How to solder using soldering acid - Metals and their processing

How to use soldering acid correctly

Every person who has had to work with radio electronics has repeatedly used a soldering iron to solve their problems, so he knows what the operating principle of such equipment is. But due to the unpleasant odor emitted when processing a structure using classic solder, as well as significant difficulties at different stages of operation, this technology is not in great demand and has a number of simpler analogues.

Purpose of soldering acid

To make the upcoming soldering more productive, many welders use special substances - fluxes, with the help of which the solder spreads evenly over the soldering site. Among the main fluxes, rosin and soldering acid are distinguished. The first option is indispensable when soldering copper and silver, and acid is used in particularly difficult cases. How soldering acid works, the composition and other features of such a substance are the main questions that concern many inexperienced beginners.

If we highlight the main recommendations for successful soldering with acid, they will look like this:

When choosing a suitable solution, you need to understand the type of metal or alloy. When soldering iron, including galvanized iron, a unique type of soldering acid is used, represented by a solution of zinc chlorate. Soldering of stainless steel is carried out using phosphoric acid for soldering, as well as multi-component fluxes. A material such as aluminum cannot be soldered , which is due to the lack of suitable fluxes capable of dissolving the oxide film of the material. Acid cannot be used for soldering printed circuit boards, as this increases the risk of the formation of corrosive elements and short circuits between conductors.
If you intend to use soldering acid for your own purposes, you can purchase it in the form of a paste at the appropriate store. Nevertheless, many welders make their own soldering acid, claiming that such an action does not require any special difficulties. You need to take about 100 ml of hydrochloric acid, put pieces of zinc in it, for example, removed from batteries, and wait for the chemical reaction to complete, during which hydrogen will be released. Given this feature, it is better to conduct the event in a ventilated environment away from sources of fire. If the hydrogen bubbles stop rising, let the solution sit until clear, and then carefully pour it into the bottle. That's it, the highly effective soldering acid is ready.

Instructions for use

Immediately before soldering, it is necessary to clean the surface with a file or sandpaper, which will avoid all kinds of contamination.
Acid should be applied to the adhesion site, for which you can use a brush.
Next, you need to cover the structure to be soldered with solder based on tin or its alloy. If the substance does not apply evenly, you will have to repeat the acid treatment again.
At the next stage solder carefully surfaces.

When working with a heated soldering iron, do not forget about safety rules and try not to clutter the work area with materials that ignite very quickly.
After completing the procedure, the acid should be neutralized using an alkali, for example, a soda solution, and then rinse the adhesion site to get rid of any remaining acid. In rare cases, acetylsalicylic acid plays the role of a flux, although its use requires a more complex approach.

Silver

If you have ever worked with a soldering iron, then you know that soldering is a unique type of permanent connection of metal products using low-melting metal. The technology itself is selected taking into account the type of metals that are to be soldered, as well as the environmental conditions where the action will be performed. For example, processing printed circuit boards from some electronics and repairing silver jewelry are significantly different from each other.

When soldering this way, you should use a soldering iron, solder, and also a flux, which is colophonium.

The step-by-step instructions look like this:

It is no secret that for soldering elements with a high silver content, solder is used, which contains about 60% tin and 40% lead, which can melt at a temperature of 180 degrees Celsius. Try to prepare solder, which will be indispensable for soldering electronic circuits. This product consists of thin tubes that are filled with resin and act as a flux.
The surface that will be solderable must first be cleaned of any defects and irregularities that may appear when exposed to the oxide film. In this case, the heated solder can create an effective connection with the silver.
The part in the soldering zone is heated to such temperatures that natural melting of the solder begins. However, at this stage, some difficulties cannot be avoided, which may be associated with insufficient power reserve of the soldering iron for sufficiently high-quality heating. When soldering silver products, it is important to protect the area from possible exposure to atmospheric oxygen. In this case, colophonium is used, which can create a protective film over the soldering area.
As for soldering jewelry, it is carried out using high-temperature solders that correspond to the metal standard, or using solders of a lower standard, but containing silver. Soldering jewelry with tin is necessary only in the most extreme cases, and only after prior agreement on all details with the owner of the ring, chain, bracelet or other item. If you do not know how to perform such an action correctly, this can cause damage to an expensive structure.

Boards

It's no secret that soldering radio components into boards is a simple process . It is much easier to do than connecting loose wires, since the holes in the boards are intended to fix the soldered parts.

However, you need to understand that the final result is directly related to the experience and responsibility of the worker. The first circuit that is assembled on a breadboard cannot be called very successful.

But don’t worry - after some time the quality of the connections will increase significantly.

Step-by-step instructions and features of such soldering consist of the following points:

The main goal of the upcoming work is to effectively connect the chip to the board so that a uniformly good soldering is obtained. The event can be divided into several separate stages.
First, you need to simultaneously bring the solder and the tip of an already heated tool to the area where the connection is required. It is important to follow the key rule, making sure that the soldering iron tip is in full contact with the pin being processed and the board itself.
During processing, you cannot change the position of the soldering iron tip until the entire contact area is covered with an even layer of solder. In most cases, this takes from 0.5 to 1 second. This time period ensures sufficient heating of the soldering area.
At the next stage, you need to circle the tip of the tool near the contact being processed in a semicircle, moving the solder in the opposite direction. In the same way, apply another millimeter of solder to the soldering area. During this period, the selected area will warm up quite well, so the solder melted under the influence of surface tension will be distributed evenly over the contact area.
After successfully applying the required amount of solder to the selected location, you can move the wire away from the soldered area.
And at the last stage, you should quickly remove the tip to the side. In a short period of time, the liquid substance, with a small layer of flux, will take its final shape and harden, creating a strong connection.

Source: https://MyTooling.ru/instrumenty/kak-pravilno-polzovatsja-pajalnoj-kislotoj

How to solder with soldering acid

The art of soldering must be learned gradually. Starting from soldering wires and moving on to printed circuit boards, each method has its own subtleties both in the selection of consumables for soldering and in technology. Today we will share with readers the basics of soldering and basic work skills.

What is the essence of soldering

Soldering uses the ability of some metals in a molten state to effectively flow over the surface of others under the influence of gravity and moderate surface tension. The connection by soldering is permanent: the two parts being connected are, as it were, enveloped in a layer of solder and remain motionless after it hardens.

