Compound of plastic and cast-iron sewage. How to connect a cast-iron sewer tube with plastic. Step-by-step instruction for connecting

Hello, dear reader! In many houses and apartments, cast-iron pipes are often adjacent to the plumbing and. Therefore, there are situations in which the question arises in front of the home master: how to combine a cast-iron pipe with plastic sewers?

In this article, consider ways to connect, step by step operations and advice-practitioners.

The need for such a procedure occurs in the following cases:

replacing cast iron elements of the sewer highway to more modern smooth plastic pipes;
performing a new layout of polymer pipes for pressure sewage;
laying plastic pipeline from home sewage to septic tank;
emergency breakdown of a tee or a crusher of cast iron;

Connection methods

Select the connection technology is based on the integrity of the cast-iron termination. Either it is also suitable for further use, or burst, damaged, cut off.

Compound fittings

The use of fitting looks like a better solution from the point of view of ensuring a reliable junction.

The press fitting is an adapter from the polymer, at one end of which the thread is located on the other - the fuse-free extension for the joint with PVC pipe.

Scheme of installation of a press fitting on cast iron:

The method is applied in cases where the cast-iron pipe does not have a crop at the end, or it cannot be used. The reliability of the compound is ensured by the tightness of the thread and the rubber fitting seal.

At the end of the cast iron tube, 5.5 threaded turns are cut.
Wash the tape-fium, you can use a plumbing paste, and fasten the fitting.
A plastic tube is inserted into the fitting cuffs on the other end.

Compound rubber gaskets

Rubber seals are suitable when the socket will be intact and unharmed, carefully cleaned, there will be no tubercle on its inner walls. Otherwise, the leakage cannot be avoided.

Rubber cuff must be selected in size.

The inner walls of the cast-iron termination and the external turns of the rubber adapter.
The seal is carefully and tightly installed in the fool.
The plastic tube is inserted deep into the crush through the cuffs at least than 5 cm, it is possible to deeper.
The joints once again are disappeared with the composition of the sealant.

This connection is quite reliable and easily disassembled.

If you have to make a joint with a pipe without crosses, a polymer adapter with a rubber cuff is used.

The end of the cast iron element is equalized by cutting off the grinder.
Rubber ring and seal are planted on it. All this is lubricated with sealant.
Over the edge of the pipe, a plastic adapter is worn, also treated with hermetic composition.
It is attached to the plastic pipe of the corresponding size.

Sealing silicone

This method is the easiest and widely applicable at home. It is suitable if it is necessary to simply make the resulting gap between the clock walls and plastic. In this case, the gap should not exceed two mm.

The socket is cleaned and dried with a construction hairdryer.
At the end of the plastic pipe, a special plumbing thread is wound, representing a kind of sealant of polyamide yarn and silicone coating.
The pipe is inserted into the socket and filled with silicone slots around it. Silicone must go into the raster as deep as possible to the very end of the plastic tube.
The drying time of silicone sealant is about 5 hours.

Connection into a squash

The most popular, which became a classic, method of compounding through the chopping pipe, is a zackecan with a linen winding and cement.

Since when the junction in the terminaby, the slits are almost always formed, the so-called zackecan is applied.

A plastic tube is inserted to the purified slurry, the end of which is wrapped with a flax rope. The winding is missing plumbing paste.
A simple screwdriver pushed and seal the winding into the slit. The seal is tightly filled with two thirds of the connection space.
The cement mortar is applied, the glue is added to it, and it is introduced into the place of the joint until the slot is completely closed.
The mixture will completely freeze only in a day, so it is not recommended to use the pipeline at this time.

With the advent of silicone, cement mortar is often replaced with silicone sealant.

It is believed that this way is unreliable: the chasing deforms the plastic part, besides, under the influence of hot water, plastic and cast iron are expanding with different strengths and the cement connection quickly looses.

Flange connection

The flange is used to dock pipes with a large diameter. Apply here fittings with carvings are difficult, and the flanges are docked hard and reliable. The compound can if necessary, repair or cleaning is easy to disassemble.

To perform the connection, welding works will be required.

Today, a large variety of flanges are represented on the market, allowing the transition from cast iron to plastic.

Step-by-step instruction for connecting

Consider more work on the flange connection with your own hands. First of all, it is necessary to prepare for surgery: decide on the size and types of flanges, materials, pick up the tool.

