Welding machines for polypropylene pipes. How to weld PVC pipes Do-it-yourself welding of plastic pipes

July 28, 2016
Specialization: Capital construction work (laying of the foundation, erection of walls, roof construction, etc.). Internal construction work (laying of internal communications, rough and fine finishing). Hobbies: mobile communications, high technology, computer technology, programming.

I have a neighbor (regular readers are already familiar with him in absentia), who began to make repairs in his bathroom and toilet. And since he had little money, he decided to install pipes on his own. And if he succeeded with the sewer the first time, then welding plastic pipes for the water supply caused some problems.

It seems that he has instructions, and the device he bought (and did not rent) is far from the cheapest, but for some reason the joints are not tight.

After spending some time, he again came to me for advice (by the way, we sat pretty well the last time over a glass of tea). Well, why should I refuse a good person? We sat down in the kitchen, and I laid out the whole process on the shelves for him.

By the way, in this connection there was an occasion to tell you, readers, about how to choose a machine for welding plastic pipes and how to use it correctly.

General rules

As a practitioner, I know two ways to weld plastic pipe parts:

with the help of bells;
butt

Below I will talk about both technologies, but before that I would like to mention some general rules that will help you follow the recommendations below and achieve the best connection quality:

I always carry out pipe welding only at positive air temperature. Otherwise, the technological process requires serious changes, which negatively affects the tightness and durability of the connection.

For the installation of pipelines by welding, I always buy parts from one manufacturer and one variety to ensure uniformity in the chemical composition of plastic.

In this case, when heated with the same temperature and a strictly fixed amount of time, the polymer acquires the same mobility, which provides a reliable and waterproof connection.

It is precisely the same chemical composition of the pipes, and not their color. Tinting is carried out by adding a small amount of a coloring substance to the raw material mass, which has no effect on the time of plastic melting.

And never take pipes for work whose price is too low compared to similar parts. Most likely, this is a fake and you will not be able to tightly fit the pipes into a reliable water supply.

The parts to be connected must be thoroughly cleaned of dust, dirt and grease stains.. It is the latter that greatly affect the quality of the weld. I always wipe the ends of the parts before welding with alcohol, white spirit, or another suitable solvent.

Make sure that the cloth you use does not leave fibers on the pipe (such as a bandage).

Damaged polymer is also a factor affecting quality.. Sometimes pipes lie in the sun for a long time, and ultraviolet light destroys plastic. In this case, the damaged layer must be removed with a special tool or take another part that was properly stored.
It is equally important to ensure that the pipes are dry.. They sometimes form condensation, which will not allow to weld products at the molecular level.

And the last moment that I wanted to mention at the very beginning. Joint cooling after joining should occur in vivo. If you pour cold water on it or accelerate the process using chilled air, you can achieve the opposite.

On the contrary, in some cases (for example, if the air temperature in the room is too low), you have to slow down the process by insulating the fitting with a pipe with a cloth or heat-insulating material.

Socket welding

Welding plastic pipes is the most common way to connect parts for plumbing. It is used for joining small diameter products, which are enough for the construction of in-house engineering systems.

General information

To connect polypropylene parts, so-called fittings are used - products in the form of angles, tees, bends, cranes and so on. They are made from the same type of plastic as the pipes themselves.

Previously, it was believed that additional fittings were a lack of technology for welding water pipes, but practice shows that it is in this way that an effective engineering system can be constructed without any special costs and difficulties. For example, the corners allow you to rotate the pipe 90 degrees, without any fear of reducing the diameter of the inner section of the product.

Briefly, I can describe the whole process as follows: when welding pipes in a bell-shaped manner, the surfaces of the connected elements melt (special equipment is used for this), after which they are connected, forming a strong connection with the mutual penetration of molecules.

Compared to butt welding, I consider this connection more reliable. The fact that you insert one part into another during operation provides additional strength. In addition, in this way, there is practically no need to worry about the correct alignment of the longitudinal axes of the pipeline.

What can I say, several times for the sake of interest, my wife tried to weld plastic pipes. And after a short training session, everything turned out quite easily and quite reliably.

Necessary tools

For work, you definitely need a soldering iron for welding plastic pipes. This miracle machine can also be called an iron or a welding machine.

Structurally, the tool is a heater with a special head, on which replaceable elements with couplings and mandrels are put on. The latter are just needed for the simultaneous heating of the pipe, which is inserted into the coupling, and the fitting, worn on the mandrel.

As a result, the parts warm evenly, which ensures a reliable and completely waterproof connection.

My iron is equipped with heating elements made in the shape of an elongated triangle. However, the store sells many other models. The appearance of the soldering iron does not play any practical role.

When buying, pay attention to the pipe of what diameter (maximum) you can weld using the device model you like.
And ask how many heating pairs (couplings and mandrels) can be installed at the same time.

I will give you some more tips for free that, I hope, will help you choose a high-quality and reliable tool that will be pleasant to work with:

The larger the area of \u200b\u200bthe heating element, the larger the diameter of the pipes can be soldered. The fact is that the couplings need to be screwed so that their lower part completely touches the heater, and does not protrude beyond its borders.