Since we will be looking at soldering specifically in the context of metal soldering, the most important parameters will be the strength of the mechanical connection and the conductivity of the electrical connection. In most cases, these are directly proportional values and if two parts are tightly grasped, then the conductivity between them will also be high. However, solder has a resistivity higher than even that of aluminum, so its layer should be as thin as possible and its hiding power as high as possible.

In order for soldering to be possible in principle, there are two conditions. The first and most important thing is the cleanliness of the parts at the soldering site. Solder attaches to the metal surface at the atomic level and the presence of even the slightest oxide film or contaminants will make reliable adhesion impossible.

The second condition is that the melting temperature of the solder must be significantly lower than the temperature of the parts being soldered. This seems obvious, but there are solders with a melting point higher than aluminum, for example. In addition, if the actual difference in melting temperatures is not high enough, when the solder solidifies, thermal shrinkage of the parts may prevent the normal formation of the solder crystal lattice.

Fluxes and solders - how to choose the right ones

For the reasons described above, the correct choice of flux and solder is almost half the success in the soldering business. Fortunately, there are quite universal brands suitable for most tasks. The area of application of almost all fluxes and solders is clearly indicated on the labels, but some aspects of their use still need to be known.

Let's start with fluxes. They are used for etching parts, removing and dissolving the oxide film with further protection of the metal from corrosion. As long as the surface is covered with flux, you can be sure of its cleanliness, as well as that the molten tin will wet it well and spread.

Fluxes are distinguished by the type of metals and alloys of the parts being joined. Basically, these are mixtures of metal salts, acids and alkalis that actively react when heated with a soldering iron. Well, since there are quite a lot of oxide forms and contaminants, the cocktail must be specially selected for a specific type of metals and alloys.

Active flux for soldering

Conventionally, soldering fluxes are divided into two types. Active fluxes are created on the basis of inorganic acids, mainly chloric and hydrochloric. Their disadvantage is that they need to be washed off immediately after soldering is completed, otherwise acid residues cause quite severe corrosion of the connection and themselves have a fairly high conductivity that can cause a short circuit. But you can solder almost anything with active fluxes.

The second type of flux is created primarily on the basis of rosin, which can also be used in its pure form. Liquid flux is much more convenient to apply; it also contains alcohol and/or glycerin, which completely evaporate when heated.

Rosin fluxes are the least effective when soldering steel, but for non-ferrous metals and alloys they are mainly used or other compounds of organic chemistry.

Rosin also requires rinsing because in the long term it promotes corrosion and can become conductive by picking up moisture from the air.

Liquid and solid rosin

With solders everything is somewhat simpler. Lead-tin solders of the POS brand are mainly used for soldering. The number after the marking indicates the tin content in the solder. The more it is, the higher the mechanical strength and electrical conductivity of the connection and the lower the melting temperature of the solder. Lead is used to normalize the solidification process; without it, the tin may crack or become covered with needles.

Solder POS-61 with rosin inside

There are special types of solders, primarily lead-free (BP) and other non-toxic ones, in which lead is replaced by indium or zinc. The melting point of BP is higher than that of conventional ones, but the connection is stronger and more resistant to corrosion. There are also low-melting solders that spread already at 90–110 ºС. These include Wood and Rose alloys; they are used for soldering components that are sensitive to overheating. Special solders are mainly used in soldering radio equipment.

Alloy Rose

Power and types of soldering irons

The main difference between a soldering tool is the type of its power source. For ordinary people, the most familiar are network soldering irons powered by 220 V. They are used mainly for soldering wires and more massive parts, because it is almost impossible to overheat a copper wire, with the possible exception of melting the insulation.

The advantage of networked soldering irons is their high power. Due to it, high-quality and deep heating of the part is ensured, plus it does not require a bulky power supply for operation. Among the disadvantages, we can highlight the low ease of use: the soldering iron is quite heavy, the tip is located far from the handle and such a tool is not suitable for fine work.

Soldering stations use thermal control to maintain a stable temperature level. Such soldering irons do not have significant power, usually 40 W is already the ceiling. However, for heat-sensitive electronics and soldering small parts, this tool is best suited.

Choosing a tip and caring for it

Soldering iron tips are distinguished by shape and material. The shape is simple: the most primitive and at the same time universal is the awl-shaped sting. Variations are possible in the shape of a spatula, a cone with a blunt end, with a bevel, and others. The task when choosing a shape is to achieve the maximum area of contact with a specific type of parts being soldered, so that the heating is powerful and at the same time short-lived.

Source: https://ostwest.su/instrumenty/kak-pajat-s-pomoshhju-pajalnoj-kisloty.php/

Phosphoric acid for soldering

If the use of rosin does not allow the necessary elements to be properly soldered together, you will need to resort to the use of soldering acid (flux). It helps remove the oxide film from the parts being soldered and perfectly prepares them for the soldering procedure.

Orthophosphoric acid H3PO4 can act as a flux. It is used for tinning copper and its alloys - brass and bronze, stainless, precious and ferrous metals, nickel alloys, aluminum, low-alloy steels and even cast iron.

The reagent creates ideal conditions for the interaction of solder with parts: it removes dirt and oxides, prevents the development of the oxidation process and reduces the tension of the solder for its freer distribution. As a result of its use, reliable soldering of elements is ensured. But you should not use it for assembling boards, since the reagent is aggressive and contributes to the destruction of copper tracks.

Security measures

The compound causes chemical burns, and if its vapors are inhaled, the respiratory system is affected, so when working with it you must follow safety rules and use protective equipment: goggles, rubber gloves, a respirator.

Procedures should be carried out only in well-ventilated areas. If the reagent gets on the skin, the affected area must be thoroughly washed with a 6% alkaline solution or soap and water.

Phosphoric acid: application for soldering

This material is used to clean rust from metal elements and for soldering together with other components as a flux. When heated, it forms pyrophosphoric acid, which degreases metal surfaces. Depending on the type of metal, the proportion of the acidic compound in the composition is calculated - it can be from 32% to 100%.

