Flux is a substance, both organic and inorganic, that ensures the removal of oxides from soldered conductors, reduces the force of surface tension, and also improves the uniformity of spreading of molten solder. In addition to its main purpose, flux can protect contacts from exposure environment, but it should be noted that not all types of fluxes have this property.
Depending on the need, flux can be in the form of liquid, powder or paste.
Solder pastes are also produced that contain solder particles along with flux, and all modern solders are a tube of solder inside which there is a flux filler.
By temperature conditions and activity interval, fluxes can be divided into low-temperature (up to 450 degrees) and high-temperature (more than 450 degrees).
In addition, the flux can be aqueous or anhydrous.
By chemical properties All fluxes can be divided into acidic (active) and acid-free. In addition, there are also activated and with anti-corrosion protection.
Active fluxes mainly consist of hydrochloric acid and chloride or fluoride metals.
The pharmaceutical drug acetylsalicylic acid (aspirin) has long been used as an active flux.
These fluxes very intensively dissolve the oxidized layer on the surface of the metal, and the soldering immediately becomes high-quality and durable, but the flux residue after soldering causes intense corrosion of the joint and the base metal in the future. Therefore, it is recommended to wash off all flux residues that remain at the soldering site.
When soldering radio-electronic elements, the use of active fluxes is not permissible, since over time their residues still corrode the place where thin radio elements are soldered.
Acid-free fluxes, mainly these are rosin and fluxes prepared on its basis with the addition of alcohol, turpentine or glycerin.
During the soldering process, rosin cleans the surface of oxides and also protects it from oxidation. At a temperature of 150 degrees, rosin dissolves the oxides of lead, tin and copper, cleaning their surface during the soldering process and the soldered joint becomes shiny and beautiful. But most importantly, unlike active fluxes, rosin fluxes do not cause corrosion and corrosion of metal.
Copper, bronze and brass are soldered using rosin fluxes.
Activated fluxes, mainly, in addition, they consist of rosin to which a small amount of hydrochloric acid or phosphate aniline, salicylic acid or diethylamine hydrochloride is added.
These fluxes are used for soldering the bulk of metals and alloys (iron, steel, high-quality stainless steel, copper, bronze, zinc, nichrome, nickel, silver), even oxidized elements from copper alloys in the absence of preparatory cleaning.
Activated fluxes are considered to be LTI fluxes, which contain ethyl alcohol (66 - 73%), rosin (20 - 25%), aniline hydrochloride (3 - 7%), triethanolamine (1 - 2%). LTI flux gives excellent results when using tin solders POS-5 and POS-10, providing increased strength of the soldered joint.
Anti-corrosion fluxes used for soldering copper and copper alloys, constantan, silver, platinum and its alloys. They contain phosphoric acid with the addition of various organic compounds and solvents. Some anti-corrosion fluxes contain organic acids. Residues of these fluxes do not cause corrosion.
VTS flux, for example, consists of 63% of those. Vaseline, 6.3% triethanolamine, 6.3% salicylic acid and ethyl alcohol. Remains of flux are removed by wiping the part with alcohol or acetone.
Protective fluxes protect the previously cleaned metal surface from oxidation and do not have a chemical effect on the alloy. This group includes inactive materials: wax, Vaseline, olive oil, sweet powder, etc.
For brazing of carbon steels and cast iron They use borax (sodium tetraborate), which appears as a white crystalline powder.
Borax melts at a temperature of - 741° C.
For soldering brass parts With silver solders, a mixture of 50% sodium chloride (table salt) and 50% calcium chloride is used as a flux. The melting point of the mixture is - 605° C.
For soldering aluminum You can use fluxes that usually contain 30-50% potassium chloride.
For soldering of stainless steel , hard and heat-resistant alloys, copper-zinc and copper-nickel solders use a mixture consisting of 50% borax and 50% boric acid, with the addition of zinc chloride.
Active fluxes are washed off with a hairbrush or an ordinary toothbrush, using warm water or alcohol.
For soldering copper conductors, and often these are the ones used in electrical and electronics, “liquid rosin” will work as a reliable means in the form of flux.
For those who are not aware, this is pine resin - a pure environmental product.
How to prepare liquid rosin yourself?
