Reading 4 min.

Each plan of the pipeline, water supply or heating system has nuances in the form of turns and bends. Therefore, when installing communications, it is often necessary to use pipe bending technology. Consider how to bend a metal-plastic pipe correctly, how to give the product the desired shape, what effective ways flexibility to take advantage.

Flexion rules

When laying heating or water supply systems, it is not always possible to purchase finished goods, which are bent at the required angle. Therefore, you often have to bend yourself.

There are 4 main bending methods. Which one to use depends on the size and characteristics of the part. Pipe with different thickness and stiffness bends differently. Therefore, it is recommended to practice on a pipe section before starting work.

Pipes with a diameter of up to 20 mm with factory insulation can be bent manually, for parts with a larger diameter it is recommended to use special tools.

To bend metal-plastic at the right angle, the first thing to do is to calculate the bending radius.

How to Calculate the Bend Radius

Before bending a metal-plastic pipe at home, it is enough to find the bending radius, it is not necessary to look for exact formulas and calculate the value of the pipe bending index. There is a universal formula for calculating the minimum bending radius of a metal-plastic pipe, according to which the radius is equal to 5 diameters of the pipe section. Consider the effect of the formula on the example of a product with a cross section of 20 mm:

1. The next step is to calculate the quarter circle. Based on the given diameter, the radius is 100 mm (20 * 5).
2. Using the formula C \u003d 2PR / 4, we calculate the size of the section for bending (a quarter of a circle). C is the required length, P = 3.14, R is the previously calculated radius. We substitute the data, it turns out: 2 * 3.14 * 100 mm / 4 = 157 mm.
3. The length of the bent section is 157 mm, we mark the middle, which is the angle of the bend, and the boundaries of the section with a pencil. Each 1-2 cm is 15° total bend, 6-12 cm is 90 degrees.

For calculations, you can also use the construction calculator.

Bending technologies

Before bending metal-plastic pipes, you need to decide which way to bend to use. Each approach has features, advantages and disadvantages. We list the methods of bending metal-plastic products:

1. Do-it-yourself bending. A simple, low cost method. The disadvantage is a high probability of deforming the part.
2. Using a pipe bender. The tool allows you to bend the pipe at the required angle, eliminating the occurrence of marriage. The high cost of a pipe bender does not justify its single use. It is recommended to purchase for permanent large-scale work.
3. The use of sand. Dusty, energy-intensive method that allows you to achieve accurate results.
4. Spring application. Accurate method that eliminates the appearance of marriage when bending. The disadvantage is the difficulty in choosing the required diameter of the device.

Consider the bending technology of each method in detail.

manual method

When bending by hand, the main rule is not to make sudden and quick movements. The product is clamped in one hand, and the other is carefully deflected by the previously calculated radius.
The first fold is recommended to be performed at 20 °, no more. Then step back 10 mm from the bend and bend with a small amplitude again. Such non-amplitude bendings should be performed 10-15 so that the metal-plastic part turns 180 °. If you need to straighten the pipe, do it in reverse order.

Sand use

This method is most often used if it was not possible to pick up a spring right size. Sifted sand is poured into the pipe so that there are no voids left. The ends of the pipe are closed with plugs to prevent sand from spilling out. The part is clamped with a clamp in a place that is remote from the bend.

Before bending, the required area is heated blowtorch. You need to heat carefully, checking the degree of incandescence of the sand with paper (smoldering paper is a sign that the sand is heated to the desired temperature). After heating, we give the product the desired shape, pour the sand.

Pipe bender application

A pipe bender is a tool with which it is possible to bend a metal-plastic product at home. The device consists of a movable roller and a template roller, a bracket, a handle and a curved pipe. The machine bends products without preheating, the maximum bend is 180°, the process is safe, the appearance of defects is excluded.

The Volnov machine is arranged simply; when using it, you do not need to have special skills. At home, crossbow or spring pipe benders are more often used. The surface that curves the tube must be oiled before using the machine. This will reduce friction and the risk of damage.

