Suppose you want to solder aluminum. Not everyone knows that rosin takes only copper and its alloys. Others need to be soldered using special fluxes, acids, solders. Even steel is amenable to this science, if you approach with the mind. Consider how to solder the soldering iron.
Inside a soldering iron there is a heating element of a certain power placed in an insulating shirt made of ceramic or other heat-resistant material. It is necessary that all the heat go inside, where the sting is located. The main difference between soldering irons in power and form. Depending on this, the master decides what is specifically required to use.
Often work as a tool in electronics. In this case, it is important not to exceed the power dissipation of relatively fragile resistors, microcircuits, capacitors. If this happens, the work is redone. With the difference that you have to buy a damaged item in the store. Therefore, it is important to learn how to solder properly.
It is difficult to say how much power will be needed in a particular case. Amateur radio guided by size.
Soldering iron power
First, the power of the soldering iron is estimated. It is clear that a 100 W unit is simply dangerous to climb into the motherboard. It’s wiser to get a 20 or 50 watt soldering iron. Please note that not all soldering tools are powered by 220 V. Many examples of non-compliance with the rule are known. The manufacturer is guided by simple logic: a low-power soldering iron requires a twisted helix that introduces large losses at a frequency of 50 Hz. It is more logical to switch to direct current. In this case, the inductance does not play a big role. If you turn on a low-power soldering iron for direct current( at the extreme right of the photo) into an AC network of 220 V, the product will burn. But the Chinese are producing small-sized soldering irons( second from left).Presented in the photo shows the power of 40 W and is powered by a standard outlet. Finally, by default, in the USSR they produced 100 W soldering irons( leftmost).How to determine the power and supply voltage? This is the main difficulty: often the soldering iron does not carry distinguishable designations. If you take Chinese, it is glued with a red-white sticker( see photo) with information, and for a device with a wooden handle, the power is indicated on the plug. The protective cover of the 100-watt soldering iron is properly marked. GOST is indicated there, it is possible to gather information from the documentation. Powerful 100W soldering iron allows you to work with coarse and large parts, indispensable for hard solders.
The size of the tip.
Often the role is played by the size of the tip( metal bar for soldering).For example, a 100-watt soldering iron has a solid copper stick. If you need to solder something more subtle, change the sting. At the soldering iron under consideration, it is simply pulled out, and where to buy a spare one is the second question. For example, the stings are sold in special shops for radio amateurs and can cost a decent amount. A 40 W Chinese soldering iron with an excellent tip cost 40 rubles( FixPrice), and a sting of this kind can cost separately and 300 rubles. The mounting system is different. For example, the DC soldering iron unscrews it, and the Chinese are screwed( like a wooden handle).Material is possible different. The bulky tips of a 100-watt soldering iron are usually copper, while the modest and miniature solders are made from an alloy of non-ferrous and ferrous metals. But both options allow you to work with all solders, amenable to melting.
Before work, the soldering iron tip is cleaned of waste materials and oxide film with a file or file. It is clear that this is not the only way. For example, for such purposes it is allowed to use dissimilar fluxes. It's time for readers to find out how the part prepares for soldering.
How the surfaces of the part and the tip are prepared for the soldering process with the help of fluxes
The surface of any metal( with rare exceptions) is covered with an oxide film. As a result, solder simply does not fall. A group of substances whose purpose is to remove the oxide film from the surface is called fluxes. They are solid and liquid, and are also sold in a mixture with solder in the form of pastes. The first category includes rosin and a number of other substances. Liquid fluxes are often acids, salt solutions. The basis becomes alcohol and other liquids.
It is important to understand that a special composition is used for different cases. The only difference is the price at which you need to try to save. Under the action of high temperatures and rosin, the oxide layer is removed from the surface of the copper wire and the lacquer insulation dissolves, if any( this is typical of transformer windings).At the same time, the flux improves surface wettability. Due to this, the solder easily spreads, and then sticks and freezes. Formed elastic, resilient and durable contact. Therefore, soldering is used not only by radio amateurs, but also by representatives of other professions. Including car repair.
A specific flux is sold for various surface types. For example, steel is poisoned with hydrochloric acid, zinc chloride is often used. It should be understood that after the soldering process the surface is cleaned, otherwise its destruction will continue. Get rid of flux residues with brushes, emery, often washed with a weak solution( 5%) of soda with a place of exposure to acids, and then with hot and cold water.
Pay attention to wettability: in order to solder aluminum, it is not enough to clean the top layer with a file. It almost does not give a result, since the solder does not spread over the surface. Wettability is bad. After acid treatment, the alignment of forces changes dramatically. As for steel, special acids have been created for it( see photo).Solder and cast iron, butchering the edges of the solder. First, the surface is treated with flux, then it is treated. Then gradually the entire volume is filled flush with the surrounding surface.