The power of the soldering iron does not play a role. If the working elements are installed correctly, the desired temperature will be reached in any case. And power only affects how much time you have to wait for this moment.
In some soldering irons, the heating element is made in the form of a cylinder. Such devices take up less space than classic ones. As for other technical characteristics, I personally do not see any differences.

The type of temperature sensor installed in the device is important for operation. The more accurately he reads the indicators, the better the connection will be. That is, the more high-quality welding machine you get.

It is best to choose a device with electronic control units that read the indicators most accurately and as close as possible to the working heating elements. Welding machines equipped with such sensors have a lower thermal inertia (they respond faster to changing device settings).

Capillary thermostats as well as bimetallic relays are not so accurate. They have a very large run between the value indicated on the scale of the device and the actual temperature of the heater.

Regardless of the type of relay used, I recommend that after a light bulb illuminates that the device is heating up, wait a couple more minutes for the work item to be brought into working condition.

In addition to the welding machine with the required number of mandrels, you need to stock up on other devices, without which the welding of pipes, although possible, is very difficult.

I advise you to have:

device for chamfering plastic pipes;
calibrator;
miter face;
special scissors for cutting parts;
liquid degreasing plastic surface.

Sometimes these devices are included with the soldering iron, but often they have to be purchased separately.

Welding technology

If you have accurate measuring instruments, then you can experimentally make sure that the actual diameter of the pipe is slightly larger than the value indicated in the technical documentation. Accordingly, the actual inner diameter of the fitting is slightly smaller than necessary.

For example, if you buy polypropylene water pipes with a diameter of 20 mm, then their actual size will be 0.5 mm larger. Accordingly, the fitting will be 0.5 mm less.

Dorns and couplings of the heating device have a conical surface and exactly in the middle, if measured from the edge, their diameter becomes equal to the nominal.

That is what I want to say. If you try to stick the pipe into the fitting without heating or push them onto a cold soldering iron, you will not succeed. This is done in order to ensure the maximum tight, tight and durable connection after the end of all procedures.

So, in the process of connecting parts with the molten outer layer, a small part of the plastic is squeezed out, forming the so-called burr (low roller). And the inner layers of the pipe are slightly compressed to enter the fitting.

As a result, it turns out that the heated surfaces of the fitting and the pipe slightly press against each other, displacing the air inside and providing mutual diffusion of the plastic molecules.

This is a little strayed towards the theory, which, however, you will need to understand the internal processes that occur during welding. As for the practical part, a brief list will be given in the scheme, and I will describe in detail about each stage later.

Pipe preparation

So, I will start with the preparation of the pipes. First you need to cut them into pieces of the desired length. To do this, it is best to use special scissors, thanks to which the cut will be located strictly at an angle of 90 degrees.

There are mechanical devices on sale, but if you have a huge amount of work to do, you can also find units that operate on an electrical network. Although I have used a hand torch and hands all my life, you can believe me, they did not fall off.

After this, you need to prepare the chopped pipes for the welding process. If you bought ordinary pipes, you just need to clean the end face of dirt and debris, and then degrease the surface of the plastic using special solutions.

But often, reinforced polypropylene pipes are used to design home water pipes. To do this, either aluminum foil or fiberglass is used. Such an engineering solution helps to reduce the coefficient of thermal expansion of plastic, as a result of which you do not need to install special compensators in the water supply and heating system.

Aluminum, among other things, eliminates the penetration of oxygen into water, which is very important for closed-loop climate systems (airing of heating mains is excluded).

So, if you are welding metal-plastic pipes, that is, parts with an aluminum reinforcing layer, you need to carefully clean the entire layer of foil with a shaver - a tool specially designed for this. If this is not done, you should not even dream of a tight connection between the fitting and the plastic pipe.

Glass fiber parts do not require special handling, they can be prepared for welding in the usual way.

I met pipes for sale where the reinforcing metallized layer was located not near the surface, but in the thickness of the plastic wall. Then, instead of a shaver, you need a special trimmer that removes metal from that part of the part that needs to be joined. Otherwise, water may penetrate through the reinforcing gap and cause plastic to swell.

To achieve the best result, you can purchase couplings that have a special design and are designed for reinforced pipes. In the process of soldering, plastic seals the hole with the foil, completely eliminating water leakage.

To be 100% sure of the final result, I advise you to always calibrate the pipe from the outside and chamfer from the end of the part. Sometimes the product may have a slightly elliptical shape, which is leveled by calibration. A small bevel will facilitate the installation of hot parts.

But this is my personal advice and such an operation is not provided for by the rules for installing plastic pipes.

Soldering Iron Preparation

So, with the preparation of the pipes, it’s kind of sorted out, now I’ll talk about how to properly prepare the welding machine or, in other words, a soldering iron.

