Do you want to repair or replace communications made of polymer pipes? Agree that it’s not a bad idea to save on calling a technician by assembling a new pipeline yourself. But you don’t know how you can connect the individual elements of the system to each other and what you will need for this.
The article we presented describes in detail the welding technology polypropylene pipes– any novice plumber can connect them with his own hands. We will tell you what you need to consider, how to use a soldering iron to join plastic elements. We will tell you in what cases other methods are used.
To help the novice master, we have selected detailed videos demonstrating step by step process performing polypropylene welding, and photo illustrations.
One of the undeniable advantages of polymer pipes is their ease of assembly.
Installation of elements can be done almost anywhere: laying open method on the walls or placed hidden under the floor.
If welding water pipes made of polypropylene correctly, the assembled system will serve without repair for decades
Polymer pipes are produced with diameters from 20 to 110 mm. For household purposes, products of sizes 20/25/32/40 mm are most often used. The area of application determines the nominal pressure of the material.
In the marking it is indicated by the letters "PN":
- PN 10– chosen for arranging cold water supply.
- PN 16- used for cold water, but with higher pressure, as well as when installing a “warm floor” system.
- PN 20– products, the only limitation of which is temperature regime liquids transported through them. It should not exceed 75 °C.
- PN 25– universal products used for arranging both “cold” and “hot” systems, the temperature of which reaches 90 °C.
On sale you can find polymer products equipped with additional reinforcement.
Reinforced products are used for laying over long sections in conditions where it is necessary to reduce linear expansion that occurs during temperature fluctuations
The main feature of polymer pipes is their inability to bend.
Therefore, all changes in the trajectory of the laid highway are carried out only from straight sections connected to each other by auxiliary fittings:
- crosses– for the possibility of branching the main flow;
- tees– flow multipliers;
- couplings– for connecting pipes in a straight section;
- bends– for changes in pipeline direction.
Fittings can be equipped with fused metal threads, which make it possible to connect a polymer pipeline with metal elements.
To ensure that the seams are as strong and airtight as possible, it is important to ensure that the diameters of the joined elements match exactly
When choosing auxiliary elements, two parameters should be taken as a basis: the internal cross-section of the products and the thickness of their walls. These parameters must match technical specifications polypropylene pipes used.
Methods for connecting polymer pipes
When joining pipes made of polymer materials, depending on the installation conditions, one of two methods is used:
- Soldering– involves heating and joining the molten ends of the elements.
- No soldering– involves connecting pipes using compression fittings or by implementing so-called “cold” welding.
The second installation method is convenient in the sense that for its implementation there is no need to use special equipment. All work can be done using simple tool– crimp key.
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Polypropylene pipes are intended mainly for organizing water supply and heating in non-fire hazardous areas. Such a pipeline is easy and quick to install and lasts about 50 years, but it has a significant drawback: when heated, polypropylene softens and is easily deformed. This parameter is important for heating and hot water supply systems, since they undergo dynamic temperature changes, as a result of which plastic pipes change their design position.
Such phenomena are absent when using a cold water pipeline. Based on the above, reinforced polypropylene pipes are used for hot water supply. Strengthening of plastic occurs through the use of aluminum foil, fiberglass or increasing the thickness of the walls of the product. Aluminum integrated into polypropylene, which can be placed inside the thickness of the plastic (non-stripping pipe) or outside (stripping pipe), significantly reduces the linear expansion of the pipeline.
Fiberglass gives a similar effect, which allows this type of pipeline to be used for heating. A pipe with thicker walls is used for hot water.
Basic rules for soldering polypropylene pipes
To receive quality indicators such as the tightness of the welded assembly, maintaining the internal diameter at the places where parts join, aesthetic appearance, etc., the following rules must be taken into account.
The connection area must be dry and free of dirt
Often, in practice, a situation arises when you need to solder a fitting into an existing plastic wiring. Although the pipeline is equipped with a common tap, due to wear and tear, it cannot fully fulfill its purpose. In such situations, water flow instead of connection is inevitable. To eliminate the leak while soldering the elements, you can take the following steps:
Step 1. Shut off the general water supply valve, drain the remaining water into the sewer through the mixer, cut off the pipeline at the junction taking into account the immersion depth, drain the water, drain the area and weld the components. In this case, it is advisable to replace the faulty shut-off valve.
Step 2. You can temporarily stop the flow of liquid by displacing or draining the water column from the pipeline, if the water supply stops for some time (30 seconds is enough). If the leak cannot be stopped, then the internal cavity of the water pipe is sealed with bread pulp, and after welding it is removed through the nearest mixer, but before that, the filter is unscrewed from its drain tube. It is not recommended to use it as a stopper toilet paper, it doesn't come out of the pipeline well.
Do not overheat the connections
Due to excessive overheating, the cross-section of the pipeline decreases, and accordingly the intensity of the water or coolant supply decreases. Overheating can occur as a result of non-compliance with the welding temperature and the holding time of the parts in the nozzle. Table 1 presents data on obtaining a high-quality seam for some pipe sizes.
The soldering iron nozzle must be securely fixed
A loose cue ball while working with parts damages the heating surface of the soldering iron and contributes to the formation of misaligned joints.
After connecting the elements, do not rotate or move them more than 5 degrees
To obtain uniform diffusion, it is advisable after joining not to rotate or align the welded elements during the hardening time of the seam.
The movement of the workpiece in the cue ball must be straight
Other movements may reduce the strength of the seam. The junction point, of course, will withstand the water pressure in the central line, which is usually in the range of 2 - 3 bar, but at nominal pressure(10, 20, 25 bar) will probably leak liquid.
