For soldering, not only pure rosin, but also its solutions are used as a flux. In particular, many people know alcohol-rosin flux. It is neutral, so residues do not corrode metals and do not need to be washed off.
The ingredients for the alcohol-rosin solution have been known for tens and even hundreds of years. Raw materials for their production are always in abundance, so this flux is inexpensive.
Rosin was obtained from cuts coniferous trees. Volatile components were evaporated. The remainder was three-quarters of the original resin mass. Rosin for soldering was used only after such preliminary preparation.
Everything would be great, but when working, you need to dip a hot soldering iron into the resin flux. The main instrument is then covered with chemical mud, so that work area becomes not very visible.
Over time, it became clear that liquid rosin as a flux is much more convenient to use. Due to the presence of natural resin substances of a soft acidic nature, it:
- perfectly removes the oxide layer on parts;
- spreads well;
- occupies the entire adhesion site.
Ethyl (wine) alcohol was and continues to be used as a solvent, producing an alcohol-rosin composition. Rosin is also highly soluble in acetone, benzene, gasoline and some other organic solvents.
Ethanol is the safest and convenient option solvent for rosin. By chemical properties Isopropyl alcohol is close to ethyl alcohol, but it is much more difficult to find in everyday practice. This is purely a chemical reagent.
Application
Alcohol-rosin flux has not lost its relevance for many years due to its ease of use and positive soldering results.
It guarantees a strong connection of many parts, especially copper products. Using alcohol-rosin flux, radio circuits and boards are soldered. It spreads well, reaching hard to reach places. When working, low-melting solders are used (up to 330 ℃).
Currently, the entire range of soldering products is on sale, including SKF alcohol-rosin flux. Both domestic and foreign manufacturers are trying.
You can buy ready-made SCF flux and not do anything on your own. If all proportions are met in accordance with the standards, the composition will live up to expectations.
How to do it yourself
Many home craftsmen prefer to prepare alcohol-rosin flux with their own hands. In this case, they are confident in the content, and the process takes a few minutes.
First, the resin must be thoroughly crushed. The better this is done, the faster the uniform distribution of all substances in the solvent will occur. The result is a high-quality alcohol-rosin flux.
You can wrap a piece in thick cloth. Some solders advise using cellophane, although it is less durable. It may tear during subsequent procedures.
The wrapped rosin is placed on durable table, then methodically smash with a hammer to a powdery state. The most dexterous craftsmen manage to use ordinary meat grinders for grinding.
In other practices, crushed rosin in a sheet is rolled out with force with a rolling pin or a thick bottle. The main goal is clear. To prepare alcohol-rosin flux, you need to obtain a dusty powder.
After grinding, the resin is carefully poured into a bottle or vial. Many people like containers for nail polish or perfumes and cosmetics. Dust should not fly across the table. You need to get used to it and do it carefully.
Then medical alcohol is poured into the bottle. The composition of the alcohol-rosin flux is almost ready. The recommended liquid to dry ratio is 2 to 3.
If you need a more viscous flux, you can increase the proportion of resin. Each master can choose the concentration of the rosin solution in alcohol independently, focusing on personal experience, the specifics of the work to be done, the nature of the details.
If the pieces of resin were not crushed enough, it will be a little more difficult to dissolve the rosin. You will have to wait a couple of days for the alcohol-rosin flux to become homogeneous.
Is it possible to replace alcohol?
Some experienced soldering workers, trying to save alcohol for other purposes, advise taking cheap colognes. The recommendation is controversial. It will smell nice, but the additives contained in the perfume can harm the soldering area.
Advice to use vodka instead of alcohol is also not very legitimate. Rosin is an organic product and does not dissolve well in water. Vodka is a mixture of alcohol and water. It is much more difficult to dissolve resin in a vodka mixture, even if high quality vodka.
Considering that at home, flux consumption is measured in moderate quantities, you can buy medical alcohol. The guaranteed quality of the alcohol-rosin mixture is worth the effort. In practice, done correctly, it is not inferior to the products on sale.
Rosin was discovered in the ancient Greek city of Colophon. It was obtained from resin various types pine by extracting turpentine and other volatile substances from it through a steam bath, while simultaneously draining the resulting non-volatile impurities. Distillation is carried out with steam, which is heated to 200°C, which does not lead to the decomposition of rosin.
Rosin found its main use in amateur radio when soldering radio components. Pine rosin is an excellent and cheap soldering flux. Despite the modern abundance of chemical fluxes, it still continues to be actively used in electronics. Rosin melted by a soldering iron tip easily removes the oxide layer from the surface of radio elements undergoing the soldering process. In addition, rosin reduces the surface tension of the solder and helps it spread evenly over the entire plane.
Before the soldering process, the tip of the soldering iron is dipped in rosin, then it is used to touch the solder, after which it is touched to the place where the parts are soldered. The main advantage of rosin, which has retained its popularity as a soldering flux, is its acid neutrality, since raw materials of natural origin are used in its production. Unlike other acid-based fluxes, the soldering area does not corrode and there is no current leakage through it. Rosin is used as a soldering flux in both pure form, and in combination with various substances. The simplest flux made from it is a solution in pure medical alcohol in a ratio of 4 to 6.
The technology for soldering metal parts using rosin is very simple and accessible to everyone. The heated tip of the soldering iron is dipped into frozen rosin, after which it takes a small piece of solder and applies it to the surface of the part to be soldered. The same algorithm is repeated with another part, which is connected to the first. Then both metal surfaces are superimposed on each other and a heated soldering iron is brought to them, whose tip is again covered with rosin and solder. As a result, the molten solder forms a special monolithic mass, which, when hardened, will well connect the surfaces into one whole.
And so we take an ordinary crystal of frozen amateur radio rosin.
Then we grind a piece of rosin into dust, for this we take some non-porous fabric or paper, place a crystal in it, and beat it with a hammer until a homogeneous mass is obtained. This is necessary for good dissolution of rosin in ethyl alcohol.
Close the bottle with a cap and put glass bottle in a bowl with warm water When the solution heats up, you need to shake the mixture well so that it turns into a homogeneous mass. That's all, now the flux is ready, swing it around medical syringes and use it comfortably.
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 details. The use of liquid flux obtained by dissolving rosin in such conditions becomes the only the right way for the successful completion of the planned work.
Consisting of natural ingredients and being neutral, rosin does not dissolve in water. Then how to get its 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. Ready solution may have precipitation, its viscosity prevents spreading and helps to apply on work surface the required layer of flux.
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 removes oxides from soldered conductors, reduces 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.
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.
It has long been used as an active flux pharmaceutical drug- acetylsalicylic acid (aspirin).
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 soldering brazing 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 silver solders use a mixture of 50% sodium chloride as a flux ( table salt) and 50% calcium chloride. 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 using a hair brush or an ordinary toothbrush, using warm water or alcohol.
For soldering copper conductors, and often these are precisely the ones used in electrical and electronics, “liquid rosin” will work as a reliable means in the form of flux.
For those who don’t know, 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).
This can be conveniently done 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 it appears the right attitude components 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.
It consists of protecting metal surfaces from oxidation. A solution of rosin in ethyl alcohol spreads better over metal surface than molten rosin, making soldering more economical and the junction itself cleaner. Rosin in the form of a solution is applied to the cleaned metal surfaces before the soldering area is heated, which in turn further prevents the oxidation of these surfaces. A solution of rosin in ethyl alcohol is the least toxic compared to a solution in acetone, so it is found greatest application in technology.
