How to choose the right glue for connecting PVC pipes and sealant for repairs

Polymer products are replacing metal and ceramic pipes. They are becoming increasingly popular due to their obvious advantages - durability, lightness, resistance to corrosion and the effects of aggressive substances. If handled with care, a plastic pipeline can last at least half a century.

The main thing is to ensure high-quality, hermetically sealed joining of elements. To assemble the parts, use a special glue for PVC pipes. The so-called “cold welding” allows you to build a water supply system with minimal labor costs. However, the use of glue has a number of nuances that must be studied before starting work.

The article outlines the advantages of the adhesive method of joining plastic pipes, provides an overview of the best manufacturers, and also provides recommendations for choosing the appropriate composition. Step-by-step instructions for gluing PVC products will help you assemble the pipeline yourself and avoid possible mistakes.

Review of properties and methods of fastening PVC pipes

Products made from unplasticized polyvinyl chloride are characterized by rigidity and high strength. Hollow materials with a round cross-section are also distinguished by their tightness, with a service life of over 50 years (reaches a century-long figure). For installation of communications, glue for polypropylene pipes is often used.

Brief technical description

PVC pipes are inert to corrosion, most chemicals and biological activity. Such properties are in demand in the construction of water supply and sewerage systems. Other characteristics are also useful here, such as:

• mechanical resistance to water hammer and pressure up to 1.6 MPa;
• maintaining quality at temperatures from -15 to +66 degrees Celsius (CPVC up to +100 degrees);
• resistance to environmental conditions (ultraviolet radiation, changes in humidity, temperature within acceptable limits);
• the smoothness of the walls determines low hydraulic resistance, absence of plaque and build-up from salts and fats (it is easy to clean the outside);
• safety for humans, animals and plants.

Plastic water supply in a residential area Source sakh.com
It is also worth noting the affordable prices and easy installation. The latter implies easy cutting, elasticity and a method of fastening individual elements. Here it is enough to have a set of inexpensive fittings and glue for PVC sewer or water pipes.

Product installation

The assembly of communication lines is carried out in three ways: using sockets, bolts or using related parts. In the first case, pipes for sewer systems are used. On one side they are made with a thickening, the inner diameter coincides with the outer diameter of the main part. That is, channels or corners with tees are simply inserted into each other. To ensure the tightness of the connections, the walls are additionally coated with glue for plastic pipes.

In the case of ventilation systems, gluing is not necessary; you can limit yourself to sealing agents. Another relevant connection here is a flange connection. The technique is applicable to large-diameter pipes (entry into the building, installation of valves, valves, taps).

Flange connection of polymer channels Source techfabinternational.com

The second technique applies to plumbing products of relatively small diameter. Fittings are additionally used here. These include connectors (at different angles), tees, adapters with different end diameters. Here, for installation, you may need not only glue, but a special iron for working with polymer pipes and a bevel remover. Due to the strong and tight connection (subject to the rules), the method is otherwise called chemical welding.

The gluing process step by step

Upon completion of preparation, you can begin gluing PVC pipes (video with instructions is attached). To glue PVC products, you will first need glue, as well as a brush for applying it. Often the brush is sold along with glue. But, if the manufacturer does not provide such equipment, purchase the tool separately, bearing in mind that it should have natural bristles. If you decide to practice hot gluing, also prepare a special soldering iron (“iron”) for plastic pipes, but a welding machine can also be used.

Cold soldering method

The adhesive connection of pipes using the cold soldering method is carried out according to the “mother-father” principle. The products to be joined have a socket, the smooth surfaces inside of which must be degreased before gluing. If you do not prepare the planes very well before gluing, the tightness and strength of the assembly will be significantly reduced. If, before carrying out work, you learn how to properly glue PVC pipes, the result will exceed all your expectations.

Video describing the gluing process:

To connect pipeline parts using glue, you need to lubricate the edges of the prepared sections with glue. It is recommended to apply it in an even and not very thick layer. After this, you can glue the elements, excluding their rotation and displacement for 10-2 seconds. This is exactly how much is required for the adhesive composition to adhere to the surfaces.

Immediately remove excess glue that has protruded beyond the edges of the marks. Then you need to leave the products for another 10-15 minutes.