Features of the stripping pipe connection
Before connecting the stripping pipe, you need to remove the foil layer from it with a special shavings (shaver) to the size of the soldering depth. In the absence of a shaver, the reinforcing layer is carefully cut off stationery knife exactly, over the entire area where the pipe is immersed in the fitting. This method looks unprofessional, but when carefully removed it does not reduce the outer diameter of the polypropylene.
What is needed for soldering
To join pipes and transition elements, you will need the following tools:
- set for soldering pipes (soldering iron, 20 mm nozzle, stand);
- scissors for plastic pipes;
- a simple pencil;
- pipe lever wrenches;
- roulette.
Do-it-yourself soldering of polypropylene pipes using an example
Let's look at the soldering technique and the sequence of installing additional shut-off valves and a pressure gauge into the existing plumbing system.
These elements participate in the apartment’s backup water supply circuit (water storage tank with pump).
The water tap is installed to switch the water supply position from the central line to the reserve position. The pressure gauge signals the appearance of water in the riser. The unit is quite difficult to integrate into the existing wiring due to limited space when connecting pipes by soldering.
To create such a unit, which is made of polypropylene pipes and transitions with a cross-section of 20 mm, the following material is needed:
- Angle at 45 degrees. in the amount of 2 pcs.
- Angle at 90 degrees. -1 pc.
- Tee - 2 pcs.
- Connecting coupling - 1 pc.
- Pipe for cold water - 1 meter.
- Coupling, internal thread (MRV) 1/2 inch.
- Bronze transition with external thread 1/2" and internal thread - 3/8".
- Pressure gauge 10 bar.
- Walk-through tap.
- Tow and FUM tape.
Tool for soldering polypropylene pipes.
Work order
Using tow and FUM tape, ensure a tight connection between the pressure gauge, bronze adapter and MRE.
On a soldering iron with a nozzle, set the temperature to 250-260 degrees and turn it on to heat.
After the cue ball heats up, immediately lean the tee against the convex part, and the pipe against the other, with the recess, and begin to feed the parts linearly until it stops.
Mentally count down 7 seconds. During this time, the surface of the parts should melt evenly. At the seventh second, pull the parts out of the nozzle and accurately insert each other into each other until it stops. Hold in this position for four seconds, this is the time when the soldering area remains plastic. Therefore, it is possible to rotate the parts being welded no more than five degrees only in this range.
From the soldered tee, mark a distance of 13 mm on the pipe.
This size corresponds to the depth of immersion of the pipe into the fitting.
Use scissors to cut the pipe according to the mark.
Solder the corner and the pass-through valve so that on the water supply it is placed to a horizontal plane at an angle of about 45 degrees.
Connect the other end of the pass-through valve to a tee, as shown in photo 9.
To the tee, which is located closer to the meter, weld a tube with a 90-degree angle for the pressure sensor.
At the wiring, in the approximate places where parts are soldered, cut the pipes and drain the residual water.
Lean the assembled unit against the installation site and calculate the joining of pipes.
Use scissors to remove excess elements.
We solder a coupling onto one end of the removed element, which will be connected back to the pipeline, consisting of a pipe and two 90-degree angles. We weld the other part at a certain angle into the tee.
We are calculating how the pipeline will be connected to another section. Based on these data, we assemble a unit from two angles at 45 degrees and pipes. We weld it into the other side of the workpiece tee.
We first connect the resulting product to a pipe located near the sewer.
Then with a flow meter.
Lastly with the mixer pipe and tank supply line.
This sequence is due to the ability to use a soldering iron in places that can be moved after joining adjacent nodes.
We determine the length of the pipe for the pressure gauge, solder it into the MVR and put on the fastener. We apply the resulting product to the corner and mark the location of the fastening on the wall. We remove the pressure gauge and mount it to the wall.
We solder the corner and pressure sensor. We check the tightness of the entire system.
Sometimes soldering polypropylene pipes with your own hands cannot be done by one worker due to inconvenient placement of parts. In this case, it is advisable to solder such nodes together.
How to make homemade soldering iron for polypropylene pipes? U good master always have high quality tools at hand. Even at home, there is always a tool, and if you don’t find a suitable one, you can assemble it yourself. If you decide to change sewer, water, or heating pipes, you will definitely need a soldering iron for polypropylene pipes.
To weld polypropylene pipes, a special soldering iron is used, which operates on the principle of an iron.
Nowadays it is very rare to find iron or cast iron pipes, plastic material has become very popular.
Which soldering iron is better?
There is very large selection of this product. Sales consultants will offer you a variety of tools, but won't tell you which one is best. Therefore, first of all, you need to pay attention to the country of origin. Now in the ranking of the most popular soldering irons, the Czech Republic occupies first place, followed by Turkey, Russia in third place, and China in fourth place.
Such a device is used to heat the ends of polypropylene pipes and further connect them to each other. The device is manufactured so that it can be used with different diameters pipes For everything to work out correctly, you need to know the temperature conditions of the equipment. The configuration of the soldering iron consists of a base, two heating elements, nozzles of various diameters, which are attached to special holes.
The soldering iron allows you to easily connect the ends of polypropylene pipes of any size.
To understand the working principle of a soldering iron, it can be compared to the operation of an iron. But the iron is equipped with one heating element, and polypropylene soldering iron– two. It also has a thermostat and an additional built-in tool - a tape measure. The kit also includes an alcohol marker, a level, and a cutter for plastic pipes.
To start working with it correctly, you must first study soldering technology. The soldering iron should be installed on special legs (they are included in your kit), and only then plugged into the network.
Choose an element according to the size of the connector, which is intended for soldering itself. Heat to maximum temperature, connect the ends very quickly and evenly and press together.
