How to connect a cast-iron pipe with a plastic one: do-it-yourself docking. How to connect a plastic pipe with a cast-iron sewer? General view of the plastic adapter

Sewer adapters are the most important link in the piping system and are widely used during its installation. Thanks to a huge range of connecting fittings, it is possible to arrange external and internal communications of any complexity.

Purpose of fittings

The role of adapters in the sewerage system is difficult to overestimate. Not a single repair of plumbing pipes and not a single construction of a new line can do without their help. Fittings are of particular value in cases where it is required to make a transition from pipes of one diameter to pipes of another - larger or smaller. Adapters are indispensable when performing repair work indoors, when it is not possible to change the entire sewer system as a whole, and only a certain section of it has to be changed.

Very often, the material of the pipes of general house networks does not correspond to the material of the pipes installed in the apartment. The most common situation is the following: a common sewer riser is made of cast iron, and the owner of the apartment plans to install plastic in his bathroom. In such cases, adapters come to the rescue, which are able to connect pipelines of different material into a single network and at the same time provide a reliable and tight connection.

In addition to connecting dissimilar materials, adapters allow you to form a network of any configuration and change the direction of an existing one. In addition, with the help of cast iron fittings, it is possible to carry out the removal of chemical effluents and polluted waters, the temperature of which exceeds 60 degrees.

Materials used

The materials used for the manufacture of adapters are steel, copper, cast iron and modern polymers. Plastic is the most common type of raw material, and is gradually replacing metal counterparts. For the manufacture of polymer fittings, polypropylene and polyvinyl chloride are used. The use of such parts greatly simplifies installation work and significantly reduces the time for their implementation.

The great popularity and high consumer demand for plastic adapters are due to a number of undeniable advantages of such parts:

the low weight of the fittings allows you to easily install the overall parts of external systems yourself;
a huge range of more than 100 types of plastic adapters allows you to quickly select the right part;
products made of PP and PVC are not subject to corrosive processes, which distinguishes them favorably from metal counterparts;
fittings are distinguished by high strength and long service life, which allows you to forget about repairs for a long time after their installation;
low cost and wide consumer availability make it possible not to save on material and to form a high-quality pipeline for little money.

The disadvantages of plastic adapters include the likelihood of deformation from exposure to high temperatures, the inability to use plastic to drain chemical effluents, and low resistance to cold.

Cast iron is also used to make adapters. Despite the fact that cast-iron pipelines are gradually being replaced by plastic ones, the material is still widely used for repairing communications of the old housing stock. Cast iron elements are installed at the joints of cast iron and plastic pipes. Installation is carried out using a threaded connection. To ensure high tightness, the fittings are equipped with rubber cuffs.

Cast iron fittings also have a number of advantages.

The service life of cast iron adapters far exceeds the service life of steel and plastic products and reaches 80 years.
After dismantling, cast iron fittings can be reused, which cannot be done with plastic and steel counterparts.
High tightness of joints. Sometimes, on particularly problematic sections of the pipeline, the joints are coated with polymer sealants, after which they are pressed in with a lock nut.
Unlike steel and plastic fittings, which are attached to pipes by welding or crimping, cast iron adapters are mounted using the threaded method. This greatly simplifies installation and makes it affordable even for a novice plumber. In addition, if it becomes necessary to eliminate the blockage, the plastic fitting must be unsoldered, and the cast-iron fitting can simply be unscrewed.

The disadvantages include the large weight of cast iron products, the presence of a high coefficient of linear expansion inherent in cast iron, and the need for periodic inspection of the joints in order to pull loose nuts.

Metal adapters are used to connect steel pipelines and are made of copper and copper alloys of low carbon steel. Some models are zinc or nickel plated. This improves their anti-corrosion properties and increases their service life. The connection of metal adapters with pipes occurs using the threaded method, and the threads on the fittings can be cut both inside and outside.

The advantages of such parts are wide consumer availability, ease of installation and a wide range of products. The disadvantages include susceptibility to corrosive processes, which is why such adapters often “stick” to the pipe and it can be very difficult to dismantle such a connection.

Classification

On the modern market of shaped elements, adapters are quite widely represented. In addition to the material of manufacture, fittings differ from each other in terms of installation location and functional accessories. At the place of installation, the adapters are represented by eccentric and concentric models. The former are intended for installation on horizontal pipelines, while the latter are used on vertical lines.

However, the main feature by which adapters are classified is their functional purpose.

