The principle of the soldering iron.
The electric soldering iron serves for soldering of pipes, both cold and hot water supply, and also heating system. The advantage is that the device is small in size, which is very convenient for transportation, not heavy in weight, but also has a convenient design. Equipped with such a device temperature controller and is designed for soldering pipes of different diameters. 
Soldering irons are available in two versions, the difference is that the first has a heating element of elongated shape, and the second has a cylindrical shape. More convenient for work is the second option, because it allows you to solder even in the most inaccessible places.
Depending on the shape of the tip, the types of soldering tips that come with the tool or are purchased separately vary. Typically, the kit is no more than four nozzles, different in diameter.
As a rule, all soldering irons are arranged in the same way and consist of:
- of the Basic case, at the end of which there is a handle;
- Temperature controller;
- Heating element( sting),
- Non-stick nozzles( their quality depends on the thickness of the Teflon coating, if it is insufficient, this leads to sticking of polypropylene and deterioration of the quality of the seam).
The function of the soldering iron is to heat the polypropylene tube to the softening state using a heating element with a nozzle mounted on it. The necessary temperature is set with a thermostat( when buying the device, be sure to pay attention to this part, and here the great value is the price - the higher it is, the better the soldering iron).
How to be guided when choosing a soldering iron.
First of all, when buying a soldering iron, pay attention to its price and the country of manufacture. A quality thing that can last for many years will not be cheap. Chinese manufacturers save on the quality of the materials used, so the tool that made them will quickly fail.
The value is also the power of the device. This figure ranges from 1.5 kW to 2 kW.The more powerful the equipment, the more the diameter of the pipe it can connect. 
Much attention should also be given to the choice of tips for soldering polypropylene pipes. When purchasing attachments, consider the nominal power of the tool, the higher it is - the larger the nozzle diameter. In order not to overpay, buy only those attachments that really will help you in your work. Choose parts only from quality materials.
Instructions for soldering polypropylene pipes.
- The work should begin with trimming the damaged pipe with a special knife or a hacksaw;
- It is necessary to clean the edges of the cut from unevenness, because the quality of the seam will depend on this;
- The soldering iron, connected preliminary to the electric network and by means of the thermostat, warming up to the necessary temperature is switched on;
- After the heating element has reached the desired temperature, the very process of heating the edge of the pipe goes by means of a suitable nozzle;
- After that, the molten edges are pressed against each other and fixed for some time until they cool down completely.
As the polypropylene cools quickly enough, their operation is possible in a few minutes after soldering.