Set of tools and materials

To dismantle the cast-iron element of the pipeline will be needed:

kiyanka with a rubber nozzle (a conventional hammer one can easily split a fragile cast iron);
bulgarian for cutting out pig-iron pipes.

For installation design, you need:

welding machine;
truboresis on plastic;
plastic pipes;
flange;
appropriate seal;
for stripping the end of the cast iron pipe - a file or cleansing disk for a grinder;
screwdriver with nozzles for bolts or face keys of suitable size.

Stroke work

The grinder cuts off the desired end of the pipe.
Clean it from the jarbed file or a special disk using a grinder.
By the end of the cast-iron pipeline weld the flange.
The crimping clutch is put on the plastic part of the structure, and its flange part is attached to the bolts to the flange of the cast iron pipe. The sealing gasket is stacked between them (Ring).

Video by connection

Flanged video

For the insertion into the sewer tube and the transition from cast iron on plastic, such a fitting can be successfully used as a compensating nozzle. It is able to compensate for the deformation and failure of the network due to its linear temperature narrowing / expansion. In addition, it can give the right slope to sewer.

The nozzle is used along with the corrugation when you need to change the height of the crossbar to create the optimal angle for installing the toilet.

Nuances

The pipeline wiring is always from the riser.

Remember that cast iron and polymer have different thermal expansion coefficients. Therefore, it is important to use plastic materials such as silicone to seal.

When using a threaded connection, be sure to wrap on the threads of the passage and lubricate it with plumbing paste.

It is always necessary to start an assembly from the riser

Do you need a dismantling of an old pipe

If we are talking about sewage cast iron riser in an apartment building, first, it should be done by experts invited by the management company, secondly, this operation in a separate apartment is very undesirable. As practice shows, it is better to change the risers entirely in the entire entrance during major repairs.

Making repairs in the house or in the apartment, there are situations when it is necessary to change the old fan pipes. Typically, cast iron is replaced with plastic, and those and others have to be interconnected. In this article, we consider the connection of plastic sewer pipes with each other and with cast iron.

Plastic and plastic

The most in demand in this market today are polyvinyl chloride and polypropylene products. It is connected with their durability and throughput, which is at times exceeding cast-iron. Now we learn how to combine sewer plastic pipes, for which there are several ways:

Glue

Take the shallow emery paper and squeak the place of gluing, and then degrease it.
Apply glue with a flat roller on the section connected. What it is even more, the better the tightness of the connection will be.
Insert the pipes one to another and do not disconnect for 60 seconds.
Loading the joint with glue again.

Welding

Prepare a special welding machine for melting polypropylene.
Put the details and pipes on the appropriate equipment nozzles.
Wait until the polypropylene melts.
Remove the pipes and details from the nozzles.
Insert them without rotating one to another.

After the polypropylene freeze hermetically welded seam, the node is not disassembled.

With the help of compression fittings

You can connect the pipes of small diameters with your own hands due to a special design, while welding and glue are not used. They will allow the required tightness of the node. To check the quality of the connection, it is enough to try to scroll the parts with each other.

Tip: Before finally dwell on one or another way, spend a number of experiments to be confident in your abilities.

Plastic and cast iron

Now consider how to combine the cast-iron sewer tube with plastic, which is often found during repairs in apartment buildings. There is 1 method using a press fitting and 4 without its use. In any case, after reading the article, you can independently create a reliable connection.

We use a rubber gasket

When, after removing the old cast-iron pipe, the inner surface of the squab remained smooth, it is possible to use a special seal. In this case, the plastic will enter it by 30-80 mm.

The option makes it possible to quickly make installation and continue the operation of the sewage system. The service life of such a compound is up to 8 years.

Usually, the sewer riser has 2 outputs - the first Ø100 mm, the second - Ø50 mm for drainage.

Connection instructions Next:

Clean the docks from dirt and rust.

Apply to the outer side of the rubber transition layer sealant.
Insert the rubber adapter into the chunks of the cast-iron.
Install a new pipe in the cuff.

If there is no roman, a plastic adapter is used.

In this case, they are as follows:

Cut part of the cast-iron pipe with a grinder and align the edge.
Put on this part rubber adapter.
Load the edge of the sealant.
Top with a pipe with a sealant with a sealant.

