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Many are wondering how to weld and what mistakes can be made when welding polypropylene pipes? The answers to these questions are presented in this article. For the installation and repair of plumbing and heating systems, not only metal elements are used, but also parts made of various types of plastics: polypropylene, or. Currently, these materials are popular: their installation can be easily done with your own hands, without resorting to the services of specialists. Welding of polypropylene pipes (PPR welding) has a number of advantages:
- Pipes from are not subject to process of corrosion.
- Their cost is lower than metal ones.
- They are light.
- There are several basic ways to install them.
- Quick assembly when working alone. With a partner, work can speed up.
- Simple soldering methods. By following a certain sequence of actions and following the basic rules, you can get a ready-made connection yourself.
- Long service life. Modern models of polypropylene products can serve for several decades.
pp pipe welding: choice of tools
It can be of several types: manual, semi-automatic or automatic. The last type will be the most expensive in terms of cost. When working with a specific unit, you should follow the rules set forth in this article, as well as the instructions for it.
In addition to the soldering iron, you will need:
- special scissors for cutting the required size of a pipe made of polypropylene.
- a marker for drawing marks on details.
- alcohol liquid for degreasing the surface of the edges.
- fittings (for example, couplings).
It is advisable to choose couplings and pipes from the same manufacturer. If you choose different ones, there is a risk that the parts do not fit together in size or material composition.
PP pipes are divided into types depending on the purpose and technology of use:
- For plumbing systems: both cold and hot.
- For the heating system, a special technology for welding polypropylene pipes for heating is used.
They are also divided into varieties depending on the marking.
- The PN 10 marking is used for cold water supply with temperatures up to 20°C, as well as for floor heating up to 45°C.
- Marking PN 16 is used for plumbing systems with cold water, as well as with hot water up to 60 °.
- Polypropylene marking PN 20 must be purchased for hot water supply up to 95 °.
- The PN 25 marking is used for hot water supply, as well as for heating up to 95 °.
Welding of polypropylene and polyethylene: differences
- The melting point of PP is higher than that of polyethylene.
- Pp - more durable and not so flexible.
- Pp is more heat and frost resistant.
Differences of propylene pipes depending on the color
- White and gray colors are mounted in the house, it is forbidden to use them on the street. They are ideal for plumbing and heating systems.
- Black color contains substances in the composition of its material that give additional stability and wear resistance. This is a great option for use in sewer systems.
- Green PPs are used, as a rule, for watering plantations. Some modern green products can also be used for cold water.
Preparation for work
Immediately before soldering, the parts must be cleaned and degreased using special alcohol solutions. They should be free of foreign objects, dust, dirt and burrs. For work, it is necessary to prepare not only the parts themselves, but also the place of work itself: it should not be dirty, dusty, it is recommended that there are no strangers and objects.
The approximate temperature for working with a soldering iron is about 260-270 degrees. All parts must be prepared in advance, before heating the equipment to the desired temperature. The connection process takes a few seconds. It is necessary to make sure that the parts are evenly located, then the seam will turn out to be of high quality and airtight. The exact bonding time may vary depending on the thickness of the part and the condition of the welding equipment. It should be borne in mind that if the soldering iron does not heat up very much, the heating time must be increased. Do not start work with slightly heated equipment. The connection may not be tight. Elements that are planned to be connected to each other must be heated at the same time.
Overheating of the elements is characterized by the fact that the material becomes very soft and can deform upon contact with each other.
The result of overheating of polypropylene pipes The table below contains approximate soldering temperatures, depending on the thickness of the part, welding and cooling time.
| Pipe volume (cm.) | Heating time (sec.) | Welding time (sec.) | Cooling time after welding (minutes) |
| 1,6 – 1,3 | 5 | 4 | 3 |
| 2 – 1,4 | 5 | 4 | 3 |
| 2,5 – 1,6 | 7 | 4 | 3 |
| 3,2 – 1,8 | 8 | 4 | 4 |
| 4 – 2 | 12 | 6 | 4. |
| 5 – 2,3 | 18 | 6 | 5 |
| 6,3 – 2,6 | 24 | 6 | 6 |
| 7,5 – 2,8 | 30 | 8 | 8 |
| 9 – 3 | 40 | 8 | 8 |
| 11 – 3,3 | 50 | 10 | 10 |
| 16 – 3,5 | 80 | 15 | 15 |
pp pipe welding
When the plastic melts, the parts must be removed from the nozzles of the soldering iron and carefully connected. This must be done quickly. It is forbidden to press hard and twist them. Keep the elements straight. If for some reason the seam turned out to be of poor quality, it is no longer possible to separate it. You can only cut this seam with scissors and solder the edges again.
