How to weld a HDPE pipe

Do-it-yourself welding of HDPE pipes: electrofusion, socket and butt welding, work procedure and quality control

To install a gas pipeline or water supply system, you can use pressure elements made of polyethylene. Welding of polyethylene pipes is used to connect the main line into a single whole.

Recently, polyethylene pipes have been increasingly used for sewerage and water supply systems. The popularity of the material is largely due to:

• Practicality, or rather, strength and ductility.
• Resistant to temperature changes.
• Tolerance to aggressive environments.

PE pipes can be connected into a single pipeline in a variety of ways, depending on specific conditions:

• The socket method using couplings and fittings is used to install an internal water supply system in a house.
• HDPE butt welding is used for installation of external communications, for laying a pipeline on top of the ground or immersed in a trench.
• using electric couplings. The coupling is a plastic device with built-in spiral elements that heat up when current is applied.

Recommendations

For personal use, you can purchase a special soldering iron for joining polyethylene materials. To obtain smooth , tight and high-quality connections, the following rules must be followed:

• Verify the authenticity of the certificate of conformity. If you purchase low-quality products, you may end up with a leaky structure.
• Compare the internal diameters of each pipe - they should be identical.
• Before carrying out welding work, clean all parts from dust and dirt and degrease them.
• Welding work must be carried out only in a dry room at normal air temperature, without drafts. It is not recommended to carry out welding at high air humidity.
• In order for the pipeline to be sealed, it is necessary to avoid even slight movement of the line until the welding areas have completely cooled.
• The welding seam must be protected from direct sunlight.
• In order not to break the tightness of the pipeline during the welding process, it is recommended to close the opposite ends of the pipes from cold air.

Socket welding

This type of welding is used for HDPE pipes with a diameter of up to 63 millimeters, using couplings and fittings. You can use a manual welding machine. Pipes with large diameters are fastened with industrial devices.

First you need to purchase the required number of couplings and fittings, as well as several components in case of defective work. You will also need a tape measure and a pipe cutter .

Welding work is carried out in the following sequence:

• Place the welding machine on a flat surface and securely fasten it. Nozzles of the required diameter are secured using a special key on the heating surface. Set the temperature on the device required for operation - not lower than 230 degrees.
• Elements prepared in advance for welding are placed on nozzles and held until the plastic is completely heated. Typically it takes no more than seven seconds.
• After warming up, the elements are connected all the way and wait in this state for about 10 seconds. You cannot move elements, otherwise they may change their position.

After welding, the internal lumen pipe becomes smooth in the seam area and sealed.

You should not heat the elements for too long so that the plastic does not take on the shape of an accordion. Such an element will be unsuitable for installation due to a leaky connection.

Excess plastic from the surface of the Teflon nozzle should be removed with a wooden spatula after each welding procedure. Otherwise, it will interfere with the procedure for fastening parts. It is prohibited to remove plastic from the Teflon surface with metal products - this may damage the nozzles.

Butt method

Using special equipment with a hydraulic or mechanical drive, it is possible to carry out complete, hermetic butt welding of polyethylene pipes.

Modern devices are equipped with software control. Such machines are used in production for large volumes of work and allow you to automate the process without resorting to human effort.

Before carrying out work, it is necessary to prepare materials with the same technical characteristics - preferably from the same batch. Such pipes will be more airtight due to welding of the polymer at the molecular level.

The process involves heating the ends of the pipe on a special plate. After welding the ends, the plate is removed and the elements are mechanically compressed until the polymers are completely mixed and soldered. The materials are then left stationary until completely cooled. Please note that after welding the pipe decreases in length by several millimeters, so you should purchase material with a small margin.

Using electric couplings

This method is used for sources with different diameters and wall thicknesses - for the installation of sewer systems. It is indispensable for working in confined spaces.

The method is one of the most expensive, but materials connected in this way can be used under pressure of 16 atmospheres. Docking is carried out using a special coupling with spiral elements:

• The materials are prepared with mandatory cleaning of dirt and degreasing of the welded surface both inside and outside. It is advisable to use wipes soaked in alcohol.
• During mechanical cleaning, the source materials should be cleared of production oxide. To ensure a tight connection, it is necessary to trim the edges of the welded surfaces.
• An electric coupling is put on the joints of the source materials and placed in the positioner for connection. It is advisable to cover the opposite sides with your hands, plugs or other available materials to prevent heat loss.
• Connect an electric current to the terminals of the electrofusion coupling and heat the materials until they are completely connected. Leave everything until it cools completely and the welding is secured.

Quality checking

Although this process is not particularly difficult, it requires careful control. The seam may turn out uneven due to the high viscosity of the polymer when melted, so the master must carefully check each connection.

The resulting seam should not be excessively convex or sunken . The surface of the seam should remain relatively flat around the entire circumference.

A seam displacement of 10% of the pipe wall thickness is allowed, a convexity of about 2.5 millimeters with a wall size of 5 millimeters. A convexity of 5 millimeters is acceptable for a pipe with walls up to 20 millimeters. Monitoring the work being carried out will make it possible to lay out a highway that will serve for a long time.

Source: https://tokar.guru/truby/rabota-s-trubami/kak-samostoyatelno-svarit-trubu-pnd.html

Do-it-yourself welding of HDPE polyethylene pipes

Polyethylene pipes for water supply systems are increasingly being used due to the properties of the material.

The main characteristics of polyethylene are plasticity, strength, resistance to aggressive environments (for tubes made of low-pressure polyethylene HDPE) and inertness to temperature changes.

