How to bend a square profile into an arc. How to bend a profile pipe: secrets and little tricks. Features of different types of profile

Profile types of pipes with a square or rectangular cross section allow you to build a variety of structures that can withstand increased loads. When erecting a private structure, you need to have the skills and knowledge of how to bend a profile pipe at home with your own hands, so as not to damage its integrity.

The main characteristics of profile pipes

The main feature of profile pipes in comparison with standard products is their cross section. It is this difference that does not in all cases allow the use of standard bending methods to create the required radius of curvature.

In addition, industrial enterprises produce profile pipe products from a variety of materials, including copper, aluminum, brass, etc. This leads to the need to use different techniques in order to eventually bend the profile pipe.

In the process of carrying out mechanical actions in order to obtain a bent product, the pipe may receive defects and then, during operation, the integrity of the structure will collapse over time. For this reason, it is desirable to study the possibility of stretching it before bending the pipe.

To achieve the desired bending radius when doing the work yourself, you should do it smoothly and slowly and control the amount of effort applied. This will significantly reduce the likelihood of damage and obtain the desired shape of the product.

The choice of the option of how to bend a square pipe at home is influenced by the wall thickness of the pipe products. With a clear idea of what the final result should be, and the right approach to determining the method of bending, the erected structure will be distinguished by strength, reliability, aesthetic appearance and durability.

You should be aware that during the thermal impact exerted on profile products, changes occur in the internal structure of the metal from which they are made. As a result, the strength and reliability of the structure may be a big question. In addition, repeated attempts to bend the profile pipe with your own hands will lead to its destruction.

Using a pipe bender

It will not be easy to bend a profile pipe without a pipe bender or other similar devices at home, especially with a large wall thickness of metal products (read: ""). If one-time work is planned, then it makes no sense to purchase a pipe bending machine. In this case, it is better to rent special equipment by contacting companies that provide such services.

If you have to bend a profile pipe with your own hands, it is most expedient and reasonable to use a pipe bender with a special drive wheel. It, moving along one of the faces, allows you to bend the profile product as needed by the home craftsman in a particular case.

Pipe benders produce:

with manual control;
with electric drive.

When the profile products are bent manually, the fixture wheel is driven by a special handle. This method should be used in the case when the pipe section has a small area, and the future design should not be cumbersome and its shape can be changed by hand.

With a large amount of work and the same size of pipes, you will need a pipe bender for a profile pipe, equipped with an electric drive, which is set in motion simply by pressing a button. The principle of operation of this device is similar - the wheel moves along the edge of the pipe, but the result is more aesthetic and less labor-intensive.

Other ways to bend pipes yourself

There are several options that allow you to bend a profile pipe at home without special machines.

To perform bending of metal products relative to the radius, there are several requirements. The thickness of their walls must exceed 2 centimeters, otherwise the bend can violate the integrity of the pipe. With a profile height (indicated by the letter Z) of more than 2 centimeters, the pipe, bent at a length of 3.5xZ, will not collapse and will not become less reliable.

An important role is played by the temperature that the product has during bending. It is known that a pipe that is in a heated state is much easier to bend. When carrying out work in a domestic environment, it is necessary to adhere to safety precautions.

To bend pipes with a profile height of up to 1 centimeter, it is not necessary to heat the products to give them a curvilinear shape. But pipe products with a profile height of more than 4 centimeters cannot be bent with your own hands without heating.

Using a grinder when bending profile pipes

In order for a do-it-yourself bent profile pipe to obtain the required bend radius, you can use a grinder.

For this:

In the place where the bend is planned, several transverse cuts must be made (as a rule, 3 will be required).
Then you should bend the profile pipe with your own hands.
At the end, the places of cuts are welded with a welding machine.

Since the section of profile products has the correct shape, the resulting product should acquire an aesthetic appearance, provided that the welded areas are carefully ground. At the same time, the strength indicators will remain the same.

Bending of profile products using a spring

This option is simple to execute, for which you will need to perform the following list of works:

They take a wire, preferably steel, about 2 mm thick, and make a spring out of it.
Then it is inserted into the pipe.
Heat the place of the future bend.
At the end of the work, the product is bent, observing the required radius.

You should immediately monitor the correct bending of the profile pipe products, since the heated product retains its elasticity for a short time.

