What is soldering acid called?

Composition of soldering acid

Fluxes created on the basis of soldering acids, subject to soldering technology, make it possible to obtain a high-quality and durable connection of materials that are difficult to solder.

The composition of fluxes created using acids may vary depending on the area of ​​their application. Different types of fluxes have their own characteristics, which should be taken into account when soldering certain metals.

If we talk about soldering acid in general, it is a solution of acid in various substances. Acid in its pure form is practically not used for soldering, since, being an extremely aggressive chemical compound, it can have a destructive effect on various materials, including metals.

It is not recommended to use soldering acid when working with printed circuit boards, since thin connection buses and contacts of radio components are not able to withstand such aggressive influence. The best option for soldering radio circuits is pine rosin or fluxes created on its basis.

Types and chemical composition of soldering acids

Let's present the most common acid-based fluxes

Flux based on orthophosphoric acid

Phosphoric acid is an inorganic chemical compound of medium potency. This is a colorless substance, however, sometimes light yellow stains can be observed in it. To obtain flux, phosphoric acid can be diluted with water, ethanol, alcohol, and other solvents.

Flux based on hydrochloric acid

Due to its high aggressiveness, hydrochloric acid in its pure form is not used for soldering. In most cases, it is diluted with water in various proportions. To improve the adhesive properties, zinc can be added to the solution. This type of soldering acid is used to create solder joints from the most difficult metals.

Sulfuric acid based flux

Sulfuric acid is an oily substance without color or odor. Sulfuric acid flux is made by diluting it in water or sulfuric anhydride in certain proportions.

Depending on the scope and technology of application, the ratio of acids and solvents in fluxes can be different - the acid content in them ranges from 25% to 85%.

Selection of acid fluxes

Before making a choice in favor of one or another soldering acid, you should determine exactly what problems will be solved with its use. Based on this, it is necessary to select a flux with the most suitable composition.

A solution with orthophosphoric acid is optimal for soldering metals affected by corrosion. This substance effectively fights oxides, which allows you to obtain a fairly high-quality compound.

Fluxes based on hydrochloric acid are considered universal; they can be used for soldering a wide range of ferrous and non-ferrous metals, as well as alloys. For soldering large-scale parts, concentrated hydrochloric acid is used, since in such cases its aggressiveness is not critical for the safety of the metal.

In all cases, the choice of acid concentration in solutions must be correlated with the cross-section or thickness of the parts to be soldered.

An important indicator of the quality of solutions is the presence of sediment in them. In fluxes, the presence of a minimum amount of undissolved substances is acceptable, but their abundance indicates poor quality of the solution.

Source: https://svarkagid.com/sostav-payalnoj-kisloty/

Composition of soldering acid for soldering

[Acid for soldering is necessary] if the use of rosin does not allow the necessary elements to be properly soldered together.

The use of soldering acid for soldering helps remove the oxide film layer from the surfaces being soldered and makes it possible to properly prepare them for joining.

As a rule, rosin is used to prepare copper parts for soldering with your own hands. But soldering acid is used for tinning not only copper, but also its alloys - bronze and brass.

And also for stainless steel, precious and ferrous metals, aluminum and nickel, even for soldering cast iron.

The need to use acid fluxes

Any soldering acid - hydrochloric or phosphoric acid - is designed to create an ideal environment for the interaction of solder with elements.

Their use makes it possible to remove contaminants and oxides from the working area, prevent the resumption of the oxidation process and reduce the tension of the solder, in order for it to spread more freely.

As a result, reliable soldering of parts is ensured.

Depending on the type of metal, the flux for soldering is selected. It is worth noting here that soldering acid is not used when assembling boards.

Acid belongs to the category of aggressive media and contributes to the destruction of components standing in its path.

In addition, it is an ideal electrical conductor and has the property of creating additional conductive channels.

Therefore, you should not even count on neutralizing the acidic environment after soldering.

DIY hydrochloric acid flux

Often, to process the parts being soldered, a flux is purchased, which is commercially available and is simply called soldering acid.

The manufacturer supplements the product with instructions on the conditions of its use, which makes it easy to navigate its purpose.

Usually this is tinning and soldering of stainless steel, silver, copper, aluminum and various alloys.

In the production of flux, hydrochloric acid is used, in which zinc is dissolved, resulting in a base - a zinc chloride compound. It is quite easy to make such a composition at home with your own hands.