First of all, the device must be firmly fixed on special legs, in the bracket or on a suitable bed. When you insert cold plastic parts to warm up, you need to make a certain effort. Therefore, in order to avoid polymer deformation, it is necessary that the coupling and mandrel are absolutely motionless.

After fixing the entire soldering iron to its heating element, you need to screw the so-called pair - a sleeve and a mandrel - the size of which will correspond to the diameter of the pipes currently being mounted.

Then you can turn on the device for warming up. After a while, it will heat up to about 260 degrees Celsius. This is much higher than the mark at which plastic gains fluidity. As a result, you can quickly melt the surface of the pipe and fitting, but do not violate the integrity of the deep layers of the part.

The end of the heating process is signaled by a light on the handle of the device (at least for me, but I don’t think that the device you bought is significantly different).

Warming up parts

Once the soldering iron has entered the operating mode, you can proceed to heating the parts. To do this, put on the mandrel at the same time and insert the fitting and pipe into the coupling, respectively. If you cannot do this at a time (lack of dexterity), first slide the fitting, it is more massive because it can warm up for 1-2 seconds longer.

All products for the installation of water supply, as I said, have a special allowance. Therefore, when putting them on the heating element, you need to apply a little effort. However, it is important not to overdo it, acting gradually.

As parts are put on, excess polymer will be squeezed out, forming a small influx (grata). If the parts for heating are installed too freely, I consider this a sign of marriage, I throw out the prepared pipe and fitting, starting the operation again. Believe my experience, a high-quality connection in this case will still not work.

It is important to feel the depth of installation of products on the heating element. As soon as the pipe rests in the bottom of the coupling, and the fitting to the edge of the mandrel - in no case need to be pressed anymore. Otherwise, you can hush the end of one part and the limiter of the other, that is, everything will have to be redone.

Some on the pipe make marks with a pencil to understand how deep it needs to be inserted into the heater. However, I can tell you with confidence that you will feel everything in the process yourself, do not bother with marks.

After installing the parts, you need to hold them on the soldering iron for a while, so that the plastic surface has time to melt a little. It is very, very important to maintain a specific period of time. If overexposed - the pipe is deformed, underexposed - the diffusion will be incomplete, the connection is leaky.

Each manufacturer of plastic pipes provides tables to navigate. As an example, I will give approximate parameters for PN20 polypropylene pipes.

You need to note the time from the second you push the parts all the way. As soon as the right amount of time has passed, the products must be removed at the same time, also applying a certain, but not excessive force to this.

Assembly parts

After warming up, without delaying for a second, you need to start welding. To do this, the pipe must be inserted into the fitting. And to do this no later than 5 seconds after the end of the heating process. Otherwise, the plastic will cool too much. You either can’t assemble the pipes at all, or the end result will be very far from ideal.

It is very important not to rotate parts relative to the longitudinal axis during assembly. The maximum displacement should not exceed 5 degrees. Otherwise, the tightness and strength of the assembly will also be violated.

The correct work will be indicated by the influx of plastic (grata), which is formed near the junction. It should be the same height around the entire circumference of the part.

Cooling parts

After connecting the parts, they must be left for a while, so that the polymer freezes. This will take only a few seconds, during which they can not be touched.

However, I recommend that you allow about 2 minutes to cool. During this time, the diffusion process will be completely completed and you can not worry about the strength of the node.

Butt welding

In addition to the socket welding of plastic pipes, which I described in detail above, the so-called butt is used in construction. Its essence lies in the heating of the sections of polymer parts with a special device (mirror) until melted, followed by connection under pressure to form an airtight seam.

The technology of the work is quite simple. The result is a very strong, tight and durable seam.

However, this is only at first glance, since I, as a person who understands this matter, can point out several features.

It is necessary to ensure a very accurate alignment of adjacent parts along the longitudinal axis. The walls of the pipes after the end of the process should coincide with each other by at least 90%.
When welding, a certain force must be applied to the products, pressing the part against the welding mirror. Then exactly what you should do during the hardening of the seam.
When cutting parts and processing the end face, it is necessary to carefully ensure that the cut is located at an angle of 90 degrees to the wall.

Everything here is quite simple, but only if you use a special device, the centralizer, which is equipped with a special drive that provides downforce. A pipe cutter and a crosscutter are also needed.

Therefore, for the installation of home water systems, where small diameter pipes are used, and the scope of the work is small, socket welding is used. Moreover, I tell you, the resulting compounds are almost stronger and more durable. In the latter case, a kind of castle is formed, which in no case will let water through.

Butt welding is more often used in the design of large trunk systems.

Common mistakes at work

Now you know everything that I could tell you about welding plastic pipes. I just want to dwell a little on the typical mistakes made by novice craftsmen when welding pipes. It was they who did not allow my neighbor to do the job well the first time.

Contaminated and wet parts

Any experienced craftsman, to which I dare include myself, always wipes the end of the pipe and the inside of the fitting before starting to solder. This is done already at the level of reflex. The fact is that during repair all parts are usually dumped on the floor, which is hardly clean. Sometimes I had to dismantle incorrectly assembled pipes, and so, there usually always was a strip of dirt or dust.