In the process of manufacturing a spring, you need to pay attention to such an important point: its segments should be 1.5–2 mm less than the parameters of the corresponding side of the section that the profiled metal product has. If you follow this rule, there will be no problems with how to insert the spring into the pipe.

Application of sand for pipe bending

For example, to get a square or rectangular bent pipe, sand is used, previously sifted and well dried. You will also need wooden wedges that have a comparable cut of the product, and which can be driven into the pipe.

The order of actions looks like this:

A wedge is hammered on one side of the tubular product.
Sand is poured inside the pipe.
The wedge is hammered from the second side, resulting in a kind of plug.
After fixing one end, they begin to bend the pipe to the desired radius. If desired, the place of the future bend can be heated to facilitate the process.

Due to the sand poured inside, the strength and integrity of the pipe structure will be ensured. After the successful completion of the work, it is removed, after removing the wooden wedges.

Bending pipes with water

You can also bend a profile pipe on your own at home with the help of water. This option is used when pipe products are made of copper or other non-ferrous metal. One end of the product is closed with a plug and poured inside its water. The product should be placed in a place where the water will freeze. After that, it will be easy to bend it yourself. To make it easier to get a square bent pipe, you need to bend it not in the middle, but closer to one of the ends.

Self-arrangement of a private plot may sometimes require bending a profile pipe for the construction of a greenhouse or gazebo. Some people think that it is impossible to do this without a special device, but there are several methods that can quite do the job.

The nuances of pipe bending

The term "profile pipe" means hollow products of square, oval and rectangular shape. Their round counterparts are also included in this definition, but they are used less frequently (more on types of pipes -). It is difficult to give a profile pipe curved configurations and at the same time maintain its technical characteristics, but it is doable if this is done on a special device using a hot or cold method.

The profile during this process is affected by two forces: from the inside - tension, and from the inside - compression. To balance these efforts, apply several nuances:

When bending the pipe, you need to monitor its outer wall. When heated, it expands very much and may not withstand the load, which leads to its crack.
It is necessary to bend slowly, then the risk of a fracture will decrease.
After completing the process, check the edges of the pipe, and if they lie in different planes, repeat the bending process to align them.
When choosing a bending machine, you need to focus on the thickness of the pipe walls and its cross section.
The inner wall of the pipe after the process may resemble an accordion, this is normal, as there is a reduction.
It is necessary to start bending the pipe from the end, and not from the middle, otherwise it will be more difficult to change the profile.

Before bending, you need to practice on unnecessary pipes to prevent marriage.

How to bend profile pipes by welding?

You can bend the profile pipe in a semicircle using a grinder. It is used to make several cuts along the entire profile of the pipe. This way is as follows:

Fix the pipe in a clamping vise.
Make thin cuts in the places of the future pipe deflection.
Clean the cuts from chip dust, and carefully bend the profile along them.
Weld the holes formed during bending using a welding machine. With a small pipe diameter, a soldering iron can be used for this purpose.
Clean and grind the formed profile bending points and treat them with a protective compound, it will protect them from corrosion.

With it, you can get a pipe of the desired radius. When choosing this method, you do not need to use a vice, the workflow is as follows:

Fix one end of the pipe in the ground and close it with any plug.
Fill the profile pipe with sand.
Heat up the blowtorch. Move it near the place of the intended fold.
Bend the pipe, but this must be done quickly so that the metal does not have time to cool, otherwise you will not bend it.

This "hot" method allows the use of water instead of sand.

Springy pipe bending method

This method preserves the integrity of the walls of the profile pipe. Before applying the method, preparatory work is carried out:

Spring preparation . It is made from steel wire. The diameter of the latter depends on the thickness of the pipe walls. For winding the spring, a square section blank is used, a wire is laid around it. The outer diameter of the spring must be smaller than the inner dimension of the pipe.
Template preparation . Pipe bending will be carried out according to a pre-made reference blank.

The deformation of the profile pipe is carried out by laying a spring in it, which will protect the material from fracture. The part is heated with a blowtorch, and when hot, it is deformed to the desired diameter.

Bending profile pipes on a manual pipe bender (video)

The video below shows how to bend profile pipes with a cross section of 25 × 25 mm and 20 × 40 mm in order to make a frame for a greenhouse from them.