If you plan to solder metal parts (radiator, pipes, buckets, pans), their surface is thoroughly cleaned with sandpaper or a file. An acid solution is applied to the cleaned areas with a brush, and then solder is melted onto the surface with a soldering iron until it becomes liquid. Liquid solder tins the stripped areas, and the acid solution comes to the surface when boiling.

After the solder hardens, the soldered parts are tightly and securely fixed. Soldering should be done with an open flame from a gas burner or a powerful soldering iron: the heat source is selected depending on the melting temperature of the solder and the area of the heated surface. The remaining composition must be washed off with a soapy, alkaline solution and water to prevent further development of corrosion. High-quality soldering will have a smooth and even surface.

Source: https://him-kazan.ru/stati/ortofosfornaya-kislota-dlya-pajki

How to properly solder with a soldering iron with acid? — Metals, equipment, instructions

Almost everyone who learned to solder on their own experienced failures at first. Either the solder did not want to stick to the workpieces and parts, or the soldered seam suddenly fell apart.

Without knowing the technology of soldering work, it is difficult to guess why this happens. And the secret is simple - the parts were not prepared for soldering, and the solder did not “stick” to the surfaces. Soldering acid, which removes oxides and promotes an excellent connection, helps to cope with the problem.

Purpose

To prepare parts for applying solder, it is necessary to clean them of particles of foreign materials - dust, sand, water. In addition, it is necessary to remove the oxide film from the surface, which is present on almost all metals.

And if the first condition is easy to cope with mechanically, using a file, needle file, or sandpaper, then the second condition is difficult to fulfill without the use of chemical compounds - an oxide film very quickly appears on the surface of the metal.

Substances that remove film and prevent the formation of a new one are called fluxes, and the most effective of them is soldering acid. It is an active flux, that is, during soldering it chemically affects the composition of the metal surface.

Professionals never question why soldering acid is needed; they know very well that very often it is impossible to complete the assigned tasks without it.

Soldering acid is used for the following metals:

copper and its alloys;
nickel;
iron;
structural steel;
alloys of non-ferrous metals.

If copper or brass parts are successfully soldered with borax, then it is often possible to solder aluminum or steel workpieces to each other only using soldering acid. Upon completion of work, the active flux must be washed off with water containing a small amount of alkali.

You can buy acid in stores, or make it yourself using chemical reagents. Although purchasing raw materials can be more expensive than ready-to-use flux.

What does it consist of?

In general, soldering acid is called zinc chloride, but the composition of the substances used in practice is somewhat different. Most often, soldering is done using preparations based on hydrochloric or phosphoric acid with the addition of solvents.

Concentrated hydrochloric acid is not applicable because it corrodes the metal. For electronic circuits, acidic substances are not used, soldering using rosin or choosing another inactive flux.

One of the universal types of liquid flux can be considered soldering acid FCA, produced by chemical industry enterprises.

This drug contains:

zinc chlorides;
ammonia (ammonium chloride);
hydrochloric acid;
water purified from impurities.

At home, soldering acid is made by dissolving zinc in hydrochloric acid. To obtain satisfactory results, you need to know how to solder metals and alloys with soldering acid, and also strictly follow safety rules when working.

General rules of application

For soldering, tin-lead solder (PLS) is usually used. Its main component is always tin, and lead is added in proportions, depending on which the solder acquires the properties necessary for soldering.

Lead makes the material softer and more fluid, while tin provides strength to the hardened joint.

Despite the presence of lead, the fluidity is often not enough to overcome the surface tension forces in a drop of solder, and with little adhesion to the metal surface, the solder remains in the form of a drop that does not want to stick to the parts.

If the surfaces are first cleaned of oxides, the adhesion force will exceed the forces of surface tension and the solder will spread over the surface, ensuring good adhesion, that is, sticking.

To clean the surface, it is mechanically cleaned using a file or sandpaper and soldering acid is applied. It can be applied with a small brush made of natural materials or with a small spatula.

Often the composition is contained in plastic bottles with dispensers that are convenient to use. The flux must cover the entire surface to be soldered, otherwise the solder will not stick well to it.

During contact of the heated solder with the surface, the soldering acid evaporates, but its presence is no longer required. After the solder is applied, it itself performs a protective function, preventing oxidation. This process is called tinning.

Both soldered workpieces are subject to tinning. After tinning, you can easily connect them by applying additional solder to the joint.

Of course, when soldering with a soldering iron, the tool must also be clean and the tip, made of copper, must not contain oxide films. To do this, the tip must also be tinned first by dipping it while heated in soldering acid and applying solder to it.

Soldering without a soldering iron

Sometimes when soldering using soldering acid, you can do without a soldering iron. One of these methods is used, for example, when soldering twisted wires during electrical installation work on electrical wiring.

In this case, flux is applied to the twist with a brush, and for a better effect, the twist is dipped in a small container with acid. After this, the twist is immersed in a container with molten solder and held for about 1 minute so that the wires warm up well and the solder penetrates to all points of their surface. This soldering provides excellent electrical conductivity when connecting wires.

It must be remembered that when installing printed circuit boards of electronic circuits, when soldering electronic components of radio devices, it is not recommended to use soldering acid, since very thin conductive traces of the boards can be damaged. When applying flux, soldering acid can dissolve them.

Safety regulations

In the production of soldering acid, hydrochloric and phosphoric acids are used. They are very active (although phosphorus is weaker) and easily react with many chemicals. When such substances come into contact with the skin, they cause a chemical burn.

Even when diluted, their vapors can damage the mucous membrane of the sensory organs.

Taking into account the above facts, safety rules when handling soldering acid include secure storage of the drug, the use of protective clothing and gloves, and good ventilation of the work area.

Source: https://spb-metalloobrabotka.com/kak-pravilno-payat-payalnikom-s-kislotoy/

Do-it-yourself soldering acid: composition and purpose, do-it-yourself production - Machine

Soldering acid is a flux that can be classified as a separate category, because it has an aggressive effect on materials that are needed during work. This flux mainly spreads in a liquid state, and this does not depend on its concentration. Sometimes you can purchase a concentrated substance and then dilute it, or perhaps buy a ready-made, diluted one. In addition, everyone can easily make soldering acid on their own.

The properties of materials must be selected according to those factors that are necessary for their use.

Soldering acid is intended for those metals that are heavily contaminated, because oxidation occurs on them, and a large amount of rust remains on the surface.