That is why pressure polyethylene elements are suitable for installing the external part of a water supply system or gas pipeline of a private house. And to connect the main line into a single whole, welding of polyethylene pipes is used.

How to connect pipe elements made of PE (polyethylene) with your own hands is discussed in the material below.

Types of PE pipe connections

Polyethylene pipes can be connected into a single pipeline using different methods. Moreover, each of them is suitable for specific conditions.

• Thus, joining HDPE tubes using fittings and couplings (socket welding) is used mainly for constructing the internal part of the water supply system in the house.
• DIY pipeline installation using butt welding. This method is used for installing an extended section of outdoor communications. In this case, pipes can be laid both on the surface of the soil and in a trench, followed by covering them with soil.
• Electrofusion welding. This method of connecting HDPE tubes is done using special plastic couplings with spiral elements built into them, which heat up as a result of the supply of current to it.

Let's take a closer look at each of the methods.

Recommendations for proper welding of PE pipes

Polyethylene pipes can be welded using special equipment called a soldering iron. At the same time, there are a number of certain rules that will make the connection of elements smooth, high-quality and airtight.

The requirements look like this:

• Before carrying out work, it is worth studying the HDPE characteristics for each pipe and verifying their compliance from certificates. Otherwise, the tubes simply will not fit together into a single sealed structure.
• The internal lumen of the tubes (diameter) must be identical for each cut intended for installation of communications.
• Before welding with your own hands, the ends of PE pipes must be cleaned of dust and dirt, and also degreased.
• The welding procedure should be performed only in a dry, heated room, in which drafts and high humidity are excluded.
• After joining two PE elements, any movement of the line should be avoided until the pipeline has completely cooled in order to prevent disruption of the communication lumen.
• In addition, it is worth protecting the welding seam from direct sunlight.

Important: the ends of the tubes, on the opposite side from those being welded, should be securely closed to prevent cold air from entering the lumen. Low temperatures can disrupt the welding technology of HDPE pipes.

Socket welding (socket)

Connecting pipes using couplings and fittings is shown for HDPE pipes with a diameter of up to 63 mm. For these purposes, use a hand-held household soldering iron (welding machine). PE tubes of larger diameter are welded using an industrial mechanical apparatus.

Important: before performing socket welding, you must stock up on the required number of fittings plus a small reserve in case of defects in the work.

To carry out socket welding, in addition to a soldering iron, you need to prepare a pipe cutter and a tape measure.

The work of welding HDPE tubes is carried out in this way:

• The welding machine is installed on the platform and securely secured. Nozzles of the required diameter are attached to the heating surface using a special wrench. The welding machine is set to the desired temperature. For pipes made of PE (polyethylene) it should be 220-230 degrees.
• The parts prepared for welding are put on nozzles and held until the plastic is thoroughly heated. As a rule, this is 5-7 seconds.
• After the parts have warmed up, it is necessary to slowly but fully connect the two elements and hold them in this state for at least 10 seconds so that the fitting and pipe do not change their welded position.
• After such manipulations, the internal lumen of the pipe remains smooth and sealed, and the polymer processed by the welding machine forms a single whole.

Important: Excessive overheating of the pipes should be avoided. Otherwise, when connecting two elements, the plastic will simply fold into an accordion, which will disrupt both the internal lumen of the pipes and the quality of the connection.

Tip: after each welding procedure, be sure to clean off the melted polymer from the Teflon surface of the nozzles. Otherwise it will interfere with the next welding process. Moreover, you need to remove the plastic exclusively with a wooden spatula. This way you can keep the Teflon intact and unharmed. It is prohibited to remove cold plastic or metal objects.

Butt welding

You can also butt weld HDPE pipes with your own hands. Butt welding is performed using special equipment with a mechanical or hydraulic drive.

Such a welding machine will allow you to join two elements of the tubes until they are completely and tightly connected. The most popular devices are those that have software control.

Such equipment is characterized by full automation and the ability to control the welding process without operator intervention in terms of physical effort.

Before doing the work yourself, you should select HDPE pipes with uniform technical characteristics. It is advisable to weld tubes even from the same batch. Since here the polymer is joined at the molecular level, this approach will make the weld more airtight and reliable.

Important: tubes with a wall thickness of at least 5 mm and a diameter exceeding 50 mm are suitable for butt welding.

The principle of butt welding is to heat the ends of the pipe on a special plate. After melting, the PE plate between the ends of the two pipes being welded is removed and the elements are mechanically compressed until the polymer is completely mixed and soldered. After which the pipes must be allowed to cool completely.

Important: when marking tubes and cutting them, it is worth taking into account the technical reduction in the length of the pipe after welding. In order to correctly calculate the length reduction factor, you can use the data below:

• So, for pipes with a cross-section of 20 mm, the melting length (welding depth) will be 14.5 mm;
• Elements 25 mm - 16 mm;
• For tubes with a diameter of 32 mm - 18 mm;
• For tubes with a cross section of 40 mm - 20 mm;
• Pipes with a diameter of 50 mm - 23 mm.

Electrofusion welding

Welding of polyethylene pipes using the electrofusion method is used if the pipeline is installed in a confined space where the technician is not able to move freely. In addition, this welding method is applicable for connecting tubes with different wall thicknesses, different diameters, or for installing sewerage systems.

Electrofusion welding of polyethylene pipes is considered the most expensive, but the joints obtained in this way are suitable for operation at a pressure of 16 atm. The work of joining tubes using this method is carried out using special couplings, the design of which has a heating spiral element.