Pipes come with a wall thickness of 2 mm. Homemade pipe bender is a welded structure. It consists of the base of two small rollers sandwiched between the uprights. In the middle of the structure rises a carriage made of corners. A square platform is welded on their upper part, into which a screw with a nut from a jack is inserted, and a removable handle is inserted on it. A handle is also attached to the first roller, with the help of which the pipe is fed to the machine. A third roller is provided inside the carriage, the deflection arrow will pass through its center.

Pipe bending process:

Put the pipe on the two lower rollers and stretch it to the required distance by scrolling the first roller.
Lower the middle roller by turning the knob.
Pass the entire pipe to the marked mark in one direction. It will become slightly arched after rolling.
Perform the previous action only in the other direction, lowering the middle roller below. The pipe remains in the device and must be returned to its original position by turning the handle on the lower roller in the opposite direction.
Run the pipe a third time through the pipe bender. The arc of its bend will sharply increase.
Repeat all steps for the 4th time.

The result will be a rather impressive radius of pipe deflection, so you can prepare the required number of profiles.

In the next video, you can clearly see how you can make and use a pipe bender with your own hands:

The described methods using sand, welding and springs are used for special cases in the household. If you need to bend pipes often or you plan to build a large building with them, then it is better to purchase a profile bender or make it yourself. When using a pipe bender, the process is faster, the profile is correct without unnecessary kinks.

In the presence and self-arrangement of a private house or cottage, almost every developer once faces the need to bend pipes. Many people think about how to bend a profile pipe at home when building greenhouses, gazebos and other buildings of this type on the site.

And this is not surprising, given that profile pipes look noticeably more advantageous in comparison with products of an ordinary round section.

However, if a pipe with a circular cross section can be bent with an ordinary pipe bender, then it will not be possible to bend the profile pipe with it, since in conventional hydraulic pipe benders the rollers and shoes have a rounded bend, which, when trying to bend the profile pipe, will lead to cracks, kinks, or the pipe will simply flattened.

Profile pipe bending methods

How to bend the profile pipe yourself in this case, avoiding its damage? For this purpose, several methods are used, one of which is bending by means of special machines that are designed specifically for shaped pipes.

Machines of this type are called profile benders. Nevertheless, the cost of such machines is very decent, and why does an ordinary homeowner need professional equipment?

If you do not need to bend a professional pipe all the time, but from time to time, you can find manual pipe benders on sale that are suitable for both profile and “round” pipes, which, moreover, are not so expensive - up to about $ 100. At the same time, it must be borne in mind that in the process a manual pipe bender will require significant physical effort.

With a single need to bend a profile pipe, it is not advisable to purchase a tool and it is better to contact a workshop or workshop of the corresponding profile, which will provide the necessary service for reasonable money, or else sell a ready-made bent product.

This option will save both time and money, while the result of resolving the issue will be exactly the one that is needed - bending the profile pipe to the desired radius.

Another method that is often practiced in such cases is to bend the profile pipe with your own hands using, so to speak, folk remedies. However, in this way it is possible to bend pipes of small sections - steel, copper, polymer.

Bending profile pipes with pipe benders

Features of bending

How to bend a profile pipe yourself? This should be done based on the size of its cross section, wall thickness, the material from which it is made, as well as the bending radius.

In addition, the production conditions, the required bending accuracy and the quality of the resulting product must be taken into account.

Bending of profile pipes is carried out within technical tolerances for wall thickness and section size. In this case, the task is to avoid such undesirable phenomena as kinks on the inside of the bent pipe and flattening of its cross section.

Before you bend a square pipe along a small radius, you need to remember that you should bend closer to the ends, since in the middle part the pipe will be more difficult to succumb to.

Performing a pipe bend

To perform the bend, you will need a pipe bender specifically designed for cold stretch bending. The tension generated by such a tool will shift the neutral axis of the pipe in the direction of the bend, which reduces the likelihood of a corrugated surface at the bend.

While in the machine, the pipe is wrapped around the edges and stretched, and at the same time it bends when the bending template moves.

How to bend a stainless steel pipe without losing the quality of the pipe? To prevent the loss of resistance of the pipe walls at the bend, bending is carried out under internal hydrostatic pressure: plugs are put on the ends of the pipe and liquid is fed into it, after which a bending template is brought to the middle of the pipe, with which the bend is performed, giving the pipe the desired shape.