Another worst enemy is moisture. Even a drop of condensed water evaporates when heated, which causes the compound to deform. By the way, I came across cases where such a “wet” connection withstood even preliminary tests, but cracks still appeared during operation (in my case, after 5 months).

And once again I will remind about the foil. Not a single piece of metallized layer should get into the compound, since reliability can be completely forgotten.

And further, not only pipes, but also the working element of the soldering iron must be cleaned of dirt. Sometimes traces of polypropylene remain on the sleeve or mandrel. They also need to be cleaned with rags before you solder the next node.

Incorrect placement

Once you have finished heating the pipe, you need to connect them immediately. And not just stick the part into the fitting, but correctly position it in relation to each other. This is where novice welders have problems.

Often after the junction, beginners begin to rotate the products or move them relative to each other, which is by no means necessary.

Another point. It is not necessary to remove the swaths of plastic near the fitting before the connection cools down. Otherwise, you can easily deform the node, which will lead to depressurization. By the way, if you heated the pipe exactly as much as indicated in the accompanying table, you will not have any flooding.

Substandard material

Very often, a welded joint fails if you saved money and bought low-quality polypropylene pipes from an unknown manufacturer. I have encountered similar situations. So, even my experience did not help me properly weld such parts.

therefore you need to purchase materials only in a trusted store.

Some more "smart guys" are trying to solder pipes from different manufacturers. I already mentioned this. The unequal chemical composition does not allow the plastic to warm up correctly, which leads to violations of the technology.

Build violation

Here I will give those violations that I most often met in my practice:

When assembling the assembly, the pipe is not fully inserted into the fitting, as a result of which a gap is formed inside. That is, the pipe wall will be thinner than specified by the technical conditions and when a force is applied (for example, water pressure), the part may burst in this area.

During assembly, excessive force is applied to the pipe that is inserted into the fitting. As a result, a plastic melting on the cut, which reduces the internal section of the pipe or completely fuses the hole. Both that, and another negatively affects work of a water supply system.
Use when assembling damaged fittings. For example, you collect a pipeline and you have only one corner fitting left, and a crack is revealed on it. Instead of going to the store and replacing it, careless masters install it in the system. I will not describe the consequences.

Output

As you can see, welding plastic pipes with your own hands is not as difficult as my neighbor imagined. If you want to consider the process itself in more detail, you can check out the video in this article. I will also be glad if you share your own tips and stories about how you soldered plastic pipes. You can do this in the comments on this article.

July 28, 2016

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Today, more and more often plastic pipes are used for the installation of water pipes. This is due not only to their durability, but also to good performance properties. Due to the high thermal parameters, they are excellent for supplying hot water. To connect them together, gluing, crimping with couplings and welding are used. The latter species is considered the most preferred. But in this case, we need an apparatus for On how to choose it, we will talk in this article.

A little about welding features

It can be mounted in the system using several types of welding: butt, socket and socket. If you have no desire to purchase couplings and fittings, then you need to choose the butt connection method, since it is considered the most economical. Of course, you will need a pipe apparatus. The principle of operation of the unit is similar to a soldering iron, so it is sometimes called just that. The device is necessary for heating the connected ends of the pipes. Docking is implemented in several ways. The most popular is contact-butt. Its essence is to connect the molten ends under pressure. The strength of the seam in most cases is not inferior to the strength of the pipe. The main condition is to ensure high temperature, so the selected soldering iron should be heated to 250-260 degrees Celsius.

Apparatus for welding plastic pipes: manual or mechanical?

We all know that welding equipment provides by heating the machined surfaces and their further connection. It is worth paying your attention to the fact that welding equipment for metal products and plastic have a number of features and design differences. Units for working with polypropylene can be divided into two large groups:

mechanical equipment - used to create permanent connections of large diameter pipes, as well as where it is necessary to apply great effort;
a manual welding machine is an ideal solution for use in domestic conditions (using this unit you can connect pipes whose diameter does not exceed 12.5 cm).

Details of mechanical equipment

If you are going to earn money on welding, then you definitely should give preference to a professional model. Most of the mechanical equipment for connecting polypropylene pipes is designed for intensive use, unlike manual units. The device is a support frame on which the instrument block and hydraulic unit are located. On both sides of the device there are half rings with grips. Between the grippers install liners, which are necessary for uniform distribution of pressure during connection and alignment. The inner diameter of each liner corresponds to the diameter of the processed pipe. The working body (heating element) is a cast disc with a special coating. Inside it are the heating elements. It is worth noting that the welding of plastic pipes takes place with temperature control. Any professional welder has such an assembly, but this does not mean that he does not have a manual apparatus. This is due to the fact that this device is better suited for large diameter pipes.