Welding is performed as follows:

• First of all, prepare all the necessary pipe sections with their obligatory degreasing and cleaning of dirt and dust. The inside of the electric coupling is treated in the same way. It is advisable to use special wipes impregnated with an alcohol volatile substance for these purposes.
• The ends of the welded pipes should be freed from industrial oxide by mechanical cleaning. In this case, the same ends should be cut evenly so that the connection is as tight as possible and prevents plastic from leaking inside the tubes.
• The pipes are placed in the positioner and an electric coupling is put on the joint. The ends of the pipes on the opposite side of the main should be closed at the time of welding with your own hands to avoid heat loss.
• An electric current is supplied to the terminals of the put-on electric coupling and the process is completed until the PE pipe melts and its connection is high-quality.

Important: the HDPE pipe welded in this way must remain motionless until it cools completely. Otherwise, there is a risk of breaking the geometry of the weld.

We control the quality of work

Welding polyethylene pipes, although not difficult, still requires careful control over the quality of the weld. Since the polymer has increased viscosity when melted, the seam may not always be smooth. Therefore, when performing work, you should carefully examine the results:

• The resulting weld should be approximately straight. Excessive hollowing or protrusion of the seam is excluded.
• The seam itself should not shift critically relative to the level of the main line as a whole. Inward displacement (deflection) is permissible within 10% of the wall thickness of the tube being welded. Convexity is allowed within 2.5 mm for a pipe with 5 mm walls. For tube wall thicknesses of 6-20 mm, the thickness of the convex is allowed within 5 mm.

Compliance with these control parameters will allow you to obtain a working and properly welded line that will last for decades.

Source: https://vodakanazer.ru/truboprovod/svarka-polietilenovyx-trub.html

Do-it-yourself welding of HDPE pipes: electrofusion, socket and butt welding, work procedure and quality control - Machine

We welcome our regular reader and bring to your attention an article about what welding of polyethylene pipes is - a very reliable method of connecting polyethylene pipelines.

When installing engineering systems in a house, connecting an estate to a cold water main, or laying a pressure sewer, inexpensive and practical polyethylene pipes are simply irreplaceable. For installation of pipelines in the ground and basements, polyethylene pipes are the best option in terms of price and technological qualities.

Polyethylene as a material for engineering systems is underestimated, although the advantages of PE pipelines are undeniable.

Polyethylene products are absolutely harmless to humans, the material is chemically inert, durable and at the same time plastic, frost-resistant (withstands freezing with water).

The disadvantages of polyethylene - instability to ultraviolet radiation and elevated temperatures - limit its use in the open air and for heating and hot water systems, but for laying in the ground polyethylene communications are almost ideal.

The flexibility of polyethylene pipes allows them to be laid without fittings at turns; the possibility of laying a single piece from the main to the metering unit in the house is also a big plus, because the financial savings are quite significant, and installation is much easier. The reliability and tightness of the seams make it possible to close and fill communications with a screed or false wall. A permanent connection does not require maintenance and regular inspections, like a detachable connection using collet couplings.

Methods for joining PE pipes

Polyethylene pipelines are installed in two ways: using fittings and flanges or several types of welding.

The connection requires special fittings (couplings and sockets) and without them. For pipes with a wall thickness less than 4.5 (diameters 50-110 mm), welding using fittings is used; for larger pipes with a thicker wall, butt welding and extruder welding are acceptable.

Diffusion

The diffusion method involves heating the ends to a viscous flow state. The prepared ends of the workpieces are joined and slightly compressed. Movable polymer molecules, under the influence of pressure, move into the parts being connected, mix, freeze in a new position when cooled, form new chemical bonds and ensure reliable adhesion of the pipes to each other.

It is incorrect to single out any welding method as diffusion. In fact, any welding of polyethylene is based on the process of diffusion of heated molecules.

Bell method

Not the most typical way. There are two options for implementation: using socket pipes and couplings. The method itself is reminiscent of welding polypropylene pipelines: the socket or coupling and the workpiece are heated using a soldering iron with a special nozzle.

Then the workpiece is inserted into the socket of another pipe or coupling, fixed, pressed and held. Welding time – 20 seconds. If couplings are used, then the second pipe is soldered into the coupling in the same way. The cost of couplings is low; products with a socket are rarely found in stores.

The connection is reliable and durable; small diameters can be welded.

Butt welding

This method is applicable to pipes with a wall thickness of more than 4.5–5 mm and a diameter of more than 50 mm.

Before carrying out work, cut off the polyethylene pipe strictly perpendicularly and thoroughly clean the ends. Then fix the pipe in the welding machine and carefully center it.

A heater is inserted between the ends of the heating pipes, the pipes are pressed against it and heated until the ends soften. Then the heater is quickly removed, the ends are compressed in such a way that a small annular bead is formed at the junction - a flash.

Cool the joint, then remove the machine. The work has its own subtleties; it requires two people.

Extruder welding

Extrusion - welding using a small apparatus from which molten polyethylene is extruded under pressure. Raw materials in the form of rods or granules are loaded into the extruder.

Extrusion is used on pressure communications with a wall thickness of more than 6 mm, but it can also be used to patch non-pressure sewer pipelines with a thinner wall. The connection point is heated by a stream of hot air.

It is advisable to chamfer the ends.

The quality of the seam is very high. The advantage of the method is that it is possible to weld an already laid polyethylene pipe without dismantling the pipeline.

Which way is better

Before choosing the best connection method, it is necessary to determine which one is applicable in a particular case, depending on the diameter of the pipeline.