To prepare the composition you need to take:

• 1 liter of HCL (concentrated hydrochloric acid);
• 412 g Zn (zinc).

Next you will need a container made of glass, ceramic or porcelain. First, zinc is placed in the dishes, then hydrochloric acid is poured.

It is very important to prepare the composition with care; fill ¾ of the container with acid.

Zinc and hydrochloric acid can be bought in special chemical stores, but if you have old AA batteries at home, Zn can be easily obtained from them.

After the reaction of dissolving zinc in hydrochloric acid occurs, the evolution of hydrogen will stop.

That is, bubbles will no longer form in the liquid, it will become transparent. The prepared soldering acid composition is carefully poured into a tightly sealed glass container.

Precautionary measures: when making flux, it is recommended to be near running water; if the composition suddenly gets on the skin or, even worse, in the eyes, it is necessary to rinse them with plenty of water.

By the way, hydrochloric acid in its pure form can be used as a flux, provided that iron parts are processed.

Phosphoric acid for flux production

The second common type of soldering acid is phosphoric acid - H3PO4. It also ideally removes oxide film from metal surfaces and prevents its renewal.

Reference: H3PO4 (orthophosphoric acid) is a component of many anti-corrosion compounds for metal processing.

To carry out high-quality soldering of elements made of nickel or chromium, such acid is used undiluted. Moreover, the composition prepared using it includes 1/3 of ethanol or ethyl alcohol.

The share of orthophosphoric acid is 32%, and 6% is rosin.

In other acid compositions used for tinning and soldering, the proportion of acid can reach 100%.

Very often, H3PO4 is combined with zinc chloride, and its mass in the finished flux can reach 50%.

The use of phosphoric acid is not limited to soldering nickel alloys; it is used to connect elements made of stainless steel, copper, aluminum and low-alloy steel.

Orthophosphoric acid is a component of the classic active flux "F-38 N", the use of which makes it possible to solder copper alloys and pure copper, various steels and chromium-nickel alloys.

“F-38 N” is an excellent option for carrying out the work process in hard-to-reach places; it has the ability to protect welded elements from corrosion.

The components of “F-38 N” are: diethylamine hydrochloride and 25% phosphoric acid.

Orthophosphorus soldering composition is characterized as fire and explosion-proof. It is recommended to store and use the product with all precautions.

In case of contact with skin, rinse for at least 10 minutes under running water.

Use of tin for soldering

Different materials can be used for soldering metals, but connecting elements with tin is much easier and more convenient.

Tin can be used to connect parts made of stainless steel, aluminum, copper, and its alloys.

Tin is melted at a temperature of 2500; for this purpose, various heating devices can be used:

A soldering iron is a device with a metal working part and a plastic handle, and can have a variety of tips.

Heats up with a gas burner.

Electric soldering iron - the set includes replaceable tips of various sizes and shapes. The structure is assembled from a soldering rod and a heating coil, which can have different heating power.

Gas burner - a portable design is a container with a handle and a nozzle for creating a fire of varying intensity.

How to properly solder tin on stainless steel?

For soldering stainless steel elements, it is recommended to use active soldering acid, for example, zinc chloride or phosphoric acid.

Flux is applied to the surface of the stainless steel right before soldering begins. The tip of the soldering iron is tinned with molten tin and the surface of the stainless steel begins to warm up well.

The procedure is repeated until the coating becomes uniform. During the soldering process, you can use rosin, which will make the surface smooth by removing oxide from the solder.

After soldering the stainless steel is completed, the product is washed from acid residues with soapy water. Excess rosin is easily removed in cold water.

It is worth noting here that high-quality soldering will have a uniform and smooth surface.

How to properly solder aluminum with tin?

Before soldering aluminum, the surface is cleaned using emery cloth, then the work area is degreased with an organic solvent.

To solder aluminum you will need a soldering iron with a power of 100 W, as well as solder made of tin - 95% and bismuth - 5%. Stearic acid can be used as a flux.

Since aluminum products are difficult to solder due to the rapid formation of an oxide layer after stripping, it is necessary to fill the surface to be joined with hot rosin.

Then, use a soldering iron tip to take the solder and transfer it to the working part treated with rosin.

After tinning the aluminum in this way, it will become easier to solder the surface; if necessary, even copper wires can be soldered to it.

