More than 1,5% which are not containing magnesium are applied to the soldering of aluminum and its alloys. Temperature of the soldering is 420 - 620 °C. It is suitable for the soldering in furnaces and torches, except oxygen - acetylene because of decrease of the activity of gumboil. It is recommended for the soldering by siluminovy solders. The remains of gumboil are removed water.
The soldering of aluminum has many difficulties connected with pronounced features of this metal. Extremely chemically active metal having in the air environment mechanically and chemically resistant film of an oxide of aluminum protecting it from chemical interactions with surrounding substances. At the same time possesses high heat conductivity.
At the flux soldering, it is necessary to remove a resistant film of an oxide and to protect a surface from oxidation. It is reached by the fact that gumboil (gumboil 34 - A) when heating destroys and dissolves an aluminum oxide, at the same time on a surface the metal zinc together with a gumboil cover protecting aluminum is besieged. Therefore at the soldering it is necessary to watch integrity of a flux cover carefully.
For uniform spreading of solder, it is necessary to provide uniform heating in a soldering zone. It is necessary to consider the big heat sink from a soldering zone through aluminum details. Solder spreads towards increase in heating better, it needs to be considered for receiving galtelny transition of solder between details. Therefore, when heating by a gas torch the flame has to "wash" a zone of the soldering and some part of details adjoining to it. It is necessary to use the middle part of a flame possessing recovery or neutral properties unlike the final oxidizing part having big temperature. The oxidizing flame can sharply reduce activity of gumboil! For compensation of unevenness of warming up of the accustomed to drinking details, various on thickness, weight, the flame of a torch needs to be displaced towards more massive detail. At an overheat and long heating, aluminum is strongly dissolved in solder that leads to the low - quality soldering.
Drawing gumboil in perhaps various ways having the advantages and shortcomings. It is necessary to consider extreme hygroscopicity of gumboil, tendency to formation of lumps in the presence of moisture and to "rasplyvaniye" at stay in the open air.
Small details it is convenient to warm up and shower slightly with gumboil (to dip into gumboil) having used effect of "sticking" of gumboil to the warmed surface. Damp gumboil will not lay down on a heated surface. It is possible to shower the details covered with a water film with gumboil (to dip into gumboil), trying to obtain "sticking". The prepared surfaces of details under the soldering have to be moistened with water well.
More rare, at mass production (with a hint on mechanization), apply mixing of gumboil on water with the subsequent drawing on a detail an okunaniye. All components of gumboil are not dissolved in water and are in solution in the form of a suspension. Gumboil needs to be mixed constantly, for uniform distribution of components on volume. Cultivation needs to be conducted extremely accurately, adding gumboil in the small portions and carefully mixing. Dissolution happens to the strongest warming up! Solution can boil and cause burns! ! ! It is necessary to wait for cooling of mix before the next addition of gumboil. Solution is not intended for long storage.
All described ways are not universal and calculated on high qualification and experience of the plumber. The surface of the accustomed to drinking details has to be fat - free. Good results are yielded by "light" solvents like acetone. If the surface was not exposed to machining, it needs to be pickled for removal of the most part of an oxide film in the corresponding solutions.
