PVC pipe welding joint

In the process of creating engineering systems, craftsmen have to decide how to connect plastic pipes. Docking technologies differ from each other and are determined by a specific type of system. Today, welding of polyvinyl chloride (PVC) pipes has become most widespread. Although its implementation is not fraught with particular difficulties, in order to avoid leaks during operation, it is necessary to carry out work taking into account the recommendations of professionals.

PVC pipes are connected by different welding methods

Types of welding

Joining PVC pipes by welding is most often carried out using a special soldering iron and the “cold welding” method. The main advantage of the latter method is the ease of implementation of the connection. Work is carried out without the use of special equipment.

These methods are primarily suitable for pipelines with low pressure medium. If the fluid flows through it with high pressure, then other connection methods must be used:

• socket welding;
• electrofusion welding;
• butt welding.

The principle of operation of these technologies is based on the fact that under the influence of high temperature polyvinyl chloride melts. With close contact, a reliable connection is formed due to the penetration of particles of the welded products from one to another at the molecular level.

Piping in which fluid circulates under pressure must be hot-welded

Cold welding

As mentioned above, this is a very simple method for socket joining PVC pipes. It is carried out using aggressive glue for hard plastics. Modern industry produces several types of such a substance. But what unites them is that the composition of any glue as a basis includes polyvinyl chloride itself, dissolved in cyclohexanone, methyl ethyl ketone and tetrahydrofuran.

Various additives are added to the two-component adhesive material to increase the adhesion efficiency and provide the ability to control the viscosity of the mixture and setting time. The glue hardening process is accompanied by evaporation of solvents and weaving of polymer chains of polyvinyl chloride. The result is a joint that has the same performance characteristics as a solid PVC pipe. Cold welding can be performed in a wide temperature range of the environment: from +5 to + 35 ° C. And the use of frost-resistant glue provides the ability to connect PVC pipes even at minus 17 ° C!

PVC pipes can be glued together, using a special adhesive

In hot weather, perform this procedure as quickly as possible. This will prevent the adhesive from drying out before installation is completed.

Helpful advice! For a quality connection, get proven and well-known brands of glue, such as Gebsoplast (Gebsoplast, France), Griffon (Griffon, Holland) or Tangit (Tangit, Germany).

How cold-welded PVC pipes join is a simple matter. This work is performed in the following sequence:

1. Cut the required pipe segment evenly.
2. Chamfer at an angle of 15 degrees.
3. Clean the pipe and bell from dust and dirt. Remove moisture.
4. Gently apply glue with a brush on a surface of a bell and a pipe.
5. Immediately after that, insert the pipe into the socket.
6. For uniform distribution of glue on surfaces, turn the pipe 90 degrees.
7. Lock the connected elements for 20-30 seconds, preventing them from turning again. The bonding procedure should be completed in no more than 1 minute.

Before submitting a trial volume of the working medium, wait a while. You can find its value in the table below.

Table 1. The duration of the formation of the adhesive bell-shaped joint. The unit of measure is the clock.

Socket Welding

This docking technique involves the use of coupling either a tee. For its implementation, you will need a manual or stationary heating device. Although such a connection is quite simple, the need for additional expensive equipment narrows the circle of adherents of socket welding.

To heat the ends of the pipe and the coupling, a special device is used - the so-called soldering iron

The implementation of this method consists in preheating the end of the pipe and the end of the coupling to a certain temperature. When they become plastic, the pipe is inserted into the hole of the coupling. To get a monolithic connection, follow certain rules and do the work very carefully. Angular deviations and misalignment of the coupling and pipe will cause the need to re-perform the operation. But with a new clutch.

The basic rules are formulated as follows:

• It is necessary to start and end the heating procedure of the pipe and coupling at the same time;
• Only heat the parts in the strictly allotted time. Start its counting only after the pipe and the coupling are completely inserted on the heating elements. Do not rotate during installation. This also applies to the heating period and the moment of removal of parts;
• when the heating is complete, quickly remove the coupling and pipe from the heater, and then connect them so that the influx of polyvinyl chloride closes the previously applied mark of the depth of welding.

Helpful information! The socket connection obtained by sleeve welding is monolithic. You can start using it as soon as the parts have cooled to room temperature.

This method is often used by masters when laying a pipeline in apartments and houses.

Socket welding can connect pipes of different diameters, only you need to choose a suitable nozzle for a soldering iron

Electrofusion welding

This connection method involves the use of special plastic couplings with built-in spirals that act as a heating element. Of the main advantages of this technology, it is worth highlighting the quick simple installation process and the formation of a high-quality tight joint. However, this method can connect PVC pipes whose wall thickness does not exceed 4 mm.

Before starting the docking procedure, clean the ends of the pipes and the outer and inner surfaces adjacent to them from dust and dirt, remove moisture and degrease them. Chamfer. After doing this, insert the pipes into the sleeve on both sides of it. Then apply voltage to this fitting from a special device. The spiral will begin to heat and melt the plastic couplings and pipes. The power will turn off automatically when the desired temperature is reached. Such convenience is ensured by the fact that on each electrofusion coupling a bar code is placed, which contains all the technological information necessary for installation. However, it is possible to set the time parameters of such a process for joining PVC pipes in manual mode. To do this, you must enter the relevant data in the above-mentioned special device.

This type of connection is made using electrofusion fittings.

At an ambient temperature below + 5 ° C, such work is not recommended.The elements of the connection become brittle, the heating period increases, while cooling takes place very quickly.

Table 2. The time intervals of the electrofusion connection of PVC pipes.

Butt welding

To connect PVC pipes in this way, you will need a manual welding machine and pipe cutting shears. The power of the device, as well as the diameter of the nozzles should be selected taking into account the diameter of the joined products. Before using scissors, make sure they are sharp enough. So you will avoid deformation of the pipe walls.

The butt welding process itself is performed as follows:

1. Clean and degrease pipe ends.
2. Put marks on the pipes of their entry into the fitting.
3. Chamfer.
4. Heat the pipes to the required temperature. For PVC products, this is + 250 ° C.
5. Join the welded segments.
6. Cool created piping element.

Many of our compatriots, having learned how to connect PVC pipes, often do mistakes when doing this work with their own hands, which can lead to a loss of operability of the installed trunk. The most common is an incorrect reduction of the connected elements. This leads to gaps. The reason - when combining the pipe was not fully inserted. It is impossible to visually control this during the welding process, it is just necessary to apply more force.

Important! Excessive efforts can also lead to negative consequences. In this case, the pipe is deformed and deposits will form in the folds formed on its inner surface, as a result of which the lumen of the main line will eventually be completely blocked.

In order not to have to redo all the work, perform the calculations with all responsibility, be meticulous. Only then will the laid pipeline work flawlessly for many years.