Source: https://strinstrumenty.com/pajka/sostav-payalnoj-kisloty-dlya-pajki.html

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 we really need to know about fatty acids in a child's diet

Yes, they should. In the first two years of life, children receive about 50% of their daily calorie intake from fats through breast milk or specialized formulas. At this age, a child’s fat intake is not limited at all. From the age of two, a child’s diet should consist of fats only 20-30% of the daily calorie content (the same as for an adult).

Why so many? Why are fats so important for baby food?

The fact is that fats are the most powerful source of energy (nine calories per gram is twice as many calories as proteins or carbohydrates). That is, the child will receive more energy for the same amount of food. This is important, because children have a smaller appetite and stomach size than adults, and they require more energy for growth and development.

In addition, it is with fats that the child receives some fat-soluble vitamins (A, D, E and K).

What kind of fats are there?

Fat molecules are shaped like jellyfish : the “head” is glycerol, and the “tentacles” are various fatty acids. It is by the tentacles - fatty acids - that fats are distinguished.

Fatty acids differ from each other in the chemical bonds between their atoms. These bonds can be single or double. Fatty acids are called unsaturated if they have double bonds, and saturated if they do not. Based on the number of double bonds, fatty acids can be polyunsaturated (if there are many such bonds) or monounsaturated.

In everyday life, it is quite simple to distinguish between saturated and unsaturated fatty acids: saturated ones will retain a relatively solid structure at room temperature (butter, coconut, palm oil), and unsaturated ones will retain a liquid structure (vegetable oils, fish oil). The more double bonds, the more beneficial the product is for the body. It is polyunsaturated fatty acids (PUFAs) that are considered essential for the body.

What does essential and non-essential fatty acids mean?

All fatty acids can be divided into essential and essential . The human body cannot produce essential fatty acids on its own, so they must come from food and drink. And the rest can be synthesized already in the body.

Such essential vitamins for humans are omega-6 linoleic acid and omega-3 alpha-linolenic acid (previously they were even designated by the term “vitamin F” , now obsolete). They take a significant part in the construction of body cells, metabolism and the synthesis of other fatty acids.

However, for babies, “conditionally essential” because their bodies have not yet learned to synthesize them in sufficient quantities, while they are very important.

Why are polyunsaturated fatty acids so important?

While other fatty acids can be synthesized in the brain, polyunsaturated ones are delivered there through the bloodstream, accumulate and participate in the formation of structures of the nervous system : the brain, retina, and nerve sheaths.

DHA and ARA have been identified as important structural components of the human central nervous system. In the last trimester of pregnancy, the fetal brain increases their accumulation.

The significant content of DHA and ARA in breast milk and a number of studies of the brain of children who received and did not receive breastfeeding confirm the special role of these fatty acids in the formation of the nervous system.

Therefore, if breastfeeding is not possible, choose a formula containing these fatty acids. This way you can be sure that they enter the baby’s body with food and help his harmonious growth and development.

Will your baby get enough fatty acids from breast milk? And from a mixture?

The American Pediatric Association recommends not limiting the amount of fat in a baby's diet before 12 months.

In the case of breastfeeding, the baby receives the required amount of essential fatty acids from mother's milk .

If not breastfeeding, it is very important that it is done with specialized formulas with a balanced content of essential fatty acids, especially ARA and DHA. Currently, certified baby food must contain these PUFAs.

What should be in complementary foods so that the child gets enough fatty acids?

From the age of two, a child’s diet should provide 20-30% of daily calories from fats, and the diet should be rich primarily in omega-3 and omega-6 fatty acids.

Daily consumption of omega-3 fatty acids should be from 0.5 to two percent of daily caloric intake, omega-6 - from four to eight percent.

This means that when complementary feeding is introduced with regular healthy foods (vegetables, fish, nuts, vegetable oils, eggs and meat) from the parent’s table, the child will also receive the optimal amount of essential fatty acids.

The main sources of unsaturated fatty acids are vegetable oils, seeds, nuts, olives, fish, fish roe and seafood.

At the same time, the source of omega-3 fatty acids is primarily fish oil (tuna, saury, mackerel, salmon, herring, pollock, mullet and sardine), as well as perilla oil, flaxseed, soybean and rapeseed oils, walnuts, chia, green leafy vegetables. Cod liver and seaweed oil are rich in omega-3 fatty acids, and now there are products on sale that are specially fortified with omega-3 (for example, eggs or pasta).

Omega -6 fatty acids are found mainly in seeds and vegetable oils - grape, corn, cottonseed, soybean and sunflower.