1. We crush the rosin crystal into dust using crushed powder or wrapping it in a cloth and tapping it with a hammer. On a large scale, some craftsmen manage to use Soviet manual meat grinder. The means are not important, the main thing is to achieve uniform fine dust from rosin crystals.
2. All dust must be filled with alcohol with a ratio of 1:1.5 (rosin: alcohol).
It is convenient to do this using the same alcohol bottle.
At the pharmacy you can buy alcohol with salicylic acid, such a solution itself can serve as a flux, and although the percentage of salicylic acid is very small, such “alcohol” wakes up the best option to enhance the desired properties of the flux.
Next, pour rosin into half a bottle of alcohol until the desired ratio of components appears and make sure that about 1/5 of the bottle remains free!
3. Close our bottle (or other container) and place it in a container with warm water (60-80C). When the solution heats up, we begin to vigorously shake the solution so that it dissolves into a homogeneous mass. IN hot water it will work out much better and faster.
Recently, a radio amateur has been given a wide selection of fluxes to choose from, all possible chemical active and super active fluxes for soldering, which are well worth the money. They all have their pros and cons, and every solderer likes his own. Opinions may vary, but I express my opinion.
In my opinion, rosin is one of the best fluxes; I have been using rosin for 3 years of my practice. And why is my rosin the best? whole line reasons:
—
First of all, it's environmentally friendly pure product. For those in the tank, rosin is pine resin, which means it is natural.
— Secondly, rosin is easily washed off with alcohol, which means removing excess rosin residues from printed circuit board will not be difficult, which means there will be no interference between the tracks...
—
Thirdly, rosin is easy to get. Where to buy rosin? Rosin can be bought at almost any hardware store, in music stores (my grandfather rosined a violin bow) and at radio markets
—
Fourthly, this is probably individuality, I adore the smell of rosin (it looks like a drug addict :))
It is especially good if the rosin is liquid. But liquid rosin also costs well, so liquid rosin can be made at home. To make liquid rosin ourselves, we will need regular rosin in crystals and regular “red cap” alcohol.
Homemade liquid rosin
And so we take an ordinary rosin crystal
1.
We crush the rosin crystal into dust, it is very convenient to do this if you have a crushed one in the kitchen (everyone has a different name for an iron deep pot), but if you don’t have it, it doesn’t matter.
You need to take some very thick paper, put it in an envelope and put rosin in it, wrap it all in some kind of non-porous fabric so that nothing spills over, and hit it all with a hammer, a rolling pin, whatever is convenient.
The crystals are broken until there is a homogeneous mass. This is necessary for good dissolution of rosin in alcohol.
Here is the dust of broken rosin
2.
All dust must be filled with alcohol with a ratio of 1:1.5 (rosin: alcohol).
It is convenient to do this using the same alcohol bottle. Pour rosin into half a bottle of alcohol until the desired ratio of components appears. And make sure that about 1/5 of the bottle remains free!
3.
Close the lid and place the bottle in a bowl of warm water (60-80C) when the solution heats up, start well - shake the solution well so that it dissolves into a homogeneous mass!
That's all, now we pump the solution into syringes and use it conveniently.
Good luck with your reps and be careful and take precautions!
Hi all! I am glad to see you all on my amateur radio blog dedicated to electronics and other technical creativity. Today it’s Saturday and it’s November outside the window, so we’re getting ready for the cold - winter is just around the corner.
And I have an article for you, which may not be very long, but it will definitely bring you a little useful information. Today I will talk about SKF alcohol-rosin flux, how you can prepare it with your own hands, and also where you can buy SKF flux. Read the article further and find out everything...but don’t forget to subscribe to updates!
We have a small table of contents here, this is for convenience...
Flux SKF
Fluxes for soldering are used mainly for two purposes:
- In order to improve the wettability of soldered parts with solder
The surfaces of the parts being soldered may have poor wettability. In this case, the solder will roll into balls like droplets of water on a greasy pan. Flux promotes better distribution of solder over the surface of the parts being soldered; the solder spreads and evenly covers the surface to be soldered.