The most reliable and universal method is welding using thermistor couplings. But couplings, especially large diameters, are expensive, expensive, and a welding machine (but you can rent one). Therefore, such welding is not very common when arranging a private home.

More often they are butt welded or using solder couplings. Butt welding is used on polyethylene pipes with large wall thicknesses; these are usually not used in private homes. Extrusion welding is not yet very widespread, mainly due to the little known nature of the method.

Recommendations for high-quality welding

For PE welding, the quality of processing of the ends of the pipes being joined is of particular importance. They must be thoroughly cleaned of chips, burrs, dust, dirt, and grease. Careful centering of the workpieces, absence of ellipse, and exact matching of the diameter and wall thickness of the workpieces are also important.

Do not touch the connection until it has cooled completely. Work must not be carried out in rain, snow or frost.

Features of working with LDPE and HDPE

These two types of polyethylene differ slightly in their technical characteristics and parameters. The information is summarized in a table.

Characteristic	PVD (PNP)	HDPE (PVP)
Melting point, °C	103-110	125-132
Softening temperature, °C	100	120-125
Rigidity	small	big
Flexibility	big	small
Fragility	small	more than PVD
Strength	average	high

When welding, it should be taken into account that LDPE requires a lower temperature to melt than HDPE. HDPE has greater strength than LDPE.

Do-it-yourself welding of PE pipes

Welding polyethylene pipes at home is not too difficult and can be done with your own hands. The problem is expensive equipment. In any case, it is worth renting rather than buying.

Before manipulation, it is necessary to cut the workpieces evenly and thoroughly clean and degrease the ends.

Required tools and materials

To weld polyethylene communications you will need pipes and possibly couplings.

List of required equipment:

1. Pipe cutter is a device for cutting.
2. It’s a good idea to use an electric trimmer to accurately align the ends of the pipes.
3. For larger diameters it would be a good idea to use a chamfer.
4. Socket welding machine. Structurally, it resembles a soldering machine for polypropylene.
5. Corresponding nozzles.
6. For end connections, a special centering machine and a heating element are used.

Stages of work

First, the pipes are cut at an angle of 90°, burrs are cleared, dust and chips are removed, and degreasing is carried out. It is more convenient to do this work with an electric trimmer.

Socket (socket) welding technology

Put the desired nozzle on the soldering iron and heat it for the time specified in the instructions. Then heat the coupling and pipe until the polyethylene softens and connect them. They give time for diffusion and polymerization - for about 20 seconds the compound cannot be touched. Then the second workpiece is connected to the coupling in the same way.

Butt connection

The workpieces are installed in the joining machine, fixed and carefully centered. Before soldering, you need to make sure that the longitudinal axes of the workpieces completely coincide.

A heating element is inserted between the polyethylene blanks and held until the material softens.

The heater is removed, the workpieces are quickly connected, and pressed with force until an annular bead is formed at the seam site. Stand until cooled.

Butt welding is not as simple as it seems at first glance and requires some experience.

Seam quality control

The reliability of the connection depends on the quality of the seam. The height of the burr bead during a butt connection must correspond to the table data.

There should be no cracks, pores or cavities near the rollers. The rollers must be the same around the entire circumference, the same height. The recess in the center should not fall below the surface of the pipes. The parts should not be offset from each other. If you solder a defect, the connection will have to be cut and redone.

Photos of defective butt joints:

Conclusion

Polyethylene is an excellent material for laying pipelines underground. It is not difficult to learn how to mount it and connect it in various ways; this work is quite doable with your own hands.

We say goodbye to our beloved reader and wish him success in laying utilities to his home.

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Welding low-pressure polyethylene pipes: technology, stages, necessary equipment

Those involved in repairs often come across polymer products. This material is often used in plumbing. Polyethylene compounds are reliable, which is why they are actively used during repair work.

Sewerage, water supply, pipe welding - this is a small list of where the material can successfully prove itself. Today we will talk about welding HDPE pipes.

It involves the use of low-density or high-density polyethylene.

Relevance

Due to its many advantages, soldering of PE pipes has gained wide acceptance today. And that's why:

1. Such pipes can operate for a long time - from 50 years.
2. They are not afraid of corrosion and the adverse effects of external factors.
3. Both professionals and beginners with little experience can carry out welding work. This is possible at home, which saves your family budget.
4. Affordable price.
5. Fast completion of work and strength of the material.
6. Light weight, crack resistant.
7. Possibility of several ways to work with HDPE pipes.
8. Easy to use, do not require professional knowledge.
9. Quickly installed.
10. They do not harm the environment due to the safe composition of the materials.
11. Can be used in areas of high seismic activity.
12. Work safety provided all rules are followed.

Reasons for the uniqueness of PE

We can talk about the noticeable rigidity of high-density polyethylene pipes. This is due to the strong bond of this product at the molecular level. For this reason, the production is considered extremely durable.

The main advantage of low pressure PE is that it is made from petroleum. This material is resistant to low temperatures, does not emit harmful substances into the environment and is not considered dangerous to people.

According to their purpose, the following types of high-density PE pipelines are distinguished:

1. Technical (used in sewerage, gas supply and cable production);
2. Food grade (suitable for designing drinking elements).

Depending on the connection method, there are detachable (easily disassembled after soldering) and permanent (they cannot be disconnected; they are used at high pressure).

Types of PE pipes and their welding

Metal processing of polyethylene pipes is:

• Coupling
• Butt
• Thermistor
• Socket method

The first and third methods are the most common.

Thermistor welding and its features

This technology is also called electrofusion technology. Contact is made through couplings that have a special heating element.