Types of soldering plastic pipes
There are three types of connection of plastic parts:
- Coupling.
The butt method is the result of joining molten edges. The parts are fixed to each other using a special butt welding machine.
Butt welding machine Coupling is a method of soldering using couplings. A coupling is a special device designed to connect parts to each other. The coupling method is also carried out using special welding equipment.
The connection method is carried out using special electrical couplings. The equipment heats the electrical couplings, or rather, the spiral inside it. Usually, brazing of PPR pipes with this method is used when it is necessary to connect large diameter products and / or in places with the possibility of seismic activity.
Machine for electrofusion welding For each of the above types of connections, there are certain types of welding equipment on sale. There are general rules for using such welding equipment, as well as instructions for welding polypropylene pipes with a specific model.
In turn, it is divided into manual, semi-automatic and automatic. Manual equipment is used when connecting elements operating under medium and low pressure. Their management is completely dependent on the person, his functions are not automated, there is no possibility of fixing (logging) data. Semi-automatic equipment is automated, but not completely. Usually, we are talking about the possibility of logging temperature data. Automatic equipment does not require human control and management. You just need to set the necessary parameters, and the machine will automatically select the desired welding mode. The last type of welding equipment is the most expensive, but also the most efficient. It eliminates the possibility of errors or defects.
In modern construction, almost 70% of pipes are made of polypropylene. They are used not only in the laying of new pipelines, but also in the repair of old systems. When installing the system, the technological rules of welding must be observed, and in order to achieve the best results, all the nuances must be taken into account, which include the welding temperature of polypropylene pipes.
Properties of polypropylene pipes
This type of pipe is currently the most common, as it combines excellent technical qualities and low price. Polypropylene pipes are strong, durable and can resist corrosive damage.
Possessing such qualities, polypropylene products can be used in various fields:
- when laying water and gas pipelines;
- for drainage outlets;
- for removal and transportation of various aggressive liquids.
The following kit is required for welding polypropylene pipes:
- thermometer;
- scissors designed for cutting pipes;
- degreaser;
- old rags made from natural fibers;
- tape measure, marker;
- scraper;
- a special device for welding polypropylene elements with a diameter of more than 50 mm.
Also, when working, you may need improvised tools: a knife, a hacksaw, if it is not possible to work with a pipe cutter or scissors.
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Preparation of the device and material for welding polypropylene pipes
Before you start welding polypropylene pipes, it is important to properly prepare the equipment.
First of all, the heating nozzles must be firmly fixed to the welding device. Using a thermostat, set the temperature to 250-270 degrees and connect the device to the power supply. The required time for heating the appliance is set according to the room temperature. To prevent damage to the working layer of the nozzles, they must be cleaned with a rag before heating.
Welding can be started if the required temperature is shown on the indicator or contact thermometer.
Before starting welding of polypropylene pipes, it is necessary to conduct a visual inspection, since the surface layer of the elements must not have any defects, the fittings must be in working condition. All threads must be checked with products with opposite threads.
Pipes and fittings to be welded must be thoroughly cleaned and degreased. All fittings must be checked for consistency. Fittings that wobble and fit poorly are discarded.
All pipes must be carefully measured and cut. If they were cut off with a hacksaw, then the edges should also be deburred.
Using equipment designed for this purpose or a sharp knife, the pipes are cut at the end of the welded edge to about 45 degrees. These manipulations are mainly performed with large-sized products (section more than 40 mm). This cut is required to avoid delamination of the material when the pipe end is inserted into the fitting.
Before starting the soldering of volumetric elements, it is necessary to check their circumference.
Before you start soldering pipes, it is important to remove the oxidized layer from them along the entire halo of the joint, since the oxide negatively affects the quality of the welds.