In some situations, special adhesive tape is used to increase the waterproofing of the pipeline. Before gluing PVC tape onto a PVC pipe, you need to apply a primer to the area near the node that can enhance the adhesion of the materials. Next, PVC tape is glued. The skeins should be arranged in a spiral, with a slight overlap on the previous turn. Gaps between the strips and the formation of air bubbles between the plane and the adhesive tape should be avoided.

Algorithm for cold gluing.

Types of glue for PVC pipes

Not only polymer products differ from each other. For pipe installation, products with different properties and rules of use are also used. Let's consider how to glue a sewer plastic pipe or water pipe.

Operating principle

The adhesive composition contains a chemically active solvent. It reacts with the polymer base of the products, due to which the polyvinyl chloride softens. Such walls polymerize among themselves during the process of rapid hardening, forming a monolithic connection.

Connection of elements in section Source aquatherm.com.au

See also: Catalog of companies that specialize in water supply, sewerage and related work

Here it is necessary to note the heterogeneous composition of adhesives. To avoid making a mistake with your choice, you can refer to the manufacturer’s recommendations for a specific type of pipe. As a rule, the differences come down to three options: for PVC or chlorinated polyvinyl chloride, polypropylene.

Review of materials for gluing PVC

The classification of adhesives is carried out along with the purpose regarding the composition of the products and their strength. Here, soft bases include water-pressure and corrugated samples. Another option is solid. These can be fittings or siphons.

The second criterion for choosing adhesive for PVC pipes and fittings is the operating temperature conditions during installation. So, there are options for hot fusion and cold welding. The first materials belong to the group of flammable and combustible materials that are unsafe for the skin.

The installation technology here involves the use of a soldering iron and welding equipment for round polymer products. Using the first, the end parts of the pipes are heated to +260 degrees Celsius.

For cold welding, universal or specialized compounds can be used.

Tool for working with polymers Source poolplanet.ru

The first are designed to work with all polymer products (for example, linoleum), the second only for PVC and its modifications. This technique is more suitable for socket type connections. Here it is especially important to ensure the cleanliness of the contacting walls so that adhesion is uniform and the result is durable and airtight.

Another selection criterion is the setting time of the materials. Thus, instant adhesive for polypropylene can be classified as a means for cold welding. To form compounds here, 4 minutes at room temperature or one at +40 degrees Celsius is enough. Hot gluing compounds dry in 30 minutes and harden in 2.5 hours. It takes a day to complete the polymerization process.

Rules for working with adhesives

When working with glue, you should always read the manufacturer's recommendations. Many compounds cannot be left open for more than a few minutes, because... they set quickly, making their further use difficult. The average time during which the glue can remain open is 4-5 minutes.

In summer and winter, the compositions harden the fastest: at high ambient temperatures, the glue may become unusable after 1-2 minutes, and at low temperatures, the viscosity increases. Therefore, you should pay attention to the manufacturer’s instructions regarding operating temperature conditions.

When purchasing a specific brand of glue, you should pay attention to its preparation for use. Some types are easy enough to mix, but two-component compositions have to be combined correctly and their consistency must be monitored.

There is a risk of incorrect mixing, which leads to loss or change in adhesive properties.

You should pay attention to the solvent for degreasing surfaces. It is best to choose a composition from the same company as the glue. Even if the packaging of the adhesive composition states that degreasing is not necessary, it still makes sense to wipe the surfaces to be glued with a high-quality solvent.

Color and viscosity matter. Experienced plumbers prefer compositions of medium viscosity. They are easy to apply, and when joining parts, such glue does not spread, so you do not have to remove it with napkins.

As for color, the colorless composition is suitable for white and colored pipes. It is not visible, even if the drops protrude beyond the glued area and freeze.

Methods and means for repairing PVC pipelines

During pipeline operation or installation work, it is impossible to completely eliminate the possibility of leaks. In this case, you need to find a solution for urgent repair of products or restoration of tightness in connecting nodes. Let's consider which adhesive or sealant for polypropylene is suitable for such purposes.