In order for everything to work out well the first time, the soldering iron must be heated to maximum temperature - about 20 minutes, then you need to wait 5 minutes for the tips themselves to warm up.
The soldering process itself will take about a minute, but it is better to read the instructions for the device. If there is a pause in the soldering process itself, do not try to reheat, since the pipes are plastic and the material itself stretches, which means that the seam may be damaged.
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Homemade soldering iron for soldering polypropylene pipes
If you can’t afford the device or don’t have the extra money to purchase a soldering iron for polypropylene pipes, you need to make it yourself.
This technique can be made using an old iron.
You will need:
- iron 800 W;
- heater (not with a spiral, but with a heating element, preferably in an aluminum casing);
- Chromel-Copel thermocouple;
- two tips;
- two wires about 1 m long each;
- old tape recorder;
- asbestos wool;
- plexiglass;
- dichloroethane.
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Stages of work completion
The most convenient way to make a homemade soldering iron for polypropylene pipes is from an old iron.
The temperature regulator is removed from the iron plate.
Remove all unnecessary protrusions and wiring, leaving only one bare slab.
Go to a turner and order two tips, one for the pipe, and the other for the fitting (for the fitting and nut). Take the dimensions yourself; to do this, measure the diameter of your pipe.
When the turner has done everything, use a drill to drill a hole with a diameter of about 6 mm, take the bolts and screw the ends.
On the opposite side from the nose of the iron, drill a hole of such a size that you can easily install a thermocouple.
All parts are connected and assembled into a casing.
Take a wire approximately 1 m long and connect it to a thermocouple.
Then they take another wire of the same length and connect it to the heating element. Exited out through the top of the handle.
The handle itself is attached with outside casing.
At the next stage, it is necessary to create a space between the casing and the tile; it must be filled with a thermal insulator; you can take simple asbestos wool.
You should end up with two tips protruding beyond the casing; they need to be thermally insulated.
Now the thermostat itself is placed; it needs to be placed separately and preferably in a plastic case. You can use plexiglass and dichloroethane.
An old tape recorder can be useful for indication; there is an indicator there, and in it there are arrows and, most importantly, a zero mark. By all rules, this mark will be 270°.
If the arrow shows in the red sector, it means the temperature is above normal, and if it shows in the yellow sector, it means below.
Another important element is the resistor; it is located outside the thermostat housing.
It will show whether the heating element is working.
The process itself is as follows. As soon as you plug in the soldering iron, use the handle to set the temperature to 270°.
The LED will light up and give a signal that the soldering iron is starting to heat up to the desired temperature, and when it goes out, you can start working.
It’s up to you to decide what’s better – to assemble it yourself or buy it. New soldering iron construction market will cost 15-18 thousand rubles. If you want to assemble it yourself, it will only cost about 2 thousand rubles. since any owner always has an old iron in the garage.
Any modern housing, be it a private mansion or city apartment, must be equipped with a variety of engineering communications. And if so, then either during the construction process, or during repairs or reconstruction, sooner or later the owners will have to face the problem of installing or replacing pipes and a heating system. Few people are now seduced by labor-intensive and fairly complex installation steel pipes VGP. They are expensive in themselves, require considerable additional costs for transportation, and their processing and connection are associated with specific operations that not everyone can do - cutting, bending, electric or gas welding, thread cutting, etc. Plus, a special approach is required to “packing” each threaded connection so that the connecting unit turns out to be of high quality, without leaks.
It's good that modern technologies allow you to avoid all this hassle by using polypropylene pipes. At making the right choice materials and high-quality installation, plumbing and heating circuits are practically in no way inferior to steel ones, and in many respects they are far superior to them. In addition, the soldering of polypropylene pipes itself is not so complicated; instructions for its implementation will be discussed in this publication.
Not all polypropylene pipes are the same
Before you start considering the installation instructions for polypropylene pipes, it makes sense to give at least general concept about this material, in particular about its varieties and areas of application. Choosing pipes based on the principles of “which ones are cheaper” or “which ones were available” is completely unacceptable. The consequences for an unscrupulous home craftsman can be very sad - from deformation of the laid pipeline to its rupture or the appearance of leaks in connecting nodes.
There is no need to explain the difference in diameter - different systems and their different sections use their own dimensions, which are predetermined by hydraulic calculations. The range of diameters, from 16 to 110 mm, allows you to almost completely provide all possible options. Moreover, practice shows that for a house or apartment, an assortment of up to 40 mm is usually sufficient, much less often - up to 50 ÷ 63 mm. Larger diameter pipes are, rather, main pipes, and they have specific installation features, but face home handyman- it’s unlikely that you’ll have to.
The difference in color between some types of pipes may immediately be apparent. This is what you should pay least attention to - white, green, grayish and other walls - they don’t say anything. Apparently, this is simply a decision by manufacturers to somehow distinguish their products from the general background. By the way, for heating circuits white will definitely be preferable, since the pipeline will unobtrusively fit into any interior without creating a disharmonious color “spot”.
But colored stripes, if they exist, already carry an informative load that is intuitively understandable to everyone. The blue stripe means the pipe is designed exclusively for cold water supply, the red stripe means it can withstand elevated temperatures. However, even this color coding(which, by the way, very often does not exist at all), is only very approximate and does not fully reveal the operational capabilities of a particular pipe. It helps you simply not to make mistakes during the installation of the system. By the way, the longitudinal line is also good because it becomes a good guide when joining mating parts during soldering.
Much more information is provided by alphanumeric markings, which are usually printed on the outer wall. This is where it’s worth being more careful.
