Pipes fastened to different parts or to each other must not leak. To this end, the adjacent edges are deformed. The technology is called rolling — increasing the edge of the pipe at an angle. This is the deformation of a section of the part. We will tell you how to flare a copper tube yourself.

Bell tubes

Features of rolling depending on the technological processes of pipe fastening

Which flare option to choose depends on the method of fastening copper tubes to each other or to structural details:

  1. If welding is planned, the hole is enlarged to the required size. The inner diameter of the pipe must exceed the outer diameter of the connected element by 0.1 — 0.2 mm. The gap between them is filled with tin or other solder. This will provide good insulation.
  2. If the elements are interlocked with a coupling, the hole is not only enlarged, but also a bell is made at an inclination of 45º. The increased contact area will increase the reliability of the connection.

The rolling steps are the same, regardless of the technology of fastening the elements.

Action algorithm

How to make rolling copper tubes with your own hands? It is necessary to carry out actions in the following sequence:

Tube cutting device


The pipe must be cut perpendicularly, the edge must be even.

  1. It is important to carefully clean the outer cut zone and its edges. If deformation occurs during cutting, it is necessary to restore the shape of the pipe.
  2. The next step is to fix the element in the matrix of a special tool for increasing the diameter or vice. 5 mm of the end of the part must be left free. If fitting fastening is supposed, a compression nut is installed on the element before fixing.
  3. An expansion cone of a suitable size must be placed in the hole and screwed in. After such an action, the copper material will stretch, and the end of the part will gradually begin to take the shape of a cone.
  4. The next step is to remove the expander and remove the workpiece from the holder.

Next, you should inspect the resulting socket. If there are bumps, scratches, micro-chips, they must be cleaned. After expanding the tube, you must wait until it cools down to room temperature and only then start bonding.

Important! Sometimes, after flaring, cracks appear on the treated area of ​​the tube, the edges are beveled with respect to the axis. Then the processed edge will have to be cut off and start all over again.

Devices and devices

To make flaring at home, you need to prepare tools. to increase the edge of a copper tube is available to a person without experience manually by pulling it on a conical blank. The disadvantage of this processing method is that it will be difficult to obtain a socket with the given dimensions, because the master applies an uneven force. Such flaring distorts the part. The flaw can be avoided using special tools.

The construction market offers devices that expand the diameter of copper products with a manual or electric drive. Power tools are used for expanding pipelines and for other purposes. For example, bending at the right angle. All devices operate on the principle of plastic deformation, which ensures that the inner surfaces of the pipe remain smooth in the process of expanding the diameter of the product.

Flaring Tool Kit



This is the simplest apparatus — a blank in the shape of a cone. Made from any metal alloy that is harder than copper. The main advantage of the template is a small price. In addition, it is easy to apply. But this method of increasing the diameter of the product is often accompanied by wall ruptures.


This is a manual device in which the increase in the diameter of copper pipes occurs as a result of the application of force. The device consists of 2 levers and a sliding cone, on which the element to be processed is mounted. When pressing on the handles of the expander, the elements of the expander diverge in different directions, the copper product is stretched. This inexpensive device does not guarantee a quality result. When using it, it is impossible to control the thickness of the pipe; gusts may occur in thinner zones.

Expanding the product with an expander is advisable to perform in two stages. First slightly expand the edge, then turn the tool and stretch the pipe to the required diameter.


cone flaring machine

It is the simplest set: a matrix and a flaring tool. The first of the 2 elements is a plate with rounded slots in the dimensions of standard pipe sections. The expander consists of the following elements:

  • corps;
  • expander;
  • lead screw.

When the lead screw begins to rotate, the expander is screwed into the hole of the product and creates a bell.

Mechanical and electrical tools


The mechanical device is similar to the conical one, only its working element is a set of rollers. They act not by stretching, but by uniformly rolling out the walls of the pipes. This technology ensures the same thickness of the material throughout the treated area. Due to this, the inner surfaces of the pipe remain smooth during the rolling process, and the socket is neat and symmetrical.

An electric apparatus differs from a mechanical one by the presence of an electric drive. It significantly reduces the process time and does not require any effort.

Electrically powered spreader

Important! The master, facing the choice of a tool for rolling, needs to determine its need. For repair, a simple device with a simple set of nozzles is enough. It is advisable for a specialist laying and repairing pipelines to buy a professional set.

Useful tips for completing the process


The tightness, reliability of fastening depends on how well the work is done. To do the flaring yourself and get a good result, you need experience. In the absence of skills, before installing a copper pipeline, it is advisable to first practice on pipes of different diameters.

In order for the flaring to be of high quality, it should be performed in accordance with the recommendations:

  • Before starting the technological process, it is necessary to visually identify the presence of burrs, irregularities on the product. Remove dirt from the inside and outside of the tube. Flaring is done only on products with a circular cross section.
  • Before starting the technological process, the outer surface of the copper part should be carefully brushed to remove dust and debris.
Abrasive sponge cleaning
  • It is important to firmly fix the product in the holder. If this is done carelessly, the tube will slide in the matrix, which will not allow for high-quality processing.
  • If the edges of the copper element are expanded manually, the cone must not be pressed in. The blank should be carefully screwed into the hole. Then the force will be evenly distributed and it will be possible to avoid breaks in the wall of the product.
  • In the process of work, it is important to ensure that the socket does not warp relative to the axial one. If this happens, the connection will not provide complete insulation, high wear resistance.
  • When installing the element in the die of a rolling device, it is important to select the hole size that matches the diameter of the copper tube.

With proper flaring, you will get a high-quality socket for a strong tight connection.


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