HDPE welding is done in the usual way in the following cases:

• It is not possible to make a butt connection;
• It is necessary to carry out welding in the old pipeline;
• Branches into working pipes are required.
• Thermistor welding elements are not cheap, but sometimes you can’t do without it.
• The stages of this type of connection look like this:
• First you need to cut off the elements, clean them of debris and dirt;
• Using a marker, we mark on the parts the places to which the finished pipeline will enter the fitting;
• Using attachments we protect those elements that cannot be welded. This is necessary so that dirt does not get on them;
• The final stage is the connection of the electric coupling with the welding machine. You need to connect the wires and turn on the device. The equipment will turn off on its own as soon as it reaches the desired temperature.

Fitting connections

The device for soldering HDPE joints using the coupling method is a soldering apparatus. In addition to couplings, the work will require angles and tees. The soldering iron has different attachments that will heat up slowly.

This is necessary in order to melt the ends of the pipeline and fitting. After this, the two elements are ready to be connected. The soldering iron nozzle has an unusual structure: it has sleeves and a mandrel.

The latter is responsible for the internal heating of the elements, and it is inserted into the first to warm up the upper part.

Let's talk in more detail about HDPE coupling connections. The basic rules of operation are:

1. Make sure that the work area is free of dirt and foreign objects.
2. Work with the basic elements needed for welding. Shorten them if necessary, and also clean them from dirt.
3. It is necessary to set the welding temperature of HDPE pipes on the equipment. When it reaches the desired level, you will hear a characteristic sound.
4. Insert the pipeline element into the sleeve and place the coupling in the mandrel. During the process, excess material will melt and come out. When the device heats up, remove the elements from the nozzle and connect them into a ring roller. It is necessary to carry out this procedure all the way. To make the job easier, mark the boundaries in advance with a black marker.
5. The larger the diameter of the PE pipes, the longer they will cook. This formula also works in the opposite direction.
6. The joint must be cooled, leaving the structure for a couple of hours.

Butt welding of PE pipes

This method of work is possible subject to special work rules. Due to the use of low pressure PE, the pipeline will be flexible.

HDPE butt welding requires skill and extensive experience of the welder: the connection must have only one seam. Otherwise, the whole structure will be sloppy.

Main phases of welding PE pipes

We securely install the welding elements in the center of the mechanism. Take alcohol and disinfect all ends of the parts.

After this, it is necessary to trim the pipeline elements. It is necessary so that the two parts become parallel to each other. You need to work until all the gaps on the parts are removed.

Take into account the fact that welding equipment must be used to warm up the ends. Large diameter HDPE pipes take much longer to process.

When all the elements are heated, connect them end to end until the parts become solid. This usually takes no more than 10 minutes. An obligatory step is checking the strength of the resulting joint.

Check out the table for welding HDPE pipes by diameter:

Summarize

It can be noted that there are clear differences between welding HDPE pipes and other types of work. The basic principles still remain the same, as is the case with plastic and polymer structures.

The important point is that each process can be adjusted independently. Butt welding is suitable for low-density polyethylene: this method is quite complex and requires a lot of experience. For this reason, butt welding is often left to professionals.

Source: https://prosvarku.info/tehnika-svarki/varim-truby-iz-polietilena-nizkogo-davleniya

Welding of polyethylene pipes: methods of soldering PE and HDPE (butt, coupling, thermistor), do-it-yourself welding technology

We welcome our regular reader and bring to your attention an article about what welding of polyethylene pipes is - a very reliable method of connecting polyethylene pipelines.

When installing engineering systems in a house, connecting an estate to a cold water main, or laying a pressure sewer, inexpensive and practical polyethylene pipes are simply irreplaceable. For installation of pipelines in the ground and basements, polyethylene pipes are the best option in terms of price and technological qualities.

Polyethylene as a material for engineering systems is underestimated, although the advantages of PE pipelines are undeniable.

Polyethylene products are absolutely harmless to humans, the material is chemically inert, durable and at the same time plastic, frost-resistant (withstands freezing with water).

The disadvantages of polyethylene - instability to ultraviolet radiation and elevated temperatures - limit its use in the open air and for heating and hot water systems, but for laying in the ground polyethylene communications are almost ideal.

The flexibility of polyethylene pipes allows them to be laid without fittings at turns; the possibility of laying a single piece from the main to the metering unit in the house is also a big plus, because the financial savings are quite significant, and installation is much easier. The reliability and tightness of the seams make it possible to close and fill communications with a screed or false wall. A permanent connection does not require maintenance and regular inspections, like a detachable connection using collet couplings.

Welding HDPE pipes with your own hands, technology and instructions

Welding HDPE pipes with your own hands

Welding HDPE pipes with your own hands

Polyethylene (HDPE) pipes with a diameter of 20 to 1200 mm are widely used due to their advantages and ease of installation. They are used for laying gas and water pipelines, internal, external, and storm sewers. Depending on the goals, polyethylene pipes can be pressure or non-pressure. The latter are specifically used for sewer systems.

Polyethylene pipes can be connected in three ways, one of which is detachable (connection using flanges and fittings), while the other two are permanently welded (butt welding with special equipment or using electric couplings). The welded connection is the most durable, the seams are sealed and resistant to chemically aggressive environments.

Preparatory process before welding HDPE pipes

Regardless of the type of welding of HDPE pipes, a number of preparatory measures should be taken before work. Namely:

• purchase and bring to the work site the pipes themselves and fasteners (straight fittings, angle fittings, tees and other connecting elements), clamps and reducing liners corresponding to the diameter of the pipes being welded;
• arrange and clear the work area where the welding equipment will be placed from foreign objects;
• mechanically process the ends of HDPE pipes and all fittings.