The international abbreviation for polypropylene is PPR. There are several types of material, and you can find the designations PPRC, PP-N, PP-B, PP-3 and others. But in order not to completely confuse the consumer, there is a clearer gradation of pipes - by type, depending on the permissible pressure of the pumped liquid and its temperature. There are four such types in total: PN-10, PN-16, PN-20, PN-25. In order not to talk at length about each of them, we can provide a plate that characterizes the operational capabilities and scope of application of the pipes.
polypropylene pipes
| Type of polypropylene pipes | Working pressure (nominal) | Pipe Applications | |
|---|---|---|---|
| MPa | technical atmospheres, bar | ||
| PN-10 | 1.0 | 10.2 | Cold water supply. As an exception - supply lines to the water-heated floor circuits, with a maximum operating coolant temperature of up to 45 °C. The material is the most affordable - due to its not particularly outstanding physical, technical and operational parameters. |
| PN-16 | 1.6 | 16.3 | The most popular option for autonomous cold and hot water supply systems, with an operating temperature of no more than 60˚C, a pressure of no higher than 1.6 MPa. |
| PN-20 | 2.0 | 20.4 | Cold and hot autonomous or central water supply. Can be used in autonomous systems heating, where there is guaranteed to be no water hammer. The coolant temperature should not exceed 80 ˚С. |
| PN-25 | 2.5 | 25.5 | Hot centralized water supply, heating systems with coolant temperatures up to 90÷95˚С, including central ones. The most durable, but also the most expensive type of pipe. |
Of course, in order for a pipe to withstand elevated pressures and temperatures, it must have thicker walls. The value of the wall thickness and, accordingly, the nominal diameter of polypropylene pipes of various types is in the table below:
| Pipe outer diameter, mm | Type of polypropylene pipes | |||||||
|---|---|---|---|---|---|---|---|---|
| PN-10 | PN-16 | PN-20 | PN-25 | |||||
| Passage diameter, mm | Wall thickness, mm | Passage diameter, mm | Wall thickness, mm | Passage diameter, mm | Wall thickness, mm | Passage diameter, mm | Wall thickness, mm | |
| 16 | - | - | 11.6 | 2.2 | 10.6 | 2.7 | - | - |
| 20 | 16.2 | 1.9 | 14.4 | 2.8 | 13.2 | 3.4 | 13.2 | 3.4 |
| 25 | 20.5 | 2.3 | 18 | 3.5 | 16.6 | 4.2 | 16.6 | 4.2 |
| 32 | 26 | 3 | 23 | 4.4 | 21.2 | 5.4 | 21.2 | 3 |
| 40 | 32.6 | 3.7 | 28.8 | 5.5 | 26.6 | 6.7 | 26.6 | 3.7 |
| 50 | 40.8 | 4.6 | 36.2 | 6.9 | 33.2 | 8.4 | 33.2 | 4.6 |
| 63 | 51.4 | 5.8 | 45.6 | 8.4 | 42 | 10.5 | 42 | 5.8 |
| 75 | 61.2 | 6.9 | 54.2 | 10.3 | 50 | 12.5 | 50 | 6.9 |
| 90 | 73.6 | 8.2 | 65 | 12.3 | 60 | 15 | - | - |
| 110 | 90 | 10 | 79.6 | 15.1 | 73.2 | 18.4 | - | - |
With all the advantages of polypropylene, it also has a rather significant drawback - very significant linear expansion when heated. If for cold pipelines located inside the building this is not so significant, then for hot water supply pipes or heating circuits this feature can lead to sagging, sagging of long sections, deformation of complex junctions, and the appearance of internal stresses in the pipe body, shortening its service life.
To minimize the effect of thermal expansion, pipe reinforcement is used. It can be aluminum or fiberglass.
The fiberglass reinforcing belt is always located approximately in the center of the pipe wall thickness, and does not in any way affect the soldering technology.
But with aluminum it’s a little more complicated. There are two types of such reinforcement. In one case, the foil layer is located in close proximity to outer wall pipes (in the illustration - bottom left). Another option is that the reinforcing belt runs approximately in the center of the wall. For each type of such reinforcement there are special technological nuances installation, which will be discussed below.
Both fiberglass and aluminum reinforcement significantly reduce the thermal linear expansion of polypropylene pipes. In addition, the aluminum layer performs another function: it becomes a barrier against oxygen diffusion - the penetration of oxygen molecules from the air through the walls of the pipe into the coolant.
The penetration of oxygen into the liquid coolant medium can cause a number of negative consequences, the main ones being increased gas formation and activation of corrosion processes, which is especially dangerous for metal parts boiler equipment. The reinforcing layer can greatly reduce this effect, which is why such pipes are most often used specifically for heating circuits. In plumbing systems, it is quite possible to get by with fiberglass reinforcement, which does not have a significant effect on diffusion.
| Types of polypropylene pipes | Designation | Thermal expansion coefficient, m×10 ⁻⁴ /˚С | Oxygen diffusion indicators, mg/m²× 24 hours |
|---|---|---|---|
| Single layer pipes: | |||
| PPR | 1.8 | 900 | |
| Multilayer pipes: | |||
| Polypropylene, glass fiber reinforced. | PPR-GF-PPR | 0.35 | 900 |
| Polypropylene, reinforced with aluminum. | PPR-AL-PPR | 0.26 | 0 |
The illustration below shows an example of marking a polypropylene pipe:
1 – in the first place is usually the name of the manufacturer, the name of the pipe model or its article number.
2 – material of manufacture and structure of the pipe. In this case, it is single-layer polypropylene. Pipes with fiberglass reinforcement are usually marked PPR-FG-PPR, with aluminum - PPR-AL-PPR.
Reinforced pipes with an outer polypropylene layer and an inner wall made of cross-linked polyethylene may be found. They will have a designation such as PPR-AL-PEX or PPR-AL-PERT. This does not affect the soldering technology, since the inner layer does not take part in it.
