Soldering polypropylene pipes: rules for carrying out work and analysis of possible errors

The ability to assemble pipelines yourself is a definite plus of polypropylene products. Using convenient and lightweight material, you can build a sewer system yourself, repair and modernize the water supply system.

The main thing is to understand the specifics of connecting prefabricated elements to each other. Agree, this is an important part of the work, responsible for the tightness of the highway and its trouble-free operation.

We offer you detailed information about how polypropylene pipes are soldered, what equipment is used in the work, and also list the most common mistakes made by novice welders.

The information we offer will help you build trouble-free communications. For clarity, the article is supplemented with graphic applications and a video guide.

Specifics of soldering polypropylene pipes

The soldering process is carried out due to the pronounced thermoplastic properties of the material. Polypropylene softens when heated - it acquires a state similar to plasticine.

General description of technology

Returning the material to normal temperature conditions helps harden its structure to its normal state. These properties have become the main soldering technology, which in technical language is called polyfusion welding.

The method of soldering plastic-based plumbing elements has become widespread. The technology is simple and requires minimal investment of effort and money.

In practice, two methods of joining welded parts are used:

1. Coupling.
2. Straight.

Coupling method. Welding technique shows how to solder polypropylene pipes, using for this purpose a shaped part - a coupling or a pipe of a larger external diameter. Typically, this method is used to solder plastic pipes whose diameter does not exceed 63 mm.

The principle of welding two parts in this case is based on melting part of the pipe along the outer circumference and part of the coupling along the inner area. Then both parts are tightly joined.

Coupling joint: 1 – plastic pipe, 2 – coupling (or fitting socket), 3 – heating element of the soldering iron, 4 and 5 – metal nozzles (blanks)

Direct method. The method is based on the same principle of melting small sections of plastic pipes and then joining them together. But in this option, the joint elements are two pipes of the same diameters, and they are joined by their end surfaces.

This, at first glance, simple method of soldering polypropylene requires high precision in processing the joint areas and precise alignment of the two parts along the axes during the process of soldering them.

Direct soldering: 4 – heating element of the soldering iron, 5 – area of ​​the pipe subject to melting.This technique for welding plastic pipes is rarely used in the domestic sector.

Along with the designated “hot” technologies, the “cold” soldering technique is also practiced. Here, a special solvent is used as an active soldering component, which can soften the structure of polypropylene. However, this technique does not have a high level of popularity.

Soldering machines for pipe welding

Both the coupling and direct methods require soldering plastic pipes with special welding machines. Structurally, soldering equipment is something similar to an electric iron.

The basis of the devices is a massive metal heating element, on the surface of which removable nozzles are installed - metal blanks of different diameters. This soldering iron is called iron for welding.

This is what a soldering iron (“iron”) for polypropylene pipes looks like. A simple electrical device, semi-automatic, thanks to which plastic soldering is done

The designs of soldering machines for butt welding are characterized by increased complexity. Typically, such equipment contains not only a heating element, but also a system for centering the parts being welded.

As a rule, direct welding equipment, like the technology itself, is rarely used in the domestic sphere. Priority of use is industry.

A more complex device, with the help of which precise alignment of the parts to be welded is carried out with the further process of heating and soldering. Used with direct welding technology

In addition to soldering irons, the master will also need:

• scissors - pipe cutter for polypropylene pipes;
• construction tape;
• bench square;
• shaver for pipes with reinforcement;
• marker or pencil;
• surface degreasing agent.

Since the work is performed on high-temperature equipment, you should definitely wear thick work gloves.

Polypropylene Welding Procedure

Important warning! Work on welding polymer materials must be carried out in conditions of good ventilation of the room. When polymers are heated and melted, toxic substances are released, which in a certain concentration have a serious impact on human health.

The procedure for welding polypropylene is simple, but it requires precision and accuracy in work. You should also avoid common mistakes, such as insufficient or excessive heating

The first thing you need to do is prepare for work:

1. Install blanks of the required diameter on the heater plateau.
2. Regulator soldering temperature set to 260ºС.
3. Prepare the mating parts - mark, chamfer, degrease.
4. Turn on the soldering station.
5. Wait until the operating temperature reaches – the green indicator turns on.

Place the mating parts (pipe - coupling) on ​​the soldering station blanks at the same time. In this case, the polypropylene pipe is inserted into the internal area of ​​one blank, and the coupling (or socket of the shaped part) onto the outer surface of the other blank.

Typically, the ends of the pipe are inserted along the border of the previously marked line, and the coupling is pushed in until it stops. When curing polypropylene parts on heated blanks, you should remember an important nuance of the technology - the holding time.

If the holding time is insufficient, there is a risk of obtaining a low degree of diffusion of the material, which will affect the quality of the junction. If you overexpose the parts, then there is a high risk of deformation of the structure of the product. This is fraught with deterioration in the quality of the soldering.

It is recommended to use a table that indicates the optimal time value for pipes with different technical parameters.