Pipe bending at home

You can bend a profile pipe with your own hands without the help of special machines and tools. And in most cases, you can achieve a bend of really good quality.

Performing bending using a grinder and welding

Before you bend the profile pipe, you will need to arm yourself with a grinder and a conventional welding machine.

Bending is performed in the following sequence:

Calculate the radius of curvature of the pipe.
Along the length of the bent section, uniformly transverse cuts are made on three sides.
After that, the pipe is easily bent.
Weld the sawn places.
Process and grind the place of welding.

In this way, an impressive external result can be achieved with the desired bending radius of the pipe.

Bending using internal countermeasures

One of these tools can be a specially made spring. Before bending the profile pipe, a square spring is wound from a steel wire 1-4 mm thick (depending on the thickness of the pipe being bent).

The value of each of the sides of the spring segment must be 1.5-2 mm less than the internal values of the pipe section so that the spring can penetrate inside the pipe without any effort.

After installing the pipe in the place of the intended bend, immediately before bending the profile pipe, the bent section is heated with a blowtorch. Next, the pipe is bent on a blank, the radius of which is equal to the required inner radius of the bending pipe.

If necessary, bend in the winter, a somewhat original method can be applied.

So, how to bend a profile pipe:

A copper pipe is filled with water, having previously closed one of its ends with a cork.
Expose the pipe to frost until the liquid freezes completely.
The bending of the copper pipe can then be carried out according to a template of the appropriate radius with virtually no loss of section and without effort.

Aluminum and brass pipes can be bent in the same way.

How to bend a professional pipe without a pipe bender? Prepare several buckets of dry and clean sand. If it was not possible to get clean sand, the usual one, lying in the yard, will also do.

It will need to be sieved and dried properly by calcining it on a fire or with a gas burner until the sand stops steaming and smoking. After processing and cooling, the sand is poured into a dry and clean container.

Before bending a square pipe, a wooden wedge is hammered into it from one side to a depth of 10-20 cm, and then prepared clean and dry sand is poured into the free hole of the pipe until the pipe is completely filled. Next, a similar wedge is hammered on the other side of the pipe and the bending process begins directly.

The operation, as in previous cases, is performed using a blank with a diameter corresponding to the required inner bending radius. If the bend is too steep (small radius), the bend can be heated with a torch. Sand, tightly packed into the pipe, will not allow it to lose integrity or be severely deformed.

At the end of bending, one of the plugs is burned out at the stake, sand is removed from the pipe, and the second plug is knocked out or burned out of the pipe. It will not take much more time to bend in this way, in comparison with how to bend a profile pipe using a pipe bender.

The methods presented in the article for bending profile pipes will be effective if all of the above conditions are met, however, bending of really high quality in every sense of the word can only be achieved with the help of professionals who will perform work on equipment specially designed for this. Approach work with skill, only thanks to this it will be possible to achieve the desired result, while spending a minimum of money and effort.

A garden bench, smooth curves of the entrance gate, a porch decorated with forged decor and a garden arch - all these items make the estate unique and cozy, give a sense of calm and tranquility.

But this is only when what was conceived has already been embodied in the finished composition, but when in the process of creativity the question arises - how to bend the profile to a touching mood is very, very far away.

And, although other technologies, such as electric welding or metal cutting, can be learned by simply buying an ordinary inverter or a grinder with a set of cutting and emery wheels, in order for a profile pipe to acquire a graceful bend, you need not only to have special equipment in your arsenal - a pipe bender, but also to have a certain idea of how the workpiece profile changes itself.

Counting on the fact that everything will turn out smoothly and simply the first time is rather naive, but on the other hand, only optimists are able to learn from their mistakes.

When working with a material such as a profile pipe, it is important not only to understand the process of changing the configuration itself, but also to imagine what changes occur in the material itself.

A profile pipe, and if we are talking about a profile pipe of a conventional rectangular or square section, has slightly different than a conventional round pipe:

The first is a feature of production, a profile pipe is basically a welded structure, made by hot or cold drawing, followed by joining the edges of the workpiece by welding.
Secondly, the section itself has a non-uniform wall thickness. For such a shape, a significant, up to 30% thickening of the metal in the corners of the rectangle is characteristic.
Thirdly, with simple efforts to apply force to the place of bending, you can quickly simply break it, because when deformed by bending, in such a shape of a part, one of the sides experiences compression, one is stretched, but the two sides of the profile have a combined deformation - in a narrow section, the profile is stretched and shrink at the same time.