3 – standard pipe dimensional coefficient, equal to the ratio of the outer diameter to the wall thickness.
4 – nominal values of outer diameter and wall thickness.
5 – the type of pipe mentioned above according to the nominal operating pressure.
6 – list international standards, to which the product corresponds.
Pipes are usually sold in standard lengths of 4 or 2 meters. Majority retail outlets practices selling with cuts in multiples of 1 meter.
Numerous components are available for sale for all pipes - threaded fittings, for switching to another type of pipe, from external or internal thread or with an American union nut, couplings, tees, diameter transitions, floor bends at 90 and 45 degrees, plugs, bypass loops, compensators and other necessary parts. In addition, it is possible to purchase taps, valves, manifolds, and “oblique” coarse water filters designed for direct soldering into polypropylene pipework.
In short, such diversity allows you to choose the most convenient diagram assembling a system of almost any degree of complexity. The cost of most of these parts is very low, which allows you to purchase them with a certain reserve, at least so that before starting practical installation conduct a short training session - “get your teeth in”, so to speak.
Methods for connecting polypropylene pipes
Polypropylene is a thermoplastic polymer - when heated, its structure begins to soften, and when two fragments uniformly heated to a certain temperature are connected, mutual diffusion occurs, or rather, even polyfusion, that is, interpenetration of the material. When cooling, the properties of polypropylene do not change, and with a high-quality connection - ensuring optimal heating and the required degree of compression, after reverse polymerization there should be no boundary as such - a completely monolithic assembly is obtained.
It is on this property that the main technological methods for joining polypropylene pipes are based - this method is often called polyfusion welding.
Such welding (soldering) can be carried out using a socket or butt method.
- Sleeve welding is precisely the technology that is most often used when installing water pipes or heating circuits in a house or apartment. It is designed for small and medium diameter pipes, up to 63 mm.
Its meaning is that any connecting unit involves the use of two parts - the pipe itself and the coupling, the inner diameter of which is slightly smaller than the outer diameter of the pipe. That is, in a normal, “cold” form, the parts cannot be paired. A coupling can be not only, pardon the tautology, the coupling itself, but also the installation section of a tee, bend, tap, threaded fitting and other components.
The principle of such welding is shown in the diagrams below.
The pipe (item 1) and the coupling or any other connecting element (item 2) are simultaneously placed on the heating elements of the welding machine.
A pair of the required diameter is pre-installed coaxially on the working heater itself, consisting of a metal coupling (item 4), into which the pipe will be inserted, and a mandrel (item 5), onto which the necessary connecting element is placed.
During the heating period, a belt of molten polypropylene of approximately the same width and depth is formed along the outer surface of the pipe and the inner coupling (item 6). It is important to choose the right heating time so that the melting process does not penetrate the entire pipe wall.
Both parts are simultaneously removed from the heater and coaxially, with force, connected to each other. The melted plastic outer layer of polypropylene will allow the pipe to fit tightly into the coupling all the way to the length of the heated section.
At this stage, the process of polyfusion, cooling and polymerization occurs. The result is a reliable connection, which, although shown in the diagram as a shaded area (item 7), in reality, if you look at the section, it is not visible at all - it is practically a monolithic wall.
- Butt welding is performed slightly differently.
One of the main differences is that the parts that are joined must be the same in inner and outer diameter.
The first step is to fine-tune the ends to ensure they fit perfectly together.
The pipes are pressed on both sides against a trimmer - a rotating disk (pos. 2) with precisely aligned knives (pos. 3)
The pipes are again pressed towards the center, and at the ends, over the entire wall thickness, areas of polypropylene melting are formed (item 5).
And, by analogy with the previous case, as the weld cools, it polymerizes, creating a reliable connection between the two pipes.
The principle seems simple, but this is only at first glance. With this welding technology, precise alignment of the mating parts is of decisive importance. In addition, during sleeve welding, the required degree of compression of the mating molten sections is ensured in to a greater extent difference in diameters of parts. In this case, a significant external force is required, directed strictly along the axis of the connected pipes. All these conditions can only be met when using a special, rather complex machine-type apparatus.
There are many machines for butt welding, but almost all of them have a powerful frame with guides and clamps for clamping pipes of various diameters - to ensure joint alignment, a removable or folding end cap and heater, a mechanism for creating the required compression - manual, hydraulic, electric, etc. .p.
This technology is used, as a rule, only by professionals when laying main pipes, and the likelihood of encountering it at the everyday level is practically zero.
There is also a “cold” welding method - using glue based on a strong organic solvent. The point is that when treated with this composition, the surface layers of the polymer soften. The parts can be connected in the desired position at this time, and since solvents are usually highly volatile, they evaporate quickly. then the reverse polymerization process begins quite quickly.
This technology is more suitable for polyvinyl chloride (PVC) pipes that do not have proper thermoplasticity. In addition, this type of connection method has, perhaps, more disadvantages and limitations in use than advantages, so it is not in particular demand, especially since there is a simple and accessible technology for sleeve polyfusion welding.
What is required for installation work
So, in the future we will consider exclusively socket polyfusion welding (soldering). To cope with this task yourself, you need to prepare a number of tools and accessories.
- First of all, this is, of course, a machine for welding polypropylene pipes. Such a tool is not so expensive, and many zealous owners already have it in their home “arsenal”.
The welding machine must be supplied with coupling-mandrel kits of the required diameters. Most devices allow you to simultaneously place two, and sometimes three pairs of working nozzles on their heating element, which allows you to install a system that uses pipes of different diameters without interruptions for replacement.
