How to bend a profile pipe at home with your own hands: video, photo

The question of how to bend a profile pipe without using special equipment is asked by many of those who are planning to build a greenhouse on their plot. Such structures, made from bent pipes, not only transmit significantly more light, but are also highly stable and durable when compared with structures made from wooden blocks. It seems that bending a corrugated pipe, creating an arched structure out of it, is not easy, but if you understand the features of this process, it is quite possible to carry it out effectively using the simplest devices.

Homemade structures made from profile pipes are characterized by good reliability and low metal consumption

What is the difficulty of bending profiles?

The essence of bending rolled metal, regardless of the shape of its profile, is that the profile pipes are given a partial or full bend. This technological operation is performed in two ways: by acting on the pipe being bent only by pressure or by additionally heating the section of the pipe in the area of which the bend is performed. During bending, two forces simultaneously act on a metal pipe:

compression force (from the inside of the bend);
tensile force (from the outer part of the bending section).

It is the influence of such multidirectional forces that causes the difficulties characteristic of the process of bending any profile pipes.

Segments of the pipe material, which changes its shape during the bending process, may lose the coaxiality of their location, which leads to the fact that individual sections of the pipe will be located in different planes;
The wall of the corrugated pipe, located on the outside of the bend and subject to tension, may not withstand the load and burst.
The inner wall of the pipe, subjected to compression, may become covered with folds that resemble corrugation.

Technical characteristics of profile pipes

If you do not take into account the subtleties of such a technological process, then instead of bending a profile pipe, you can simply crush the product, ruining it irrevocably.

To prevent this from happening, it is necessary to take into account not only the characteristics of the pipe material, but also its geometric parameters - cross-sectional dimensions, wall thickness, radius to which the bend must be made. Knowledge of the above will allow you to choose the appropriate technology and bend the corrugated pipe correctly, without crushing it and without getting a corrugated surface.

What is the operating principle of channel bending?

During operation, the channel is subject to pressure from an external weight in the bending direction. Therefore, designers calculate upcoming loads in advance. What do experts start from?

The first thing designers calculate is the maximum value of the moment in the channel profile (M). They use a complex formula for this. The distribution load and channel length are taken into account.

In the second step, experts look for the value of the moment of resistance of the channel section. There is a formula for this too. The previously obtained value of M and data on the material’s yield strength are substituted into it. For the last value, data is taken from technical tables; the values differ for different steel grades.

Experts compare the results obtained from the second formula with GOST 8278 in the “moment of resistance” category. Based on this, for each project they select a rolled or bent channel that meets all the criteria.

The need to take into account the profile

The category of profile pipes includes products with different cross-sectional shapes - round, square, oval or flat-oval. Despite this diversity, rectangular or square pipes are predominantly used to construct a greenhouse or canopy. This is due to the fact that it is much easier to install an external covering on their flat walls.

The range of modern profile pipes is very diverse. Their geometric parameters, the main ones of which are the cross-sectional area and wall thickness, determine the plastic capabilities of the product. The latter are characterized by such an indicator as the minimum permissible radius of curvature. It is this parameter that allows you to determine the minimum radius to which the corrugated pipe can be bent so that it does not suffer damage.

Avoid common mistakes that lead to damage to workpieces

To determine such a parameter of a pipe with a square or rectangular profile as the minimum bending radius, it is enough to know the height of its profile. If you are going to bend a profile pipe with a cross section in the form of a rectangle or square, you should adhere to the following recommendations.

Pipes whose profile height does not exceed 20 mm can be bent in sections whose length exceeds 2.5xh (h is the profile height).
Products whose profile height exceeds 20 mm can be successfully bent in areas whose length corresponds to 3.5xh or more.

Minimum bending radii of steel pipes

Such recommendations will be useful to those who are going to bend profile pipes with their own hands in order to make racks, canopies and various frame structures from them. However, it should be borne in mind that the possibility of high-quality bending of pipes is also influenced by the thickness of their walls. It is better not to bend products whose wall thickness is less than 2 mm at all, and if it is necessary to create structures from them, use welded joints.

At home, it is possible to bend corrugated pipes that are made of carbon or low-alloy steels only taking into account certain nuances. After bending, such pipes can spring back and return to their original state, so the finished structures must be re-fitted according to the template. The amount of springback is characterized by such a parameter of profile pipes as the plastic moment of resistance - Wp. This parameter is indicated in the accompanying documentation (the lower it is, the less the corrugated pipes will spring back during bending).

Models of domestic manual profile benders

One of the popular profile bending machines is the manual machine “PG-1” and “PG-2”. The first option is a fairly mobile device. Thanks to this, the bending process can be carried out directly on the job site. They can bend pipes measuring 40x40 mm. According to its design, the equipment has a frame and 3 rollers that are attached to it. The central one, which is the pressure roller, pulls the pipe. The comfortable handle makes the work process quite easy.

Profile bender PG2

As for the other model “PG-2”, its design is more powerful. This machine can bend pipes 30x60 mm. If necessary, this machine can bend the pipe into a ring.

