How to use a soldering iron to solder aluminum components
Aluminum can be soldered with a soldering iron and tin. The key is to use a special flux to remove the oxide layer of the aluminum. Aluminum conducts heat relatively quickly, so a high-power soldering iron is required.
Due to its very active chemical properties, aluminum will oxidize rapidly in the air to form a dense oxide layer on the surface. First apply flux to the welding area of the aluminum piece, then dip the hot soldering iron into the tin and place it on the welding area for preheating. When the temperature rises, add some flux and solder after the solder becomes thicker and thinner, so that the solder can cover the soldering iron tip, and then rub the soldering iron tip back and forth on the welding joint. The friction distance should not be too large, generally between 3 and 5 mm. Use the soldering iron tip to scratch the aluminum oxide film on the surface of the aluminum component. Because the welding area is covered with molten tin and is isolated from the air, it is impossible to produce a new oxide film, and the tin can promptly stick to the aluminum parts with the oxide film that has just been removed. When the row of molten tin changes from a spherical shape to a flat shape, it indicates that the aluminum part has been firmly bonded to the tin. At this time, stop rubbing and wipe off the remaining solder while it is hot, and then solder it to the wire heads or other components that have been dipped in tin in advance. It's very convenient. Aluminum can be welded by fusion welding or pressure welding. The melting point of aluminum is only 660 degrees Celsius, which is too low and is not suitable for brazing.
First, drop a few drops of dilute hydrochloric acid on the welding joint of aluminum components to remove the surface oxide film. Wait for a while, then add a few drops of concentrated copper sulfate solution. When the welding joint is completely covered with copper, wash off the excess sulfuric acid with water. Copper solution and hydrochloric acid solution, and then use a 45-75W soldering iron to solder, and the effect is good.
It is very convenient to put a piece of aluminum into a crucible and heat it to melt, then add 2 to 5 times the amount of tin to melt it and set it aside for use. Then weld it according to the conventional method.
On the clean aluminum surface, apply a layer of mercury nitrate solution, use a 100w soldering iron tip to absorb more tin, and rub the soldering iron tip on the welding surface while applying the mercury nitrate solution. This will allow for a firm welding. But note: mercury is poisonous, welding should be done in a ventilated place, and do not use highly toxic mercury chloride.
Aluminum parts are welded by the local method. Prepare the white powder from the fiberglass board in advance and place it on the surface of the welding joint. Use a 75w soldering iron to rub the welding surface hard until a layer of tin is attached to the aluminum surface. Then use a cloth to mix the white powder with the welding surface. After the rosin mixture is removed, the general method can be used for welding. After practice, this method is simple and the welding effect is satisfactory. You can also mix rosin and iron filings, then use sandpaper to polish the aluminum surface, place the rosin and iron powder on the smooth surface of the welding joint, rub it repeatedly with a soldering iron to coat the aluminum surface with a layer of tin, and then follow the normal method. Smooth welding.
Polish the surface of the welding joint of the aluminum parts brightly, then add a few drops of sewing machine oil, the amount of oil should be sufficient, then use a sharp knife to scrape back and forth on the welding joint several times, then use a soldering iron dipped in solder and rosin and rub the welding joint back and forth, the tin will quickly It will be firmly attached to the aluminum parts. This method is also simpler and more practical.
Tin-soldered aluminum appears to be solid on the surface, but in fact the mechanical strength is very low, and it will peel off with a little more tearing. The key is that the complex formed on the bonding surface is physically wetted. Due to the barrier of part of the oxide layer, the affinity of tin-aluminum It is also not good, the welding surface is not fully combined and the strength is very low.