Coupling. This fitting is used to form a pipeline from pipes of the same diameter. The size of the inner section of the coupling corresponds to the outer diameter of the pipe. Couplings can be produced with both external and internal threads or be compression (capable of being fastened using a crimp method).

The compensation sleeve is a type of connecting sleeve and serves to ensure the integrity of the connection under the influence of thermal linear expansion. It is often used in systems with large volumes of hot water discharge, which leads to a change in the dimensions of the pipes in length and width.

The transition sleeve provides the transition of the pipeline from pipes of a larger diameter to a smaller one.
A branch is used when it is necessary to change the direction of the pipeline. Products are available in different types of turning angles, the most common of which are angles of 30, 45, 60 and 90 degrees. Many models have a deviation from the central axis in the direction of rotation of the system, which facilitates the free flow of sewer masses and reduces the likelihood of blockage.
The fitting is designed to connect a plastic drain hose and a metal pipe into a single network.

The cross is used in cases where two branches must be made from one pipe. Each side of the cross can have its own cross-sectional size, and the connection angle of the pipes is 90 degrees.
The tee, like the cross, branches the network and is often used to connect the drain of dishwashers and washing machines to the sewer. Fittings allow you to connect pipes at an angle of 45, 67, 88 and 90 degrees. The inlet nozzles of the product have sockets equipped with sealing rings, and the outlet channel is fully compatible with the socket of the main pipeline.

The bypass is a curved fitting with which one system bypasses the other when they intersect in the same plane.
The saddle consists of two parts that compress the pipe and is used to cut into the main pipeline.
Flanges are a type of adapters used to connect metal pipes to PVC pipes.
Reduction - a fitting that allows you to connect elements of the sewerage system that have different diameters.

The compensator is a kind of adapter and is installed on the lower sections of the pipeline. With its help, pipes from different materials are connected, the necessary slope is formed, and water hammer is extinguished. However, the main function of this fitting is the deformation compensation of pipes and their connections, which occurs due to exposure to high temperatures.
An adapter with a ball valve is installed before the sewer network enters the house and is located in the inspection hatch.
The two-legged siphon is designed to provide ventilation and timely removal of toxic sewer gas.

Dimensions

The sizes of the adapters fully correspond to the dimensions of the pipes involved in the formation of sewer systems. For the arrangement of internal networks, the most common cross-sectional sizes are 110, 100, 50 and 32 mm. Such fittings can be installed both by means of a threaded connection and by welding, in contrast, for example, to overall products with a diameter of 250 mm, the installation of which is carried out only using a welding machine. The connection in this case is completely one-piece, and to dismantle it, cutting the connection will be required.

When installing a new sewerage system in an old building, it is necessary to make a transition from cast iron to 110 mm plastic. The reasons are different. The most common unsuitability of old cast iron products for further operation. But the complete replacement of vertical pipes (risers) often stumbles upon the resistance of neighbors. This is where the new plastic structures have to be joined with the old and rusty cast iron ones.

How pipes are connected

Old cast-iron sewer systems are falling into disrepair. They were replaced by plastic products (photo No. 1). They compare favorably with cast iron pipes and have a number of advantages:

the walls of plastic products have less resistance and clog much less often;
plastic is light in weight and easy to install;
you can mount it with your own hands;
installation does not require special equipment;
putties and seals in the form of cords are almost never used;
plastic products are not afraid of corrosion;
The service life of plastic products is measured at about 50 years.

The disadvantages include:

if hot water is drained for a long time (60 ° C and above), the pipes may warp;
very low soundproofing ability.

When switching from cast iron to plastic 110 mm, it is recommended to use special adapters and cuffs. They are made of plastic. If the cast iron pipe has a socket, you also need to purchase an adapter. Consider the connection process using the example of a riser with sockets of 110 and 50 mm.

First, the sockets are cleaned. Remove all dirt and rust from them, lubricate the rubber cuff with sealant (photo No. 2) and connect the pipes. It is desirable to introduce a plastic product into the socket to a depth of 3-8 cm. Such a connection can last at least 8 years. You can use it immediately after docking.

The connection of new plastic pipes with old cast-iron pipes without a socket is somewhat different:

the edge of the cast iron product is leveled with a grinder;
a rubber adapter is put on this place;
the edge of the pipe and the adapter are lubricated with sealant;
new and old products are joined.

Adapters and cuffs must exactly match the diameters of the pipes.

The connection can be made by caulking. For this method, linen winding is needed. The order of work is this:

a plastic pipe at the junction is wrapped with several layers of sanitary winding;
with a narrow spatula or screwdriver, the winding is hammered into the gap between the pipes;
the cast-iron product is coated with several layers of a polymer-cement composition of water, cement, PVA glue;
You can use the pipeline in a day or two.