Leakage in the hub connection with the fitting Source tumentoday.ru

Causes and consequences of leaks

Identifying root causes is often helpful in finding problems and solutions. More often this is a depressurization of the connecting seam. To prevent or minimize the risks of “gaps” appearing, you need to monitor:

• temperature conditions during the soldering process;
• degree of reliability of fixation of nut fasteners or crimp fittings;
• correct preparation of elements for soldering, welding or other connections (cut angle, evenness of edges, cleanliness of walls);
• the applicability of the adhesive for a specific section of the pipeline;
• admissibility of the use of sealing and sealing materials.

It is not difficult to identify problems in polymer pipelines in a timely manner. In places of depressurization, condensation (dew), leaks appear, or the pressure in the system changes downwards. Without urgent intervention, the situation may turn out to be an emergency. This applies not only to the water supply or sewerage system itself, but to neighboring premises, apartments, houses, furniture and interior items, household appliances, and electrical wiring.

Consequences of failure to detect a leak in a timely manner Source ytimg.com

Review of methods and materials for pipeline repair or restoration

The action algorithm includes three stages: turning off the water, troubleshooting, testing the system for serviceability. Only after this can you return to full operation of communications.

To stop the transportation of liquid, it is not always necessary to turn off the central riser in a particular house. Today, plumbers are trying to create separate circuits or bypasses by integrating shut-off valves or tap fittings into the system. This way, it will be possible to de-energize only part of the pipeline and continue to use the rest as before.

Before carrying out restoration measures, you need to decide how to seal the plastic water pipe. Here are the main criteria for choosing funds:

• efficiency;
• performance;
• ease of use.

More often, connections of polymer products are made with the creation of conditions for polymerization. In this case, it is impossible to disassemble the monolithic assembly and create it back. Therefore, it is necessary to cut out part of the contour and insert a new one using a similar technology (which was used previously).

Replacing a damaged section of a pipeline Source homify.com

Advantages of using “cold welding”

The links are connected to each other either mechanically, or by welding or using special glue. The welding method is the most popular, but it requires a special machine, which is very expensive, or you can call a specialist, which also costs money. The adhesive connection method is less common, but very effective. The “cold welding method” is often used. The seams are reliable and durable, in no way inferior to other joining methods.

There is only one disadvantage of this method: the composition is intended for gluing PVC pipes of cold water supply only; it can dissolve or simply lose its adhesive properties when exposed to high temperatures.

Advantages of joining using an adhesive composition:

• the pipeline remains smooth from the inside, there is no roughness or various damage, which helps to avoid blockages in the future;
• no risk of leakage;
• components adhere at the molecular level;
• the seams are absolutely sealed and may leak if exposed to hot temperatures;
• there is practically no labor and cash costs, gluing takes place in five minutes;
• no additional tools are needed for work;
• a fairly simple method that can be performed by a non-professional;
• there is no need to buy a welding machine.

How to Seal a Hole with Sealing Tape

Using this modern material, you can efficiently eliminate small leaks in pipes located in bathrooms. Externally, it is an adhesive fabric impregnated with special substances. Most often, joints and connecting elements are sealed with sealing tape. As for straight sections, they can also be repaired using this method.

When using sealing tape, it is important to follow the following sequence of work:

• The damaged area must be thoroughly cleaned and dried.
• After stretching a small piece of tape, it is wrapped around the pipe. It is important that this procedure is accompanied by constant tension in the tape, otherwise folds will appear.
• When winding, each new turn should be laid on half of the previous one. It is best to pack the pipe with two layers of sealing tape.

The main disadvantage of this method is the insufficient resistance of the repair material to sunlight. To achieve a good service life, the wound tape is coated with additional protection.

Conclusion

This article discussed in detail the following issues: how to glue polypropylene pipes, how to choose glue for this work, and also why defects may occur during the connection. This is an alternative method that does not yet have the same recognition as the use of welding equipment.

However, if all instructions are followed, it is no different. The video in this article will help you find additional information on this topic.

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Safety precautions

The adhesive composition is very toxic:

1. 
   Performing work in a respirator irritates the respiratory system.

2. In case of contact with eyes, rinse with plenty of water.
3. Perform work at temperatures above 5 degrees
4. Do not smoke, do not work near fire. The glue is highly flammable.
5. Work in a well-ventilated area.
6. Keep glue tightly closed. In places far from food and fire.
7. Observe the shelf life.