The material is very active, so it is necessary to work with it carefully and avoid contact with human skin and mucous membranes. You must first carefully familiarize yourself with the rules and methods of using acid, and only then begin to use it for its intended purpose.

In the process of producing soldering acid yourself, it is necessary to use special technology. In the end, the result should be a material that will have the properties prescribed by GOST. This is what will make the flux high-quality and reliable so that the connections are strong.

It is necessary to ensure that the properties and functions of the acid work even after soldering the metals, because the material removes films and rust from the surface, and also prevents their reappearance.

You should also take into account the spreadability of the materials being soldered over the surface and the adhesion to metals and products.

Characteristics, composition and properties

It is necessary to know exactly what the material should consist of, and only then begin its production. Soldering acid includes:

wetting additive;
ammonium chloride;
deionized water;
zinc chloride;
hydrochloric acid.

Soldering acid, created independently, may consist of other components. You just need to do everything to ensure that the flux has all the necessary properties. It is necessary to ensure high activity of this material.

It must interact with the necessary materials in a minimum amount of time, and also destroy all substances that prevent normal soldering. However, it is worth considering that small parts may be damaged and deteriorated when exposed to acid.

Solder active fat has the same properties.

The acid has a rather unpleasant odor, so when a person inhales it, his health may suffer. That is why it is recommended to use a respirator when working with this material.

Well, the work area must be constantly ventilated.

It is necessary to protect your hands, skin and mucous membranes from acid; it is necessary that the workpiece gets only into the places necessary for soldering.

Materials and tools for making acid

You need to know that the soldering acid you make yourself will have a slightly different composition than the purchased one. However, it will be simpler. To prepare such acid, you need to use some equipment:

Glass container or jar for mixing and preparing the material.
Zinc granules or cups from used batteries containing this element.
Tap clean water.
Concentrated hydrochloric acid, which is capable of dissolving unnecessary impurities and substances.

Making acid yourself

First you need to take a container or jar for mixing the acid. This is where the zinc or batteries and their remains are placed.

Only after all of the above can hydrochloric acid be poured into the container. The main thing is to act with great caution, because if it comes into contact with the skin, you can get a serious burn.

The acid in the container should not be more than 3/4 of the volume of the entire composition.

As a result, it turns out that the proportions should be like this. For 1 liter of hydrochloric acid, 412 grams of zinc are needed, but this can only be measured using special tools. Therefore, it is worth knowing that there will be some deviations in one direction or another.

When further preparing soldering acid, you must wait for the reaction of the chemicals to finish. Zinc and acid come into contact with each other, the metal gradually dissolves. During this process, active hydrogen evolution occurs, so many bubbles can be seen in the liquid.

The liquid gradually becomes clearer and cleaner. When all processes are completed, it is necessary to pour the liquid into a tightly closed container. All these materials can be easily purchased in stores specializing in the sale of chemicals and reagents. When using batteries, you can see that almost any of them will do.

If you need to make a material with weaker properties, then you should slightly reduce the aggressiveness. In this case, it is recommended to add a little water to make the solution more liquid and with weaker properties.

However, you need to be careful, because the liquid can splash and get on the skin and mucous membranes of a person.

In this case, you should choose the proportions yourself, adhering to the specifics of the required soldering.

Making soldering acid yourself

First, you should take care of your own safety, because using acid is very dangerous and can cause irreparable harm to your health. If acid production is carried out in enterprises and industrial areas, then everything must be done in special-purpose cabinets.

The reagents are reliably protected from outsiders, and they are poured strictly under special hoods. At home, it is recommended to use protection, gloves, goggles, respirators and other devices. Dissolving the acid should only be done in a well-ventilated area or even outside.

Indeed, in the process of creating acid for soldering, hydrogen is constantly released into the air in large quantities. It is also necessary to take care, just in case, of water, with which you can quickly rinse the area of skin on which the substance has come into contact.

It is best to use cold tap water because in the event of an accident, it will reduce pain and quickly clean the wound.

If this substance is spilled on the surface, it is best to wash it off with a special mixture of water and alkali.

You must also remember that this material must be stored correctly, the container must be closed and sealed, storage is carried out in a dark and cool place.

It is recommended to prevent unauthorized people from accessing the soldering acid to avoid danger to others. Flux is sometimes made from pure hydrochloric acid without zinc and water. However, it is mostly used only for iron products.

Source: https://regionvtormet.ru/beton/payalnaya-kislota-svoimi-rukami-sostav-i-prednaznachenie-izgotovlenie-svoimi-rukami.html

How to properly solder with a soldering iron with acid

» Soldering iron » How to properly solder with a soldering iron with acid

Among all fluxes, soldering acid stands out in a special category, since this variety has a number of distinctive properties that set it apart from the rest. First of all, this variety is distributed only in a liquid state. Even concentrated brands of acid are liquid, and if necessary, they can always be diluted to reduce the intensity of their properties. The question immediately arises: how to use soldering acid?

Types of soldering acid

Naturally, special properties create special conditions for how to use soldering acid. The fact is that this is one of the few fluxes that are harmful for direct contact with human skin.

Even if it is used as a strong diluted solution, in no case should it come into contact with mucous membranes, as well as open small wounds on the skin. At high concentrations, the substance can corrode skin and muscle tissue.

Thus, the rules on how to use soldering acid will not only help make connections better and more reliable, but will also preserve a person’s health.

The main purpose of this substance is to use it as a flux during soldering. Due to its high aggressiveness, when it gets on the surface of the base metal or solder, the acid eats away all the fatty films that have formed on it, metal oxides, and other contaminants. This helps to obtain a sufficiently clean surface, which will bring the soldering conditions in this area as close as possible to ideal ones.

Using soldering acid during soldering

These are not all the properties for which soldering acid is needed. Another ability of the material is that it remains after application. When you apply flux to metal, it will remain there for a long time, which will prevent the re-formation of oxides and deposits.

Also, during the application of solder, the flux will provide better spreadability and adhesion of the material. It does not hold back viscous components, allowing them to flow freely over the entire surface. Thanks to this, a high-quality and reliable connection is formed.

These products are manufactured in accordance with GOST 23178-78.