Such joints are of fairly good quality and high reliability. You can use this method under the bathtub or under the sink (photo No. 3).

Currently, a new material is often used - plumbing silicone. This is a very efficient connection method. To connect pipes, do the following:

the joint must be thoroughly dried with a building hair dryer;
pipes are joined to a depth of 3-8 cm;
silicone is injected into the remaining slots with a gun;
the joint should dry well for 3-5 hours.

During drying, it is not recommended to use the sewerage system.

Sometimes you have to combine several connection methods. If a rather large gap forms when joining products, rubber gaskets can be used along with caulking. Corrugated plastic products are connected to cast iron using linen winding along with joint treatment with sanitary silicone. When performing caulking, you can use silicone instead of a cement-polymer composition. It seals the joint quite well.

Conclusion on the topic

Deterioration of sewer systems in old houses is a fairly common phenomenon. Instead of cast-iron elements, plastic structures are placed.

it turns out pretty easy. The most difficult thing in this matter is the dismantling of the cast iron system. At the transition of cast iron-plastic DN 110 with or without a cuff, it may be necessary to dismantle the riser. For this work, you may need a grinder. But most often the riser is not touched, but only the pipes from the bath, sink, toilet bowl and washbasin are changed (photo No. 4). The joints between the pipes are treated with building silicone. For work, you should purchase cuffs, sealant, press fittings, plastic adapters. Everything can be done with your own hands. The main thing is not to rush and perform all operations carefully.

Old and bulky cast-iron pipelines can still be found in many apartments. But no matter how reliable they may seem, sooner or later their service life comes to an end. An excellent solution would be to completely replace cast iron with plastic, but, unfortunately, this is not always possible.

Someone stops the financial side of the issue, others fail to agree with their neighbors. It is in such situations that it becomes necessary to connect plastic and cast-iron sewer sections. There are several techniques that allow you to carry out such work quickly, efficiently, and without the involvement of professional help.

The whole complex of works can be conditionally divided into four stages:

Preparation of the place of work and the necessary tools.
Dismantling of the old pipeline.
Installation of plastic pipes.
Connection of elements.

To make the connection of a plastic pipeline with a cast iron one reliable and durable, it is worthwhile to prepare all the necessary tools and materials in advance:

Special hammer with rubber or wooden head. An ordinary iron hammer will not work here, since it can easily damage such a strong-looking, but very sensitive to impact cast iron.
Cutting tool. It can be a grinder, or a hacksaw for metal.
Wrenches.
Depending on the chosen connection method, a hand press, a thread cutter or a welding machine may be required.
Plastic pipes of suitable size. To connect the toilet to the riser, elements with a diameter of 110 mm are required, for laying pipes to the bathtub and sink, plastic with a diameter of 50 mm is best suited.
Required adapters, gaskets, couplings, seals, sealing agents.

Note! Installation of a plastic pipeline should provide for the presence of inspection hatches. Neglect of this rule will significantly complicate the repair work, if the need arises for them.

Dismantling the old pipe

It is necessary to dismantle the cast-iron pipeline very carefully to prevent the appearance of chips or cracks.

Hello dear reader! Cast iron pipes are gradually disappearing from our apartments and houses. Taking this opportunity, many during the repair try to replace them with more modern and lightweight polymer products. And the question often arises: how to make the transition from cast iron to plastic or plumbing.

The need for such a transition arises:

when replacing a cast-iron sewer tee that takes up too much space;
when inserting a plastic tee into a cast-iron riser;
when installing polymer wiring to new plumbing;
when replacing cast iron batteries;
during the construction of a private house, when it is necessary to "crash" into the central pipeline;
when installing new or replacing old meters.

Advantages and disadvantages of such a connection

The advantages of a transitional connection of PVC products to cast iron products include:

high technical characteristics of plastic products, lack of rust in them, lightness and ease of installation compared to cast iron pipes;
less time-consuming joining process in comparison with joining of cast iron products;
the ability to make a connection with your own hands;
a variety of ways to install polymer pipes with cast iron pipes, each of which brings a reliable result;
no need to purchase expensive equipment, use welding, etc.;
a large selection of connecting elements.

The disadvantage is the difference in the heating temperatures of these materials. Plastic products heat up faster, while they begin to deform, which leads to loosening of certain types of joints and loss of their strength.

For this reason, detachable connections of cast iron and plastic lose their reliability over time.