In specialized stores, there are also more advanced models of pipe benders. But the purchase of hydraulic or electromechanical machines is only advisable if a large amount of work is performed.

Spring application

Using a spring to bend metal-plastic pipes is a proven method. This process will require a suitable spring diameter. To give the product the desired shape, you need to follow a simple instruction:

1. Place the fixture in the pipeline part. The spring should be located directly at the bend.
2. Gently, without sudden movements, bend the part at the desired angle.
3. Take out the spring.

Each of the presented methods is reliable and effective. Acting slowly, carefully, it is possible to bend a metal-plastic pipe of different diameters at the required angle. You don't have to buy expensive fixtures.

Metal-plastic pipes have confidently replaced metal counterparts, due to their flexibility, speed and ease of installation. They do not require welding, so they are widely used in the private sector.

To lay the product in the heating system, you must first bend it. This is easy to do at home using one of the methods below.

Article content

How to choose a pipe bending method?

Although plastic pipe is flexible in nature, it does not respond well to mechanical manipulation. As a result of improper bending, it can crack, and even break. The fact is that on the inner surface, it is surrounded by an aluminum layer, which can be damaged during sudden movements.

After a significant deformation, it is almost impossible to return the product to its previous appearance, therefore, before proceeding with bending, it is better to practice.

There are the following ways to bend pipes at home:

• manual bending;
• application ;
• sand application;
• heating the surface with a hairdryer.

Warming up with a hairdryer and the use of sand can be used as concomitant methods in addition to the main ones. For example, with the help of bulk material, it is possible to correct the marriage obtained during bending. The pipe bender is effective if you need to make many bends, the radius of which is different. If the metal-plastic pipe needs to be bent once, then you can limit yourself to manual method.

Pipe bending by hand

The simplest and most common method of bending is done by hand. All that is required from the master is a little sleight of hand. The product modification process looks like this:

1. Carefully fold so that the resulting radius is no more than 20˚.
2. Step back 1 cm from the bend and bend the metal-plastic pipe a little more.
3. Perform up to 15 of these mini bends to rotate the product 180.
4. If necessary, straighten the pipe again, it should be leveled only in the reverse order.

The main rule in the manual method - smoothness and slowness of movement. You should not strive to bend the product in one go. Sudden movements can cause damage.

Manual bending is effective when working with products up to 20 mm thick. Thicker products are difficult to modify manually. The method is suitable for processing factory-insulated pipes. They are easy to install and do not need additional insulation.

Material of different thickness and stiffness bends differently, so it is better to practice before starting work. For training, you can use meter segments.

How to bend a metal-plastic pipe without special tools? (video)

Bending pipes with a pipe bender

• hand spring (mobile, can be used at home);
• hydraulic spring (works with products up to 120 mm). It withstands mechanical shocks and heavy loads, as it has a hardened body. In combination with the pump provides high productivity;
• electric spring with program control;
• electro-hydraulic accumulator presses.

The hand spring works with metal-plastic from 5 to 125 mm. It is characterized by a minimum weight - only 10-50 kilograms. With its help, you can modify the material with just one hand.

The procedure for bending metal-plastic:

1. Insert the machine into the pipe. outdoor type springs are used if you plan to work with a long pipe and make many bends along its entire length. The internal type is effective if the bend is carried out along the edge of the pipe.
2. . Bending occurs with light, gentle movements. A single bend should have a radius of no more than 20˚.
3. Remove spring.

Using sand and a hair dryer to bend

Sand is a simple, affordable material that will allow you to achieve a neat bend of a metal-plastic pipe at home, without the help of bulky and expensive tools.

Working with sand includes only three stages:

1. One of the openings of the pipe must be tightly closed.
2. Fill the product with sifted sand.
3. Slowly bend the pipe to the desired radius.

Sand is good because it fills the entire cavity of the product evenly, so no defects should occur while working with it.