It is important to insert the pipe into the fitting before soldering and make marks for the depth of its entry, but taking into account the fact that the pipe is inserted all the way. To avoid narrowing of the pipe in the seam, you need to leave a gap of 1 mm.
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Heating temperature of the welder
Compared with butt welding, where the parts are heated at a surface and low temperature for a long time to avoid stress inside the material, in propylene socket welding, the temperature of the apparatus is increased and it heats up faster. The choice of heating temperature of the welded device is subject to several restrictions:
- Melting of welded surfaces must be carried out quickly, pipes may lose their original appearance, and it will be difficult to combine them. This is the reason for the high heating temperature of the device.
- If the welded device is overheated, then the polypropylene elements may undergo thermal deformation.
- The Teflon coating that covers the working part of the apparatus remains in excellent condition if it is constantly operated at a temperature of 260 degrees, but if higher temperatures are used, the device gradually fails.
Considering all the nuances of socket welding, the optimal temperature for heating the working surface of the nozzles was set at 260 degrees, with deviations of plus/minus 10 degrees.
Such a heating regime can adversely affect the internal stress at the joints. But this is compensated by the almost double wall of the pipeline system at the joints and the maximum welding area.
Many models of devices for socket welding of polypropylene pipes are equipped with a temperature setting regulator. The thermostat is designed in such a way that when the appropriate temperature is set, it corresponds to the temperature on the welded nozzles. The heater temperature is 15 degrees higher.
Most models of welded devices are outdated and do not have a regulator knob, and their temperature regime is set by the manufacturer immediately to 260 degrees. Given the working technology, according to the masters, this is correct, since the regulator knob is most likely installed to increase popularity.
Quite a few types of repair work involve the complete replacement of pipes. For the arrangement of many types of pipelines (water supply, etc.), components made of polypropylene are used today. These products are characterized by sufficient strength and long service life, and are inexpensive. They are connected by the method of special polypropylene welding, designed to join materials of a similar composition.
Various designs can act as this element. Couplings are made for straight sections.
To make a turn, use a special square. There are threaded fittings on sale: one part of it is attached to a polypropylene pipe, the other is mounted to a metal pipe or plumbing unit.
The type and number of required fittings must be thought out and determined in advance, so it is advisable to make a drawing of the planned pipeline.
Soldering polypropylene pipes: how to work
Polyethylene pipes: cold welding
Since we are talking about pipe welding, it will not be superfluous to recall the cold method. Cold welding is usually hardened with steel. It is used to quickly and firmly seal joints, repair and restore lost elements of products made of ferrous and non-ferrous metals, which are operated at t from minus 60 to plus 150.
This method is perfect for repairs, for example, heating in an apartment. It can be used even in rooms with excessively high humidity levels. This method is characterized by excellent adhesion to wet and oily surfaces. The plastic pipes themselves will be in a plastic state for no more than five minutes from the start of the process. 
Any modern housing, be it a private mansion or a city apartment, is necessarily 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 heating systems. Few people are now attracted by the laborious and rather complicated installation of VGP steel pipes. 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, threading, etc. Plus, a special approach is required for the “packing” of each threaded connection in order for the connecting assembly to turn out to be of high quality, without leaks.
It's good that modern technologies make it possible to do without all this trouble by using polypropylene pipes. With the right choice of material and high-quality installation, plumbing and heating circuits practically do not retreat from steel in any way, in many respects they are far superior to them. In addition, the soldering of polypropylene pipes itself is not so complicated, the instructions for which will be discussed in this publication.
Not all polypropylene pipes are the same
Before starting to consider the installation instructions for polypropylene pipes, it makes sense to give at least a general idea about this material, in particular, about its varieties and applications. The choice of pipes according to the principles “which is cheaper” or “what were” is completely unacceptable. The consequences for an indiscriminate home master can be very sad - from the deformation of the laid pipeline to its rupture or the appearance of leaks in the connecting nodes.
There is no need to explain the difference in diameter - in different systems and in their various sections, their sizes are used, 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 enough, much less often - up to 50 ÷ 63 mm. Pipes of larger diameter are, rather, main ones, and they have specific installation features, but it is unlikely that a home master will have to deal with it.