Do the work yourself or call the master

It all depends on the complexity of the connection. Replacing a cast-iron riser in an apartment building, for example, can only be done by a specialist invited by the management company. Plastic eyeliner from a cast-iron channel to plumbing can be made by almost any man on his own.

More complex work, including the dismantling of cast iron pipes, is best left to professionals.

Approximate cost of work

The master names the cost of his services after inspecting the scope of work. The price of installation work depends on the number of connection points of the pipeline segments, their complexity. Dismantling works are estimated by the number of running meters. The dismantling of the cast iron tee will be evaluated separately.

On average in Moscow, the price of work on replacing a cast-iron sewer (1 point) starts from 1200 rubles. Dismantling of cast-iron sewer pipes - from 380 rubles. per running metre.

Connection methods

The choice of connection method is determined by the presence or absence of a socket in the cast-iron segment.

If there is no socket or it is damaged and cannot be used, the best solution would be a threaded connection through a polymer adapter, which will have a thread at one end and a socket for connection with a plastic sleeve at the other.

Along with this method, there are other technologies. Let's consider each method in more detail.

Application of rubber gasket

If the cast-iron channel is with a socket, a simple connection method is used through rubber gaskets. They are rubber stepped cuffs of various diameters.

The inside of the bell is thoroughly cleaned.
Lubricate the edges of the bell and the outer surface of the cuff with sealant.
The seal is placed tightly in the cross.
Then a plastic input is inserted there until it stops by at least 3 cm. The joint is treated again with a sealant.

A similar method is often used when connecting the liner from the sink.

The transition with a rubber cuff is shown in this video:

Using a plastic adapter with a rubber seal

Such a connection is used when the cast-iron pipe does not have a socket.

Cut the end of the pipe exactly with a grinder.
They put a rubber ring on it, then a cuff.
All this is coated with sealant.
Next, a plastic adapter is put on.
A ring is installed on the adapter and the socket of the polymer pipe is put on.

Using a press fitting

Fitting connection, and at the same time the most time-consuming in execution. Its reliability is ensured by a threaded connection of the adapter with a cast-iron pipe. The adapter sleeve has a thread at one end, and a socket for sliding connection with a polymer sleeve at the other.

A chamfer is cut off at the end of the cast-iron pipe, after which threads are cut to a depth of 5 cm.
The thread is sealed by winding tow or FUM tape using sanitary paste.
Screw the adapter along the thread by hand so that the fitting does not crack. In the future, after the start of operation, tighten it with a key.
A plastic pipe with a crimp collar is inserted into the socket at the other end of this coupling and crimped with a special manual press.

This video demonstrates the threaded connection:

Linen embossing

Chasing has long been used in the socket connection of sewer pipes.

The inside of the cast-iron socket is cleaned, making its surface as smooth as possible.
Insert the end of a plastic pipe into it until it stops, wrapped with linen winding, lubricated with sanitary paste.
Using a simple screwdriver, seal the gap with winding. Fill the free space with a sealant by two-thirds.
The remaining space is covered with cement mortar with the addition of PVA glue.
Leave the solution to solidify at the junction for a day.

Currently, instead of cement mortar, silicone sealant is increasingly being used, which, due to its plasticity, does not allow the joint to lose strength during temperature changes. This is especially important when switching from cast iron to plastic, given the difference in their heating temperatures.

This photo shows how to properly caulk:

Silicone sealing

This method is very simple and takes very little time. It is used to seal cracks, the size of which does not exceed two millimeters.

The socket must be cleaned and dried, for which a building hair dryer is used.
The connected end of the polymer pipe is wrapped with plumbing thread, inserted into the socket and the gaps formed around it are sealed with silicone.
Silicone must be pushed deep into the plastic, to the very end.
It is better not to use the pipeline for the drying time of the sealant (about 5 hours).

flange connection

This type refers to detachable connections. It is used when working with pipes of large diameters, where it is difficult to thread and use threaded couplings. If necessary, it will be possible to disassemble, repair.

The order of work is as follows:

Cut the grinder exactly cast-iron pipe.
Clean the welding place from notches.
A flange is welded to the resulting pipe.
A special compression sleeve is put on the attached plastic part, the flange part of which is bolted to the cast iron flange. A gasket is laid between the flanges.

Which way is better

The strongest and most reliable way, as we have already emphasized, is a threaded connection on adapter couplings.

Easy to use are connections on silicone, rubber gasket.

Flange connection is suitable for work with large pipelines, where detachable fasteners are more relevant.

