Plastic pipes today more confidently displace metal products. For this reason, their welding remains one of the urgent problems of everyone who decided to replace the pipeline in the house. You can assemble a plastic communication system, guided by a specific scheme of actions. At the same time, the elements must be interconnected, complemented by valves and fasteners, as well as sealed.
On sale you can find elements that provide the ability to assemble a pipeline of any complexity and configuration. The only drawback of such pipelines is irreversibility, because the dismantling of the welded joint is impossible. Therefore, polypropylene pipes should be handled with particular care, otherwise they will have to be replaced.
Among other tools for assembling the system, you will need an apparatus for welding pipes made of polypropylene. With its help it is possible to heat the parts and perform their connection. Fixation of elements should be carried out before cooling of the weld. Strength and tightness will be quite high, so the pipeline will be able to work even at fairly impressive pressure.
The apparatus for welding polypropylene is structurally simple, it consists of:
- from the pen;
- heating stove;
- temperature regulator.
The plate usually has two holes for mounting welded elements or nozzles. If you get closer to the standard set for pipe welding, you can understand that the kit includes four welded nozzles, with which you can solve any problems associated with laying a polypropylene pipe.
More about nozzles
Nozzles for welding polypropylene usually have a diameter in the range from 20 to 40 mm. The intermediate values are 25 and 32 mm. The working surfaces of the nozzles have Teflon spraying, so it is not possible to make welding elements yourself, since plastic will stick to the unprotected surface.
Pipes can be prepared by degreasing the ends. Some homemasters ignore this recommendation. The pipes will be welded, but the quality of the connection will be lower. Before welding, the inside of the fitting must be treated with alcohol.
This also applies to the outer end of the pipe. This will eliminate dust and abrasive particles that can damage the Teflon coating of the nozzles. In order not to damage the equipment for welding polypropylene, nozzles should be treated with alcohol, which will prevent sticking of plastic and damage to Teflon.
Marking the landing depth
Another quite important point is the marking of the depth of the pipe in the fitting. The latter can have a different caliber, and therefore, a certain depth of the welded joint. Therefore, before starting work, it is necessary to make measurements using a ruler or vernier caliper. This will eliminate the introduction of the pipe too deep. Ignoring this recommendation, you can cause a narrowing of the hole section or provoke a pipe seal.
If you will be welding pipes from polypropylene, then for marking you can use a special device that will save time and nerves. It can be performed independently from a pipe whose diameter is 32 mm. The element is suitable for a 20 mm pipe. For the reason that the landing depth of such a pipe is 15 mm, it is necessary to cut a workpiece from a 32-mm piece, the width of which will be 15 mm. This tool can be used to mark the depth line.
It is very convenient to use the workpiece if it is supposed to weld pipes of the same diameter. A dimensional ring can be improved by gluing a cardboard or plastic bottom to it, this will simplify the marking process. If you weld pipes from polypropylene quite often, then experts recommend making such copper rings for all diameters.
If you weld pipes at their location, then you will need the help of another person who will hold the welding machine. Whereas at this time you will be able to dock the pipe and fitting with welded nozzles, and then between each other. Quite often, some home craftsmen overexert the heating elements, this leads to a narrowing of the lumen of the pipe. In order to know the heating and cooling times, you must use the manufacturer's recommendations.
Before welding the polypropylene, it is necessary to determine where the pipes will be laid. This will reduce the number of welds per weight. Experts recommend assembling the elements on a flat surface, and then fix them in the system.
To connect the pipes, the edges of the elements are heated. The inner wall is in the coupling, and the pipes should be heated from the outside. To do this, they are almost completely put on the nozzle and held for several seconds. Then the elements need to be interconnected. You will only have a couple of seconds to center them. Usually these works are done by eye. Scrolling elements in relation to each other is not worth it.
The width of the seam and the thickness of the plastic will determine the welding time. Welding polypropylene will provide a reliable connection if the material has been heated to the desired temperature. Before welding the pipes, the valve on the coupling must be opened, otherwise air will push it out of the nozzle. Part of the plastic when connected comes out, forming an influx on the coupling. If problems occur during donning and the plastic is severely deformed, it is recommended to chamfer the edge.
If you follow German standards, the stripping should have an angle equal to 15 °, while the recess reaches 3 mm. Russian experts are guided by other rules, they say that the bevel is 45 °, while the recess is one third of the thickness. In practice, any chamfer within the mentioned limits is suitable, but its uniformity is the main condition.