The hair dryer allows not only to bend a flat pipe, but also to correct the defect of the old one. Before bending the metal-plastic pipe, need to warm it up a bit. The main thing is not to overheat the product so that it does not lose its shape. The basic rule when working with a hair dryer is the same as with other methods - to perform movements as smoothly as possible.

Bend Radius Calculation

The correct calculation of the radius depends on the diameter of the product. The example gives a calculation method for a section of 1.6 cm.

To make the bend even, you need to get 1/2 of the circle. If the diameter of the product is 1.6 cm, then its radius will be 80 mm. To calculate the starting points of the correct bend, you must use the formula C = 2πR / 4, in which:

• C - the size of the segment on which you want to bend;
• π is the value of pi = 3.14;
• R is the radius.

Substituting known values, we get the length of the section sufficient to perform the bend 2 * 3.14 * 80 mm / 4 = 125 mm.

Then you need to transfer the resulting value to the product and select its middle, which will be equal to 62.5 mm. The center of the segment will be the middle of the bend. Then a nylon twine is taken, which measures the depth of the shipment.

To do this, tie a twine to the shipment and run it to the required distance inside the product. The string also removes the conductor after completion of work.

Next, you need to smoothly bend the product, starting from the middle of the marked segment and remove the mandrel. Both the outer and inner mandrels should be used at the same time to prevent distortion at the folds. After completing the described manipulations, the material is ready for installation.

Hello our reader! If you yourself install a warm water floor or a heating system at home, it often becomes necessary to lay pipes with bends. The question is not as simple and banal as it seems at first glance. In this article, we will be happy to share all the intricacies of the bending process and talk about the fixtures used.

If you are, then you can learn how to bend pipes manually. But before that, you should definitely practice on scraps.

If you are not confident in your abilities, then you can call the master. But is it worth it to lay a heating or water supply system on your own, if a specialist will stand over your soul and periodically perform minor auxiliary work?

Approximate cost of work

It doesn’t cost anything, and even the call of the master itself costs money. Performing bending work by a master costs about the same as the cost of materials. The cost of leaving and using a pipe bending machine depends very much on the conceit of the master (and his spoiled mood - time is wasted, and the installation work floated away from under his nose).

By bending, we get savings due to the lack of fittings.

Can plastic pipes be bent? Can. Plastic reinforced with aluminum foil has sufficient flexibility. For pipes with different stiffness various ways. More ductile HDPE pipes can be cold bent, harder products made of polypropylene or PVC must be heated with a building hair dryer.

Bending methods

There are many ways to manually bend metal-plastic, below we will give a brief description of them.

Manual bend

This is the easiest, fastest and most unreliable method of bending without tools. So it is possible to bend products made of high density polyethylene with a diameter of up to 20 mm. PVC and Polypropylene bend worse.

Bending technology: the pipe is clasped with both hands at some distance, the thumbs are under it and almost rest against each other. The tube is bent at an angle of just over 30°. The thumbs serve as a support (like a template for the pipe). Then, the workpiece is intercepted in a similar way at a distance of one diameter (20 mm), bent by 30-40°. Then they shift another diameter and repeat bending. As a result, the workpiece will bend at an angle of 90°.

Before performing work on the pipeline, it is worth practicing on scraps, otherwise the workpiece may be damaged - there will be cracks or folds on it.

With a sharp bend in one step, a hall (kink) will form on the pipe, the shape of the pipes will change - such a blank cannot be used.

Hand bending with fillers

- sand or table salt. The cavity inside the pipe is filled with filler, the holes are closed with plugs or sealed with adhesive tape, fixed in a vice and bent. Then pour out the filler.

Wire

Finely cut wire is sometimes used as a filler. Bending is carried out in the same way as in the case of sand and salt.

After pouring out the wire, you should check if there are any pieces left inside the workpiece.

Fillers and building hair dryer

When bending with the use of sand, salt, wire, you can heat up the place of bending with a building hair dryer.

Machine Volnova

It is best to bend pipes with a pipe bender. The bend is smooth and neat, without folds and cracks. But buying it, if you need to replace the heating system or plumbing once, does not make sense.