Guests and standards

The production and dimensions of cast iron sewer pipes are regulated by GOST 6942-98.

For plastic pipes, there are many GOSTs and SNiPs that regulate their individual characteristics.

For each type of polymer, depending on the scope of application (sewerage, heating or water supply), there are their own GOSTs.

For example, the characteristics and dimensions of plastic tubular products intended for systems of cold and hot water supply and heating of buildings for various purposes are regulated by GOST R 52134-2003.

Diameter standards

For domestic domestic sewage, cast-iron pipes with an internal section of 50 mm (DN) and 100 mm (DN) are used.

The dimensions of the external sewage system are determined by the norms of SNiP. In the intra-quarter network, a diameter of 150 mm is used, in street networks - 200, 250 mm.

Polypropylene products are manufactured in accordance with GOST 26996-86. A specific size for the sewer sector is not established by the standard. But in practice, the following diameters of sewer plastic pipes have developed: 32, 40, 50 and 110 mm.

For polyethylene pipes, working diameters - 40, 50, 90 and 110 mm - were determined by GOST 22689.2-89.

For PVC products, the cross section of sewer products is regulated by GOST 51613-2000. His requirements: PVC pipes must have a Ø of 10 to 315 mm.

In order to make drainage, lay an external sewer, septic tank pipes, you will need products with a cross section of 110-200 mm.

Do-it-yourself step-by-step technique for connecting pipes

The work execution technology includes the following steps:

Preparatory stage.
Selection of tools and materials.
Dismantling of part of the old pipeline.
Preparation of two parts of pipes for connection.
The operation of joining parts.
Necessary tools and materials

At the first stage, they determine the place of connection and choose a method for its implementation. Make the necessary measurements, determine the need for materials.

Necessary tools and materials

Polymer pipes are bought in the right size. To connect the toilet to the crosspiece, elements with a diameter of 110 mm are required; for laying pipes to a sink or bathtub, plastic with a diameter of 50 mm would be the best option.

In accordance with the project, the necessary connecting materials are purchased: sealant, fitting, sealant, etc.

Select the required tool. It may include:

a set for dismantling the cast-iron part - a hacksaw for metal or a grinder, a mallet hammer, it is possible with a rubber pad;
screwdriver;
spanners.

You will need a thread cutter to cut threads.

For plastic joints, you will need either a hand press or a welding machine - an iron.

Work progress

If you have to do wiring, mark up all its sections. In the case of a short wiring, mark the place of the cast iron cut.

Mounting Features

If you have to disassemble and remove the old part of the cast iron from the socket, care should be taken: cast iron is a brittle metal and the socket can crack from a hammer blow, strong turning of the piece being removed in it. Caulking may require the use of a blowtorch or torch if the joint is sulphurised. Here you can not do without a respirator or gas mask.

For insertion into the sewer riser and the transition from cast iron to plastic, compensating pipes are used. They compensate for the deformation of the polymer during temperature changes. And in combination with a corrugated sleeve, they can give the necessary slope to the outlet.

Wiring always begin to collect from the riser.

Frequent connection problems and errors

Often, rubber seals are tried to be inserted into the socket without proper preparation of its inside. It must be understood that any tubercle on its surface can cause leakage. The inlet part of the cast iron must be carefully cleaned mechanically.

Insufficient slope of the outlet from plumbing fixtures to the riser causes constant and frequent stagnation in the sewer system.

The reason for poor tightness of connections is often the lack of elemental lubrication, an insulating layer, loose or overtightened threaded connections.

The insert into the sewer riser is carried out using a polymer tee. When assembling a gravity sewer system, the sockets must be directed against the movement of drains.

When tightening a threaded connection, be sure to wrap tow on the turns and lubricate it with sanitary paste. Tow or FUM tape is wound along the thread in the direction of twisting.

The plastic channel does not provide complete sound insulation. You can solve the problem by installing an additional protective box.

Due to the difference in thermal expansion coefficients in cast iron-plastic joints, it will be correct to use silicone as a sealant.

Combination of several pipe joining methods

In order to be guaranteed to protect yourself from leaks, a combination of several connection methods is used.

So, docking on a rubber gasket can be supplemented by coating the cracks with either silicone or a cement-sand mortar with PVA glue.

Today, many want to replace the old ones with plastic ones. Is it necessary to do this, and if so, in what cases is the transition from cast iron with a diameter of 110 mm to plastic carried out?