And therefore, before bending a profile pipe on your own, in order to obtain the correct, desired size and shape of the workpiece, you must at least take care of using even the most primitive, but extremely necessary equipment for pipe bending.

The main methods of bending a profile pipe

Before bending a profile pipe at home, even using some mechanization or simple hand tools, you should pay attention to some methods for working with a profile pipe. For a separate piece product, for example, a gate or buying special equipment, there is no practical sense, but knowledge on how to give the profile an unusual look still follows.

Today, as for ordinary profile pipes having a square, rectangular, complex and round section of pipes, there are several methods for changing the shape:

bending with a template
manual roller pipe bender
mechanical pipe bender with adjustable bending radius
hot bend method
segment method

The use of any of the above methods allows you to get the desired shape of the profile, while the quality of such a change in shape, the ability to correct errors largely depends on the qualifications and ability to work with metal.

Attention! It is very important to understand that with profiled pipes, it is also necessary to know about the properties of the metal of manufacture itself, for example, for steel pipes, bending is possible by all methods, but for copper pipes, in addition to all of the above methods, there are two more - the water method and bending using a flexible cable.

In any case, the experience of how to bend a profile pipe with your own hands, an understanding of the methods of working with pipes of different cross sections and sizes will come with time, as well as an understanding of what mistakes were made and methods for correcting them.

Errors when working with a profile pipe

The process of bending a profile pipe is nothing more than the deformation of a metal in order to give it the necessary shape. At the same time, as practice shows, in the process of when you have to most often there may be the following problems:

the appearance of small folds on the inner surface of the profile
bending with violation of the axis - torsion of the part, bending in several planes
plane or weld break
crushing or fracture, the appearance of cracks at the bend

Such shortcomings mainly arise due to several reasons:

low-quality metal profile
wrong choice of bending radius
applying too much force
incorrect, multidirectional application of effort during work

But these are common problems when using bending machines and fixtures. But how to bend a profile pipe without the slightest experience and additional equipment is worth considering.

Indeed, in this case, much more problems will arise, ranging from simple abrasions and bruises, ending with a broken tool and disappointment in the project that has begun. Therefore, before proceeding with the profile bending process, one should seriously consider the feasibility of using bent elements in the project.

From simple to complex

When using a bent profile, you should keep in mind the possibility of its independent bending.

Before bending a profile pipe with your own hands, you should critically evaluate your capabilities and make the most optimal decision, do the work yourself or find an enterprise where the machine will perform this process.

Most often, at home, small-sized profiles 15 * 15, 20 * 20, 20 * 40 mm are theoretically used independently, without the use of machines and devices, you can bend the profile to a size of 60 mm, but this is only theoretical. But using a grinder to bend a pipe of the desired size and radius is quite possible.

In practice, this process looks like this:

a curved pattern is cut out of paper
segments are cut out of a strip of paper equal to the thickness of the profile pipe in such a way that the required template radius is obtained as a result of bending
using a scriber or pencil, a paper template with cutouts is transferred to the pipe
a grinder with thin cutting wheels 1.2 mm thick makes appropriate cuts, the segments are removed
the pipe is bent, the correct radius is checked
if necessary, electric or gas welding welds the seams at the bends

From a technological point of view, it is the simplest and quite effective to give the desired bending radius to a large section profile. In order to perform this operation, it is enough to have basic skills in working with power tools and correctly calculate the places for cuts.

Using templates for bending a profile pipe

To put on stream the formation of several identical parts, in their small-scale production, for example, for fencing a balcony or terrace, it is recommended to use a template method for bending a profile pipe.

For this operation, it is quite enough to have a minimum number of tools and materials:

locksmith vice
a hammer
workpiece template

The overall process can be represented as follows:

a profile template is made
fixed in a vice
the workpiece is fixed in a special clamp and then passes to give the profile the required shape

From the point of view of how to bend a profile pipe at home, this method allows you to form the required number of blanks of the same type with minimal deviations from the template.

Most often, this method is used to form parts from a thin-walled profile pipe of a small size from 15 to 40 mm.