The difference in color between some types of pipes may immediately catch your eye. This is the least you can pay attention to - white, green, grayish and other walls - do not say anything. Apparently, this is just a decision of manufacturers to somehow distinguish their products from the general background. By the way, for heating circuits, white color will definitely be preferable, since the pipeline will unobtrusively fit into any interior without creating a disharmonious color “spot”.
But the colored bars, if they exist, already carry an informative load, intuitively understandable to everyone. The blue stripe - the pipe is designed exclusively for cold water supply, the red one - is able to withstand elevated temperatures. However, such a color marking (which, by the way, very often does not exist at all) is only very approximate, not fully revealing the operational capabilities of a particular pipe. It helps not to make a mistake 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 given by alphanumeric marking, which is usually applied on the outer wall. This is where you should be more careful.
The international abbreviation for polypropylene is PPR. There are several varieties 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 allowable 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 for a long time about each of them, you can give a plate that characterizes the operational capabilities and scope of 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 contours of the water "warm floor", with a maximum operating temperature of the coolant up to 45 ° C. The material is the most affordable in terms of cost - due to not particularly outstanding physical, technical and operational parameters. |
| PN-16 | 1.6 | 16.3 | The most popular option for autonomous systems of cold and hot water supply, with an operating temperature of not more than 60 ° C, a pressure of not more than 1.6 MPa. |
| PN-20 | 2.0 | 20.4 | Cold and hot autonomous or central water supply. It can be used in autonomous heating systems, where there are guaranteed to be no water hammers. The coolant temperature must not exceed 80 ˚С. |
| PN-25 | 2.5 | 25.5 | Hot centralized water supply, heating systems with coolant temperature up to 90÷95˚С, including central ones. The most durable, and also the most expensive type of pipe. |
Of course, in order for the 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 are 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 - a very significant linear expansion when heated. If for cold pipelines located inside the building, this is not so significant, then for hot water pipes or for heating circuits, this feature can lead to sagging, sagging of long sections, deformation of complex interchanges, and the appearance of internal stresses in the body of the pipe, reducing 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 affect the soldering technology in any way.
But with aluminum - a little more complicated. There are two types of such reinforcement. In one case, the foil layer is located in close proximity to the outer wall of the pipe (bottom left in the illustration). Another option - the reinforcing belt runs approximately in the center of the wall. For each type of such reinforcement, there are special technological nuances of installation, which will be discussed below.
Both fiberglass and aluminum reinforcement significantly reduces the thermal linear expansion of polypropylene pipes. In addition, the aluminum layer also performs another function: it becomes a barrier against oxygen diffusion - the penetration of oxygen molecules from the air through the pipe walls into the coolant.
The penetration of oxygen into the liquid medium of the coolant can cause a number of negative consequences, among which the main ones are increased gas formation and activation of corrosion processes, which is especially dangerous for metal parts of boiler equipment. The reinforcing layer is able to repeatedly reduce this effect, so 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 reinforced with fiberglass. | PPR-GF-PPR | 0.35 | 900 |
| Polypropylene reinforced with aluminium. | 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.
2 - material of manufacture and structure of the pipe. In this case, it is a single-layer polypropylene. Pipes with fiberglass reinforcement are usually marked PPR-FG-PPR, with aluminum - PPR-AL-PPR.
There may be reinforced pipes with an outer polypropylene layer and an inner wall made of cross-linked polyethylene. 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 participate in it.
3 is the standard pipe dimension coefficient, equal to the ratio of the outer diameter to the wall thickness.
4 - nominal values of the outer diameter and wall thickness.
5 - the type of pipe mentioned above according to the nominal working pressure.
6 - a list of international standards to which the product complies.
Pipes are usually sold in standard lengths of 4 or 2 meters. Most retail outlets practice selling with a cut that is a multiple of 1 meter.
Numerous accessories are on sale for all pipes - threaded fittings, for switching to another type of pipes, with external or internal threads or with an American union nut, couplings, tees, transitions in diameters, bends at an angle of 90 and 45 degrees, plugs, bypass loops , compensators and other necessary details. In addition, it is possible to purchase taps, valves, manifolds, "oblique" coarse water filters designed for direct soldering into polypropylene piping.
In a word, such a variety allows you to choose the most convenient scheme for 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 margin, if only in order to conduct a small training session before starting practical installation - so to speak, “get your hand on”.