In such cases, the Volnov machine is used - a simple device that can even be made independently. A template roller and a moving roller with a handle and a clamp, a bracket for fixing the pipe during bending are fixed on a sheet of metal or a board.

pipe bender

If you regularly repair plumbing systems, then you should buy a pipe bender industrial production. It prevents the pipe from flattening or wrinkling at the bend.

The quality of bending on them is the best, but they are quite expensive, and it makes no sense to buy them for one-time work.

Spring

Special spring conductors are available for sale various diameters, external and internal. You can also pick up the most durable spring made of thick wire with frequent turns. A wire should be fixed to the end of the inner conductor to help push it into the pipe hole and remove it after bending.

It is correct that the center of the spring and the future bend exactly coincide - then you get an even, neat bend.

Which method is better

The best method is with a pipe bender. When bending, a round section is maintained, does not form creases and cracks. Among manual methods, the best results are obtained using a spring jig.

Flexion rules

Minimum bending radius for metal-plastic

The bending radius must be at least 5 pipe diameters. This rule applies to all diameters.

Calculation of the length of the bend section

The length of the bend section is calculated by the formula:

2*π*R*φ/2, where

• R is the radius of curvature (equal to five pipe diameters), in mm;
• φ is the bending angle in radians,
• 2 - full angle in radians, equal to 2.

Translated into Russian: a bend angle of 90 ° = 0.5 radians; 30°= 1/6; 60°= 1\3; 180°= 1; 45° = 0.25.

It is necessary to know the length of the section to be bent when using bending with a mandrel - so that the bending point is completely occupied by a spring mandrel.

Step-by-step instructions for folding at home

Training

You can independently obtain ideal bends using spring conductors or a Volnov machine. For the installation of long coils for the "warm floor" system, it is very convenient to use an external spring conductor, which will move outside the pipe in the right direction and be used at certain points.

Before starting work, it is necessary to determine the diameter of the bend and the length of the bend section according to the formula above. This is necessary so that during the bending process the conductor completely covers the bent section, otherwise the pipe will deform. Before work, you need to practice on small pieces.

Bending thin products can also be done by hand. With certain skills, this also works out well.

What tools will be needed

For work you will need: a grinder or a jigsaw for cutting, an external jig or a Volnova machine, depending on the chosen method, a building hair dryer.

Video by fold

Our video shows the most simple ways metal-plastic bending. Many of the nuances of the work are easier to understand by seeing the sequence of actions with your own eyes.

How to bend PVC pipe

Polyvinyl chloride is an inflexible material, therefore, such pipes should only be bent when heated to a temperature of 80 to 170 ° C.

Working surfaces of tools must be lubricated with machine oil.

To accurately obtain the desired angle, the pipe can be “bended” a little, and then straightened. This makes it easier to achieve greater accuracy of the bend angle.

Conclusion

If you, dear reader, decide to replace pipelines with your own hands, you can also learn how to bend pipes. Don't invite experts. We wish you good luck in your endeavors. Share useful information from the site with friends in social networks, subscribe to our newsletter and invite friends to subscribe.

Add to bookmarks

Methods for bending a metal-plastic pipe during the installation of highways

In this article, we will consider a process that gives a detailed answer to the question of how to bend a metal-plastic pipe correctly.

How to bend a metal pipe?

Currently replacing the old metal pipes came new - metal-plastic. The advantage of a metal-plastic pipe is its flexibility, which makes it possible to lay it, as required by the main line of the planned wiring of the system, without disturbing the aesthetics.

A big plus of metal-plastic materials is quick and easy installation, which excludes the operation of welding systems.

But when installing the wiring system, you need to take into account how to properly bend the metal-plastic in order to avoid a fracture, violation of its integrity and correctly calculate the angle of rotation. So let's start with the basics.

Metal-plastic pipes are composite products consisting of several components, in particular, a polymer base and a reinforcing layer consisting of aluminum foil or metal mesh. This reinforcement helps the metal-plastic product to take a certain shape and configuration. However, it does not lose its properties. There are several ways to bend the corners of a metal-plastic line, several methods and calculations are given below:

The reinforced layer helps the metal-plastic product to take a certain shape and configuration.