Universal pipe bender for large radii

From the point of view of work productivity, a three-roll pipe bender is best suited to obtain a large bending radius of a profile pipe.

Such a mechanical device allows you to obtain blanks of any length and size. Simple in design and effective, the device has a frame base in its design, three shafts rigidly mounted on bearings with a toothed chain drive.

Two shafts are located on the base, and the middle shaft, which has an upper location, is located on a movable slide. To form a profile, the sled has a screw that regulates the degree of clamping of the workpiece.

The profile pipe is pulled through the shafts, gradually forming the desired bending radius. By pressing the upper shaft, the desired profile bend is formed.

Among the ways to bend a profile pipe, this is the most effective and high-quality method.

The video shows how to bend a profile pipe at home:

July 24, 2016
Specialization: Capital construction works (laying the foundation, erecting walls, constructing the roof, etc.). Internal construction works (laying of internal communications, rough and fine finishing). Hobbies: mobile communication, high technologies, computer equipment, programming.

Recently, it occurred to me to make a gazebo at a summer cottage out of rolled metal, and not simple, but with fashionable frills and bends to show off to friends and acquaintances and surprise them with something. For this, bent parts were needed, but I didn’t bring a pipe bender from the city and didn’t want to go after it (I already took a little cognac for mood). Therefore, I had to get out of the situation and decide how to bend the profile pipe at home.

Features of bending profile pipes

If you recently began to do something around the house with your own hands, you may not understand the importance of the problem. Indeed, what is difficult there: rot it to yourself with a hammer in any direction and that's it.

However, it is not so easy to give a profiled pipe a smooth and curved configuration, while retaining all its technical characteristics. This is usually done with a special tool under pressure in a cold or hot way.

The bottom line is that two forces simultaneously act on a rectangular profile when bending:

compression - from the inside;
stretching - from the outside.

As a result, several difficulties arise, due to which the locksmith comes up with various tricks for bending pipes:

Rolled metal in the process of mechanical action can change its shape, as well as lose the alignment of individual parts. As a result, the edges of the part will lie in different planes, which will not allow it to be used during installation.
The outer wall, which is stretched during the bending process, may not withstand the mechanical load and crack, losing the necessary strength.
The inner wall, on the contrary, will contract incorrectly and form folds, resembling a corrugated pipe in their appearance.

In principle, I have met more than once with cases when an incorrectly bent workpiece is simply crushed, after which it can only be thrown into scrap metal. This leads to an unjustified increase in construction costs, which is similar to death for a zealous owner.

That is why you should not immediately rush into battle with pipe cuts, but study pipe bending technologies. And they, by the way, directly depend on the technical characteristics of the rolled products used. I want to talk about this further so that you understand the whole mechanics of the process.

Influence of material characteristics on the choice of bending method

If you do not know yet, then I inform you that the concept of "profile pipe" includes pipes of all geometric shapes, including round ones. But for ease of understanding, it is customary to call only products of the following forms:

square;
rectangular;
oval;
flat oval.

This is due to the fact that a metal round pipe is used to design water and gas transmission systems, as it is ideal for this and has strong walls that can withstand significant pressure well.

Pipes of other shapes are more used in construction to create various structures and design furnishings. Further, I will only talk about square pipes, since I am going to use them for construction.

So, there are also many square pipes in the store. They differ from each other in cross section and wall thickness. And these two parameters, in turn, affect the minimum angle at which square rolled metal can be bent without damaging it.

I do not want and will not now go into engineering subtleties and features that home craftsmen do not need for nothing. I can only say that in order to determine the minimum bending radius, you need to know the cross section of the pipe.

The radius is defined like this:

for thin pipes, the cross section of which does not exceed 20 mm, the pipe must be bent in a section 2.5 times greater than the height of the profile;
for thick pipes, bending must be done in a section 3.5 times larger, otherwise the metal will crack on the outside or wrinkle on the inside.

For wall thickness. Personally, I do not advise bending large pipes with too thin walls, otherwise the parts will lose alignment.
It is better to use a grinder and a welding machine.

Before bending a profile pipe, it would be useful to know that the carbon steel pipes you use tend to spring back a little, that is, return to shape after the impact stops. Therefore, in order to bend the pipe under the desired radius, plasticity must be taken into account, making the bend a little larger than necessary according to the drawing or pattern.