Before work, welding equipment should be carefully checked for serviceability and functionality. The procedure for preparing the equipment is as follows:

• The components of the welding machine are inspected visually, the grounding conductors and electrical wires are checked for serviceability, the cutter knives are checked for the degree of sharpening;
• Next, prepare the electric generator by filling it with fuel and performing a test switch-on;
• Before work, equipment parts (scraper, trimmer, heater) are cleaned of existing contaminants and traces of adhering polyethylene, then degrease all surfaces with a solvent;
• on the hydraulic system of welding equipment, be sure to check the presence of oil and its level, test the operability of the movable clamp, after which all rubbing parts of the equipment are lubricated with special compounds;
• check all available control and measuring instruments.

Principle of electrofusion welding method

Device for electrofusion welding of HDPE pipes

The electric coupling is a shaped part made of polyethylene with electric spirals implanted into the coupling body.

Couplings are produced for pipes of various diameters and are calibrated with a bar code, which indicates the temperature conditions, heating duration and other information for operation.

If straight-line welding of HDPE pipes is carried out, then a simple-shaped coupling is used; for the installation of other structures, there are electrofusion tees, saddle bends and other parts made of polyethylene with similar electric spirals.

Connecting parts for installation of polyethylene pipes

The principle is as follows: after applying electric current to the coupling spirals, the temperature of the nearby polyethylene layer increases and it melts. After this, the ends of the polyethylene pipe under the coupling are heated. At the same time, the HDPE pipe expands, creating the pressure necessary for high-quality welding. After turning off the power supply, the pipe cools down, and the weld with the welded coupling, hardening, forms a rigid, hermetically sealed connection.

Sectional view of a pipe after electrofusion welding

Technology for welding HDPE pipes using an electrofusion coupling

Before the welding process, preparations are carried out: dirt is removed from the pipes, their edges are cleaned, and the inner surface of the electric coupling is degreased.

After this, the edges of the pipes are inserted into the coupling and the entire structure is fixed in the positioner.

To find out the welding parameters, read the barcode on the shaped part or manually enter the specified values ​​into the electric welding machine.

The contacts of the electric coupling and the welding machine are connected to each other and voltage is supplied.

After completing the process of connecting the coupling and the ends of the pipes, the power is turned off, and the structure is left to cool, strictly observing its immobility. After the pipe has cooled, it is removed from the positioner and the welding report is printed.

Welding protocol

If the pipe being welded has a large diameter, an additional heating point for parts can be added to the technology.

Prices for equipment for welding HDPE pipes

HDPE pipe welding equipment

Do-it-yourself butt welding of HDPE pipes

Equipment for butt welding of HDPE pipes

Butt welding is a technologically more complex process than connecting HDPE pipes with an electric coupling. You can take on work only if you have a welding qualification and relevant work experience.

Equipment for butt welding of polyethylene pipes

When butt welding, a monolithic seam is formed, which is not inferior in technical parameters to other surfaces of polyethylene pipes and does not interfere with the flexibility of the structure. In this way, pipes are connected to each other, and fittings and other parts are also installed.

Butt welding diagram

Butt welding is applicable only for connecting parts of the same grade of polyethylene, diameter, SDR with a wall thickness of more than 4.5 mm and a diameter of more than 50 mm. The operating temperature must correspond to the range from -15°C to +45°C.

Technology of butt welding of polyethylene pipes

At the preparatory stage, the ovality of polyethylene pipes is checked, the thickness of their walls is compared, and the SDR compliance of the welded parts is compared. After this, chips and irregularities are struck from the ends (you can use an electric trimmer, which will cut the pipes at an angle of 90°), and cleaned of contaminants (dust, sand, moisture, etc.).

The pipes are installed in a centralizer, maintaining a distance between the ends of about 4 cm.

The pipes are installed in a centralizer, maintaining a distance between the ends of about 4 cm

After this, the primary flash is formed by melting the ends of the pipes on a welding machine.

The heater is applied to the ends of HDPE pipes. In this case, heat spreads deep into the polyethylene, and the process of its melting begins.

After keeping the heating part of the welding machine on the ends of the pipes for a certain time, which is selected depending on the size and thickness of the products, it is carefully removed, and the heated pipes are joined together. It is important that the time spent removing the welding machine and joining the heated ends of the pipes is minimal.

A final burr forms on hot polyethylene after joining. The proper pressure is ensured by a machine with a hydrodynamic mover.

When the polyethylene cools down, you will get a uniform sealed seam - a collar. If errors are made in the technological process/installation, the seam turns out to be uneven or crooked. It is important not to allow the pipe walls to shift relative to each other by more than 10% of their wall thickness.

Appearance of correctly and erroneously butt-welded HDPE pipes

Table with recommended time parameters for butt welding of polyethylene pipes

Butt welding of polyethylene pipes

The pipes are installed in a centralizer, maintaining a distance between the ends of about 4 cm

Sectional view of a pipe after electrofusion welding

Table with recommended time parameters for butt welding of polyethylene pipes

Butt welding diagram

Connecting parts for installation of polyethylene pipes

Electrofusion welding

Welding HDPE pipes with your own hands

Welding protocol

Equipment for butt welding of HDPE pipes

Equipment for butt welding of polyethylene pipes

Appearance of correctly and erroneously butt-welded HDPE pipes

Source: https://kanalizaciyaseptik.ru/truby/svarka-trub-pnd-svoimi-rukami.html

Devices for welding HDPE pipes

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Installation of the sewer system is carried out using special pipelines, which can be made of plastic, ceramics or metal. As with many plastic elbows, HDPE pipe welding can be done using heat tools or cold press couplings.

