so as not to damage the boards and contacts. Do-it-yourself liquid FLUX (FIM) from citric acid!!!

Source: https://metalloy.ru/obrabotka/pajka/flyus