Recommendations for using soldering acid

To understand how to solder correctly with soldering acid, you should familiarize yourself with the basic rules. First of all, this concerns safety. Here you need to be as careful as possible so that nothing gets on your hands or other parts of the body. At best, you need to wear gloves and protective clothing with long sleeves. At home, these rules are not always followed, so basically you need to focus on accuracy.

The second harmful factor is fumes from acid. Before soldering with soldering acid, the area should be well ventilated. This can be natural or forced ventilation.

As additional protection, you should use a respirator or similar product. The problem here is not only that a person inhales the vapors, but also that they have a very specific, sharp, unpleasant odor.

At home, this procedure can be difficult to carry out.

If you are thinking about how to solder microcircuits, then soldering acid is clearly not suitable here. It's all about the aggressiveness of the environment. Microchips use relatively thin and small metal parts. Contact with concentrated soldering acid may damage small contacts.

It will simply burn them out, since thin metal is easily corroded. In addition, soldering acid conducts current. If you don’t dry the board well enough after soldering, it may simply short out. The same applies to salt residues that may form on it after using this flux.

There is no need to take risks here, even with the use of a solution.

Another recommendation would be mandatory cleaning of the soldered surface after work. The acid leaves behind salts after its use. During operation of the product, their presence is unacceptable, therefore mandatory mechanical cleaning is necessary.

There are several varieties of this material. Basically it all concerns the proportions in which the acid is produced. Most often it is diluted, but for particularly difficult cases, concentrated is also used.

If you need to use it for standard soldering procedures and you do not know in what proportion it is best to use this type of flux, then you should use the standard version, which is a 10% solution.

This is the most popular variety encountered by many amateurs and professionals.

Soldering technology

The use of this flux is not much different from the others in terms of direct application. It needs to be prepared separately in order to be conveniently used, for example, in some insulated container. Before soldering parts, they need to be tinned.

Metal tinning process

The method of tinning a soldering iron with soldering acid is practically no different from working with rosin. Here it is enough to soak the tip in the liquid itself.

"Important!

To tinning the surface of the workpiece, you need to use solder soaked in acid, which should spread in a thin layer over the surface of the metal.”

After everything is tinned, you can drop a few drops of acid onto the soldering area so that it covers the entire surface where the connection will be made.

Applying soldering acid to the soldering area

After this, you can proceed to direct soldering, where molten solder is applied to the surface of the connection of two parts.

Soldering process using acid

A mandatory procedure is removal of salts. A visible plaque forms here, which must be removed mechanically.

Conclusion

Despite the obvious disadvantages regarding safety of use, soldering acid has been and remains one of the most popular fluxes for difficult soldering cases. In the private sphere, due to its specific smell and high aggressiveness, it is not used so often, but professionals often use it. Proper use will provide you with safe working conditions and high quality results.

Source: https://i-perf.ru/payalnik/kak-pravilno-payat-payalnikom-s-kislotoj.html

Soldering with soldering acid

Every craftsman has a variety of general and special-purpose tools in his arsenal, which he uses during his work. Such devices include a soldering iron.

With its help, you can solve many problems, so the scope of application of the device is very wide, ranging from tinning and soldering the joint of electrical wires to welding radiators.

This article discusses how to solder aluminum, types of soldering irons and soldering methods, as well as what solder paste is and the correct algorithm for using acid.

Soldering methods

In general, the soldering process, regardless of the method used, boils down to one thing: it is heating the tin and the mating metal pad to the required melting temperature and joining these materials to form a single structure. There are several soldering methods that are most often used in industry and everyday life:

Soldering with a device powered by current. Electric soldering irons have a heating element inside their body, which, when voltage is applied to it, raises the temperature of the sleeve to the maximum value. Many of them are equipped with a heat control device to allow you to set the desired heating;
Soldering using a gas torch. This method is applicable in conditions where it is necessary to cover a large area with solder, for example, to solder an aluminum radiator or perform tinning. In this case, an open gas flame acts as a heat source, and special metal rods are used to apply tin, which, after heating, maintain the set temperature for some time;

Joining two materials or wires without a soldering iron. This technology appeared relatively recently. Its advantage is that to seal the surface of the radiators, no additional equipment or electricity is needed; for restoration, a ready-made soldering paste is used, which contains tin and binding components. It is applied to the material in a dense layer, after which it is heated with an open fire or an industrial hair dryer. After cooling, the tin melts over the entire contact, forming a single structure. It is very convenient to use it for emergency repairs of radiators made of aluminum or copper, when it is not possible to remove the part from its seat. Recently, on the market you can find paste in the form of a tape, which is wound into a cylinder and looks like PVC electrical tape. This product is comfortable to store and convenient to apply to the surface. Soldering without a soldering iron is used only for small jobs, for example, when you need to solder wires at a joint.

The listed soldering methods are the most common and are used in many areas of industry, installation of electrical equipment or in everyday life. Separately, it is worth noting the classification of soldering according to the type of insulating material, which is rosin or acid. In the first case, wood resin envelops the surface of the heating element or soldering iron, creating a thin layer that prevents the tin from sticking to the rod.

The use of acid allows you to save on material, since its consumption is much less than that of rosin, moreover, the liquid better envelops the coating and additionally degreases the material.

Important! When working with acid, it is necessary to observe safety precautions, protect the respiratory system and avoid contact of the substance with mucous membranes and skin. If this happens, you should rinse the area with plenty of water and consult a doctor.

The concentration of acid varies, the most common is a 10 percent solution. Of course, it is safe for human skin, but during the heating process it can emit harmful fumes. Depending on the problem being solved and the coverage area, the composition of the reagent can be changed by adding acid to the liquid.

Acid soldering process

Methods for soldering LED strips

How to solder without a soldering iron? In order to properly perform this type of work, which can be used for tying copper wires, as well as for soldering brass, you will need an open flame source, a metal tip and tin solder. The action algorithm will be as follows:

At the first stage, it is necessary to clean the surface of visible dirt, old paint and oxidation. Most often, a metal brush is used for this, which is mounted on a drill and, when rotated, tears off old pieces. You need to clean both materials that are planned to be joined;
A metal tip is heated over an open fire and dipped into an acidic composition. The surface to be coated must also be lubricated with a reagent to degrease the material. If you plan to seal the hole, then the elements are heated simultaneously, for which a gas burner is used with oxygen supplied through a special gun;
When the surface has reached the desired temperature, tin solder or copper wire is applied to it. Then the burner forces one layer onto another by bringing the nozzle closer to any area. You can also use a copper rod for this, which will melt during the straightening process and create an additional layer;
Finally, you need to remove the heat source and wait for the coating to cool. Acid has a side effect: after cooling, salt deposits form on the material, so when the structure turns black, you need to clean the joint with a wire brush.