- To protect against oxide film (this film interferes with the normal soldering process)
Thanks to the oxygen in our air, the surface of the metal can oxidize, and a certain oxide film appears. This oxide film prevents solder from penetrating into the pores of the metal and attempts to solder anything become simply useless. Flux forms protective film and it, in turn, protects the metal from exposure to oxygen.
For various metals Various fluxes are used since each metal achieves these goals differently. So, for soldering aluminum parts, you need to use some fluxes, and for soldering copper parts, others.
SKF flux or simply alcohol-rosin flux is one of the best fluxes used for soldering copper parts. The best temperature Range application 250-280°C. Due to its liquid form, alcohol rosin easily penetrates into hard to reach places soldered surfaces.
In addition, SKF flux is made on the basis of rosin, so it does not require rinsing after soldering; rosin itself does not contribute to the formation of corrosion on the metal. In short, after soldering you don’t have to worry - it won’t rust :)
Composition of SKF flux
The composition of SKF flux is quite simple and the name of the flux speaks for itself; the flux is a solution of rosin in alcohol.
To be honest, I have always been interested in what rosin is and what distinguishes it from the resin itself. And everything is quite simple, rosin is obtained from tree resin coniferous species. The resin is collected, then it is heated, as a result of which various substances contained in it are evaporated, mainly turpentine.
How to use
In general, rosin itself is a good flux, but it is not very convenient to use. Rosin has to be applied to the surfaces to be soldered with the hot tip of a soldering iron; this causes both the soldering iron itself and the soldering area to become dirty. It happens that you overdo it with rosin so much that the junction itself is not visible.
It was another matter when I took a bottle of alcohol rosin, opened it and immediately smelled alcohol, like in an operating room. You take a brush and, like an artist, apply flux with neat strokes in the style of abstractionism. In general, flux can be applied in very measured doses this way. By the way, if the bottle is not equipped with a brush, then don’t worry, you can take a brush from nail polish (take it from your wife or sister :)).
However, some prefer to use the drip method of dispensing flux. Bottles with a “spout” are filled with alcohol rosin, as for eye drops, and only then used. This is of course a matter of taste, but in my opinion it is more convenient to use a brush and easier to dose the flux.
How to make alcohol-rosin flux?
To prepare alcohol-rosin flux we will need:
- Rosin
- Thick cellophane bag
- Hammer or something weighty
- Alcohol 90%
- Acetone
- Nail polish bubbles
We made sure that we prepared everything necessary and continued. First you need to prepare bottles of nail polish. They can be found on any young lady, and some of them may have an unexpected amount of this stuff. Next, the bubbles need to be washed from any remaining varnish; acetone will help us cope with this task.
We fill the bottles with acetone and go about our business. Acetone copes well with the task, so after some time (maybe a couple of hours or maybe a couple of days) you can take away the already cleaned bubbles; all that remains is to rinse them in running water.
The bottles are prepared, now we need rosin. As I already said, you can prepare it yourself, but to do this you will have to take a walk in the forest and then perform a few more technological manipulations. But you can do it easier, you can take it and not worry about it.
Next we need to grind the pieces of rosin into powder, for this purpose we will need a bag. We put the pieces of rosin in a bag and, once wrapped, we can easily chop them, using a hammer, of course, or what did you take for this purpose?
Now carefully pour this powder into the bubbles. You shouldn’t add too much, just add one third of the volume of the bottle. And all that’s left is to fill the whole thing with alcohol.
But finding alcohol, as it turned out, is not so easy; in pharmacies alcohol is now only by prescription, and I have not seen it in hardware stores. I came across an opinion on forums that alcohol can be replaced with acetone, but I don’t really like this option, after all, acetone vapor is not very good for health. In the end, I got some alcohol from the factory, because I only needed a little bit... :)
Fill the bottles with rosin with alcohol, close the lids and place in a warm place. Now you need to wait some time for the rosin to dissolve thoroughly in the alcohol. By adding alcohol or adding rosin, you can achieve the desired concentration.
In addition, I found a couple of videos on YouTube about making alcohol-rosin flux, which might be useful...
That's the whole recipe.
Where can I buy alcohol rosin?
However, you don’t have to worry about preparing alcohol-rosin flux, but buy it at finished form. Everything is great and wonderful if you have stores in your city that sell radio products. As a rule, there are many different fluxes, among which you can find alcohol rosin.