What about fish oil? To give or not to give?

The US Environmental Protection Agency (USEPA) recommends that children under two years of age be given no more than 60 grams of fish per week, given the potential risks of contamination, and that fish oil preparations should never be given to children without a doctor's prescription.

Side effects of such supplements include headaches, heartburn, indigestion, vomiting and diarrhea, but their benefits (including in studies on autism spectrum disorders, ADHD, etc.) have not been proven. It is better to ensure that your child’s diet includes fish 1-2 times a week.

For example, toast with sardines, noodles with salmon or pasta with tuna, the taste of which is masked by tomato sauce (in case the child is not a big fan of fish).

What fatty acids should you avoid?

Trans fatty acids ( trans fats ), which are artificial saturated fats, should be avoided. They are structurally different from the unsaturated fatty acids naturally found in plant foods and differ in their health effects.

Trans fats increase bad (LDL) cholesterol and lower good (HDL) cholesterol. Eating trans fats increases the risk of developing cardiovascular disease, stroke and type 2 diabetes.

They can be found in a wide variety of foods. Margarine, fast food (burgers, deep-fried dishes), confectionery and popcorn are especially rich in them. To avoid them you need to:

• carefully study the composition of finished products (especially ready-made baked goods, cakes, cookies, pies, crackers, chips, popcorn, frozen dough, mayonnaise) - in some countries, products free from trans fats have a special label (“Trans Fats Free”), in Russia this, unfortunately, is not mandatory, so you need to look for the phrase “ hydrogenated fats ” in the composition - and not eat foods that contain them;
• avoid the use of margarine and spreads;
• Avoid deep-fried foods.

What about butter for the porridge? Previously they always gave!

If the child does not have intolerance to cow's milk proteins, then butter can be given to him.

To date, there is no clear data regarding saturated fatty acids and cholesterol (which butter contains) - whether it is worth limiting them in the children's diet.

Although there is evidence of a link between their use and less flexible thinking, this has not yet been replicated in other studies. It is worth remembering, however, that unsaturated fatty acids should still be a priority.

As you can see, fatty acids, especially polyunsaturated ones, are an important component of children's nutrition from an early age. They are needed for the development of the brain and its functions, the formation of the nervous system, and even influence behavior.

Therefore, their use - first with breast milk or a specialized ready-made formula, and then with food - must be adequate and comply with modern recommendations. This is not difficult: it is enough that the child’s diet is varied and consists of fresh and healthy foods.

After all, familiar foods are the source of essential fatty acids - from greens to fish. For even more information about fatty acids in your child's diet, head to the #FoodForMind website, created specifically for caring parents.

Source: https://nen.ru/fatacid/

DIY soldering acid - Metals, equipment, instructions

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://spb-metalloobrabotka.com/payalnaya-kislota-svoimi-rukami/

Search data for your request:

Soldering acid, also called pickling acid, is used in the preparation or repair of various metal objects or devices, when some parts or small parts need to be connected to each other very firmly.

Not everyone knows what soldering acid is, why it is needed, where you can get it and the principles of working with it. Welding is the process of heating metals to their melting point and then joining them to each other through interatomic molecular bonds.

Before soldering, as before any other work, it is necessary to perform a number of procedures that contribute to a better result of the work:.

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Chemicals for soldering

Soldering is a complex physical and chemical process that results in a reliable and durable connection of any metal parts. Soldering acid is an indispensable soldering attribute that ensures high-quality connection of parts.

Phosphoric acid is used for soldering as a flux. The substance can also be used to clean metal surfaces from rust. Thanks to it, the treated metal surface is covered with a protective film, which prevents the material from further corrosion. Phosphoric acid is inorganic. The composition has the chemical formula H3PO4 and is colorless hygroscopic crystals under standard conditions.

When heated to a temperature above C. The composition of the substance turns into pyrophosphoric acid H4P2O7. The composition is highly soluble in water. Externally, the substance is a colorless or light yellow solution.

It is worth noting that the composition of the substance may have a cloudy tint. Applications of the substance - the connection of carbon and low-alloy steels, nickel alloys, copper alloys at a temperature equal to c. The mechanism of action of the substance is the dissolution of the oxide film of the metal, as well as solder and further loosening, floating to the surface of the flux.

A protective film of the substance is formed in the area of ​​the cleaned metal, preventing the appearance of oxide films. The remaining substance is washed off with water. Phosphoric acid is an explosion-proof and fireproof product of the chemical industry.