Why and what is it for

There are several cases where it is necessary to replacement of sewer cast-iron pipes with a diameter of 110 mm with plastic ones:

during the construction of a private house, when it is necessary to "crash" into the central pipeline;
with a complete update of communication systems, if a major overhaul of the dwelling is being carried out;
when installing new or replacing old meters.

When updating plumbing or changing the sewer system, they often encounter unpleasant surprises. The most common among them is the presence of old cast-iron risers, which must somehow be connected to brand new plastic pipes.

But before proceeding with the installation, it is necessary to consider that:

cannot narrow in the direction of movement of the filling medium;
protrusions, burrs should not be allowed, as they will cause clogging of the pipe in the future;
in cases of liquid transition, it is necessary that the plastic is inserted into the cast iron, and not vice versa. Only in such cases will there be an extension.

Table. Dependence of the price on the linear parameters of plastic pipes

In everyday life, plastic pipes with diameters of 50 and 110 mm are very popular for laying water or sewer systems. A significant advantage of these products is an acceptable price, as you can see by looking at the table.

		Length, mm	The price of 1 piece, c.u.
50	1,8	500	0,52
50	1,8	1000	0,97
50	1,8	3000	2,68
50	3,2	1000	1,56
50	3,2	2000	2,92
110	2,2	500	1,22
110	2,2	1500	3,45
110	2,2	3000	6,20
110	3,2	1000	2,92
110	3,2	2000	5,52

Characteristics and assortment of materials plus GOSTs

To form a high quality of industrial products, standardization was introduced. This also applies to polymer communications. Each enterprise engaged in production is guided by GOSTs. These regulatory documents reflect the main requirements for manufactured products, determine their technical characteristics and parameters.

Information on quality indicators, the scope of polypropylene pipes is reflected in regulatory documents, the main of which is, which began to operate in 2003.

Important!

The standard regulates not only the quality, but also determines the main parameters of pipes made of different plastic materials. Plus, the document contains the necessary ones used in and .

GOST also defines those indicators that directly affect the service life of products:

duration of operation;
pressure;
temperature range of application;
safety factor.

Cuff with a diameter of 110 mm

There are several ways to change from cast iron to 110 mm plastic. The simplest and cheapest is the transition with a cuff. Preparation for work should begin with the dismantling of unnecessary sections of the old cast-iron pipe. The easiest way to do this is with a grinder. To avoid all sorts of negative consequences, goggles and a respirator should be worn before work.

Approximately from the middle of the pipe, and then try to rotate it around the axis, if possible. The rest of the pipe may either burst into several pieces, or you can simply pull it out. In any case, it is necessary to clear a place for a new plastic riser. After that, proceed to cleaning the outer and inner parts of the socket from the possible presence of rust, old sealant, hardened pieces of cement mortar. After that, using coarse-grained sandpaper, polish the inside of the socket as far as possible, dry it, remove unnecessary dirt and dust residues, and degrease.

Important!

Be aware of the brittleness of cast iron, so cleaning must be done very carefully so as not to damage the socket. Now you can start installation.

For this you need:

Apply silicone sealant to the inside of the socket.
Coat the outer part of the rubber cuff with sealant.
Place the cuff inside the bell, make sure that it fits completely into the hole.
Insert a plastic pipe into the socket, securely fix it and secure with a clamp or other means.

Since it is now possible to purchase a cuff, an adapter, a seal of any parameters, in this way it is possible to make the transition from cast iron to plastic, not only DN 110, but also for other nominal diameters.

For example, when replacing an external sewage section, a taper or 110x124 is used, which ensures a smooth transition from cast iron to plastic.

The minimum price of this method of connecting a cast-iron and plastic pipe is the main plus of this relatively easy technical operation.

With a clutch

If you want to connect cast iron and plastic of the same diameter, then use this procedure to carry out this procedure. Before installation, it is necessary to thoroughly clean the desired part of the surface of the cast-iron pipe from contamination, rust, and then grind it with coarse and fine-grained sandpaper. Then connect the pipes, and for greater certainty, tighten the edges of the coupling with clamps. If the pipes are of different diameters, then a taper or adapter can be used.

Transition with and without flare

Consider 2 cases of how to qualitatively connect a plastic pipe with a cast iron one: with a socket and without a socket.

So, we have a pipe with a socket, to which we must connect a plastic pipe.

In order to connect "plastic" to it, you need:

purchase a cuff of the required diameter;
clean the socket from dirt, the remnants of the old coinage, after which it should be dried;
apply silicone along the inner contour of the socket, making sure that even the smallest recesses are tightly filled;
apply silicone sealant to the outer part of the cuff;
insert the rubber seal into the socket;
insert a plastic tube into the cuff.