When welding polypropylene with your own hands, you should leave the device on a stand, which has the form of a special clamp. A temperature of 260 ° C is set on the controller; however, for speed this parameter can be increased to 280 ° C. If you use a different temperature limit, this can cause a decrease in the reliability of the connection, so when buying a unit, you must choose a model with a temperature controller.
The elements are difficult to put on the heating nozzle, so they must be rotated along the axis. However, the pipes must not be inserted all the way, otherwise they may melt inside. In order to avoid such troubles, it is recommended to make marks with a pencil, but over time you will feel the desired depth. Once all the elements have been assembled, you can start welding on weight. In this case, we are talking about transitions between walls, water supply inlets and battery connections.
How to avoid mistakes
Plastic pipes are usually used for cold water systems; they should not work under pressure. When laying heating systems, polypropylene reinforced pipes should be used . For their welding, it is necessary to remove part of the reinforcement using a shaver.
When approaching the pipe to the boiler in these areas there should be no plastic. To do this, adapters are used that allow you to replace the welded joint with a threaded one. A shut-off valve must be installed in front of the new section, this will facilitate the work when installing a new point or during repair. As soon as a new segment is launched, you will understand whether the soldering process has passed correctly. After opening the shut-off valve, all connections should be checked for leaks.
General welding rules
Welding polypropylene can be carried out in the socket or in the butt. The cuts and apparatus must be cleaned not only of contaminants, but also of grease, as well as oils, the latter of which are especially dangerous. Alcohol, acetone or other solvents can be used for degreasing. As for the tool, it can be cleaned with alcohol.
It is important to ensure that the rag for degreasing does not leave fibers. Pollution should include polymer layers that have collapsed under the influence of ultraviolet radiation and air. They should be removed mechanically. If necessary, condensate is removed from the surface of the pipes, and the elements are well dried.
Polypropylene welding should not be accompanied by cooling the seam with water or cold air. In this case, the process will occur too quickly, which will cause stress and reduce the strength of the seam. If welding was carried out at low temperatures, then cooling should be slowed down with a cloth or insulation.
Polypropylene Sheet Welding
Welding polypropylene sheet hair dryer involves heating the edges and the location between the sheets of polypropylene wire. All three elements must be connected to each other. When choosing a hair dryer, you should prefer one that has quite impressive power. As for the wire, it must be made of the same material to be joined, otherwise the elements will melt unevenly.
To begin, the sheets should be laid on a flat surface and process the edges with sandpaper. Using a hair dryer for welding polypropylene, it is necessary to act on a principle that is similar to the use of a fusible electrode. This indicates that the operator needs to move the equipment along the seam, filling the joint with the melting material of which the bar consists. After 7 minutes, the welded sheets can be used for their intended purpose.
Applying the described technology for welding sheet polypropylene, it should be remembered that too slow exposure can cause severe heating, this will lead to deformation of the seam. Therefore, you should act promptly. Before starting work, you need to evaluate the advantages and disadvantages of such welding. Thus, the created seam will have the least strength compared to those that were created using other technologies.
The maximum strength coefficient during such melting does not reach a value of 0.7. This suggests that connecting parts using this technique is possible only when they have not too thick edges within 6 mm. For fast melting of thin parts, this approach may be the best solution.
Additional recommendations for using a soldering iron
If you decide to weld polypropylene with a soldering iron, first you need to shut off the water supply and dismantle the old piping system. Then the equipment is installed on the legs and is well fixed in this position. The heating and cooling times for different pipe diameters will be different.
For example, if the outer diameter is 16 mm, then the heating time of such a pipe should be 5 seconds, it is necessary to connect the elements within 4 seconds, and to cool - 2 seconds. The bore diameter should be 3/8 inch. If the outer diameter increases to 40 mm, then the heating and joining times should be 12 and 6 mm, respectively. It is necessary to cool such pipes within 4 seconds. With an increase in the outer diameter to 90 mm, the heating and joining time will be 40 and 8 seconds, respectively. In this case, it is necessary to cool the pipes within 8 seconds.
When using a soldering iron, the heating temperature is usually 260 ° C. It is important to use the described equipment in conjunction with a socket that has a grounding contact. After turning on the soldering iron on the case, press the special button. The green indicator lights up. After the lamp turns red, it is important to wait until it goes out, this will indicate that the desired heating temperature has been reached.
Welding polypropylene pipes at home is quite common today. If you have special equipment available, you can start laying a plastic pipeline yourself. After completing all work, make sure the quality and tightness of the joints. To do this, a certain segment is blown. If air passes unhindered, then adhesions did not form.