This process is universal, so it is applicable for soldering wires of different sections made of copper or aluminum. Some craftsmen use another acid soldering method, when soldered copper conductors are dipped into a container of molten tin, after which a thin metal film is formed on the material; this process is also called tinning.

Soldering aluminum

How to choose the right socket

Brass and copper can be soldered using the same technology, but this approach is not entirely applicable for aluminum, since it quickly oxidizes, which prevents normal contact of the solder with the surface.

For example, to restore batteries from this material, both parts must be heated simultaneously so that their oxidation does not interfere with fusing and the formation of a protective layer.

In this case, acid acts as an excellent remedy for grease: it dissolves it completely and forms a film for smooth spreading of solder.

Important! Aluminum soldering should be carried out in a well-ventilated area, with artificial ventilation, to remove smoke and harmful impurities.

Soldering brass

How to solder brass and copper? An ordinary soldering iron powered by current is not suitable for this, since its temperature is not so high and the structure will be fragile. The most appropriate method is to use a torch and wire, which, when melted, fills the hole or other defects, forming an airtight coating.

How to solder copper

For this, any method can be used, since this material is not fussy, has a low oxidation coefficient and melting temperature.

How to solder metal of different composition? If you need to join brass and copper elements, then they can be soldered by heating with an open fire, for which a gas burner and a rod are used.

Important! When heating, do not touch the soldered element with open areas of the body, since the overall temperature of the part will be high; to hold it, use a remote clamp or thick gloves.

Thus, before replacing the soldering iron with a torch and using the listed metal processing methods, you need to carefully understand the issue of how to properly solder with a soldering iron using acid, take into account the characteristics of the materials and other indicators.

Source: https://rem-serv.com/payka-s-payalnoy-kislotoy/

What acid is used for soldering - Metalworker's Guide

Anyone who knows how to solder knows that in addition to a good, proven soldering iron, work also requires high-quality solder and flux. The solder is usually an alloy of tin and lead, made in the form of wire. The thickness of the wire, as well as the quantitative proportions of the composition, may vary depending on the purpose of the solder.

Rosin is most often used as a flux for soldering at home. It allows you to quickly and accurately solder copper parts: wires of various sections, tubes or other products.

In addition to rosin, tinning with soldering acid is common. It can be used to solder various products made of aluminum, bronze, stainless steel, brass, nickel and steel. The types and methods of using soldering acid will be discussed further.

Types of acid fluxes

Two types of specially prepared acid are used as flux for soldering:

Their main purpose is to remove various contaminants and oxidation products from the soldering area, to create conditions for high-quality, uniform spreading of solder over the working surface. This ensures a reliable connection of the two parts with a neat seam.

In addition, the use of acid flux prevents the formation of oxides during product operation, which has a positive effect on the durability of the connection.

Note! The use of acid flux to work with electronic boards is strictly prohibited. In addition to its destructive effect on fragile elements, acid can create additional conductive channels, which will inevitably lead to board failure.

Orthophosphoric acid

When a metal surface is treated with this flux, a protective film is formed that protects the material from further rusting.

Description and characteristics

Phosphoric acid is usually colorless. In some cases it has a light yellow tint. Occasionally there is a composition that has a somewhat cloudy color, which is not a violation or an indicator of poor quality of the product.

Note that orthophosphorus flux is a material of inorganic origin. Under normal conditions, it is a paste-like substance with a pronounced hygroscopic structure. When heated, it turns into liquid pyrophosphoric acid, which spreads well over the surface. What is important, after hardening back, it easily dissolves in water.

Application

Using orthophosphorus composition, carbon steels, nickel and copper alloys can be soldered. The operating temperature should be 300–350 °C. When applied to metal, the oxide layer dissolves. After applying solder, the acid film loosens and floats to the surface. After hardening, the film retains its protective properties, protecting the joint from re-oxidation.

After soldering is completed, the product must be washed with water to remove acid residues.

Hydrochloric acid

Flux based on hydrochloric acid is a complex chemical substance. Usually sold in small bottles called soldering acid. It has a yellowish tint and a sharp, specific odor. It has the ability to dissolve most metals and corrodes skin and muscle tissue. Therefore, soldering with this composition must take precautions.

DIY making

With some knowledge, it is quite possible to make soldering acid at home. To do this you will need the following ingredients:

Pure hydrochloric acid;
Pieces of zinc, which can be purchased at a chemical store or taken from a disassembled AA battery;
A small glass vial with thick walls.

The vial is filled with hydrochloric acid to ¾ of its volume. When zinc is added, a chemical reaction begins, during which hydrogen is released. Therefore, it is better to carry out such manipulations outdoors. Pieces of zinc are added until the reaction stops and a gray precipitate is formed.

The finished soldering acid should be poured into another container for storage and use.

How to solder with acid

As already noted, acid fluxes are used for soldering various metals and their alloys. Such work has its own nuances, which are discussed below:

Surfaces that need to be soldered are cleaned of dirt and rust. This is done with a file or sandpaper;
Next, acid flux is applied to both surfaces. This can be done using a brush. It is convenient if the storage container is a plastic bottle with a dispenser or just a narrow nozzle. This will allow you to carefully apply the acid in the right amount;
After this, with a heated soldering iron, solder is applied to both surfaces treated with soldering acid. This is called tinning.

Two tinned parts are easily soldered together: an even film of solder allows you to make an even and uniform joint, which is reliable and durable.

After finishing soldering, you need to remove any remaining acid so that it does not further corrode the metal. To do this, use a powder of regular baking soda, which is then washed off with water.

Precautionary measures

Since soldering acid is an aggressive substance, handling it requires special precautions.

The container with acid flux should be stored in a tightly closed original container. Exposure to sunlight should be limited; it is better if the room is cool. It is also important that the storage location of the container is inaccessible to children.