Classification

All PVC fittings can be divided according to installation method into:

• adhesive (cold welding);
• threaded;
• flanged.

A large group consists of combined parts that combine two different connection methods. For example, adhesive and flange, adhesive and threaded. Fittings are not used for high-temperature welding of polyvinyl chloride pipes. This connection method is used on large-diameter pipelines in industrial construction. Butt welding is carried out using professional, expensive equipment.

PVC fittings allow you to mount metal shut-off valves into a plastic system, connect a polymer segment of a water pipeline with a metal one, and make the transition from one diameter to another.

According to the manufacturing method, PVC fittings are divided into cast and segmented. Cast parts have a one-piece body. During their production process, molten polymer is poured into a finished mold, where it cools and hardens. The resulting part does not have connecting seams on the body. Segmented ones are assembled from blanks, gluing them together during the production process. Cast fittings are more resistant to mechanical pressure.

According to the performance characteristics, PVC materials are divided into:

• pressure, intended for water supply systems;
• non-pressure – sewerage, storm drains, installation of electrical networks;
• for rarefied environments.

According to their purpose, PVC fittings can be divided into three large groups:

• Connecting. This includes adhesive, threaded, and flange couplings, which are used to connect straight sections of a pipeline.
• Branching - straight and angled tees, crosses.
• Regulating – shut-off valves, plugs.

For installation of turns, manufacturers offer corners with a large turning radius. They avoid sewer blockages that are typical for sharp turning points (starting from a right angle).

American coupling

The American coupling is a popular type of plastic combined fittings that allows you to mount both a straight joint and a corner connection. A distinctive feature of the American one (the connection method was invented by the Americans) is the union nut, which allows you to mount a high-strength detachable connection. It is convenient to use an American coupling in the installation of hard-to-reach areas.

About connection technology

Installation of PVC pipes using the gluing method is more accurate and visually less noticeable than the traditional method using O-rings. This method is more preferable from the point of view of reliability - as a result, we get a high-quality and durable monolithic joint of two pipes without intermediate rings, which tend to age and wear out. Adhesive joints are practically unlimited in use, except for work under conditions of high temperatures and excessive loads.

It should be said that by means of an adhesive connection, a significant part of the pipeline can be assembled before connecting to the system, in a place convenient for work. But for successful installation you will need to strictly follow the instructions.

Checking the system before use

The launch is carried out shortly after installation of the drainage pipeline elements; the PVC connection needs time to completely dry out and set, if an adhesive composition or sealant was used. When using the detachable method or welding technology, control of the operation of the system according to the sewerage flow diagram is carried out immediately after installation.

The pipeline is checked for leaks and bends as the temperature of the effluent increases. For this purpose, water is supplied - you need to turn the valve on the water riser. As the drains move, the condition of communications is monitored. For greater clarity, the pipe joints are covered with paper napkins, then you can notice the appearance of even a slight leak. To ensure that the pipeline is in a suitable condition for operation, you need to observe the movement of wastewater over a certain period of time.

Why do breakdowns occur?

Damage in a plastic sewer pipe is often difficult to notice. However, this is indicated by several circumstances, for example, if there are small puddles on the floor surface and/or a characteristic unpleasant odor in the room. This causes inconvenience for homeowners.

Leaks also appear at the junctions of elements, which is associated with unprofessional installation. A similar disaster can befall a sewer pipe for the following reasons:

1. Incorrect calculations of pipeline length during design. Cracks appear in cases of lack of size. The initially imperceptible error increases and manifests itself with increasing load.
2. Unreliable installation of pipes in connections. The cause of the breakdown is the wrong brand of sealant or careless application of this material.
3. Low quality of shaped elements.
4. Tracking of sealing cuffs for plumbing fixtures.
5. Temporary wear of the material.
6. Mechanical damage (excessive pressure, shock).

If serious breakdowns occur, the question of how to repair a plastic pipe product in the drain system is decided by a qualified specialist. If the damage is minor, then you can deal with it on your own.