Storage must comply with all required safety standards: the composition is stored in a tightly closed container, away from exposure to sunlight, heat, and children. Before starting soldering, it is necessary to open the windows wide to create through ventilation of the room where soldering will be done. After soldering is completed, the room should be thoroughly ventilated for half an hour. During soldering, it is necessary to use personal protective equipment (PPE) for the respiratory organs, eyes, and skin of the hands.

If the substance gets into an open area of ​​the body, for example, on the hands, the area of ​​the body is thoroughly washed with plenty of running water for ten minutes, preferably with soap. If the substance gets into the eye area, they should be rinsed under running water for a longer time. Guaranteed shelf life is six months from the date of manufacture.

Hydrochloric acid is a solution of hydrogen chloride in water. The chemical has a colorless or yellowish tint with a pungent odor. The product of the chemical industry is a caustic and non-flammable liquid that has the property of dissolving most known metals, as well as their oxides.

The following materials are stable in it: porcelain, fluoroplastic, graphite, ceramics, glass. Hydrochloric acid smokes when exposed to air. Can be mixed with ether, benzene. The substance has a corrosive effect on the surface of metals, and also has highly toxic properties, corroding muscle tissue and skin. Sold in polyethylene cans or glass bottles.

Hydrochloric acid is stored in sealed containers. During soldering, as well as other work, the chemical is a harmful chemical solution, and therefore it is necessary to use PPE and ventilate the room before and after work. The substance must be stored away from direct sunlight, contact with heat, and out of the reach of children. If the substance gets on the skin or in the eye area, the damaged area is immediately washed with copious amounts of water.

Getting the substance into the respiratory tract is unacceptable. The shelf life of the substance is unlimited. The soldering process requires the use of special fluxes - substances that help the solder spread over the soldering area and create a high-quality metal connection. The main fluxes are rosin and acid.

Rosin is mostly used during soldering of silver and copper, while the use of acid is preferable for joining more complex materials. The choice of substance depends entirely on the type of metal being fused and its alloys.

For example, to solder iron it is necessary to use so-called soldering acid - a solution of zinc chlorate; Soldering stainless steel requires the use of phosphoric acid, as well as specialized multicomponent fluxes.

It is worth noting that acid is not suitable for soldering printed circuit boards and other similar parts.

If you are determined to use acid, you can purchase it in ready-made paste form. It is worth knowing that the substance can be made independently. It is worth noting that any work with a chemical should be done in a ventilated area, away from the sun and heat.

Soldering of metals. Soldering stainless steel: important features of the procedure.

Soldering acid: what do you need to know about this procedure?

Register Login. Mail replies. Questions - leaders How to properly lay low-current cables in an apartment? Why do attempts to implement laws on criminal justice encounter tactics of active resistance and hatred?

But as for the use of soldering acid, there are questions. He did not wash the connections; the twisted wires were completely soldered.

Rosin or soldering acid?

How much time has passed I came across this post in someone’s collection of saved files on Pikabu and now I feel like a time traveler But still I hope that they will answer my question on the topic: I sometimes solder with aluminum flux, what do you say about it or can you advise?

A little information that may be useful to you, both in everyday life and in other areas of life. A short lesson on soldering. No duplicates found. All comments by the Author. After some time they will simply be eaten away! In radio engineering, acid fluxes are generally used in very rare cases.

What other acid?!

How to solder with soldering acid

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.

An electronics engineer I know said that only rosin should be used for soldering circuit boards, and the presence of acid is strictly prohibited. This is true?

DIY soldering acid

Soldering is a complex physical and chemical process that results in a reliable and durable connection of any metal parts. Soldering acid is an indispensable soldering attribute that ensures high-quality connection of parts.

Phosphoric acid is used for soldering as a flux. The substance can also be used to clean metal surfaces from rust.

Thanks to it, the treated metal surface is covered with a protective film, which prevents the material from further corrosion.

Soldering phosphoric acid

Habr Geektimes Toaster My circle Freelansim. DIY Electronics. Actually a question for those who do soldering at home on an ongoing basis. What are the main differences? How harmful? Is a hood absolutely necessary or is it not critical for soldering on a non-production scale? Victor nehrung. There are more than two positions in this alternative.

C. Guaranteed shelf life is six months from the date of manufacture. Orthophosphoric acid (soldering acid, 85%) is often sold in tanks.