Features of the most popular pipe bending methods

In industrial or home conditions, corrugated pipes are bent both with heating and in a cold state. Heating, which is produced using a gas burner, significantly increases the ductility of the metal, so that less effort is required for bending. Pipes with a small cross-section can be bent without heating, since they already have good ductility.

Regulatory recommendations regarding the use of heating are available only for products with a round cross-section. Thus, it is recommended to heat pipes with a cross-sectional diameter exceeding 10 cm before bending. In cases where it is necessary to bend square or rectangular pipes, you should rely on your own experience or the advice of other home craftsmen.

Pipes whose profile height does not exceed 10 mm are bent without preheating.
If the profile height of the pipes exceeds 40 mm, they must be heated before bending.

Before starting work, decide on the bending method

If you have a pipe bender at your disposal, with its help you can easily cope with the task of cold bending pipes whose profile height is in the range of 10–40 mm. In the absence of such a device, it is necessary to solve the question of how to bend a pipe without a pipe bender, having first carried out simple tests. They will help you determine whether the corrugated pipe should be heated before the flexible pipe or not. These tests are carried out as follows. One end of the pipe is clamped in a vice, and a pipe with a large internal cross-section is put on the other. If, with the help of such an arm, it is possible to bend a pipe clamped in a vice, this process can be performed without preheating.

Pipe bending using various methods is well demonstrated by a training video, but it would be a good idea to first study this process in detail.

Bending of corrugated pipes with preheating

To bend a profile pipe using the hot method with your own hands, you must first fill it with sand. This will make the bending better and more uniform. Since you will have to deal with hot metal, all work should be done in thick canvas gloves. The bending itself, the implementation of which can be seen in the video, is performed in the following sequence.

Both ends of the profile pipe must be closed with plugs, which are made from wooden blocks. The length of such plugs should be 10 times greater than the width of their base, which, in turn, should have an area twice the area of the hole in the pipe that is closed with their help.
After adjusting the plugs to the internal cross-section of the pipe, 4 longitudinal grooves are made on one of them, which are necessary to remove the gas that accumulates in the pipe when the sand filling it is heated.
The section of the corrugated pipe that you plan to bend must first be annealed.
Medium-grain sand should be used as filler for the pipe. If there is no purified construction sand, you can take any sand, even from a children's sandbox, but it should be prepared accordingly. Thus, the sand is first sifted through a sieve with a mesh size of 2–2.5 mm to remove gravel and small pebbles from it, and the final sifting is performed on a sieve with a mesh size of 0.7 mm. Final sifting is necessary in order to remove dust inclusions from the sand, which can sinter when heated.
The prepared sand must be calcined at a temperature of 150 degrees Celsius.
Before filling with sand, one end of the pipe is closed with a plug that does not have gas outlet channels. A funnel is inserted into the second end, through which prepared sand is poured in portions. To ensure that the sand evenly and tightly fills the entire internal cavity of the pipe, when filling it, it is necessary to tap the walls of the product, using a wooden or rubber mallet.
After the pipe is completely filled with sand, its second end is also closed with a plug.
The area that will be heated for further bending must be marked with chalk.
The pipe must be secured in a vise with a template or in a pipe clamp. In this case, it is important that the weld, if there is one on the surface of the product, is on the side. This requirement must be adhered to because it is undesirable to subject the weld to compression or tension.
A section of the pipe, previously marked with chalk, is heated red-hot using a gas burner. After complete heating, the pipe is carefully bent, without making sudden movements, in one step, applying forces strictly in the vertical or horizontal plane.
After the bent pipe has cooled, the result obtained is compared with the template. If everything is fine, then remove the plugs from the ends of the product and pour out the sand.

The correct technology for manual hot bending

This method, which is easy to implement at home, is best used in cases where a single angular bend needs to be formed on the corrugated pipe. Repeated heating of metal can cause it to lose its strength, and this cannot be avoided if you are bending a pipe for use as an element of an arched structure.

The principle of using a pipe bender

It is not always possible to bend a profile pipe (especially for large-diameter products) with your own hands. For these purposes, there are special devices - pipe benders. A standard pipe bender is equipped with a drive wheel, which, moving along one of the edges, carefully bends the pipe section in the required direction.

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There are two types of pipe benders:

Manual. The wheel of the device is operated manually using a special handle. Well suited for pipes with a small cross-sectional area.
Electrical. The use of such devices is justified in cases where the volume of work is quite large, and the pipes themselves have substantial dimensions. The device is connected to a standard power supply, and the wheel moves by means of an electric drive. Allows you to obtain smoother products with significant time savings.

If the work is one-time, purchasing your own pipe bender may not be profitable. In this case, you should consider renting the device, or consider one of the alternative bending methods.

How to bend a pipe without preheating

You can bend a profile pipe yourself without preheating it, either with or without filler. Pipes whose profile height does not exceed 10 mm do not require filling with sand or rosin.

The nuances of bending small-sized thin-walled pipes

There is another technique that involves using a spring with tightly wound coils instead of a filler, which is inserted into the internal cavity of the corrugated pipe and protects the walls of the product from deformation, as well as from excessive changes in their thickness during the bending process.