But if you don’t have such a store nearby, don’t despair, you can order from the online store. For some reason in Chinese online stores I couldn’t find a type of aliexpress and dealextreme flux made from alcohol and rosin, maybe I wasn’t looking well. But nothing, this flux can be purchased in other places, for example.
Well, that’s basically all I wanted to tell you today. I think the information will be useful to you and you will take it into account.
I wish you good luck, success and wonderful sunny mood. And I’m not saying goodbye to you, but saying goodbye and see you again.
P.S. Below we have social media buttons, don’t forget to share with your friends :)
From n/a Vladimir Vasiliev
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We will not dwell in detail on the properties and advantages of using rosin. Let us only emphasize that a more well-known, popular and used flux for soldering cannot be found. Most often, rosin is used by craftsmen in its natural state - a hard and brittle material. But sometimes such an application becomes problematic or undesirable - soldering in hard-to-reach and inconvenient places, the need to cover a large area of material with flux, the inadmissibility of strong heating of the soldering area, working with very small parts. The use of liquid flux obtained by dissolving rosin in such conditions becomes the only sure way to successfully complete the intended work.
Consisting of natural components and being neutral, rosin is not soluble in water. Then how to get it liquid version? Most easy way– purchase of ready-made liquid flux industrial production, which is not uncommon in hardware stores and building departments. Another option is self-production. It is not difficult to obtain such a flux and it will differ little in quality from the store-bought one, but the master will enjoy the effective work on preparatory stage rations.
Solvents for rosin
- Alcohol. This solvent has become the most applicable due to its availability, relative cheapness and its activity when interacting with rosin. Preparation of flux includes the following operations:
The rosin content in the solution can range from 25% to 75%. The higher its concentration, the more active the properties of the flux are. This must be taken into account and compared with the required soldering results. If shaking and additional heating do not help to completely dissolve small powdery particles and they settle to the bottom, then the maximum concentration of rosin in alcohol has been reached. To work, you need a liquid phase, which must be carefully, without precipitation, drained into another container.
2. Turpentine. Being chemically active, it dissolves flux well even without crushing. The concentration of rosin in turpentine can be increased to 85%.
3. Gasoline, ether, acetone and other organic solvents. If these substances are available, then rosin should be dissolved in them according to the scheme described above with crushing, heating and stirring (shaking). Considering the volatility of the substances used, the prepared flux solution must be used quickly or stored in an airtight container. Respiratory protection and ventilation (ventilation) are appropriate when working with them.
4. Oils. To obtain a solution, it is necessary to finely crush the flux and use heating. The finished solution may have sediment; its viscosity prevents spreading and helps to apply the required layer of flux to the working surface.
5. Glycerin. Usually added to the already mentioned and alcohol for greater effectiveness. After soldering with this flux, the residues are washed off thoroughly, since glycerin is a cause of surface electrical leaks and a source of corrosion.
conclusions
- a liquid rosin solution, absolutely not inferior to sold samples, can be easily obtained at home;
- dissolved rosin does not require preliminary melting and is easily applied to any surface using improvised means - a regular syringe, brush, toothpick and others;
- solutions are effective even with low concentrations of rosin;
- they are easily removed after work;
- For better and faster solubility of the flux, heating of the solvent is used.
Flux is a substance, both organic and inorganic, that ensures the removal of oxides from soldered conductors, reduces the force of surface tension, and also improves the uniformity of spreading of molten solder. In addition to its main purpose, flux can protect contacts from environmental influences, but it should be noted that not all types of fluxes have this property.
Depending on the need, flux can be in the form of liquid, powder or paste.
Solder pastes are also produced that contain solder particles along with flux, and all modern solders are a tube of solder inside which there is a flux filler.
According to the temperature regime and activity interval, fluxes can be divided into low-temperature (up to 450 degrees) and high-temperature (more than 450 degrees).
In addition, the flux can be aqueous or anhydrous.
Based on their chemical properties, all fluxes can be divided into acidic (active) and acid-free. In addition, there are also activated and with anti-corrosion protection.
Active fluxes mainly consist of hydrochloric acid and chloride or fluoride metals.
The pharmaceutical drug acetylsalicylic acid (aspirin) has long been used as an active flux.