Soldering acid has many specific properties and characteristics that make it significantly different from other types of fluxes. One of the main features of this substance is its form: the acid is available exclusively in a liquid state. Naturally, in this regard, a reasonable question arises about how soldering acid can be used in practice.

Experienced electronics engineers and home radio amateurs know that for a high-quality connection you will need not only a soldering iron, but also additional accessories. For soldering, flux and solder are used, the latter is made on the basis of lead and tin, often offered in the form of wire.

The characteristics of the ratio of wire and flux may differ in parameters depending on the type of product. The second component is flux; a common form is used in the form of rosin. It helps to quickly and efficiently solder copper parts, wires and other materials.

Soldering acid can be used to work with materials such as brass, nickel, stainless steel, etc.

Any home craftsman who works with radio electronics knows how to use a soldering iron. The fact is that, unlike welding, joining with solder requires more careful preparation of the surfaces to be joined.

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.

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.

Appropriate soldering will help to connect two metal parts efficiently and reliably. To perform this procedure, you will need a special set of tools and consumables. To help car enthusiasts, we offer special soldering kits, the kits of which contain everything necessary to perform high-quality soldering of any metals and their alloys. During the operation of a car, sooner or later, every car enthusiast is faced with the need to solder some parts.

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What acid is used for soldering? — Machine tools, welding, metalworking

Any home craftsman who works with radio electronics knows how to use a soldering iron. Soldering classics: POS series solder and pine rosin, which produces a characteristic “fragrant” smoke when working with it.

What is rosin and other fluxes used for?

The fact is that, unlike welding, joining with solder requires more careful preparation of the surfaces to be joined. Molten solder behaves like an ordinary liquid.

If the surface tension of the melt is higher than the adhesion, the liquid metal simply will not “stick” to the part, but will remain on its surface in the form of a ball.

Why is this happening? Oxides form on the surface of any metal. This thin film prevents the metals from making normal physical contact. Of course, the surface can be mechanically cleaned before soldering.

But when heated, the oxide film will instantly cover the prepared surface. Flux works against this effect. In addition to their cleaning function, fluxes create a protective film on metals that prevents the formation of oxides.

But these “helpers” do not interfere with solder adhesion. On the contrary, it only intensifies with the use of fluxes. The result is a strong connection with excellent electrical conductivity.

When working with copper, silver, silver-plated or gold-plated contacts, you can get by with rosin made from the resin of coniferous trees.

But this drug has significant disadvantages:

• Rosin begins to melt when heated (the usual state is crystalline). Accordingly, the contact sometimes has time to oxidize.
• Low cleaning abilities do not allow working with metals whose oxide film is too strong: aluminum, stainless steel. When soldering, it is necessary to use chemically active fluxes.

In some cases, the oxide layer can be “broken” only with the help of acid or preparations containing it in their composition. Soldering acid can be universal or used with specific metals.

The composition of soldering acid (in addition to the main component) includes thickeners, neutralizers, oxide converters, and other chemicals. However, acid-based fluxes are available on the market at relatively low cost.

Unfortunately, many manufacturers do not indicate the composition on the label, limiting themselves to the inscription “soldering acid”. When purchasing such compositions, inexperienced craftsmen are faced with incompatibility between the flux and the metal being processed.

Popular: Do-it-yourself pulse soldering iron - not easy, but very simple!

For example, stainless steel soldering acid does not treat copper contacts well. And the composition that is used for copper and silver is not suitable for aluminum parts.

Therefore, many radio amateurs prefer to use homemade compositions. Do-it-yourself soldering acid is made from available materials.

An experienced soldering specialist can select the proportions in such a way that the effectiveness of the preparation will be higher (for specific soldering cases).

Types of soldering acids and application features

In order not to spoil the product, and at the same time get a high-quality oxide cleaner, you need to know what each soldering acid is needed for.

If you don't know how to use soldering acid correctly, you can end up with a time bomb. The PCB traces, or wire connection, will slowly deteriorate when exposed to the corrosive component.

At the most inopportune moment, the connection will disintegrate. The second version of the problem is that the use of an incorrectly selected acid leads to the formation of a thin dielectric layer at the soldering site.

The strength of the connection may be high, but the electrical conductivity parameters will be impaired. This contact will become the weak link of the entire circuit. Finding the fault is quite difficult.

It is undesirable to replace soldering acid for a specific metal with a composition based on another active element.