Often they confuse a solution of ammonia with ammonia. The first is ammonium hydroxide( 10% solution), and the second is chloride. It is impossible to solder the wires in pure form either way, but they are used for the manufacture of various fluxes. For example, dilution of ammonia with water makes it possible to obtain hydrochloric acid. Here lovers invent their own recipes, many of them can be read in the public domain. And also it is advised to solder aluminum with a soldering iron using an aspirin tablet.
What is solder, solder variations
Solder is a mixture of metals. The main task: to obtain maximum strength and electrical conductivity at minimum cost. More often it is necessary to work with tin-lead solders, but zinc is also used for soldering aluminum. The melting point of the latter is higher, and this is one of the criteria according to which the distinction is made:
- Extremely fusible - the melting point is below 145 degrees Celsius.
- Fusible - melting point is higher than 145 degrees Celsius, but lower than 450.
- Mid-melting is an indicator of melting temperature higher than 450 degrees Celsius, but lower than 1100.
- High-melting - melting point is higher than 1100 degrees Celsius, but lower than 1850.
- Refractory solders indicatormelting point above 1850 degrees Celsius.
It is already necessary to use the burner in the upper part of the third group: the melting point is high for the soldering iron to take. We add that the specific electrical conductivity of tin is higher than that of lead, for this reason, compositions with a higher metal content are more expensive for soldiers. But this is not the only reason. When tinning pots, it is important to withstand the harmlessness conditions for humans. It is clear that lead in this case is out of the question.
The percentage of more expensive metals usually appears in the brand name. For example, in the PIC( tin-lead solder) it is possible 10, 60 or 90%.The composition often includes antimony. Its percentage usually stands after a dash, for example, POSSU 40-0.5.Antimony is added, like many other impurities, to improve the quality of the solder. In particular, it reduces the oxidation of the melt, which leads to a quality appearance, and there is no need to protect the varnish with a varnish. Antimony increases the heat resistance of the compound to temperatures above 100 degrees Celsius.
In Europe, a ban on lead-containing solders is being introduced. They are replaced by silver, although the melting point increases. And the cost increases, of course. But do not think that high price means an indispensable quality. Tin is expensive, but the Scott expedition to the South Pole died due to tin plague in 1912. Even at four degrees Celsius, negative changes are possible, but the process worsens as the temperature drops. Imagine what is happening with pure tin in the cold.
No one can explain the process of the plague thoroughly. It is believed that tin needs to be infected, and then the solder seams will crumble. The Scott Expedition took the barrels of fuel, brazed pure metal. Studies have been conducted and it has been established that the addition of a small percentage of lead blocks the development of the plague. Even PIC 90 is not afraid of frost, but it is expensive, and in technology PIC 40 and lower is often used, despite its relatively low electrical conductivity.
In addition to those listed, copper solders are used in places. Their melting point is relatively high, it is necessary to use a burner. In such a case, the flux is usually poured onto the surface( less commonly used) for stripping. Then it all depends on the nature of the task. For example, for soldering the cable tip, the first one is clamped in a vice with the flask up, and a crumb of solder is poured in. All this is heated by a burner. Then the cable is inserted inside, and the outer insulation is fused. It is recommended to cool the place by force, for example, by blowing.
Before starting work, prepare a soldering iron. The sting is first cleaned. Dense carbon is removed by shearing with a sharp instrument. The photo shows a soldering iron, part of the tip cleaned with a needle file. It can be seen that from long-term use, the surface has become uneven, hilly. It interferes with the soldering process.
Weak carbon is removed after warming up. The same acids and rosin are used for this. The task is to expose the sting. Often, under the action of fluxes, a thick crust, which is difficult to grind off, falls off.
Isolation of electrical wires is cleaned to the desired distance. Then the vein is treated with a melt of rosin or acid. This is done with a soldering iron, and in many cases a good hood is required. For example, formic acid vapors are often used in industry, but for humans this substance is very dangerous. Before using a chemical to solder copper wires, carefully search the Internet for what is said about the safety of such actions. From the nature of the influence of formic acid becomes terrible.
If you properly solder the electric wires, then already in the process of removing the oxide film, you can see how the solder creeps on the surface. This can be seen especially clearly on the reverse side of printed circuit boards. It is necessary to cover the tracks with a thin layer of solder. In vain worry those who think that this is a long time to do. Literally it is necessary to bypass the installation of smoking rosin, and then take in solder, and it will spread over the surface. On a typical power supply time takes a few minutes. To poison a payment in a blue vitriol longer.
We believe that readers have already realized that soldering aluminum with tin is possible only after removing the oxide film.