Iron, or manual machine for welding plastic pipes

Most of us choose to perform one-time jobs. Of course, in the future this tool will come in handy, but it is unlikely that it will be intensively used. The device is called an iron for a reason, because by the principle of operation it resembles precisely this household appliance. The main differences are only in design. The design implies the presence of a heating plate and a temperature regulator. For the comfort of the work performed there is a special handle. At the end of the heating plate there are two holes in which the two ends of the pipes are inserted. The Teflon coating prevents the molten pipe from sticking to the plate.

Pay attention to the product structure.

When buying a product, it is extremely important to pay attention to the configuration in which it is provided. It all depends on the manufacturer's company, however, you can highlight the main elements that must be present.

If you are going to work with pipes of one, a maximum of two diameters, then the set, in addition to the unit, can only include a key for nozzles. Again, this is a very modest configuration, which is not always suitable. If you are an amateur, then it is better to give preference to a set where there will be nozzles for working with polypropylene pipes of the following dimeters: 20, 25, 32 and 40 mm, which are the most common.

There is also a complete set. This option is the most expensive, so it is very popular only among professionals. If you are an amateur, then this equipment is unlikely to be useful to you. Well, now we will go directly to the criteria by which you need to buy a tool.

Equipment power

Of course, the apparatus for welding plastic pipes should be quite powerful. This parameter determines not only the maximum possible machined diameter, but also the speed of the work. Based on this, we can conclude that the larger the estimated amount of work, the higher the power required.

In many cases, an average power tool of 1.5-2.0 kW will be sufficient. But in most cases it is advisable to use a slightly different approach. It consists in the fact that the diameter of the processed pipe is multiplied by 10. As a result, you can get the minimum required power of the equipment. In this case, the welding of plastic pipes will take place, without any problems. It turns out that if you want to solder pipes with a diameter of 50 mm, then 50 x 10 \u003d 500 watts. But it is strongly not recommended to buy a low-power tool, it is better to take with a margin of 20-40%.

Manufacturer's choice

When choosing, it makes sense to pay attention to the company that produces welding equipment. It is worth noting that plastic welding is a very important task, and the condition of the joint and its durability will depend on the quality of the tool.

To date, the best soldering irons are made in the Czech Republic by Daytron. Equipment from this manufacturer has earned worldwide recognition. Distinctive features: high quality and wide functionality. It is worth noting that a soldering iron for welding plastic pipes from the Czech Republic costs a lot, so Turkish products will be a good alternative. For example, the Kandan welding unit is designed to work with pipes with a diameter of 16-160 mm. Moreover, the quality is very good, and the price is acceptable.

Conclusion

That, in principle, is all that can be said about the choice of equipment. Remember that welding plastic can cause burns. For this simple reason, when you purchase equipment, instructions are attached to it. If this was not included in the kit, then consult with professionals or experienced welders. They will tell you how to weld plastic pipes. The instruction, however, is nevertheless desirable and should be read in any case, and all the requirements given there should be followed. Do not forget about it. And all will be well.

The word welding for many is associated with sparks and bright light. Yes, this is true when welding metal structures, but today we will consider a completely different welding - plastic pipe joint using a welding machine.

I don’t know how anyone, but when I was repairing it on my own, with the advent of plastic water pipes and this welding technology, the mountain just fell off my shoulders.

If someone remembers how difficult it was to make the water distribution in the bathroom with metal pipes or to tie them up, he will understand me. It was required not just a welder, but a very qualified welder, able to cook very cool and high quality.

With the advent of this technology, everything has become much simpler and anyone can do it.

Consider plastic pipe joint on the example of the most popular material - polyvinyl chloride using an apparatus for welding plastic products. The main components of the installation are pipes, fittings and the welding machine itself.

Of the necessary tools we need

1. The welding machine for welding plastic parts (in common people nicknamed the iron).

It is a heating element with a handle and stand, allowing you to cook in any position. It has an adjustment wheel, which makes it possible to set the required heating temperature, stand and holes in the heating element, which allow fixing nozzles of the desired diameter.

2. Paired nozzles coated with teflon.

They are attached to the heating element and serve to simultaneously heat two welded parts. Depending on the diameter of the elements to be welded, the same diameter and nozzles are installed.

These are special reinforced scissors with which plastic, in fact, bites. The lower jaw supporting - motionless, the upper - sharpened, descending to the bottom and making a cut. Cutting scissors allow you to cut very accurately and quickly.

4. Stripping tool (if pipes reinforced with aluminum are welded).

They are a head with well sharpened knives, during rotation of which the upper reinforcing layer is removed. The depth of stripping to the stop in the head determines the welding depth.

With frequent welding, it will be rational to purchase a complete welding kit, sold in a briefcase. The average price in 2012 ranged from 2000 to 3500 rubles.

The kit includes the following items:

A heating element;
Four sizes (20, 25, 32, 40 mm.) Nozzles with teflon coating;
Scissors for cutting;
Bolts for attaching nozzles to a heating element;
Level;
Stand for heating element;
Hexagon for tightening bolts.

If welding is performed one-time, it will be more rational to rent welding equipment (in 2012, the price ranged from 250-350 rubles per day).