Tip: Transitions and cuffs must correspond to the size of pipelines.
The connection using the transition technology is the same for any diameters.

Winding from flax

This compound of cast-iron and plastic sewer pipes is often used at docking first, however, it is also suitable for our case.

You must do the following:

Mix on a plastic tube at a joint point of several layers plumbing winding, its price is small. It is not necessary to regret it in this case.
A narrow spatula or wide screwdriver tightly plug in the gap between the products. Because of this, the method was called the chasing.
Melt several times the transition to a cast-iron polymer-cement solution consisting of cement, water and plow glue.
Sewage can only be operated in a day.

Such a junction will be quite reliable. Although today the silicone sealant came to shift, the linen winding is often used when docking under a washbasin or washing. If there is a breaking time later, this is not related to this node.

We use Santechnic Silicone

Typically use the method when the mix of the plastic pipe with the cast iron has a slot to a width up to 2 mm. At the same time, special attention to the seal of the junction at the bottom.

In this case, you need:

Dry the place of the joint, for which it is best to apply a construction hairdryer.
Talk Silicon in the gap with a construction pistol.

Tip: The deeper the Silicone can press, the connection will be more reliable.

Wait until the silicone layer is driving out, which usually takes 3-5 hours. Consider - than it will be thicker, the time it will dry out.

Combined Methods

To increase the reliability of the connection between plastic and cast iron, use the combination of methods:

For the sealing of a large slit, a rubber gasket is used with the zackecan.
When using corrugations to connect the toilet to the system, the zackecan with a linen winding with a sanitary silicone, which is wetted at the place of junction of rubber seals and cast-iron crosses.
Instead of a polymer-cement solution, silicone sealant is often used.

Press fitting

In this case, a fum-tape or passion is used.

Technology work as follows:

Cut together the future connection to the old tube with a grinder or unscrew the clutch installed on the cast-iron.
Lubricate the edge of the pipe with solidol or butter.
Cut the threads with threadar, wipe the place and wrap on it a fum-tape or a pass.

Lubricate Silicone Winding.
Screw the press fitting with a handlet (Do not use the key so that it does not burst). You can then twist it after turning on the water supply if you need to stop the leak.

Tip: Do not screw the press fitting from polyvinyl chloride for metal.

Output

From this article, you learned how to connect with each other, as well as plastic and cast-iron pipelines. It was described about the frequently used methods that use press fittings, a plumbing silicone, a winding of flax, a rubber gasket or a combination thereof. The video in this article will help you find additional information on this topic.

When replacing the old sewage, there may be a compound of a plastic pipe with cast iron. It is desirable that such work be carried out by experts, but if you wish, you can do everything yourself.

In order for the pipeline after replacing the pipeline, leaks or blockages, it is necessary to combine the connection of plastic pipes with the cast iron. In this article we will deal with how to combine the cast-iron pipe with plastic.

All work can be divided into several stages:

preparation;
dismantling pig-iron pipes;
plastic installation;
compound.

Preparatory work

First of all, it is necessary to carefully measure the replaceable area to know the number of pipes and what diameter needs to be bought. The diameter is also an important aspect, for example, with a replacement, pipes with a diameter of 50 mm are used, and with or a portion of the toilet bowl -. In addition, it will also have to acquire a certain number of adapters, corners and other fittings.

Before the start of work, prepare the material and tool:

plastic pipe of the desired diameter;
coupling with which the transition from cast iron on plastic will be performed;
wooden or rubber cynica;
bulgarian or hacksaw for metal.

The replacement of the sewer pipeline is desirable to do for 1 day.

Video: Installation of the transition from the cast iron sewer pipe on the plastic.

Removing cast iron pipes

Pipe connection is made using press fittings. At one end of such a product there is a thread, and on the second - the socket for connecting the plastic pipe. You also need a tape from Teflon (Fuma Ribbon) or Plumbing Flax for sealing and two divorce keys.

Installation steps:

Unscrew the clutch or cut off the piece from the cast-iron nozzle in the place where it will be held
connection with a plastic pipe.
Cut the thread, if necessary, on the cut area.
Clean the thread from dust and wind the tape or flax on it, lubricate with silicone lubrication.
Hour a press fitting.

Tip!

The press fitting is screwed by hand, without a key, since with a strong effort it can crack. It will be possible to twist it after turning on the water.