After the silicone has dried, you need to check the functioning of the system.

In the absence of a socket, you should carefully cut the pipe, clean and align the end. In order to carefully insert the cast-iron riser into the plastic, an adapter pipe made of plastic with a larger diameter is often used than in a cast-iron product.

Work is carried out in the following sequence:

clean the old riser from dirt and dry it;
in the place of future docking, cover the cast-iron pipe with sealant and put a cuff on it;
on the second end of the cuff, slowly, slowly, so as not to damage the product, put on a plastic pipe.

Application of a special press fitting

To eliminate problems in the existing sewer system, as well as when combining cast-iron pipes with plastic ones, you can use (see photo).

Its advantage: increased service life (within 50 years!) and the ability to withstand high pressure.

Installation should begin by cutting off part of the old pipe, regardless of whether there is a socket or not. To remove burrs, it is good to clean the cut end with coarse-grained sandpaper, correct it with a file, and then smear it with grease or mineral oil.

After that, it is necessary to cut a thread (4-5 cm wide), on which to wind a special thread for plumbing work. Then take the press fitting (), and without much effort screw it to the ends of the plastic and cast iron pipes. After supplying water to the system, it is necessary to tighten the connecting product again. Simple and reliable.

In order to make the transition from a cast-iron pipe to a plastic one without unnecessary problems, it is necessary to adhere to good advice and recommendations from specialists.

Proper preparation should be made for repair work. This means that you first need to decide on the area that needs to be replaced, the amount of material needed.
Prepare all the necessary tools: an adjustable wrench, gas (pipe) wrenches, a grinder, a mallet or a rubber mallet, a sealant, etc. Depending on which docking method is chosen, other materials and tools may also be needed in the process.
Thoroughly clean the socket from dirt, mortar residues or other old sealant, sand with coarse sandpaper.

It should be remembered that:

the easiest way to dismantle old cast-iron pipes with a grinder;
it is impossible to break off an old notched pipe, since it is impossible to foresee how it will break off;
in order to avoid the appearance of chips, strike the pipe with a wooden or rubber mallet;
it is necessary to equip an inspection hatch;
in order not to pay twice, do not use cheap, not always high-quality, Chinese fittings;
you can get rid of cracks with silicone;
when using silicone, do not allow mechanical impacts on the joints for 4-6 hours until the process of polymerization of the substance is completed;
sealing with silicone is possible only if the joints are completely immobile, otherwise the tightness may be broken;
You can get rid of the old sulfur fill with a blowtorch or gas burner. To do it neatly in another way will not work. Be aware of the toxicity of sulfur fumes, so it is best to wear a gas mask when doing work;
to prevent damage to plumbing fixtures, it is better to disconnect the bathroom, toilet bowl, washbasin from the system. If a cement base is also used to fasten the toilet bowl, then it is better to immediately break it and remove it in parts, since it is unlikely that it will be possible to carefully detach it;
during installation, do not forget that there is a big difference in thermal expansion coefficients between cast iron and plastic.

Questions and answers (FAQ)

How is the connection of a cast-iron pipe with a plastic product made correctly?

Old cast-iron structures are gradually being replaced by modern plastic systems. Therefore, the transition from cast iron to plastic is not uncommon.

To properly connect risers made of different materials, you must:

accurately select parts by diameter and length;
depending on the gap between the connected elements, choose the method of docking;
determine the materials necessary for sealing;
withstand the period of time required for the final solidification of the sealant, glue, weld;
adhere to the algorithm for performing work on connecting pipes.

Before you start pairing cast iron with plastic, you need to stock up on the necessary tools and materials.

Only when the above conditions are met, it is possible to correctly connect the plastic product and the cast-iron pipe.

How to switch from cast iron to plastic 50

Plastic pipes with a diameter of 50 mm diverge from the risers to the outlet points. In such areas, it is often necessary to perform a cast-iron-plastic transition. This is due to the fact that in many apartments and private houses old cast-iron systems are used, which gradually fail and need to be replaced with modern designs. This raises the problem of connecting elements.

It can be solved in several ways, among which docking can be distinguished using:

1. Press fittings

When switching from cast iron to plastic 50, a press fitting is used in the form of a sleeve with an internal thread at the non-socket end. Such a connection is quite reliable, since the thread provides complete sealing of the seam.