1. This is by hand. Philistine fast method, which does not require special skills and special expensive equipment. This method can be used by anyone, even without special skills.
2. Mechanical bending of the structure using a pipe bender. The most efficient and fastest method used by professional installers of metal-plastic systems. Bending pipe lines with a mechanical pipe bender helps save time and achieve maximum quality installation.

With a simple manual method, you can make a bend on pipes of small diameter from 16 to 20 mm, which are more popular. To do this, we need two tools: a tape measure and a flexible external or internal mandrel, called a conductor in the language of plumbers. Well, a little skill and knowledge of mathematics to calculate the bending radius of the turn. There is a universal formula for calculating the radius - this is 5 diameters of the pipeline section. Consider the calculation on the example of a pipe with a diameter of 16 mm.

Calculation of the radius on the example of a product with a diameter of 1.6 cm

An alternative method of bending in the absence of a mandrel is to fill the bending area with salt or sand.

1. For a clear and correct bend, we need to get a quarter of the circle. To do this, we take the diameter of the product, 16 mm, then we get the radius we need. According to the universal formula, it is equal to 80 mm. The next step we will have is the calculation of the starting points for the exact bending of the corner. To do this, according to the formula C \u003d 2πR / 4 (where C is the size of the section necessary for work to produce a bend; π (pi) is a mathematical constant equal to 3.14; and R is the radius obtained by us according to the universal formula) we find : 2*3.14*80mm /4= 125mm. We get the length of the section on which we will bend the metal-plastic water pipe.
2. The next thing we put on the surface is the area we calculated, the middle of which is the bending angle of the pipe.
3. We take a nylon twine, measure on it the distance necessary to deepen the mandrel. We tie a twine to the mandrel and run it to the desired distance inward. The twine is needed in order to remove our jig after the bend is ready. After smooth movements from the middle of the segment, we bend the pipe in even sections of several centimeters and take out our mandrel with the help of twine. It is recommended to use the inner and outer mandrel at the same time to avoid the appearance of corrugated deformation on the folds. Our bend is ready to be laid into the system. With the necessary skill, this method can be used to bend metal-plastic pipes and a slightly larger diameter.

An alternative method of bending in the absence of a mandrel is to fill the bending area with salt or sand. To do this, we fill the internal cavity, seal the holes of the filled area with adhesive tape. Then, using the same method from the middle of the segment, we bend to the desired degree.

With the help of a segment pipe bender, you can bend the pipe up to 180 degrees.

So, we got the most correct and aesthetic angle of the pipe for installation in the route with a turn, while avoiding fracture and damage. A similar method is also used to bend pipe contours.

Mechanical pipe bending is more efficient, faster and of higher quality. If you often encounter work on, then it is recommended to purchase a pipe bender, divided into several types:

1. Segment - pipe bend is made on the basis of a special segment. The shape of each segment is specially designed for a clear required diameter and shape. With this pipe bender it is possible to 180 degrees.
2. Dornovye - a pipe bender of this variety helps to bend the pipe without any flaws. The advantage of a mandrel pipe bender is a segment that moves inside the pipe and helps to avoid deformation, allowing bending in several planes.

The principle of operation of devices for the correct bending of pipes is identical to the manual bending process, with the exception that with manual bending of a metal-plastic product, the beginning comes from the middle of the segment, and with mechanical bending, from the beginning of the section marked by us and the required degree or segment (template) is set on the machine. After preparing the tool for work, we insert a pipe into it and bend the configuration of the section of the mounted line we need.

Metal-plastic pipes are made of polymeric materials reinforced inside with aluminum foil or metal mesh.

This design provides sufficient strength and reliability, and also makes it quite easy to give the desired bending shape, which is very convenient when installing systems.