Pipe bending methods

In general, I decided that it’s enough to load your heads with theory (although you can’t do without it). Therefore, I will go directly to how to bend a profile pipe at home.

Quite often in my practice, I bent profile pipes, while heating the bend with a blowtorch. High temperature increases the plasticity of the material and reduces the risk of damage to the part.

But if for construction you use thin rolled metal of a small section, you do not need to resort to additional tricks. Square pipes and so will take the shape you need. Of course, if you approach this matter with due skill.

I cannot give you unambiguous advice on when to use heat and when not. I can only say that the current building regulations provide that it is necessary to heat a round (not square) pipe if its diameter exceeds 10 cm.

However, I will give my own considerations, which have developed as a result of many years of work at construction sites:

if the pipe section does not exceed 1 cm, I would not even mention any heating;
in cases where the pipe cross section is more than 4 cm, I would still advise using a blowtorch so as not to spoil expensive rolled metal;
between the two extremes above, decide for yourself.

You can try to bend the pipe by holding one end in a vise. If, when applying force, the pipe bends easily and does not wrinkle, you can not heat it. If it's hard to bend, warm it up. I'll tell you about that, and about that way.

Hot bending of profiled pipes

I'll start with hot bending, as more difficult. To avoid deformation of the pipe, its cavity must be filled with sand. In this case, you will get a detail, the appearance of which will satisfy even the most strict OTC master (inspired from the past).

The process of hot bending of a profiled pipe is as follows:

From suitable pieces of wood (I take two blocks) I grind out two plugs that are suitable in size for the existing pipe. They should fit snugly into the side holes of the part and not hang out.
Then, on the side of the plugs, I select small grooves through which hot gases and a bent metal pipe will be vented to the outside.
The section that will be bent is pre-annealed.
Then I prepare the filler, the role of which is played by pure river sand (although, in principle, any fine-grained sand can be used).

Sand is poured into the pipe according to the following scheme:

I plug one end of the pipe with a cork;
I pre-calcined the sand with a blowtorch;
I pour sand into a workpiece installed perpendicular to the ground or at an angle;
while falling asleep, I tap on the pipe so that the grains of sand are distributed evenly, leaving no voids;
after the blank is completely filled, I close the second end of the pipe with a cork.

I recommend sifting sand before use, getting rid of gravel and small pebbles. First you need to use a large sieve, and then a fine one, with a mesh size of 0.7 mm, to get rid of dusty particles.
If this is not done, the sand will bake inside the pipe and it will be problematic to pour it out from there.

After filling the filler, I turn to bending. To do this, I clamp the workpiece with one end in a vice and mark with chalk the place that will need to be bent. The part must be fixed so that the weld seam of the pipe (if it is not seamless) is on the side. Otherwise, it may burst.
With a blowtorch, I heat the desired area to a dark cherry color and give the pipe the desired shape. This should be done with a quick but smooth movement, making sure that the bending is done in the same plane.

After the metal cools down, I knock out the plugs and pour the sand out of the pipes. If the wooden bars cannot be knocked out, I burn them out with a blowtorch.

I will immediately warn you that this method is suitable if you need to bend the workpiece under a certain (not very large) radius in one place. That is, the metal will have to be heated only once.

Otherwise, constant temperature fluctuations will violate the strength of rolled metal and the part may simply burst.

Cold bending

It is possible to bend a profiled pipe without heating it with or without filler. If the section of the part does not exceed 10 mm, you can do without filling the cavity. It is better to pour sand into a large pipe.

Sometimes profiled pipes I bent using a dense spring of the right size. It is placed in the cavity of the pipe, after which it is bent at the desired angle, without fear of displacement of the axes of the part.

In this case, it is important to choose the correct spring size. It should enter the pipe tightly, but move freely. Otherwise, then this part may not be available.

If you need to bend the pipe to the desired radius, and there is no blowtorch at hand, I suggest using another method, which I also had to resort to. To implement it, you will need a grinder with a disc for cutting metal and a welding machine.

The scheme of work is as follows:

It is necessary to calculate in advance the radius of the bend of the pipe and the segment that will be bent.
Cuts should be made along the length of this section on one side, leaving one side of the pipe intact. The number of these cuts depends on how small the bend radius needs to be.
After that, thanks to the resulting cuts, you can easily bend the part by holding one end of it in a vice.
The next step is welding the damaged areas using an electric or gas welding machine.
Once the seams have cooled, they can be cleaned and welded.