If you don’t have your own device, and circumstances currently do not allow you to purchase one, then many stores practice short-term rental with a daily fee - you can take advantage of this opportunity.
If you decide to buy a machine for welding polypropylene pipes...
All welding machines are designed approximately the same and operate on a similar principle, but they also have certain differences in layout and functionality. Useful information for those who have decided to make such a purchase, it is posted in an article on our portal, specifically dedicated.
In the text you may find the definition of a pipe soldering machine - but this is just a “play on words”. There is no difference between these concepts in this case.
- To cut the pipe, special scissors are required. Moreover, they must be sharply sharpened, with a working ratchet mechanism that ensures a smooth cut. The blade should not be jagged or bent.
Of course, you can cut the pipe with a hacksaw, just a metal blade, or even a grinder, but this is absolutely not a professional approach, since the required accuracy and evenness of the cut cannot be achieved with such tools.
machine for welding polypropylene pipes
- It is necessary to prepare a marking tool - a tape measure, a ruler, a construction square, a marker or a pencil. To correctly place the pipes, you have to resort to a level.
- If you plan to solder polypropylene pipes with aluminum reinforcement, then additional tools are required.
- if the pipe has external reinforcement, then you will need a shaver that will clean the aluminum layer at the place of penetration.
- if the aluminum reinforced layer is located deep in the thickness of the wall, then the pipe still requires preliminary preparation, but in this case a trimmer is already used.
A trimmer is often similar in appearance to a shaver, but there is a difference between them - it lies in the arrangement of the knives. With a shaver, the cut goes tangentially parallel to the axis of the pipe, and with a trimmer, as even their names make clear, the knife processes the end and removes a small chamfer.
Read a useful article, and also familiarize yourself with the varieties and selection criteria on our portal.
We will dwell on this point in more detail when considering pipe soldering technology.
- Many people overlook this, but the welded sections of pipes and couplings must be cleaned of dirt, dust, moisture, and then degreased. This means you need to prepare a clean rag and an alcohol-containing solvent (for example, regular ethyl or isopropyl alcohol).
But you should not use solvents based on acetone, esters, or hydrocarbons, since polypropylene is not resistant to them, and the walls may melt
- It is also necessary to take care of protecting your hands. They will have to work in close proximity to the heating element of the device, and getting a serious burn is as easy as shelling pears.
Suede work gloves are best suited for this task - they practically do not restrict movement, will not begin to smolder from contact with a hot heater, and will reliably protect your hands.
And one more important warning. Majority installation work very often it can be carried out not locally, but, for example, on a workbench in a workshop - some devices even have special brackets with clamps for secure fixation on the table. This is convenient in the sense that the assembled unit is then quickly installed, for example, in cramped and uncomfortable conditions of a bathtub or toilet.
In any case, wherever soldering is carried out, it is necessary to provide highly effective ventilation. When polypropylene is heated, a gas with a pungent odor is released. The smell is not the worst thing - with prolonged inhalation, serious intoxication can occur. Believe me, I tested it on my own skin. The author of these lines spent a day with a temperature of 39° after seven hours of work in a fairly spacious combined bathroom, with a ventilation vent that seemed to work well. Don't repeat the mistakes!
How to solder polypropylene pipes
General technological methods for welding polypropylene pipes
- First of all, a novice master must have a clear idea of what he is going to mount. Must be prepared detailed diagram-drawing, with dimensions and specific details indicated - this same “document” will become the basis for the purchase required quantity pipes and components.
- If conditions permit, for example, there is no finishing in the room where the installation will be carried out, then it is best to transfer the diagram directly to the walls - it will be more clear, and you can measure the required lengths of pipes literally on the spot.
The key to success is to try to complete the maximum possible number of knots in a comfortable working position, on a workbench. Working with a soldering machine directly on site, and even alone, without an assistant, is an extremely difficult task, and it is very easy to make an error. It is clear that such operations cannot be completely avoided, but their number should be reduced to the possible minimum.
- The soldering machine is getting ready for work. Working pairs - couplings and mandrels of the required diameters for operation - are put on its heater and tightened with a screw. If you plan to work with one type of pipe, then there is no need to be clever - put on one pair, as close as possible to the end of the heater.
There are welding machines with a cylindrical heating element - it has a slightly different fastening of the working elements, like a clamp. But figuring this out is not difficult.
- It will be much more convenient to work if the device is rigidly fixed to work surface workbench. It’s great if the design provides a clamp-type screw for fastening to the edge of the tabletop. But even with a conventional device you can try to come up with some kind of fixation. For example, if the surface allows, the legs of the stand are screwed to the workbench with self-tapping screws.
Even with the stand fixed, the device can “wiggle” in it - there will definitely be some play. Here, too, you can provide your own fastening - drill a hole and screw in a self-tapping screw. When you need a soldering iron for remote work, removing this mount is a matter of a few seconds.
- The soldering iron is connected to the network. If it has temperature control, it is set to approximately 260 °C - this is the optimal temperature for working with polypropylene. You should not listen to anyone that for the 20th pipe you need 260 degrees, for the 25th – already 270, and so on - in increasing order. The temperature is the same, the heating time of the mating parts simply changes. In any case, those tables that the manufacturer provides in the product data sheet, and which will be posted below in this article, are designed for exactly this level of heating.
- Usually the soldering iron has a light indicator. A lit red light indicates that the heating element is working. Green – the device has reached operating mode.
However, many models have their own display features. Some devices even have a digital display with temperature indication. In any case, the device will “let you know” that it has warmed up to the required level.
- The mating parts are prepared for work - the required piece of pipe is cut off, the connecting element is selected according to the installation diagram.