Drawing and details of a mechanical pipe bender for profile pipes

The design of a basic pipe bending device is simple and accessible for self-production

For those who need to bend profile pipes with their own hands without heating them first, you can use the training video and the following simple recommendations.

You can obtain the required bend on profile pipes using the simplest devices - a vice, mandrels, bending plates.
You can use a manual pipe bender for products with a round profile. In this device, it is necessary to remake the working rollers, the shape of the recess in which must correspond to the profile of the pipe.
The most efficient and accurate way to bend pipes is with a roll forming machine, which you can purchase or make yourself.

Pipe bending equipment

The question of how to bend a pipe without a pipe bender will not cause difficulties if you use the simplest devices to perform this operation. You can perform cold bending of pipes using the following devices.

In cases where it is necessary to bend a soft (aluminum) or steel pipe with a profile height of no more than 10 mm, a horizontal plate with holes is used into which stops - metal pins - are inserted. Using these pins, products are bent according to the required parameters. This method has two serious drawbacks: low bending accuracy, and also the fact that when using it it is necessary to exert significant physical effort.
It is better to bend products with a profile height of 25 mm using roller devices. The pipe is securely fixed in a vice, and force is applied to the part that needs to be bent using a special roller. This device allows you to get a better bend, but also requires physical effort.

The option, as they say, is a quick one. The long lever of this extremely simple device allows you to cope with fairly thick pipes

Basic tools will help you make a one-time pipe bend.

To form a bend with a large radius of curvature on steel or aluminum professional pipes, stationary round templates are used, on which special clamps are mounted to fix the product. Using such a device, the pipe is also bent manually, placing it with force into the groove of the template, the shape of which exactly corresponds to the required bending radius.

Plywood and metal staples are all you need to make a bending template

Bending plate

To effectively bend steel or aluminum pipes at home, you can make an upgraded bending plate using the following guidelines.

The role of such a plate is played by a panel cut from thick sheet metal.
The panel made in this way is welded to a stand, which is installed on a special pedestal.
Two holes are drilled in the panel, which are necessary for installing bolts that serve as stops for the profile pipe.
A special attachment is installed on one of the stop bolts, with the help of which the bending radius is adjusted.
To ensure the alignment of the pipe sections adjacent to the bend, a metal plate is placed above the workpiece, secured with bolts.

Scheme of a stand for bending profile pipes

The principle of manufacturing a simple homemade bending device

When you are not using this upgraded pipe bender, its pedestal can be adapted to perform various plumbing operations.

Mandrel bending

For bending profile pipe products at home, the wall height of which does not exceed 25 mm, you can make a special mandrel. For these purposes, it is better to use a large workbench, on the surface of which there will be enough space for such a device. To select the optimal location for the element securing the bent pipe, frequently spaced holes are made at one end of the workbench. A special template is responsible for ensuring the required bending radius of the corrugated pipe, which can be made from thick plywood or a metal corner if you are going to use it often.

Bending a profile pipe using a mandrel

Alternative bending methods

Fortunately, you don't need any special equipment to bend pipes. People's ingenuity has long invented more than one way to achieve the desired result without using a pipe bender.

We use an angle grinder

In the area where it is necessary to bend the pipe using a grinder, several cross cuts are made. The smaller the bend radius, the more cuts will be needed. In most cases, three is enough. Next, the profile pipe is bent without much effort, and the cut points are sealed using welding.

If the welded areas are carefully sanded, the resulting product will look very decent . There will be no folds or significant loss of strength at the bend. But this method will not give ideal roundness, because the bend will consist of several straight sections located at an angle to each other.

Spring method

To make a spring you will need steel wire with a cross section of 2 mm. The wire is bent to the shape of the profile so that the side of each segment is several millimeters smaller than the corresponding side of the pipe profile and can move freely along its internal length.

Next, the spring is simply inserted into the pipe and bent to the required radius. To facilitate the bending procedure, the pipe section can be heated.

Note! To avoid problems with removing the spring from the cavity of the profile pipe after the bending procedure, a piece of wire should be securely attached to its nearest end.

Filling the pipe with sand

This method is striking in its simplicity and efficiency, because all the necessary materials are literally under your feet:

We first prepare two wooden wedges that can tightly close the pipe cavity.
We hammer the wooden wedge tightly into the end of the pipe.
We fill the pipe with sand, previously sifted and dried.
We drive in the second wedge.

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Next, one of the ends of the pipe is fixed and bent. To facilitate the procedure, the pipe section can also be heated. At the end of the work, the wedges are removed and the sand is poured out.

Using a dense sand bed will help prevent warping by ensuring an even and strong bend.

Plain water will help

One end of the profile pipe is closed with a plug, after which water is poured into the cavity. An indispensable condition is the presence of a negative temperature sufficient to freeze the liquid. After the water freezes, the pipe will bend without any problems, and the bend will be beautiful and durable.

It is important! The method is suitable for pipes made of non-ferrous metals that are not subject to corrosion.