Consider the process of joining plastic pipes or their welding

We prepare the welding machine:

We set the temperature 260˚;

We fix paired nozzles (if connections of different diameters are used, we install several pairs of nozzles);

We warm up the device to the desired temperature (when the operating temperature is reached, the indicator lamps light up).

2. Prepare the pipe and fitting:

Degrease the welding spots (if the pipe is reinforced, remove the top layer of aluminum);

We measure the required length of the workpiece and cut it to the desired size;

Mark the alignment on the elements to be welded with a marker for the correct location of the fitting relative to all other water supply structures.

We measure the depth of the nozzle into which the pipe will enter and mark this size minus 2 mm.

Step 1. We take a pipe in one hand and a fitting in the other and at the same time insert them into the nozzles.

Fitting to the stop, the pipe along the previously marked strip (not to the stop, otherwise the end will warm up and when connected, an influx of the inner diameter will form) and we stand for a certain time (column heating time, sec). The specific holding time depends on the diameters of the products to be connected and is indicated in the table below. When heated, the rotation of parts on Teflon nozzles is unacceptable.

Outer diameter mm	Width of the welded belt, mm.	Heating time, sec	Connection time, sec.	Cooling time, min

Step 2After warming up the parts, we connect them together, maintaining coaxiality and observing our marks for the correct orientation of the fitting relative to our welded structure. We enter the pipe into the fitting and very smoothly, without rotation, we make the connection. The connection time should not exceed the time indicated in the table for the selected diameter.

Step 3. We fix the welded assembly until the material has completely hardened for the time indicated in the table (column, cooling time, min.).

When working with any kind of tubular products, inevitably there is a need for connections between them. Plastic PVC pipes are no exception, one of the main connection methods between which is the welding process.

Welding PVC pipes is not particularly difficult, but in order for the connection to be reliable and durable, it must be carried out in accordance with the instructions and recommendations of qualified specialists.

Varieties of methods for welding PVC pipes

There are several different options for welding polyvinyl chloride pipes, the features of which should be familiarized with before you cook PVC pipes:

"cold welding;
butt welding;
socket welding;
electrofusion welding.

"Cold welding

This method of joining PVC pipes is characterized by maximum ease of implementation. The term "welding" is applied to it very conditionally: in fact, it is a bell-shaped adhesive joint. In order to carry it out, special varieties of glue for plastic materials are used. Regardless of the brand of such an adhesive, it always contains a base of polyvinyl chloride itself, dissolved in cyclohexanone, tetrahydrofuran and methyl ethyl ketone (read: ""). When the glue dries, the solvents evaporate, after which the polymer structures of the PVC pipe material and the glue are intertwined. This leads to the formation of a durable complex with a solid structure.

In order to achieve maximum compound efficiency, various additives are also added to the adhesive. Their use makes it possible to adjust the viscosity of the adhesive mixture and the curing time of the compound.

Usually cold welding of PVC pipes can be carried out at temperatures of +5 - +35 ˚С, however, there are frost-resistant varieties of glue that allow installation even at -17 ˚С. In summer, manipulations should be performed as soon as possible so that the glue does not dry out ahead of time.

Stages of work performed:

A pipe section of the required length is cut off.
The chamfer is removed at an angle of 15 °.
The connected pipe sections are thoroughly cleaned of any dirt and dust.
The glue is evenly applied by brush on articulated surfaces.
The pipe is quickly inserted into the socket and rotated 90 ° to ensure even more even glue distribution.
The connected elements are fixed for about half a minute, motionlessly held by hands.

All manipulations after applying the glue should take a total of no more than one minute, since the glue dries in about this time. However, for the complete formation of a reliable monolithic compound, it takes from several hours to 1-2 days. The greater the planned working pressure in the pipeline and the lower the ambient temperature, the longer should be the waiting time, at the end of which the plastic pipeline can be considered ready for use.

Butt welding

This is one of the popular methods of joining between polymer pipes, however, this method is used less often for PVC pipes than for products from other polymers. This is due to the fact that the time allocated to the welding process in the case of plastic pipes is very limited and is calculated in literally seconds. In order to manage to do everything correctly in such a short period, considerable skill in work is required, which not everyone can boast of.

Butt welding requires a special manual welding machine for PVC pipes and nozzles. The pipes themselves are cut with special scissors before joining, which should have good sharpness (otherwise cutting leads to deformation of the walls of the products).

Butt welding stages:

The pipes are cut into pieces of the required length.
The ends of the pipes are cleaned of dirt and grease.
Marks are applied to the pipes and they are trimmed with chamfering.
The connected sections of products worn on the welding machine are heated to the desired temperature (for products made of polyvinyl chloride it is +250 ° C).
Welded products are quickly connected to each other.
The resulting structure is cooled, and after a short time is ready for operation.

Socket Welding

The method of socket welding is one of the most popular when connecting pipes made of polyvinyl chloride. Accordingly, information on how to weld PVC pipes in this way is of considerable interest.