Methods for connecting polypropylene pipes
Polypropylene is a thermoplastic polymer - when heated, its structure begins to soften, and when two fragments evenly heated to a certain temperature are joined, mutual diffusion occurs, or rather, even polyfusion, that is, the material interpenetrates. 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 the reverse polymerization of the boundary as such, there should not be a completely monolithic assembly.
It is on this property that the main technological methods for connecting polypropylene pipes are based - this method is often called polyfusion welding.
Such welding (soldering) can be carried out by coupling or butt welding.
- Sleeve welding is just the technology that is most often used when installing plumbing or heating circuits in a house or apartment. It is designed for pipes of small and medium diameter, up to 63 mm.
Its meaning is that any connecting unit involves the use of two parts - this is the pipe itself and the coupling, the inner diameter of which is somewhat smaller than the outer diameter of the pipe. That is, in a normal, “cold” form, the parts cannot be paired. The coupling can act not only, sorry for the tautology, the coupling itself, but also the mounting section of the tee, branch, tap, threaded fitting and other components.
The principle of such welding is shown in the diagrams below.
The pipe (pos. 1) and the coupling or any other connecting element (pos. 2) are simultaneously mounted on the heating elements of the welding machine.
A pair of the required diameter is coaxially installed on the working heater itself, consisting of a metal sleeve (pos. 4), into which the pipe will be inserted, and a mandrel (pos. 5), on which the necessary connecting element is put on.
During the heating period, a belt of molten polypropylene is formed along the outer surface of the pipe and the inner surface of the coupling, approximately the same width and depth (pos. 6). It is important to choose the right warm-up time so that the melt process does not capture the entire wall of the pipe through and through.
Both parts are simultaneously removed from the heater, and coaxially, with force, are connected to each other. The molten plastic outer layer of polypropylene will allow the pipe to fit tightly into the sleeve until it stops, for the length of the heated section.
At this stage, the process of polyfusion, cooling and polymerization takes place. As a result, a reliable connection is obtained, which, although shown in the diagram by a shaded area (pos. 7), but in reality, if you look at the section, you can’t see it at all - it’s almost a monolithic wall.
- Butt welding is done a little 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 so that they fit perfectly together.
Pipes are pressed from both sides with a facer - a rotating disk (pos. 2) with precisely set knives (pos. 3)
The pipes are again pressed to the center, and at the ends, for the entire thickness of the wall, polypropylene melting areas are formed (pos. 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 it is only at first glance. With this welding technology, the most accurate alignment of the mating parts is of decisive importance. In addition, in sleeve welding, the required degree of compression of the mating melted areas is provided to a greater extent by the difference in the diameters of the parts. In this case, the application of a significant external force is required, directed strictly along the axis of the connected pipes. All these conditions can be met only when using a special, rather complex machine-type apparatus.
There are many devices for butt welding, but almost all of them have a powerful frame with guides and clamps for clamping pipes of various diameters - to ensure the alignment of the connection, removable or reclining trimmer 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 probability of encountering it at the household level is practically zero.
There is also a "cold" method of welding - using glue based on a potent organic solvent. The point is that when treated with such a composition, the surface layers of the polymer soften. Parts can be connected at this time in the desired position, and since solvents are usually highly volatile, they evaporate quickly. then the process of reverse polymerization begins quite quickly.
This technology is more suitable for polyvinyl chloride (PVC) pipes that do not have the proper thermoplasticity. In addition, a similar connection method has, perhaps, more disadvantages and limitations in use than advantages, therefore it is not in particular demand, especially since there is a simple and accessible technology for socket polyfusion welding.
What is required for installation work
So, in the future we will consider exclusively sleeve polyfusion welding (soldering). To cope with this task yourself, you need to prepare a number of tools and accessories.
- First of all, it is, of course, a machine for welding polypropylene pipes. There is such a tool - not so expensive, and many zealous owners already have it in their home "arsenal".
Coupling-mandrel kits of the required diameters must be attached to the welding machine. 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 various diameters without interruptions for replacement.
If you don’t have your own device, and circumstances at the moment do not allow you to purchase it, then many salon shops 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 arranged in approximately the same way and work according to a similar principle, but they also have certain differences in layout and functionality. Useful information for those who decide on such a purchase is available in the article of our portal, specially dedicated to.