Also combine the cast-iron tube with plastic can also be using cast fitting. For this:

Degrease the place of docking.
We proceed with a joint glue for plastic and sprinkle sand, waiting for a complete drying of the glue.
The socket is cleaned and degrease.
We proceed with a sealant.
Mount the sealing ring.
The narrow part of the fitting is inserted into the ring-seal.
Insert the edge of the plastic pipe into the fitting cuff.

Compound rubber gaskets

This method is suitable if you managed to remove the old tube of and its edges and the inner surface remained smooth. In the nickname, the nozzle must enter an average of 5 cm. With this method of compound, the sewage can be used immediately at the end of all works. Installation stages:

clean the parts from rust, dirt, etc.;
fracture a rubber adapter with a sealant from the outside.
rubber adapter insert into a cast-iron socket;
insert the nozzle into the cuff.

If the pipes are connected not having a termination, then a plastic adapter is used. Then come as follows:

cut a piece, equalize the edges;
we wear a rubber adapter;
we wist the edge of the sealant;
we wear a plastic adapter with a sealant with a sealant.

Sealing silicone

Formed when connecting pipes, the slot (up to 2 mm) can be sealed with plumbing silicone. This method is quite effective if special attention is paid to the bottom of the junction.

The place of the joint is dried with the help of a construction fene.
Fill the slot silicone, as deeper, is used for this special construction gun for glue.
We wait until Silicone is dry, usually it happens for 3 - 5 hours.

Connection into a squash

For this type of connection, it is necessary to buy a special adapter that is intended for installation in a squash. Such item can be purchased in any construction store, it is usually required products with a diameter of 50 or 110 mm. But there are pipes and other diameters, so it is better to decide in advance with.

The compound process takes place in several stages:

clean all the connected parts from dirt, dust and other things;
we wash their sealant;
adapter insert, until it stops, in a cast-iron socket;
in the adapter insert the plastic tube.

This method is the easiest and most reliable, and if necessary, the connection can be disassembled and re-assembled.

Flange connection

In this method, special connecting parts are used. In addition, the use of welding will be required, which does not always allow work independently.

We clean the nozzle adjacent to the main pipe.
We weld the metal flange part.
We put the crimp coupling on the workpiece.
We connect flange parts by placing a sealing ring between them, bolts.

Wire work in the case of repair or planned replacement of pipes from cast iron on plastic can only be observing the installation stages. I also want to notice that it is better to perform these works in advance, and not wait for the accident.

Video: Transition with cast iron on plastic pipe, nuances and tricks in replacing plumbing, PVC and sewage pipes

If the question is solved, how to combine the cast-iron sewer tube with plastic, you need to consider all possible ways. Metal communications are operated for a long period, but sooner or later they need to be changed. Sometimes it is required to update only the pipe. This method has its drawbacks, because Cast iron and plastic are characterized by different properties. When choosing a suitable method, you should consider the state of the communications, the presence of free access to the pipes. All actions must be made in accordance with SNiP.

Casting sewer pipe compound with plastic

The compound of pig-iron and plastic sewer tubes is performed in stages. First you need to prepare a workplace. Release space on a plot where repairs will be performed. It is necessary to determine the form and number of components for installation. More often than others use 2 sizes: 50, 110 mm. If you plan to change the sewer pipe in the toilet, use the second option. Communications with a diameter of 50 mm are installed in the bathroom.

At the next stage, the number of knees is calculated. A straight pipe is installed on the open area. If the room is small or there are encouraging elements that interfere with the installation of communications, turns are planned by 45-90 °. Their number varies depending on the configuration of the room. However, the larger the knees installed, the stronger the sewerage is hampered. You should not install more than 2-3 similar items. Before starting work, it is necessary to overlap the water riser.

Removing cast iron pipes

Prepare the following tools:

angular grinding machine (EMS), it is called a grinder;
hammer (rubber or kiyanka).

Cast iron communications differ in brittleness, so you need to work with them. If you remove a pipe area with a hammer, you can damage the pipeline that is planned to be combined with plastic products. The likelihood is great that the chunks of the cast iron will fall into the hole of the riser and is formed by a difficult landing. For this reason, it is better to use the ESM. Slices will be smooth, so that it will be possible to connect a plastic pipe.