Installation options

Technologically, it is possible to connect HDPE pipes without welding or using a special welding machine. Both methods have their advantages and disadvantages; let’s look at the advantages of each fastening method.

Cold welding or pressing is the simplest option; it is a very cheap and accessible method, which is performed through the use of special couplings. This technology is used mainly for large diameter pipelines - from 20 to 300 mm. Compression fittings for cold welding have the following advantages :

1. Ease of use;
2. Large selection of sizes;
3. Ensuring a tight connection with high sealing performance.

But pressing is mainly used only for fastening non-pressure water connections. Plastic pipes have relatively low rigidity, due to which, under strong internal pressure, the seam can simply separate, unlike welding fasteners, which are considered “dead.”

Classic welding, or as they say, soldering of HDPE pipes can be performed using the electrofusion method, or a specific welding apparatus is used to carry it out.

Electrofusion couplings are a very practical method of connecting metal gas pipes, as well as plastic water supply communications. A coupling of a certain diameter is installed on the free section of the outlet, after which the second section of pipe is pushed into it.

This kind of soldering is also called butt soldering, due to the fact that in order to achieve the most durable and tight fastening, it is necessary to install parts of the pipeline very tightly with a minimum gap.

Photo - fittings

It is convenient to work with couplings on large diameters, but this is not the best solution for washbasin outlets or heating communications. But flanged HDPE connections, if necessary, can be removed and urgent repairs can be made.

Photo – butt

Manual soldering of pipes is carried out using a soldering iron; it requires special equipment for organizing HDPE connections. To carry out such work, the temperature of the heating elements and the holding time are very important. Please note that these parameters are selected based on the technical characteristics of the soldering device, the thickness of the HDPE and the diameter of the taps.

Advantages of the technique:

1. This is the most durable and reliable option. Due to the implementation of permanent fastening, it can be used both for pressure HDB and for non-pressure connections of shut-off valves;
2. Flange connections can be used both when attaching an external system and when installing internal main pipes;
3. No prior training required. It is enough to watch the video and read the SNiP standards, which detail how to trim, install and fasten.

But the disadvantages are that the connection cannot be removed if necessary. Despite all the advantages of this, sometimes it is necessary to open and clean the pipe.

Socket installation

It should be noted that in domestic documents you will not find any standards for flared soldering. It is described only in European standards DVS 2207-15. Step-by-step instructions on how to weld HDPE pipes with couplings :

1. Before starting work, you will need to prepare communication. To do this, the outer surface is cleaned of various contaminants: dust, grease. This can be done with a damp cloth and an alcohol solution or a special mixture. It is sold in plumbing stores;
2. Afterwards the joint is put in order. The tightness of the fastening depends on the smoothness of the cut. You should walk along the end of the pipe with sandpaper or clean it with crumpled newspaper. After the joint of the HDPE pipes is trimmed to form a chamfer of 1 mm at 45 degrees, this is very important for tight fastening;

   Photo – docking

3. Next, you need to install the bends into the coupling. It is divided into two halves: the first is put on the pipe (this is the mandrel), and the second section is inserted into the second (this is the sleeve). It should be noted that putting on the coupling should only begin after the tool has warmed up;

   Photo - connection

4. The preheated nozzle is inserted onto the communication as quickly as possible, after which the second outlet is inserted into it;
5. You need to move the segments very carefully, but quickly, otherwise you can overheat the polyethylene. If everything is done correctly, liquid plastic will begin to come out from under the coupling.

After heating and welding is completed, you need to remove the coupling and fix the pipes on a solid surface.

https://www.youtube.com/watch?v=ooY-UcQuIbU

Flanges are even easier to work with. They are threaded connections for installation. Accordingly, a thread is cut at one end of the communication, into which the element is screwed, and a pipe is put on it. The joint is heated with a hairdryer or coupling.

Photo – HDPE flange

Price overview

You can buy a machine for welding HDPE pipes in any city; if the price is not suitable, now many companies provide rental equipment. Let's look at the cost of the V-Weld R063 model:

City	Price, y. e.
Voronezh	28
Ekaterinburg	28
Kazan	30
Krasnodar	28
Moscow	33
Novosibirsk	30
St. Petersburg	33

Source: https://www.kanalizaciya-stroy.ru/svarka-pnd-trub.html

How to weld HDPE pipe at home

• Possibility of long-term operation (more than 50 years).
• Fearless to corrosion, not afraid of aggressive environmental conditions.
• Welding parameters are very versatile. This is used by people far from the profession of welder and builder, using special equipment for welding polyethylene pipes at home. Considering that welding services are subject to payment, this option is very profitable for many people.
• Relatively affordable price.
• Strength.
• Availability of several technologies for soldering HDPE pipes.
• Equipment for welding PE pipes is easy to use.
• The instructions for welding PE pipes are simple for the average person.
• Fast welding time.
• A do-it-yourself device for soldering HDPE connections is relatively inexpensive.
• Welding HDPE pipes with your own hands is safe, subject to a small number of conditions and safety rules.
• A light weight.
• Elastic and do not crack.
• Suitable for regions with seismic activity.
• Environmentally friendly.
• Quick installation.

Why is high-density PE so special?

High-density polyethylene pipe is quite rigid. The molecular bond of this product is very strong, so the manufacturing is very durable. Low pressure PE is obtained from petroleum. It is frost-resistant, does not emit harmful substances into the environment and is safe for human health. Low pressure PE is biologically inert and easy to recycle.