Soldering time table for polypropylene pipes

After holding the parts on the blanks for an optimal period of time, they are removed and quickly joined with heated parts. The joining procedure must be performed clearly, quickly (according to the time in the table), while maintaining the alignment of the parts being soldered.

It is allowed to make minor adjustments along the axes (within 1-2 seconds), but turning parts one relative to the other is unacceptable.

This is what a welded structure looks like - a fragment of a polypropylene pipeline. High quality soldering is indicated by a characteristic seam at the entry point of the pipe into the fitting.

The indicated soldering time for any polypropylene pipes can be adjusted depending on the work conditions and material characteristics.

For example, if installation is carried out at sub-zero ambient temperatures, naturally the specified standards increase to 50% of the nominal value. For each individual non-standard conditions, the heating time is selected using the test soldering method.

Connecting pipes by soldering with reinforcement

Let's look at how to properly solder reinforced polypropylene pipes. Here it is mandatory to remove the protective material. The presence of a reinforced layer (aluminum foil) in the pipe structure requires additional heating. But that's not the main thing.

Typically, such products have an increased diameter and do not fit standard soldering iron tips. They need to be cleaned before the soldering process. The exception is fiberglass reinforced pipes. They are soldered as standard.

Given the variety of technologies for reinforcing polypropylene pipes, various processing methods are used before soldering. Traditionally, a seamstress is used for stripping.

This name has a special device in the form of a metal sleeve with knives. The seamer is put on the end part of the pipe to be soldered, and with rotational movements around the axis of the pipe, the reinforced layer is cleaned to clean plastic.

If the reinforced layer is located in the middle part of the wall of the plastic pipe, it is more reasonable to use another tool for processing - a plastic pipe cutter.

Another device is a trimmer, needed for welding reinforced pipes. As a rule, the end trimmer is used on pipes whose wall structure contains a reinforced layer in the central area

The device is not much different from a seamstress, except for the placement and design of the cutting elements. After processing with a trimmer, the end part of the pipe is aligned with the end, plus a part of the reinforced layer is cut out to a depth of 2 mm along the entire circumference. This treatment allows soldering to be performed without defects.

Impact of errors on welding quality

Unhurried, carefully considered actions are a guarantee against mistakes that can ruin all the work. You should take into account all the little details of soldering technology and not deviate one step from them.

Common mistakes that result in defective components of the installed propylene water supply network:

1. The surface of the pipe has not been cleaned of grease film.
2. The cutting angle of the mating parts differs from the value of 90º.
3. Loose fit of the end of the pipe into the fitting.
4. Insufficient or excessive heating of the parts being soldered.
5. Incomplete removal of the reinforced layer from the pipe.
6. Correcting the position of parts after the polymer has set.

Sometimes on high-quality materials, excessive heating does not produce visible external defects. However, internal deformation is noted when molten polypropylene closes the internal passage of the pipe. In the future, such a unit loses its functionality - it quickly becomes clogged and blocks the flow of water.

An example of a soldering defect resulting from erroneous actions. The master overheated the plastic pipe, which, in turn, became deformed from the inside

If the cut angle of the end parts differs from 90º, at the moment of joining the parts, the ends of the pipes lie in a beveled plane. A misalignment of parts occurs, which becomes noticeable when a line several meters long has already been installed.

Often for this reason it is necessary to redo the entire assembly again. Especially if pipes are laid in grooves.

Poor degreasing of joint surfaces contributes to the formation of “rejection islands.” At such points, polyfusion welding does not occur at all or occurs partially.

Pipes with such a defect work for some time, but a burst can occur at any moment. Also common are errors associated with loose fitting of the pipe inside the fitting.

A common mistake when soldering polypropylene pipes is that the end of the pipe does not fit tightly into the socket. The pipe must extend to the border of the rim or marking line

A similar result is shown by connections made with incomplete cleaning of the reinforcing layer. As a rule, a reinforced pipe is installed on high pressure lines. Residual aluminum foil creates a non-contact zone in the soldering area.It is at this point that leaks often occur.

The biggest mistake is an attempt to correct the soldered elements by scrolling around an axis relative to each other. Such actions sharply reduce the effect of polyfusion welding.

However, adhesions are formed at individual points, and a so-called “tack” is obtained. With a small tensile force, the “tack” holds the connection. However, as soon as you put the connection under pressure, the solder will immediately fall apart.

Additional information on welding polypropylene pipes is presented in this article.

Conclusions and useful video on the topic

There is always something to learn from professionals. You can see how to work with polypropylene in the following video:

Installing polymer pipelines by hot soldering is a convenient and popular technique. It is successfully used in the installation of communications, including at the household level.

People without extensive experience can use this welding method. The main thing is to correctly understand the technology and ensure its execution exactly. And technological equipment can be purchased or rented.

Do you have experience soldering polypropylene pipes? Please share information with our readers. You can leave comments and ask questions on the topic in the form below.