When disassembling the socket is not necessary. Thanks to this element, the design can be obtained a reliable connection. After removal of the pipeline section, the cut is cleaned. You need to remove the remains of the cement mortar, which is used when installing cast-iron communications. Additionally pay attention to the rusty sites. From the cavity of the pipe remove all the contaminants, the inner and outer surfaces are cleaned, wipe dry. If you plan to use silicone sealant, the products of the future joints are additionally degreased.

Ways to connect cast iron sewage with plastic

There are various methods of installation of the pipeline from materials characterized by different thermal expansion coefficient. At the same time, it is permissible to use aids (sealant, rubber gasket, flange, press fitting), but it is allowed to apply combined methods that suggest the need for simultaneous use of different ways. If the question is solved, how to connect the cast-iron pipe with plastic sewage, the choice of option should be made with the status of communication.

Connection using rubber gasket

This method is considered the most simple in sales and affordable. The cost of rubber gasket is minimal, and it does not require experience. The advantage of this method is an increased degree of elasticity, which is important, because Cast iron and plastic are characterized by different indicators of thermal expansion coefficient. As a result, the probability of product deformation is reduced thanks to a flexible ring.

The period of operation of the rubber seal is 8-10 years, but, given its minimum cost, the problems will not arise when replacing. If you do not change this element for a long time, it loses elasticity, cracks, ceases to restore the form after exposure to loads. As a result, there will be a flow on this site. The dismounting process when replacing the seal is made by the same scheme as the installation.

Rubber cuff is characterized by a complex configuration. The surface of this element has many protrusions that pass along the entire length of the circumference of the product. This ensures maximum seal when installing pipes. With the help of the cuffs, it is preferable to comply compound cast-iron communications with a socket. In this case, the extension on the pipe makes it easy to install a plastic product.

Cast iron pipe with fools

Connecting pig-iron communications through a rubber adapter can be performed, guided by the instructions:

Cleaning the metal pipe from rust, contaminants. To do this, use abrasive devices (metal brush). In the case when deepening was formed on the inside of the pipe, irregularities can be smoothed by means of silicone sealant. It is applied and equally distributed. When the irregularities are eliminated, the excess material needs to be removed, and it should be done carefully, otherwise the deformed areas are reproduced again from the sealant.
So that the rubber seal is firmly fixed, before installing the metal pipe, it is necessary to apply to the outer surface of the product of the sealant. After that, you need to immediately install the adapter into the pipeline.
It is necessary to start a plastic tube into the chopping pipe terminal. The depth of the installation is 50-80 mm.

Cast-iron pipe without squab

If for some reason there is no extension on the communication slice, the connection can still be produced, however, the degree of its reliability will be lower, because In this case, the plastic adapter is additionally used. Instructions for mounting a pipeline from different materials:

If the slice is uneven, you should remove the pipe area with it. Then the edge is cleaned.
A rubber gasket is installed in the cavity of the pipe, after overlooking its outer side with silicone sealant.
In this area, the plastic adapter is installed in the cast iron pipeline. The configuration of this product varies. The plastic adapter can be made in the form of a knee or have a cylinder form. It is installed in the cavity of the cast iron pipe to a depth of 50-80 mm.
At the last stage, the installation of a plastic pipeline in a pre-mounted adapter is performed. This should also use a rubber seal. When it is installed, the outer surface is treated with silicone sealant.

Zackecan

This method is applied for a long time. It is used when installing the cast-iron pipeline. In this case, rubber seals do not apply. The joints of the communications sections are sealed with a pacle (winding of flax). Cement mortar is used for hardening. This method is used in the case when the looseness between the walls of cast-iron and plastic pipes is 3-5 mm. Instructions for the installation of communications using the method of the Zackecanka:

Plumbing paste is applied on the plastic tube, the pack is wound on top. The depth of the zackecanque is 2/3 from the length of the termination.
The product is crushed into the cast iron pipeline until it stops.
Take the pass, using a narrow spatula, a screwdriver.
The remaining 1/3 part of the termination is filled with polymer-cement mortar. At home, it is prepared from cement, water and glue PVA.

The advantage of this method is a high degree of reliability. If the rubber adapter is operated for 8-10 years, then thanks to the method of the stack of the pipeline, it will serve much longer. He has disadvantages. So, note the need to wait 1-2 days until the cement solution freezes. Throughout this period, it is impossible to use the pipeline. This will lead to the deformation of the suture compound, which in the future will cause the destruction of the polymer-cement layer, and the appearance of leaks.