In the text, there may be a definition of an apparatus for soldering pipes - but this is just a "play on words." There is no difference between these concepts in this case.
- Pipe cutting requires special scissors. Moreover, they must be sharply honed, with a serviceable ratchet mechanism that provides a smooth cut. The blade must be free of nicks or warps.
Of course, you can cut the pipe with a hacksaw, just with a metal blade or even a “grinder”, but this is absolutely not a professional approach, since such tools cannot achieve the required accuracy and evenness of the cut.
machine for welding polypropylene pipes
- It is necessary to prepare a marking tool - a tape measure, a ruler, a building square, a marker or a pencil. To properly place the pipes, you have to resort to the help of a level.
- If you plan to solder polypropylene pipes with aluminum reinforcement, then additional tools are needed.
- if the pipe has external reinforcement, then a shaver will be required, which will clean the aluminum layer at the point of penetration.
- if the aluminum reinforced layer is located deep in the wall thickness, then the pipe still requires preliminary preparation, but in this case a trimmer is already used.
The trimmer outwardly often looks like a shaver, but there is a difference between them - it lies in the location of the knives. For a shaver, the cut is tangentially parallel to the axis of the pipe, and for a trimmer, as even their names are clear, the knife processes the butt and removes a small chamfer.
Read a useful article, and also check out the varieties and selection criteria on our portal.
We will dwell on this point in more detail when considering the technology of soldering pipes.
- Many people overlook this, but the welded sections of pipes and couplings must be cleaned of dirt, dust, moisture, and then degreased. This means that it is necessary to prepare a clean rag and an alcohol-containing solvent (for example, ordinary ethyl or isopropyl alcohol).
But solvents based on acetone, esters, hydrocarbons should not be used, since polypropylene is not resistant to them, and the walls can float
- Care must also be taken to protect the hands. They will have to work in close proximity to the heating element of the apparatus, and getting a serious burn is as easy as shelling pears.
Suede work gloves are best for this business - they practically do not restrict movements, they will not start to smolder from contact with a hot heater, and they will reliably protect hands.
And one more important warning. Most installation work can often be carried out out of place, but, for example, on a workbench in the workshop - some devices even have special brackets with clips 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 in a bath or bathroom.
In any case, wherever soldering is carried out, high-performance ventilation must be ensured. 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've tested it on my own skin. The author of these lines lay around for a day with a temperature of 39 ° after seven hours of work in a fairly spacious combined bathroom, with a seemingly well-functioning ventilation outlet. Do not repeat mistakes!
How to solder polypropylene pipes
General technological methods for welding polypropylene pipes
- First of all, the novice master must clearly understand what he is going to mount. A detailed drawing should be prepared, with dimensions and specific details indicated - the same “document” will become the basis for acquiring the required number of pipes and components.
- If conditions allow, for example, in the room where the installation will be carried out, there is still no finishing, then it is best to transfer the scheme directly to the walls - this will be more clear, and you can measure the required pipe lengths literally in place.
The key to success is to try to complete the maximum possible number of nodes in a comfortable working position, on a workbench. Working with a soldering iron directly on site, and even alone, without an assistant, is an extremely difficult task, and it is very easy to make an error in this case. It is clear that such operations cannot be completely avoided, but their number should be reduced to a possible minimum.
- The soldering iron is getting ready for work. On its heater, working pairs are put on and tightened with a screw - couplings and mandrels of the diameters necessary for operation. If it is supposed to work with one type of pipe, then there is nothing to be wiser - one pair is put on, as close as possible to the end of the heater.
There are welding machines with cylindrical heating elements - it has a slightly different fastening of working elements, like a clamp. But understanding this is easy.
- It will be much more convenient to work if the device is rigidly fixed to the working surface of the workbench. It's great if the design provides for a clamp-type screw for mounting on the edge of the tabletop. But even with a conventional apparatus, 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 screws.
Even with a fixed stand, the device can "wobble" in it - there will definitely be a backlash. Here, too, you can provide for your own fastening - drill a hole and screw in a self-tapping screw. When a soldering iron is needed for remote work, removing this mount is a matter of a few seconds.