The use of socket welding involves connecting pipe products to each other through fittings: couplings, tees, adapters, etc. The great advantage of the method is its simplicity. At the same time, a certain disadvantage that impedes the even greater use of socket welding can be considered some high cost of equipment.

In general, the working process boils down to the fact that the ends of the pipe and couplings, being inserted into the welding device, are heated to the required temperature. After that, upon reaching the required ductility, the products are removed from the device, and the pipe is inserted into the coupling hole, being held until hardening with the formation of a monolithic connection. Then, in exactly the same way, the other pipe to be joined is welded from the opposite side.

As you can see, the process of such welding as a whole is quite simple, however, to achieve the strength of the structure, certain rules must be observed:

Begin and end the heating of the pipe and coupling should be done simultaneously.
The pipe and coupling must be fully fitted on the heating parts.
Upon completion of heating, the pipe and coupling are quickly removed from the device, and then connected so as to close the influx of polyvinyl chloride pre-made mark the depth of the connection.
Even the smallest angular deviations should be avoided and the products should be positioned along the same axis during welding.

The method of socket welding of PVC pipes is very convenient, reliable and simple, but due to the fact that the equipment for its implementation is not available in every house, for the most part it is used by craftsmen in arranging pipeline lines in residential buildings.

Electrofusion welding

This method of connection between PVC pipes is the most high-tech. For its implementation, special plastic couplings equipped with built-in spirals are used. Spirals perform the function of heaters when voltage is applied to them, melting plastic around.

The advantages of such welding are speed, simplicity and reliability of installation. At the same time, its disadvantages are a certain high cost of equipment and used parts, as well as the fact that the method is not applicable to products with a wall thickness of more than 4 millimeters.

Before starting the welding process, the pipe ends to be connected and the adjacent areas should be thoroughly cleaned of dirt, dust, moisture and grease. Then the chamfers are removed from the ends, after which the pipes from both sides are inserted into the fitting. Next, voltage is applied to the coupling spirals, which, when heated, melt the plastic of the coupling and pipes. In addition to the spirals, the clutch is also equipped with a special barcode with embedded technical information, so that when the desired temperature is reached, the power automatically shuts off.

It is undesirable to carry out the process of electrofusion welding at an ambient temperature below +5 ˚С, since this is accompanied by an extension of the heating time and shortening of the cooling period. The result is the fragility of the obtained compound and its low quality.

What you need to know when welding plastic pipes

One of the common mistakes in some types of welding of PVC pipes (butt, socket) is the introduction of the pipe not all the way, which leads to the formation of gaps in the connection and the violation of its tightness. To avoid this, more force should be applied when connecting the pipes to be joined.
At the same time, excessive force is also undesirable and can lead to pipe deformations with poor connection quality. This should also be avoided, and force should be applied in compliance with the measure.
For a "cold" connection, it is recommended to purchase high-quality brands of glue from well-known manufacturers, for example Griffon (Holland), CH (Spain), Gebsoplast (France), Cepex (Spain), Tangit (Germany) and others. Despite the higher price of such products, the reliability and quality of the connection are sufficient compensation for the costs incurred.
Different types of welding equipment may have some differences, and therefore, the instruction for their operation should be carefully studied in advance, and then carefully observe it.
Work must be carried out scrupulously and responsibly, without neglecting such nuances as accuracy of marking, compliance with the speed of work, strict arrangement of products on one axis, etc. Only in this case can you get a reliable and high-quality connection that can perfectly last for many years without problems and complaints.

During the construction and repair of heating systems, hot and cold water supply, steel pipes are increasingly replaced with plastic pipes. This is understandable, for their installation does not require high qualification of the welder, anyone can handle the installation and connection.

The process is clean and fireproof compared to welding metal pipes. Among plastic, polypropylene pipes are most popular for their consumer properties. For welding such products, special apparatuses are used.

Polypropylene pipes have a low cost, a large range, various connectors and locking devices are sold to them, which makes it possible to build engineering networks of any degree of complexity in the shortest possible time. This allows you to use a special welding machine for plastic pipes.

Some of its species are of high cost, but they are designed mainly for large diameters. For the installation of internal engineering networks of most residential buildings, pipe welding equipment is available for sale at a very attractive price.

Polypropylene has thermoplasticity. When it is heated to its melting point, it passes into the liquid phase. After cooling, it hardens, while retaining all its strength characteristics.

If certain sections of preforms made of polypropylene are heated to the melting temperature, and then they are pressed against each other by molten sections, then diffusion of the molten layers will occur.

If you fix the parts and wait until they cool, then the result is a new monolithic product. It is impossible to see the junction of parts at the cut. These properties of plastic are successfully used in apparatus for welding polypropylene pipes.

The most common are:

socket or socket welding devices;
butt welding devices;
electrofusion equipment.

The last two varieties are expensive, they are much more expensive than bell-shaped devices.

Butt joint

The peculiarity of the operation of the butt welding apparatus is as follows. Polypropylene products must be of the same diameter and thickness. The ends of the pipes should be perfectly cleaned and fit snugly against each other.