Soldering with acid should be done in a ventilated area, preferably with cross ventilation (open windows and doors). You need to work in safety glasses, use a gauze bandage and gloves. In case of contact with the skin, the area is treated with alkali and then washed with running water.

Let's sum it up

Having understood the types and characteristics of acid fluxes, you can safely begin the practical application of the knowledge gained. Such skills are widely used by home craftsmen for soldering leaky pots, buckets and other household items.

Source: https://ssk2121.com/kakaya-kislota-primenyaetsya-dlya-payki/

What is soldering acid and why is it needed?

Almost everyone who learned to solder on their own experienced failures at first. Either the solder did not want to stick to the workpieces and parts, or the soldered seam suddenly fell apart.

How to prepare soldering acid at home

All existing metals, as well as their alloys, can be combined with each other using two different technological processes. We are talking about welding and soldering. Welding of metals means short-term heating of two metal surfaces at the point of contact to extremely high temperatures.

At these temperatures, the surfaces to be joined undergo complete melting. As a result, a connection of two metals occurs at the level of interatomic bonds of the crystal lattice.

The consequence of this process is a monolithic welding seam, whose strength sometimes even exceeds the strength of the metal products being welded themselves.

What is soldering

Soldering is a completely different process. It does not affect the internal structure of the metal in any way. It occurs exclusively on the surface of the materials being soldered. No monolithic connections are formed at the atomic level during soldering.

To perform soldering, the presence of a third, lower-melting metal, which is called solder, is necessary. With the help of solder, the soldering process occurs directly. Pure tin or its various alloys are most often used as solder.

The task of any soldering is to melt the solder and ensure its good spreading over the surface of the metals being soldered.

As the solder hardens, it changes from its molten liquid state to a solid state and provides a reliable connection between two metal products.

In practice, everything turns out to be a little different. The fact is that all metals, without exception, have a fairly hard and chemically inert oxide film on their surface. The strength of this film varies among different metals. The most durable oxide film is formed on the surface of aluminum. This film, as well as all kinds of mechanical impurities that are always present on the surface of any metal, lead to the fact that the solder does not want to spread over the metal.

That is, in professional terms, tinning of the metal does not occur. Instead, the solder becomes a moving ball that rolls around the metal surface without connecting to it in any way. This suggests that the surface tension of the molten solder is much higher than the adhesion (sticking) of this solder to the metal surface. To enhance the adhesion of solder and ensure reliable soldering of two metals, so-called fluxes are used.

Acid fluxes

Why are fluxes used? The task of any flux is to:

Dissolve the surface oxide film on the metal.
Clean the surface from mechanical contamination.
Prevent oxidation and the formation of a new oxide film.
Reduce the surface tension of the molten solder, thereby facilitating its free flow over the metal.

Rosin

Among radio technicians, the most common flux is rosin. It is essentially pine tree resin from which the turpentine has been removed through an evaporation process.

It is widely used due to its low cost, ease of storage and chemical inertness. Rosin is used as a flux for soldering products made of copper, brass, silver, and nickel.

That is, those metals on the surface of which the oxide film is not very strong and is quite easily destroyed by the weak influence of molten rosin.

But when it comes to metals such as aluminum, cast iron, all kinds of steel alloys or iron, rosin stops working and its use in these cases turns out to be extremely ineffective. The rosin needs to be replaced and the flux made more aggressive to make the soldering process easier.

Soldering acid

chemically active acid fluxes were invented . There are several types of acid fluxes due to the fact that different metals form oxide compounds of different strengths on their surface.

The so-called soldering acid can be easily purchased at a specialized store and is inexpensive. But there is a small problem.

Most often, manufacturers do not indicate the exact composition of the chemical they sell under the name “soldering acid.” But, as you know, soldering different metals requires acid fluxes of different compositions.

Therefore, sometimes it will be much more rational to make one or another flux for a specific metal at home than to buy a pig in a poke.

Zinc chloride flux

For soldering, so-called pickling acid is used. This is one of the most common acid fluxes. This is the same soldering acid that is most often sold in specialized stores. This flux is mainly used for soldering iron. For example, pure hydrochloric acid can be used to solder roofing iron. Usually this is a solution of zinc in hydrochloric acid, in other words, zinc chloride.

All the necessary reagents for this reaction can be freely purchased at a chemical store, namely: granulated zinc and chemically pure hydrochloric acid. This is the composition of soldering acid.

The proportions are as follows:

Concentrated HCl: 1000 ml.
Pure zinc: 400 gr.

For mixing, you must have an appropriate glass, porcelain or ceramic container.

The zinc is first placed in the container, and only then hydrochloric acid is slowly added to the zinc in a thin stream.
In no case should you do the opposite and add zinc to hydrochloric acid. This can lead to very sad consequences, namely the splashing of acid in all directions.
During the chemical reaction, hydrogen will be released. This gas, when combined with oxygen in the air, forms an extremely dangerous gas mixture called detonating gas. This gas explodes at any opportunity. Therefore, before you start dissolving zinc in hydrochloric acid, think about good ventilation. It would be ideal to carry out the reaction outside, in the fresh air.

Olein flux

The basis of this flux is oleic acid, which is found in olive oil or any fat. To prepare the flux, technical olein is used, which is mixed with lithium iodide.

It is used for soldering both pure aluminum and aluminum-based alloys. This is the only flux that can dissolve the extremely durable aluminum oxide film, while the protective flux layer remains until the end of the soldering process.

It is impossible to make oleic flux at home. Yes, this is not necessary. It is freely sold and inexpensive.

Salicylic acid

Or the well-known aspirin. Purchased in tablet form at your nearest pharmacy. It costs a penny.

It belongs to the so-called inactive fluxes, that is, after soldering is completed, salicylic acid does not affect the contact point in any way and therefore no additional treatment is required after soldering to remove flux residues. Moreover, after hardening, salicylic flux protects the soldering area from corrosion.

You can solder with pure acid , using it in the form of a powder or a whole aspirin tablet. But it is much more effective to use aspirin as part of a multicomponent flux, which is called VTS.

VTS flux is used for soldering copper conductors, as well as products made of silver and platinum. The flux contains technical petroleum jelly as a filler, ethyl alcohol and acetylsalicylic acid.

