Plastic pipes today are increasingly replacing metal products. For this reason, their welding remains one of the pressing problems of everyone who decides to replace the pipeline in the house. You can assemble a plastic communication system, guided by a certain scheme of actions. In this case, the elements must be interconnected, supplemented with shut-off and fastening fittings, and also sealed.
For reference
On sale you can find elements that provide the ability to assemble a pipeline of any complexity and configuration. The only disadvantage of such pipelines is irreversibility, because the dismantling of the welded joint is impossible. Therefore, special care should be taken with polypropylene pipes, otherwise they will have to be replaced.
Welding equipment
Among other tools to assemble the system, you will need a machinefor welding pipes made of polypropylene. It can be used to heat parts and connect them. Fixation of the elements should be carried out before the weld cools down. Strength and tightness will be quite high, so the pipeline will be able to work even with quite impressive pressure.
The machine for polypropylene welding is structurally simple, it consists of:
- from pen;
- heating plate;
- thermostat.
The plate usually has two holes for attaching welded elements or nozzles. If you take a closer look at the standard pipe welding kit, you can understand that the kit includes four welding nozzles, with which you can solve any problems associated with laying a polypropylene pipeline.
More about nozzles
Nozzles for polypropylene welding usually have a diameter ranging from 20 to 40 mm. 25 and 32 mm act as an intermediate value. The working surfaces of the nozzles are Teflon-coated, so it is not possible to make welding elements on your own, since plastic will stick to an unprotected surface.
Pipe welding
Pipes can be prepared by degreasing the ends. Some home masters ignore this recommendation. At the same time, the pipes will be welded, but the quality of the connection will be lower. Before starting welding, it is necessary to process the inside of the fittingalcohol.
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 tips. In order not to damage the equipment for welding polypropylene, the nozzles should be treated with alcohol, which will prevent plastic sticking and damage to the Teflon.
Marking the landing depth
Another rather important point is the marking of the depth of the pipe into the fitting. The latter may have a different caliber, which means a certain depth of the welded joint. Therefore, before starting work, it is necessary to take measurements with a ruler or caliper. This will prevent the insertion of the tube too deep. Ignoring this recommendation, you may narrow the hole or cause pipe sealing.
Marking device
If you will be welding pipes made of polypropylene, then you can use a special device for marking, which will save time and nerves. It can be done independently from a pipe with a diameter of 32 mm. The element is suitable for 20 mm pipe. For the reason that the planting depth of such a pipe is 15 mm, it is necessary to cut off a workpiece from a 32 mm piece, the width of which will be 15 mm. This fixture 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. The measuring ring canimprove by gluing a cardboard or plastic bottom to it, this will simplify the marking process. If you weld polypropylene pipes quite often, then experts recommend making such copper rings for all diameters.
Welding tips
If you are welding pipes in situ, then you will need the help of another person who will hold the welding machine. Whereas at this time you will be able to join the pipe and fitting with welded nozzles, and then between them. Quite often, some home craftsmen overexpose the heating elements, this leads to a narrowing of the pipe lumen. In order to know the heating and cooling time, you must use the manufacturer's recommendations.
Before polypropylene is welded, it is necessary to decide where the pipes will be laid. This will reduce the number of welds on weight. Experts recommend assembling the elements on a flat surface, and then fix them in the system.
To connect pipes, the edges of the elements are heated. The inner wall is in the sleeve, 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 connected to each other. You will only have a couple of seconds to center them. Usually these works are carried out 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 allow you to get a reliable connection if the material has been heated to the desired temperature. Before welding pipes, the valve on the coupling must be opened, otherwise the air will push it out of the nozzle. Part of the plastic comes out when connected, forming an influx on the coupling. If there are problems when putting on, and the plastic is severely deformed, it is recommended to chamfer the edge.
Work methodology
Following German standards, the stripping should have an angle of 15°, while the recess reaches 3 mm. Russian experts are guided by other rules, they say that the bevel of the chamfer is 45 °, while the recess is a third of the thickness. In practice, any chamfer within the mentioned limits will do, but the main condition for this is its uniformity.
When welding polypropylene with your own hands, you should leave the machine on a stand that looks like a special clamp. The temperature is set to 260°C on the controller, but for speed this setting can be increased to 280°C. If you use a different temperature limit, this may cause a decrease in the reliability of the connection, so when buying a unit, you must choose a model with a thermostat.
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. As soon as everythingthe elements have been assembled, you can start welding on weight. In this case, we are talking about transitions between walls, water supply inlets and connections to batteries.
How to avoid mistakes
Plastic pipes are usually used for cold water systems, they should not work under pressure. When laying heating systems, reinforced polypropylene pipes should be used. To weld them, it is necessary to remove part of the reinforcement with a shaver.
When the pipe approaches the boiler, these areas should be free of plastic. For this, adapters are used that allow replacing a 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 repairs. As soon as a new segment is started, you will understand if the soldering process went right. After opening the shut-off valve, all connections should be checked for leaks.
General welding rules
Polypropylene can be welded into a socket or butt. The segments and the apparatus must be cleaned not only of dirt, but also of grease and oils, the latter of which are especially dangerous. You can use alcohol, acetone or other solvents for degreasing. As for the instrument, it can be cleaned with alcohol.
It is important to ensure that the degreasing cloth does not leave fibers. Pollution should include polymer layers that have been destroyed under the influence of ultraviolet radiation and air. They must be removed mechanically. Condensate is removed from the surface of the pipes, if necessary, andelements dry well.
Welding of polypropylene 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.
PP sheet welding
Welding polypropylene sheet with a hair dryer involves heating the edges and placing polypropylene wire between the sheets. All three elements must be connected to each other. When choosing a hair dryer, you should prefer one that has a fairly impressive power. As for the wire, it must be made of the same material that is to be connected, otherwise the elements will melt unevenly.
To begin with, the sheets should be laid on a flat surface and the edges should be processed with sandpaper. Using a hair dryer to weld polypropylene, it is necessary to act on a principle that is similar to using a fusible electrode. This indicates that the operator needs to move the equipment along the seam, filling the seam with the consumable material that makes up the bar. After 7 minutes, the welded sheets can be used for their intended purpose.
When using the described technology for welding sheet polypropylene, it should be remembered that too slow exposure can cause strong heating, this will lead to deformation of the seam. Therefore, you must act quickly. Before starting work, you need to evaluate the advantages and disadvantages of such welding. SoThus, the seam created will have less strength than those created using other technologies.
The maximum strength factor during such melting does not reach a value equal to 0.7. This suggests that it is possible to connect parts using this method only if they have not too thick edges within 6 mm. For fast melting of thin parts, this approach may be the best solution.
Additional tips for using a soldering iron
If you decide to weld polypropylene with a soldering iron, then 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. Heating and cooling time will be different for different pipe diameters.
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 cool down - 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 warm-up and connection times 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 this equipment in conjunction with an outlet thathas a ground contact. After turning on the soldering iron on the case, press a special button. At the same time, the green indicator will light up. After the light turns red, it is important to wait until it goes out, this will indicate that the desired heating temperature has been reached.
Conclusion
Welding of polypropylene pipes at home is quite common today. If you have special equipment available, you can do the laying of a plastic pipeline yourself. After completion of all work, it is necessary to verify the quality and tightness of the connections. To do this, a certain segment is blown. If the air passes unobstructed, no adhesions have formed.