These fluxes very intensively dissolve the oxidized layer on the surface of the metal, and the soldering immediately becomes high-quality and durable, but the flux residue after soldering causes intense corrosion of the joint and the base metal in the future. Therefore, it is recommended to wash off all flux residues that remain at the soldering site.
When soldering radio-electronic elements, the use of active fluxes is not permissible, since over time their residues still corrode the place where thin radio elements are soldered.
Acid-free fluxes, mainly these are rosin and fluxes prepared on its basis with the addition of alcohol, turpentine or glycerin.
During the soldering process, rosin cleans the surface of oxides and also protects it from oxidation. At a temperature of 150 degrees, rosin dissolves the oxides of lead, tin and copper, cleaning their surface during the soldering process and the soldered joint becomes shiny and beautiful. But most importantly, unlike active fluxes, rosin fluxes do not cause corrosion and corrosion of metal.
Copper, bronze and brass are soldered using rosin fluxes.
Activated fluxes, mainly, in addition, they consist of rosin to which a small amount of hydrochloric acid or phosphate aniline, salicylic acid or diethylamine hydrochloride is added.
These fluxes are used for soldering the bulk of metals and alloys (iron, steel, high-quality stainless steel, copper, bronze, zinc, nichrome, nickel, silver), even oxidized elements from copper alloys in the absence of preparatory cleaning.
Activated fluxes are considered to be LTI fluxes, which contain ethyl alcohol (66 - 73%), rosin (20 - 25%), aniline hydrochloride (3 - 7%), triethanolamine (1 - 2%). LTI flux gives excellent results when using tin solders POS-5 and POS-10, providing increased strength of the soldered joint.
Anti-corrosion fluxes used for soldering copper and copper alloys, constantan, silver, platinum and its alloys. They contain phosphoric acid with the addition of various organic compounds and solvents. Some anti-corrosion fluxes contain organic acids. Residues of these fluxes do not cause corrosion.
VTS flux, for example, consists of 63% of those. Vaseline, 6.3% triethanolamine, 6.3% salicylic acid and ethyl alcohol. Remains of flux are removed by wiping the part with alcohol or acetone.
Protective fluxes protect the previously cleaned metal surface from oxidation and do not have a chemical effect on the alloy. This group includes inactive materials: wax, petroleum jelly, olive oil, sweet powder, etc.
For brazing of carbon steels and cast iron They use borax (sodium tetraborate), which appears as a white crystalline powder.
Borax melts at a temperature of - 741° C.
For soldering brass parts With silver solders, a mixture of 50% sodium chloride (table salt) and 50% calcium chloride is used as a flux. The melting point of the mixture is - 605° C.
For soldering aluminum You can use fluxes that usually contain 30-50% potassium chloride.
For soldering stainless steel, hard and heat-resistant alloys, copper-zinc and copper-nickel solders use a mixture consisting of 50% borax and 50% boric acid, with the addition of zinc chloride.
Active fluxes are washed off with a hairbrush or an ordinary toothbrush, using warm water or alcohol.
For soldering copper conductors, and often these are the ones used in electrical and electronics, “liquid rosin” will work as a reliable means in the form of flux.
For those who are not aware, this is pine resin - a pure environmental product.
How to prepare liquid rosin yourself?
1. We crush the rosin crystal into dust using crushed powder or wrapping it in a cloth and tapping it with a hammer. On a large scale, some craftsmen manage to use the Soviet manual meat grinder. The means are not important, the main thing is to achieve uniform fine dust from rosin crystals.
2. All dust must be filled with alcohol with a ratio of 1:1.5 (rosin: alcohol).
It is convenient to do this using the same alcohol bottle.
At the pharmacy you can buy alcohol with salicylic acid, such a solution itself can serve as a flux, and although the percentage of salicylic acid is very small, such “alcohol” is the best option for enhancing the desired properties of the flux.
Next, pour rosin into half a bottle of alcohol until the desired ratio of components appears and make sure that about 1/5 of the bottle remains free!
3. Close our bottle (or other container) and place it in a container with warm water (60-80C). When the solution heats up, we begin to vigorously shake the solution so that it dissolves into a homogeneous mass. It will work much better and faster in hot water.