- Not many people do this, and yet the technology requires mandatory cleaning of the connection area from possible dirt and dust, and degreasing. In addition, even the slightest drops of water or a wet surface are completely unacceptable - water vapor can enter the melt layer and create porous structure, and this connecting unit runs the risk of leaking sooner or later.
- The next step is to mark the connection. On the pipe it is necessary to measure from the end and mark the length of the penetration belt with a pencil (marker). It is up to this mark that the pipe will be inserted into the heating coupling, and then into the connecting piece. Each diameter has its own value - it will be indicated in the table below.
The second mark is applied if the relative position of the mating parts is important. For example, on one side of a pipe section a 90° bend has already been welded, and on the other side it is necessary to mount, say, a tee, but so that its central channel is located at an angle to the bend relative to the axis. To do this, first accurately determine the position of the parts, and then apply a mark across the border, along both sides.
There won’t be much time spent choosing the correct position during soldering, and such a “trick” will help accurately position the mating parts.
- The next step is directly soldering the connection. It, in turn, also includes several phases:
— From both sides, the pipe is simultaneously inserted into the soldering iron coupling, and the connecting element is put on the mandrel. The pipe must go up to the mark made, the connecting element - all the way.
— After the pipe and connecting element are inserted completely, the warm-up time begins. Each diameter has its own optimal time, which should be followed.
- Once the time has expired, both parts are removed from heating elements. The master has literally a few seconds to give the parts the correct position and, of course, alignment, insert one into the other with force and bring it to the same mark. Light adjustments, without turning relative to the axis, are allowed only for one to two seconds.
— In this position, the parts must be held, without the slightest displacement, for the specified fixation period.
— After this, the assembled unit should not experience any load during the established period of cooling and polymerization of polypropylene. And only then can it be considered ready
Now - about the main parameters that must be adhered to during installation. For ease of perception, they are summarized in a table:
| Name of indicators | Pipe diameter, mm | ||||||
|---|---|---|---|---|---|---|---|
| 16 | 20 | 25 | 32 | 40 | 50 | 63 | |
| Length of the pipe section to be welded, mm | 13 | 14 | 16 | 18 | 20 | 23 | 26 |
| Heating time, seconds | 5 | 5 | 7 | 8 | 12 | 12 | 24 |
| Time for rearrangement and connection, seconds | 4 | 4 | 4 | 6 | 6 | 6 | 8 |
| Time to fix the connection, seconds | 6 | 6 | 10 | 10 | 20 | 20 | 30 |
| Time for cooling and polymerization of the unit, minutes | 2 | 2 | 2 | 4 | 4 | 4 | 6 |
| Notes: - If thin-walled PN10 type pipes are welded, the heating period of the pipe itself is halved, but the heating time of the connecting part remains the same as indicated in the table. - If work is carried out outdoors or in a cold room at a temperature below +5°C, then the warm-up period is increased by 50%. |
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There is no question of reducing the set warm-up time (except for the case mentioned in the note to the table) - a high-quality connection will not work, and the unit will definitely leak over time. But regarding some slight increase, the masters do not have a unified view. The motivation here is that pipes from different manufacturers may differ slightly in material, that is, harder or, conversely, soft polypropylene is found. But the masters have accumulated experience and precise knowledge of the material used, but for a beginner, the recommended indicators should still be taken as a basis.
Good advice - when buying pipes and components - take a small supply of the cheapest connecting elements and conduct an experiment - training. You can prepare a few pieces of pipe and perform test soldering.
With high-quality soldering, a neat collar about 1 mm high is created inside the connecting node around the circumference, which will not interfere with the free passage of water. A neat collar will also be formed on the outside, which will not spoil appearance connections.
pipe cutters
But overheating can already lead to a defective connection. When the parts are combined, molten polypropylene begins to be pressed inward, where a “skirt” is formed and hardens, largely covering the passage. The water pressure in such a water supply system may be reduced, and in addition, such a defect often becomes a place for blockages to form over time.
Conducting such a practical lesson will help you accurately determine all soldering parameters and avoid mistakes.
Features of working with pipes with aluminum reinforcement
As mentioned above, there are two options here - the reinforcement layer is located near the surface of the pipe, or deep in the wall. Accordingly, the methods of preparing the pipe for welding also differ.
- It is clear that the layer of aluminum located near the surface simply will not allow for complete heating and connection of the assembly. In addition, such pipes always have a slightly higher diameter and simply will not fit into either the heating coupling or the connecting element. This means that it is necessary to peel off this layer to “pure” polypropylene.
For this, a special tool is used - a shaver. A piece of pipe is inserted into it and they begin to turn - installed knives carefully sequentially cut off the top polymer coating and the aluminum underneath.
Processing is carried out until the pipe stops at the bottom of the tool - the dimensions of the shaver are such that it will cut the foil exactly in the strip that is required for the welded joint at a given diameter, that is, you don’t even have to carry out the appropriate markings.
When soldering, the entire cleaned area must be heated and then completely inserted into the connecting piece. Leaving even a thin strip of protected pipe outside is prohibited.
- If aluminum foil is hidden in the back of the material, then it would seem that it does not allow for high-quality soldering. But there is another nuance here.
If the pipe is not protected at the end, then water passing under pressure will try to delaminate it and find a way out between the aluminum layer and the outer polypropylene sheath. Aluminum, in addition, can begin to corrode and lose its strength. The result of such delamination first becomes “blisters” on the pipe body, which then inevitably end in a major accident.
The solution is to create conditions such that during welding the end of the pipe and the aluminum layer are completely covered with molten polypropylene. And this can be achieved by processing with a special tool, which was mentioned above - a trimmer.