This flux can be used to solder almost any metal, with the exception of aluminum.

The only disadvantage of aspirin: during soldering, extremely caustic smoke is released, which can damage the respiratory tract with frequent contact. Therefore, good exhaust is a prerequisite for productive work with this flux.

How to solder correctly

How to use soldering acid? The key to successful soldering is not only the correctly selected flux, but also the correct preparation for soldering. To do this you need to know the following:

Before soldering, metal surfaces must be cleaned of rust and other contaminants using a file and sandpaper.
All liquid fluxes are best applied to the surface using a special brush. In this case, maximum application accuracy and uniformity of distribution are achieved.
The acid flux should cover the surfaces to be soldered with an even, uniform layer, without gaps. Otherwise, uniform distribution of solder over the metal surface will not be achieved.
The tip of a well-heated soldering iron picks up a small amount of solder and transfers it to the metal surface pre-treated with flux. The solder is distributed in an even layer over the entire surface of the metal. This is called "tinning". The second metal surface is tinned in the same way. After this, both tinned surfaces are soldered.
After completing the soldering process, it is necessary to remove any remaining acid solder. Otherwise, the acid will begin to destroy the metal and a corrosion center will arise, which can lead to destruction of the soldering area.
Acid is neutralized by alkali. For the latter, it is best to use baking soda. The soldering area is sprinkled with soda and then washed with water.

Source: https://respect-kovka.com/kak-prigotovit-payalnuyu-kislotu-v-domashnih-usloviyah/

How to solder correctly with a soldering iron and rosin

Knowledge of how to solder correctly is needed not only by radio amateurs and electrical installation specialists. Every home handyman has to deal with the need for soldering when repairing electrical appliances.

Preparing the soldering iron for use

Before soldering with a soldering iron, you should properly prepare it for work. In everyday life, an electric soldering iron with a copper tip is most often used, which, during storage and use, gradually becomes covered with a layer of oxide and is subject to mechanical damage. To obtain a solder joint of good quality, the soldering iron is prepared for use in the following sequence:

Using a finely cut file, clean the working part of the tip to a length of 1 cm from the edge. After cleaning, the tool should acquire a reddish color, characteristic of copper, and a metallic luster. During stripping, the tip is given a wedge-shaped, beveled, cone-shaped shape in order to solder what the master needs.
Plug in the soldering iron and heat it to operating temperature.
The tip must be tinned and covered with a thin layer of tin - the same solder used to solder the connected conductors. To do this, the tip of the tool is immersed in rosin, and then a piece of solder is passed along it. You should not use a solder rod with rosin inside for tinning a soldering iron. To distribute the solder evenly, rub the working edges against a metal surface.

During operation, the half-plate will burn and wear off, so the soldering iron will have to be cleaned and tinned several times during the soldering process. You can clean the tip with a piece of sandpaper.

If the master uses a tool with a nickel-plated, non-burnable rod, it will have to be cleaned with a special sponge or damp cloth. They tin such a sting in molten rosin, running a piece of solder over it.

Soldering can only be learned on the job, but before that it is advisable to become familiar with the basic operations.

Fluxing or tinning

The traditional and most affordable flux is rosin. If desired, you can solder with a solid substance or its alcohol solution (SKF, Rosin-gel, etc.), as well as TAGS flux.

The legs of radio components or chips are covered with half-milk at the factory. But to get rid of oxides, you can tin them again before installation, lubricating them with liquid flux and covering them with an even layer of molten solder.

Before processing with flux or tinning, copper wire is cleaned with fine emery cloth. This removes the oxide layer or enamel insulation. Liquid flux is applied with a brush, and then the soldering area is heated with a soldering iron and covered with a thin layer of tin. Tinning in solid rosin is done as follows:

melt a piece of the substance on a stand and heat the conductor in it;
feed the solder rod and distribute the molten metal evenly over the wire.

Correctly soldering massive copper, bronze or steel parts should be done using active fluxes that contain acids (F-34A, Glycerin-hydrazine, etc.). They will help create an even layer of poluda and firmly connect parts of large objects. Tin is applied to large surfaces with a soldering iron, spreading solder evenly over them. After working with active flux, acid residues should be neutralized with an alkaline solution (for example, soda).

Preheating and temperature selection

It is difficult for beginners to determine at what temperature the tool can start working. The degree of heating should be selected depending on the type of material:

soldering microcircuits requires heating no higher than +250°C, otherwise the parts may be damaged;
large individual radio components can withstand heating up to +300°C;
Tinning and joining of copper wire can occur at +400°C or slightly lower;
massive parts can be heated at the maximum power of the soldering iron (about +400°C).

Many models of instruments have a thermostat, and it is easy to determine the degree of heating. But in the absence of a sensor, it is worth keeping in mind that a household soldering iron can be heated to a maximum of +350 +400°C. You can start working with the tool if the rosin and solder melt within 1-2 seconds. Most POS grade solders have a melting point of about +250°C.

Even an experienced craftsman will not be able to solder correctly with a soldering iron that is not heated enough. With low heat, the solder structure becomes spongy or granular after solidification. Soldering does not have sufficient strength and does not ensure good contact between the parts, and such work is considered a defect.

Working with solder

When heated sufficiently, the molten solder should become flowable. For small jobs, you can take a drop of alloy on the tip of the tool and transfer it to the parts to be joined. But it is more convenient to use thin wire (rod) of different sections. Often inside the wire there is a layer of rosin, which helps to solder correctly with a soldering iron without distraction from the process.

With this method, a hot tool heats the surface of the connected conductors or parts. The end of the solder rod is brought to the tip and pushed a little (1-3 mm) under it. The metal instantly melts, after which the remainder of the rod is removed, and the solder is heated with a soldering iron until it acquires a bright shine.

When working with radio components, you need to take into account that heating is dangerous for them. All operations are performed within 1-2 seconds.

When soldering connections of single-core wires of large cross-section, you can use a thick rod. When the tool is heated sufficiently, it also melts quickly, but you can distribute it over the surfaces to be soldered more slowly, trying to fill all the grooves of the twist.

Source: https://odinelectric.ru/knowledgebase/kak-pravilno-payat-payalnikom

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