Work sequence:

cutting the edges of a cast-iron product with an angle grinder;
chamfering along the perimeter of a metal part, lubricating this part of the riser with grease, lithol or mineral oil;
threading 40-50 mm long using a die or thread cutter of the appropriate diameter;
applying a sealing material to the thread (fum tape, plumbing paste or silicone with tow);
screwing the press fitting. It should be noted that in the process of performing this procedure, no special effort is required, since cast iron is a brittle metal.

Important! For the reliability of the connection, it is desirable to re-compress the threaded joint after 10-15 days.

2. Rubber seals

If, during the dismantling of the old section of the system, the remaining part of the pipe is flat and there are no chips or cracks on it, then this docking option is ideal. The main element is a special rubber cuff, the service life of which is 10-12 years.

The pairing process is quite simple. First you need to clean the cast iron part from rust, dirt. After that, the rubber part is inserted into the socket expansion, the PVC pipe is inserted to a depth of 45-75 mm. If there are sinks, they must be sealed with a sealant.

In the absence of a bell, use a plastic adapter. Cleaning the edges with the help of a “grinder”, cleaning from rust and dirt is carried out in the same way, after which a rubber seal and an adapter are placed on this part. Then the expanded part of the PVC pipe is attached. All operations are accompanied by silicone sealing.

3. Coinage

When switching to a riser with a section of 50 mm, chasing is often used. This method is optimal if the connection is of the "pipe-bell" type.

It is good to caulk the docking point if there is a gap of 4-6 mm. At smaller distances between the riser and the socket, sealants are used. Minting algorithm:

apply a thick layer of sanitary paste on the edge of the product and wind the tow;
place a plastic element in the cast-iron socket, inserting it all the way;
using a chisel or a narrow spatula, fill the gap between cast iron and plastic with flax fibers to 2/3 of the socket height;
fill the remaining gaps with water-cement-adhesive mortar.

Important! The pipeline will be ready for operation in 24 hours. That is how long it will take for the sealant to completely dry.

4. Silicone

If the riser is in good condition, and the gap between the joining elements does not exceed 2.0 mm, then you can connect them together using a sealant. It should be remembered that the connecting parts must be dry and clean at the junction, and silicone must be supplied under pressure, since with this method possible sinks and voids are ideally filled.

Important! The operation of the connected parts is possible after the complete polymerization of the sealant, which occurs after 4-5 hours.

You can also find adhesive joints of plastic with cast iron, docking by welding, and other less popular methods.

How to switch from cast iron to plastic plumbing

When switching from cast iron to plastic in a plumbing structure, they often use a non-standard method. Its essence is as follows:

A) Heat the end of an ordinary (without a socket) pipe with a building hair dryer or over a flame to such an extent that it becomes plastic.

B) With your hands (wearing gloves), slightly stretch the heated part so that a kind of bell is formed.

C) Put the stretched pipe element on the cast-iron pipe, making sure that the plastic is evenly placed on the riser around the entire circumference.

After cooling, the connection, not only with hands, but with a hammer, cannot be removed from cast iron. Simple, versatile, reliable.

You can also use traditional docking methods.

How to change from cast iron to plastic without a socket

In the absence of a bell, use a plastic adapter. Work according to the scheme:

level the cast-iron edge with a “grinder”;
an adapter is placed at the flat end;
The “dressed” part of the part is coated with silicone sealant;
a plastic adapter is applied to the pipe surface, having previously lubricated it with a sealant.

General view of the plastic adapter

1- pvc pipe socket

2 - rubber seal

3 - adapter element

4 - rubber cuff

5 - second seal made of rubber in the form of a ring

6 - socketless riser made of cast iron.

How to switch from cast iron to plastic 110 if the cast iron pipe does not get

When replacing a metal product, it is best to cut off a section of the old pipe at the transition point to the socket. With this dismantling option, it will take a minimum period of time to join the old cast iron product with a new plastic pipe and the least effort will be spent.

Important! The best way to dismantle cast-iron risers is to cut individual sections of the system with a grinder. It is forbidden to break products, since cast iron has isotropic properties and the direction of the split in this area cannot be predicted.

When it is not possible to get the pipe out of the socket, then it is necessary to make cuts along the entire circumference with a grinder through 20-25 mm along (not across !!!) the pipe, reaching the expansion. After such a procedure, all unnecessary remnants of the risers are very easy to get.

If it was not possible to dismantle the old section of the metal structure (for example, it cannot be removed from the concrete screed, and its upper part is located at the same level as the concrete), then you can connect the cast-iron and plastic riser using special adapters of the appropriate diameters. You can buy them at any plumbing store.