The popularity of these products, in our opinion, is due to the fashion for the installation of water heated floors, where metal-plastic systems are simply irreplaceable due to the large length of the heating main and, accordingly, the large number of bends.

No other type can be so easily and at the same time bent to the desired shape with high quality.

Connection options

Metal-plastic pipes are connected using special fittings by crimping them with a sleeve with rubber gaskets.

The range of docking fittings is quite high and includes a variety of bends, tees, connectors, splitters, angles of various slopes.

And yet, quite often, in order to provide the necessary shape of the structure, one has to resort to bending the pipe itself.

Theoretically, you can do without bends and use the desired shape of the fitting, but this significantly increases the number of connections, which greatly increases the cost and the likelihood of leakage.

Methods

First you need to remember that the minimum bending radius must be at least 5 pipe diameters.

You can bend with a smaller radius, but at the same time you are guaranteed to get dangerous deformations and creases, which either immediately or within a short time will make itself felt in the form of leaks and flooding.

For the correct marking of the area to be bent, we suggest recalling the school geometry:

• L=2p*R/4;
• L is the length of the section to be bent;
• R-bending radius (not less than 5 pipe diameters);
• P-constant equal to 3.14
• Having carried out these simple calculations, you will not be mistaken and will not spoil the bend.

Basic ways

You can bend manually and with the help of devices.

Products of small diameter (16 - 20 mm) can be bent by hand.

To do this, you need to tightly take the pipe with both hands into fists, rest against it with your thumbs and gently bend it at a small angle (maximum 10-15 degrees at a time), then move 1.5-2 cm and repeat the procedure.

Thus, you need to act until you get the desired result.

It should be noted that different products have different stiffness, so it is advisable to pre-train on a small piece.

Satisfactory is the result, in which there is no sagging in the form of an accordion on the inner radius.

Hand bending with fillers

A more reliable result is achieved with dense filling inner space bent pipe section.

To do this, we pour salt, sand, any other bulk materials into the pipe, close the ends with plugs and carry out bending.

You can use pieces of hard wire, which are tightly driven into the pipe, and after giving it the desired shape, they are removed one by one.

This method is preferred because the filler prevents fracture of the walls of the inner radius.

To simplify and improve the quality of bending, as well as for large diameters of thick-walled products, it is possible and necessary to use mechanical devices made specifically for this purpose.

Bending devices

Mechanical or electromechanical devices designed to bend pipes are called pipe benders. Consider the types of designs of these devices:

Crossbow. The basis of these devices are special sets of dies, on which the pipe is stretched with a mechanical device, giving it the required shape. This type is compact, easy to use and gives good results. It is important to understand that an individual matrix is ​​used for different diameters and for each bending radius. This must be taken into account when planning work.

Spring. Such devices consist of a rigid spring itself inserted into the pipe and limiting the deformation of the bending radius.

The essence of the work is the following. A section is marked where it is necessary to form a radius, and a spring is driven into this place from the inside, the pipe is bent and the spring is subsequently removed. To facilitate removal, the spring is rotated simultaneously with pulling it out.

IMPORTANT! - the torsion movement must coincide with the direction of the coils of the spring itself, otherwise it will be unrealistic to remove it.

Such a device is very easy to use, but for each diameter you will have to purchase your own spring.

Segment. The principle of their work is the same as that of the crossbow. The difference lies only in some design features.

Dornovye. These devices are professional. They are designed for bending steel pipes of large diameters with thick walls.

IN Lately some simplified similarities of these devices appeared for working with soft metal-plastic, copper, thin-walled, steel pipes of small diameters.

They are segments of various shapes, laid on suspensions inside and gradually moving in the pipe as it bends.

Their shape allows bending without dangerous deformations.

This process is quite versatile and gives good results, but it requires a fair amount of skill and professionalism, so we recommend that amateurs choose the simpler option from the above.

Prices for spring mechanisms for bending pipes range from 50 to 1000 rubles, depending on the composition of the kit and the manufacturer.

Bending a pipe using mechanical devices will cost you from 12,000 - 15,000 rubles.

We wish you success.