- The soldering iron is connected to the network. If it has a temperature control, then approximately 260 ° C is set - 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 25 - already 270, and so on - on the rise. The temperature is the same, the heating time of the mating parts just changes. In any case, those tables that the manufacturer attaches in the product passport, and which will be placed below in this article, are designed specifically for this level of heating.
- Usually there is a light indication on the soldering iron. A burning red light indicates that the heating element is working. Green - the device has reached the 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 being prepared for work - the necessary piece of pipe is cut off, the connecting element is selected, according to the installation scheme.
- Not many people do this, but meanwhile the technology requires - obligatory cleaning of the connection area from possible dirt and dust, and degreasing. In addition, even the slightest droplets of water or a wet surface are completely unacceptable - water vapor can get into the melt layer, create a porous structure there, and this connecting unit runs the risk of leaking sooner or later.
- The next step is to mark up the connection. On the pipe, it is necessary to measure from the end and mark the length of the penetration zone with a pencil (marker). It is up to this mark that the pipe will be inserted into the heating sleeve, 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 matters. For example, a 90° bend is already welded on one of the sides of a pipe segment, and on the other, a tee is to be mounted, 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 put a risk across the border, on both.
There will no longer be a lot of time to choose the correct position during soldering, and such a “trick” will help to 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 should go to the mark made, the connecting element - to the stop.
— Once the pipe and connector are fully inserted, the warm-up time begins. Each diameter has its own optimal period, which should be followed.
- Once the time has elapsed, both parts are removed from the 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 effort and bring it to the same mark. Light adjustment, without turning around the axis, is only allowed for one or two seconds.
- In this position, the parts must be held, without the slightest displacement, for the specified fixation period.
- After that, the assembled unit should not experience any load during the set period of cooling and polymerization of polypropylene. And only then can it be considered ready
Now - about the main parameters that must be followed during installation. For ease of understanding, they are summarized in the table:
| The name of indicators | Pipe diameter, mm | ||||||
|---|---|---|---|---|---|---|---|
| 16 | 20 | 25 | 32 | 40 | 50 | 63 | |
| The length of the welded section of the pipe, mm | 13 | 14 | 16 | 18 | 20 | 23 | 26 |
| Heating time, seconds | 5 | 5 | 7 | 8 | 12 | 12 | 24 |
| Time for permutation 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 node, minutes | 2 | 2 | 2 | 4 | 4 | 4 | 6 |
| Notes: - If thin-walled pipes of type PN10 are welded, the heating-up period of the pipe itself is halved, but the heating-up time of the connecting piece remains the same as indicated in the table. - If the work is carried out on the street or in a cold room at a temperature below + 5 ° C, then the warm-up period is increased by 50%. |
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As for reducing the set warm-up time (with the exception of the case mentioned in the note to the table), there can be no question - a high-quality connection will not work, and the node will surely leak over time. But about some slight increase - the masters have no unity of views. The motivation here is that pipes from different manufacturers may differ slightly in material, that is, there are more rigid or, conversely, softer polypropylene. But the masters have accumulated experience, accurate knowledge of the material used, and for a beginner, the recommended indicators should still be taken as a basis.
Good advice - when buying pipes and accessories - take a small supply of the cheapest connecting elements, and conduct an experiment - training. You can prepare several pieces of pipe and perform trial soldering.
With high-quality soldering, a neat bead about 1 mm high is created around the circumference of the connecting node, which will not interfere with the free passage of water. Outside, a neat bead will also be formed that does not spoil the appearance of the connection.
pipe cutter
But overheating is already fraught with getting a defective connection. Molten polypropylene begins to squeeze inward when the parts are combined, where a “skirt” is formed and solidifies, which largely closes the passage. The pressure of water in such a water supply can be reduced, and in addition, such a defect often becomes a place of blockage over time.
Conducting such a practical lesson will help you accurately determine all the soldering parameters and avoid mistakes.
Features of working with pipes with aluminum reinforcement
As mentioned above, two options are possible here - the reinforcement layer is located near the pipe surface, or in the depth of the wall. Accordingly, the methods of preparing the pipe for welding also differ.
- It is clear that the aluminum layer located near the surface simply will not allow for a full heating and connection of the assembly. In addition, such pipes always have a slightly higher diameter, and simply will not enter either the heating sleeve or the connecting element. This means that it is necessary to clean off this layer to “clean” polypropylene.