They must be coaxial and able to move along the axis under the influence of muscle efforts of a person, electrical or hydraulic forces.

Technology

First, the joined ends of the polymer pipes are simultaneously heated to the melting temperature of the plastic, then tightly connected.

The molten plastic from different parts interpenetrates when compressed. In this position, the pipes are fixed until the molten polypropylene layer is fully polymerized. The result is a monolithic one-piece connection.

The process looks very simple, as it is when working with pipes of small diameter. But when using polypropylene products of medium and large diameter, technological equipment is required.

Only with it it is possible to ensure the required cleanliness and accuracy of the ends, alignment, the necessary pressure to connect the joint.

Equipment

Butt welding machine in private housing construction is rarely used, except for the installation of external engineering networks.

Outwardly, it looks like a machine tool. It has guides along which pipe clamps move. They have a screw or worm gear. To fix polypropylene pipes of different diameters, sectional inserts are attached to the clamps.

In addition, the electromechanical trimmer, which is a two-sided circular knife, is included in the equipment set. It simultaneously cleans the ends of the pipes to be joined.

The cutter is usually mounted on a hinge, but it can also be removable. There are two hinges, on the second there is a flat round heater. If it is one, then there is a fixture for fasteners. Hinges are also mounted on rails.

After trimming the polypropylene pipes, the miter leans back and moves to the side along the guides.

In its place, the heater moves and is installed between the joints. The pipes should snuggle against it, but without effort. Then the joints are heated to a predetermined temperature.

The last step is the compression process. The heater is removed, the products are shifted towards each other along the guides ensuring their alignment. The required pressure is created mechanically through a worm gear, or hydraulic.

Butt welding equipment is expensive, it is used in the construction of medium and large diameter trunk plastic pipelines.

Electrofusion equipment

The technology of electrofusion welding is as follows. In each coupling at the production stage from the inner surface, a heating element is laid with two leads on its outer surface.

The connected pipes are inserted into the coupling. With a special cable, the terminals of the coupling and the welding machine are connected. After this, the element inside the coupling is heated.

Due to this, a portion of the polypropylene pipe and sleeve is melted in the region of the heating element. When the device is turned off, reverse polymerization of the connected parts of the product occurs. As a result, a monolithic compound is formed.

They can work with products of almost any diameter. They can weld polypropylene pipes, as well as products from low pressure polyethylene (HDPE).

The main element is a microprocessor unit with a regulated power source. It saves the welding protocol for monitoring operation and generates the necessary current to obtain the required heating temperature.

At a given time, depending on the diameter of the product and other conditions, he turns off the device. The device can work in open areas in the temperature range -20 ... + 60 ° C.

For example, the Rothenberger ROWELD ROFUSE PRINT device with low weight and dimensions (a small box weighing about 20 kg) allows you to connect HDPE and polypropylene pipes with a diameter of up to 1200 mm.

Data on them can be entered manually or read from a barcode installed on the pipe by the manufacturer. Using the device is easy, it comes with detailed instructions.

Socket and coupling technology

The technology of socket or socket welding was most widely used in the fusion of small-diameter polypropylene pipes, which are mainly used in housing construction.

The essence of the welding process is to heat the outer side of the pipe and the inner part of the coupling to the melting temperature and the subsequent introduction of the product into the coupling.

During cooling, polymerization occurs and an inextricable compound is obtained. The outer diameter of the pipe slightly exceeds the inner diameter of the coupling, in the cold state it is impossible to connect them.

When they are heated to the required temperature, then enough human effort. The device is very simple. It is an electric heater with nozzles and a temperature controller.

The most widely used are devices with a xiphoid and cylindrical heater.. A set of equipment usually includes a set of nozzles, a cutting tool and a device for installing a heater.

The device has a handle with temperature control and a heating indicator. A network cable is usually connected through a handle. The nozzles are mounted in pairs on a cylindrical heater and can be installed at any angle.

There is a heater in the cylinder, which allows you to evenly warm up all the nozzles mounted on it. On the xiphoid heater, nozzles are mounted on both sides.

Welding device selection

Due to the abundance of the equipment offered, the question arises, which welding machine to install polypropylene pipes to choose?

There is no need to chase power or versatility. You need to determine for yourself with what diameters you will have to work in the foreseeable future. In the vast majority of cases, these are products from 16 mm to 50 mm.

Based on this, nozzles for welding polypropylene pipes are also chosen. The choice of power of the device is carried out at the rate of 10 W per 1 mm of pipe diameter, it is enough to have 500-800 W, it is enough to work with any products used in individual construction.

Sometimes it is required to combine something from a sheet polymer, for example polyvinyl chloride. In this case, a special one is used, if not, then an ordinary electric soldering iron.

For welding products of complex design and thin-walled pipes of large diameter, hot air guns and are used. They are indispensable in hard-to-reach places where it is impossible to arrange traditional apparatus for pipe welding.