Oleic acid

An indispensable composition for soldering aluminum. It is not used in its pure form. Actually, it does not exist in its pure form. The so-called technical olein is used.

To maintain the stability of the substance, oleic acid is mixed with other fatty acids. The resulting mass is mixed with lithium iodide, and an ideal flux for aluminum alloys is obtained.

Why do you need soldering acid when soldering aluminum? The layer of oxide film on this metal is practically unkillable. When stripped mechanically, a new film immediately grows.

Technologists have been looking for something to replace acid for many years. The task is to protect the soldering area from exposure to oxygen.

No other flux is suitable in place of soldering acid, but you can mix iron filings with machine oil and rub the joint point while heating and adding solder.

Olein flux performs two tasks at once: it dissolves the oxide film (which is very difficult), and preserves the protective layer until the end of soldering. When heated, the acid evaporates, but the soldering area is already securely tinned.

It is impossible to make olein-based soldering acid at home. But flux is inexpensive and always available.

Flux VTS

The basis of the drug is salicylic acid. The same one used in aspirin tablets. Flux is used for working with copper and precious metals (including silver-plated and gold-plated contacts).

The main advantage is excellent protection of the soldering point from oxidation. Flux can (and even should) not be removed unless there are aesthetic requirements for the work.

Cheapness and versatility of use could make this flux the most popular. The exception is the same aluminum. However, the emissions from heat treatment are so caustic that an exhaust hood is required for operation.

This limits the home use of the drug. However, with normal ventilation, you can even use self-made flux.

The easiest way: grind an aspirin tablet and sprinkle it on the adhesions. When tinning the ends of the wire, just put the bundle on the tablet and press it with a soldering iron.

More convenient formulations are made based on technical petroleum jelly. It is mixed with the powder in a ratio of 1 to 2, and the composition can be applied to the soldering surface.

Bottom line:
There are no absolutely universal acid-based fluxes. Each composition works better with one metal or another. You will find information on how to use acids on the label.

When making flux yourself, safety issues also come first. The general rule is to add acid to the rest of the ingredients, not the other way around. Washing parts after processing is not always necessary; in some cases, the acid composition, on the contrary, protects the soldering area.

Source: https://stanki-info.com/kakaya-kislota-ispolzuetsya-pri-payke/

How to properly solder with a soldering iron with acid

Fluxes created on the basis of soldering acids, subject to soldering technology, make it possible to obtain a high-quality and durable connection of materials that are difficult to solder.

The composition of fluxes created using acids may vary depending on the area of ​​their application. Different types of fluxes have their own characteristics, which should be taken into account when soldering certain metals.

If we talk about soldering acid in general, it is a solution of acid in various substances. Acid in its pure form is practically not used for soldering, since, being an extremely aggressive chemical compound, it can have a destructive effect on various materials, including metals.

It is not recommended to use soldering acid when working with printed circuit boards, since thin connection buses and contacts of radio components are not able to withstand such aggressive influence. The best option for soldering radio circuits is pine rosin or fluxes created on its basis.

Types and chemical composition of soldering acids

Let's present the most common acid-based fluxes

Selection of acid fluxes

Before making a choice in favor of one or another soldering acid, you should determine exactly what problems will be solved with its use. Based on this, it is necessary to select a flux with the most suitable composition.

A solution with orthophosphoric acid is optimal for soldering metals affected by corrosion. This substance effectively fights oxides, which allows you to obtain a fairly high-quality compound.

Fluxes based on hydrochloric acid are considered universal; they can be used for soldering a wide range of ferrous and non-ferrous metals, as well as alloys. For soldering large-scale parts, concentrated hydrochloric acid is used, since in such cases its aggressiveness is not critical for the safety of the metal.

In all cases, the choice of acid concentration in solutions must be correlated with the cross-section or thickness of the parts to be soldered.

An important indicator of the quality of solutions is the presence of sediment in them. In fluxes, the presence of a minimum amount of undissolved substances is acceptable, but their abundance indicates poor quality of the solution.

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.

After soldering, it is necessary to remove the remaining soldering acid from the joint in order to avoid metal corrosion and destruction of the joint in the future.

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.

How to properly solder with a soldering iron with acid

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Soldering acid what is it

Any home craftsman who works with radio electronics knows how to use a soldering iron. Soldering classics: POS series solder and pine rosin, which produces a characteristic “fragrant” smoke when working with it.

What acid is used for soldering?

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.