Use of special equipment

All of the methods described above can be used if there is a small amount of work to be done. However, when giving a smooth bend to a large number of parts, you will have to use specialized equipment. You can make your own, buy or rent.

I’ll tell you about this in a little more detail, since there are quite a lot of questions of this kind, so I consider the topic relevant.

The simplest manual pipe benders

At one time, I had to bend a considerable amount of rolled metal, so even offhand I can give many examples of simple bending devices. As I said, the specific mechanism depends on the pipe section, wall thickness and the required bending radius.

For home craftsmen who have decided to build an arched structure from profiled pipes, I offer the following options:

Thin profiled pipes can be bent using a horizontal steel plate with drilled holes. Pins are inserted into them, which play the role of stops when giving the workpiece the desired shape.

It is necessary to place the pipe between the stops and bend it at the desired angle. You need to start from the middle of the part and move to the edges. As a result, it is possible to bend the pipe, but you will not achieve the ideal shape, and you will have to apply a lot of force.

I recommend bending pipes of medium thickness with the help of rollers interconnected like a Volnov machine. In this case, the part must be fixed in a vice, and then the workpiece must be bent using special rollers.
The quality of the bend is better than the technology described in the first paragraph. However, given the thickness and cross section of the workpiece, you need to be a strong athlete to bend the parts. Especially if there are a lot of them.

To bend parts under a small radius (for example, arches for a gazebo), you can use home-made patterns with a groove at the end and a collar for which the pipe is hooked.

As in all previous cases, bending requires considerable physical effort. But the part takes the ideal shape, due to the configuration of the sample.

bending plate

If you like DIY and often use shaped pipes, I recommend taking the time to make a stationary bending plate that will help you bend any square and rectangular pipes to the desired angle.

It may take the form of a mobile panel, which is attached to the work surface with clamps for work. Also, the slab can be welded to a channel or rail, concreted into the floor of the workshop.

The scheme for manufacturing a universal bending plate is as follows:

The basis for the fixture will be a thick metal plate. It is better to take thicker metal so that the device does not deform when bending thick pipes of large cross section.
It is necessary to cut or drill several holes in the plate, where to insert the bolts, which will serve as stops for bending the pipes at the desired angle.
The bending radius of the pipe during operation can be adjusted with nozzles of a suitable diameter, which are put on the bolts.
To maintain the alignment of the workpieces while working on them, you can install another plate that prevents the part from bending in a different plane.

Mandrel for pipe bending

This locksmith fixture is used to process pipes whose cross section does not exceed 2.5 cm. To make it, you will need a workbench and a large free space around it. On one edge of the working surface of the workbench, you need to drill a lot of holes in different places, which are necessary to secure the support bolts.

In addition, you will need a piece of thick plywood, along which the workpiece will be bent. The shape of the part after processing will exactly match the diameter along which the plywood was cut.

The disadvantage of this solution is that you need to change the template every time you need to bend the pipe to a different radius.

The scheme of work with such a mandrel is as simple as possible:

The end of the pipe is fixed between the bolt and the mandrel (pattern), which, in turn, is tightly attached to the workbench using several clamps.
After that, you just need to bend the pipe, resting it on the pattern.
If the workpiece is short, a pipe of a larger section (or diameter) can be put on its end, which will play the role of a lever.

Manual bending machine

If you are going to open your own business for the manufacture of arched structures from profile pipes, all manual fixtures will not suit you. After a few days of work, your hands will simply fall off, so it’s better to mechanize the whole process right away.

For bending pipes in this case, it is better to use a home-made or purchased bending machine, consisting of two fixed and one movable roller. By adjusting the position of the latter, you can change the bending radius of a square or rectangular pipe. Although the price of the machine is rather big, it will save you a huge amount of time and effort.

Conclusion

Now, I hope you understand how to bend a profile pipe without a pipe bender and using special equipment. As you can see, if you know some secrets and technologies, there is nothing complicated in this process. You can safely get to work.

And if you have your own technologies for bending square or rectangular pipes, I will be very grateful if you share them in the comments.

You can get more creative ideas regarding the construction of houses and the arrangement of suburban land plots from the video in this article.

July 24, 2016

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