Depending on the purpose, a high-density PE pipeline can be:

• Food grade (for drinking water supply)
• Technical (for gas supply, sewerage, cables)

Connection methods can be detachable or permanent. By the name you can immediately determine what the difference is: detachable ones can be disassembled after soldering, one-piece ones cannot. The latter are usually used when it is necessary to work with high pressure levels.

Welding of PE pipes and its types

Welding of polyethylene pipes is of the following types:

1. Thermistor.
2. Coupling.
3. Butt welding (butt welding of HDPE pipes).
4. Socket method.

The methods that are most often used are indicated in the first two paragraphs. The technology of socket welding of HDPE pipes is used very rarely.

Thermistor welding of polyethylene pipes

This technology for welding HDPE pipes is also called electrofusion. Direct contact occurs using fittings (couplings) that have a special electric heater. Welding of polyethylene pipes with couplings is usually carried out if it is not possible to make a butt connection, if welding is required in an old pipeline, if bends into existing pipelines are needed. The parts for this type of connection are quite expensive. Stages of thermistor type connection:

• We cut the elements to the required size, clean them of dirt, grease and other debris.
• We make marks on the parts with a marker so that we know the limits up to which we need to insert the finished pipeline element into the fitting. It is better to protect elements that cannot be welded, but have already been cut to the required size, with special attachments from potential dust and dirt.
• The electrofusion must be connected to the welding device through wires and turned on. After heating to the desired temperature, the equipment for welding polyethylene pipes turns off automatically. And voila! Soldering of polyethylene pipes with electric couplings is completed.

Sectional view of a pipe after electrofusion welding

Coupling connections

The device for soldering HDPE connections using the coupling method is an ordinary soldering iron. In addition to couplings, tees and angles are also used. The soldering iron has special nozzles of various sizes.

These nozzles are heated so that when they come into contact with a pipeline element or fitting, their ends “melt” and are ready for assembly. The soldering iron attachment consists of a mandrel and a sleeve. The mandrel heats the element inside, and it is inserted into the sleeve to heat the outer surface.

As mentioned above, the technology for welding PE pipes is simple and soldering HDPE pipes with your own hands is easy to do.

Below we list the basic rules of coupling connections:

• Before starting work, clear the room of debris and unnecessary objects.
• Prepare the necessary welded elements: cut them to the required size, clean them of small debris and dirt.
• The welding equipment must have a set welding temperature for HDPE pipes. The machine for welding PE pipes will give you a signal when the required mark is reached.
• The pipeline element must be inserted into the sleeve, and the fitting into the mandrel using physical effort. During the insertion of the element and fitting, excess molten material flows out, forming an annular bead. After heating, the elements must be removed from the nozzle and connected until they stop into the annular roller. To know when to stop “pressing”, it is better to mark the desired boundary with a marker in advance.
• Welding large diameter polyethylene pipes requires more heating time, and vice versa.
• The finished compound must be cooled without exposing it to any external influences.

Butt welding of polyethylene pipes

Butt welding of polyethylene pipes is characterized by main features and differences. It requires special equipment. This welding of low pressure polyethylene only makes the pipeline flexible. This type of connection requires skill. It is important that it turns out with only one seam, otherwise the design will be of poor quality.

Source: https://MyTooling.ru/instrumenty/kak-svarit-pnd-trubu-v-domashnih-uslovijah

Welding methods for joining polyethylene pipes

Pipes made of polymer materials are actively replacing the usual metal when installing or repairing household communications. Pipelines made from polyethylene pipes are used for heating, sewerage, water supply, in centralized construction and in the private sector. Welding a polyethylene pipe is the most reliable connection method, which is used for the construction of communications operating under pressure.

Features of installation of polyethylene pipes

Installation of polyethylene pipelines is carried out using welding or fittings. Only in one case do the connections become dismountable - when assembled using compression fittings. Their strength is sufficient to withstand the loads of individual water heating, but are not designed for industrial pressure or water hammer of a central water supply.

Welded joints of polyethylene pipes are more durable, but installation requires special equipment and some skills.

Methods for welding polyethylene pipes

Welded joints on polyethylene pipelines can be obtained in several ways:

• Socket method using fittings.
• Butt welding. Requires special equipment. The method is most used when installing polyethylene pipes with a diameter of more than 110 mm.
• Extruder welding. Convenient to use to change the direction of the pipeline without additional fittings.
• Electric welding using special fittings.

All of the listed methods for welding polyethylene pipes are based on molecular diffusion (mutual penetration, mixing) of the polymer when heated to its melting temperature. Hence the name of the methods – diffusion.

Note! For a high-quality connection, parts from the same manufacturer are required! Only this can guarantee complete identity of the polymers being joined.

Welding with electric welding fittings

Installation using electric welded fittings requires the purchase of expensive components. To operate, you will need a special welding machine without a heating segment.

Electric welded fittings are parts for connecting pipes made of polymer materials, inside of which heating elements are mounted to melt the outer part of the pipe and the inner part of the fitting. The result is the fusion of components into one whole. For connection to the welding machine, the part has ready-made contacts.

According to the technology of work, installation of a pipeline using electric welded fittings is the simplest. It is enough to insert the ends of the pipes to be connected into the fitting and connect it to the welding machine. The process of heating and melting the material of the pipe and coupling is automatic. For this purpose, each part has a special barcode with information about the temperature and heating time.

This method of connecting polyethylene pipes has one drawback - its high cost.