Outwardly, it may be similar to a shaver, but its knives are located differently - they precisely align the end, cut a chamfer and remove a thin, about 1.5 - 2 mm from the edge, strip of aluminum foil around the circumference. During heating and during the mating of parts, the created bead of molten polypropylene will completely cover the end of the pipe, and the assembly will receive the necessary reliability.
Pipes with fiberglass reinforcement do not have any installation features.
- The soldering process, as stated, is best carried out on a comfortable, spacious work site, assembling ready-made water supply (heating circuit) units as much as possible, and only then installing and connecting them in place.
Working “next to the wall” is always more complex, time-consuming and nerve-wracking, since you have to hold a fairly heavy apparatus with one hand, while simultaneously providing heating to both mating parts. It is often almost impossible to make such a welded joint without an assistant. Therefore, it is worth reducing the number of such operations to a minimum.
But it is important to avoid mistakes. To connect the assembly, it is necessary to provide a certain degree of freedom to the mating parts - they need to be moved apart to be installed between them welding machine(plus the heating pair also has a certain width), then carefully, without distortion, insert it into the mandrel and coupling, after warming up, ensure progressive removal, and then connection. It is necessary to foresee this point in advance - whether the available play is enough to perform all these manipulations.
- It happens that inexperienced craftsmen, having not foreseen this nuance, are faced with the fact that there is only one weld left, and there is no way to complete it. What to do?
The solution may be to weld a dismountable connecting pair into the cut pipe - a threaded fitting and a coupling with an American union nut. The connection turns out to be reliable, and soldering such elements even in such difficult circumstances is no longer difficult.
- If at least some component during installation raises even the slightest doubt, without any regret it should be cut out and other parts welded. Believe me, it won’t take much time and won’t entail serious expenses. But if, over time, such a questionable area suddenly leaks, the consequences can be very sad.
- The next group of errors has already been mentioned above - a violation of pipe soldering technology. This may include insufficient or excessive heating. The force applied to the parts during connection should be moderate. Compressing too hard will cause an inner “skirt” to form. No less dangerous is the insufficient application of force - the pipe does not enter the socket of the connecting part completely, it remains there small area with an increased diameter and thinned wall - a potential breakthrough site!
- Do not forget to clean the welded parts from dirt and grease. This may seem unimportant, but in practice there are quite a few cases where such neglect subsequently resulted in a weak connection and the formation of a leak.
- It is very dangerous to try to change the position of parts during the setting and cooling of the connection. This may not appear outwardly, but microcracks appear in the connecting seam, which subsequently lead to accidents. If you don’t like the connected node, throw it away and make a new one, but don’t try to change it!
- When stripping a reinforced pipe, not even a tiny fragment of foil should remain in the cleaned area - this can become a potential site for a future leak.
- One more recommendation. It is clear that the material must be of high quality - you should not chase cheapness, since you can lose a lot more, especially since even branded polypropylene pipes and components for them are not so expensive. But there are cases when, during the installation of high-quality pipes, carried out in strict compliance with the technology, the connecting nodes nevertheless began to fail over time. And the reason is simple - it was really used quality material, but from different manufacturers. Seemingly insignificant differences in chemical composition and the physical and technical characteristics of polypropylene gave such an unexpected result - full diffusion of melts was not achieved.
Therefore, one final piece of advice: use high-quality pipes from one manufacturer. It’s probably clear that all components should also be of the same brand.
At the end of the publication, there is an educational video about soldering polypropylene pipes:
Video: a master shares the secrets of high-quality soldering of polypropylene pipes
Wonderful material - polypropylene!
I use it to make various homemade items for myself and for friends.
Recently they asked me to make a small homemade project, or rather a stand. In total, six fittings and a couple of meters of pipe had to be soldered.
But here’s the problem: I just lent my soldering iron to friends, but I didn’t ask for it back so quickly.
I started thinking about what else I could use to solder polypropylene. I know they are soldering gas burner, but I don’t have it.
Materials and tools
But I have an old “bucket” soldering iron, which I haven’t needed for a long time. So I decided to make something out of it.
I needed a few more details.
Aluminum wire and plate;
Textolite sheet;
Thermostat and iron indicator lamp;
Ceramic insulators;
Thermal paste;
Thermal tape;
Nozzle for welding polypropylene pipes (25mm);
New electric plug;
Various bolts and nuts.
Making a soldering iron for polypropylene pipes
Two blanks were made from an aluminum plate: a substrate for a thermostat and a holder for a polypropylene nozzle.
The legs and parts of the body for the thermostat are made of PCB.
I connected an indicator light to the thermostat terminals. And connected the insulators using thermal tape.
I connected the top and bottom of the case with screws and nuts through insulators. Bottom part the body does not touch the boiler tubes.
To connect the thermostat in series, a break was made in the power cable. I soldered and insulated the wires with electrical tape along with the kettle handle.
I made the legs from aluminum with insulators from PCB plates at the end.
The 25 mm nozzle fits perfectly inside the boiler spiral. A U-shaped aluminum plate is already placed on top of the nozzle. The connection points are coated with thermal paste.
For soldering I needed a 20 mm nozzle. I connected it homemade screw made from an 8 mm bolt.
Al was also wound on top as an additional radiator. larger diameter wire.
Testing a homemade soldering iron
During the first test, one defect was revealed, not counting the smoke and smell from the burning of the new “device” - not quite convenient work indicator. The light is on when the soldering iron is turned off and off when it is running. But this is not scary, it’s just a matter of habit. Perhaps I will upgrade it in the future.
Soldering pipes with a homemade soldering iron
The thermostat was set to low. Heating occurs quickly. I didn’t notice any difference in the quality of soldering, since the nozzle itself remained the same, only the heating element changed.
So I managed to make a couple of welding joints with my experimental soldering iron.