For this, a special tool is used - a shaver. A piece of pipe is inserted into it and they begin to turn - the installed knives carefully cut off the upper polymer coating and the aluminum located under it.
Processing is carried out until the pipe stops at the bottom of the tool - the dimensions of the shaver are such that it cuts the foil exactly in the strip that is required for the welded joint at a given diameter, that is, you can even not carry out the appropriate marking.
When soldering, the entire cleaned area must be heated, and then completely inserted into the connecting part. Leaving even a thin strip of a protected pipe outside is prohibited.
- If the aluminum foil is hidden in the skin of the material, then it would seem that it does not fit in any way with high-quality soldering. But there is already another nuance here.
If the pipe is not protected from the end, then the water passing under pressure will try to delaminate it, find a way out between the aluminum layer and the outer polypropylene sheath. Aluminum, in addition, may begin to corrode, lose its strength. The result of such stratification first becomes "blisters" on the body of the pipe, which then necessarily end in a major accident.
The way out is to create such conditions that during welding the end of the pipe and the aluminum layer would be completely covered with molten polypropylene. And this can be achieved by processing with a special tool, which was mentioned above - with a trimmer.
Outwardly, it may be similar to a shaver, but its knives are located differently - they will precisely align the butt, cut the chamfer and remove a thin, about 1.5 - 2 mm from the cut, 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 mentioned, is best done on a comfortable spacious work area, assembling ready-made water supply units (heating circuits) to the maximum, and only then installing and connecting them in place.
The work "near the wall" is always more complicated, time-consuming and nervous, since one has to hold a fairly heavy apparatus with one hand, while simultaneously providing heating for both mating parts. Often, without an assistant, such a welded joint is almost impossible to perform. Therefore, it is worth minimizing the number of such operations.
But at the same time it is important not to make an oversight. 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 install a welding machine between them (plus, the heating pair also has a certain width), then carefully, without skew, insert into the mandrel and coupling, after warming up, ensure translational removal and then connection. It is necessary to foresee this moment in advance - will the existing backlash be enough to perform all these manipulations.
- It happens that inexperienced craftsmen, without foreseeing this nuance, are faced with the fact that the last weld is left, and there is no way to complete it. What to do?
The way out can be welding into a cut pipe a collapsible connecting pair - a threaded fitting and a coupling with an “American” union nut. The connection is reliable, and soldering such elements even in such difficult circumstances is no longer difficult.
- If at least some node during installation raises even the slightest doubt, without any regret it should be cut out and other parts welded in. Believe me, it will not take much time and will not entail serious costs. But if over time such a dubious area suddenly leaks, the consequences can be very sad.
- The next group of errors has already been mentioned above - this is a violation of the pipe soldering technology. This may include insufficient or excessive heating. The force applied to the parts when connecting should be in moderation. Too much compression will result in the formation of an internal "skirt". Equally dangerous is the insufficient application of force - the pipe does not enter the socket of the connecting part to the end, there remains a small area with an increased diameter and a thinner wall - a potential breakthrough!
- Do not forget about cleaning the parts to be welded from dirt and grease. Perhaps this seems insignificant, but in practice there are quite enough cases when such neglect subsequently turned into a weak connection and the formation of a leak.
- Attempts to change the position of the parts during the setting and cooling of the connection are very dangerous. Outwardly, this may not manifest itself, but microcracks appear in the connecting seam, which subsequently lead to accidents. If you don't like the connected node - "into the furnace" it, and make a new one, but don't try to change it!
- When stripping a reinforced pipe, even a tiny piece of foil should not 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 much more, especially since even branded polypropylene pipes and accessories for them are not so expensive. But there are cases when, during the installation of high-quality pipes, carried out with strict adherence to technology, the connecting nodes nevertheless began to fail over time. And the reason is simple - really high-quality material was used, but from different manufacturers. Seemingly insignificant differences in the chemical composition and physical and technical characteristics of polypropylene gave such an unexpected result - full-fledged diffusion of melts was not achieved.
Therefore, a final tip: use high-quality pipes from one manufacturer. It is probably clear that all components must also be of the same brand.
At the end of the publication - an informative video about the soldering of polypropylene pipes:
Video: the master shares the secrets of high-quality soldering of polypropylene pipes