Sealing silicone

This method is recommended for use in the case when the gap between communications does not exceed 2 mm. Use the pass and cement mortar is inappropriate, because It will be problematicly tumped by flax. The tool will not pass into the narrow slit. The level of efficiency based on the use of silicone, during the sealing of major loosses, it decreases, and it is suitable for small gaps, because Provides a high degree of reliability.

For this purpose, a sanitary or universal silicone sealant is used. The substance is applied to the surface of communications using a special pistol and plastic nozzle. Installation instructions:

The cutting of the pipeline must be carefully cleaned. Remove rust, large litter and dust. It is important to degrease the surface of communications, which will contribute to the increase in the adhesion of materials.
Before applying, it is necessary to dry the junction area, it is recommended to use a construction hairdryer for this purpose.
The plastic tube is installed in a cast-iron socket.
Silicone fill the gap between communications. If possible, it is recommended to compact the connection along the entire length of the termination, then the degree of reliability of the fastening will increase.
Additionally, you can process the sealant connection area and on the outside.

The material dries over 3-5 hours. Previously, the end of this term should not use the pipeline. Important condition - communication must be securely fixed during the performance of work, because The mobility of the junction will lead to a deterioration in the quality of sealing.

Combining different methods

If the looseness between the pipes is quite large (from 5 mm), it is recommended to simultaneously use various ways:

Rubber seals and silicone sealant. First of all, a flexible adapter is established. Then the plastic tube is started into the slot, and the slot is filled with silicone sealant. The principle of using these materials is described above. In this case, technology is combined, but the installation is performed in stages.
Method of zackecking and silicone sealant. At the same time, instead of a polymer-cement solution, a sealant is introduced into the slot between communications, but it is partially filled with pacles.

Connection using a fitting

In this case, a special adapter is used made of metal (steel). From one side of it - a thread for a compound with a cast-iron pipe, on the other - the fool for connecting the plastic pipeline. It will take ESM, threadaris. Installation instructions:

It is necessary to prepare the cast-iron pipe. Make a cut by grinding. If the coupling is installed on this site, it is twisted. The threaded connection is already ready. Otherwise, the thread needs to be made independently, for which threadaris is used.
On the prepared slice impose a sealing tape. Alternatively, a package can be used.
To harden the threaded connection, the sealant is applied from above.
Install a press fitting. However, twist it on the pipe should be manually. It is impossible to use the adjustable key at the same time. The fitting can burst.
On the other hand, a plastic tube with a crimp cuff is connected.

In order for this section of the pipeline to be operated without interruptions, it must be remembered that the fitting made from polyvinyl chloride cannot be installed on the metallic basis.

Flange connection

This method is more suitable for mounting large-section communications. The flange is distinguished by strength, provides a reliable connection, but it can damage the plastic pipe if there are burrs, sharp edges. The selection of the flange is made taking into account the diameter of the pipeline:

to increase strength, a straight bourge with a conical transition is used;
free flanges (emphasis on a straight bourge) are prepared for connecting light pipes with a diameter of 30 cm, as well as heavily products with a diameter of up to 15 cm;
free flange (focus on the conical bourge) is used to install communication with a diameter of 20 cm.

First make a cut on a cast iron pipe. It must be smooth without errors. Then the rubber sealing ring is then installed on the tube. At the last stage, the flange is coming to the seal and fix it with bolts. It is important to ensure a uniform tightening at all points.

Sometimes when conducting sanitary work, it becomes necessary to combine pipes made from different materials. For example, metal-plastic pipes used today have to be combined with cast iron. This is usually required when you need to connect the plumbing pipes of the water supply system of the apartment to sewage. In the old houses, the risers are made just from cast iron, and therefore the question is how to combine the plastic pipe with the cast iron is quite pressing.

From a technical point of view, the methods will be somewhat different, and therefore it is worth considering each of them separately.

Simple connection

First of all, it is necessary to estimate the state of the cast-iron part, which is supposed to be connected. If the strength is at a sufficient level, then you can move to the work.

First of all, you need to remove the old metal pipe. After that, it is necessary to estimate the condition of the pipe, which is supposed to be connected. If it is durable, smooth and has fallen, then you can start working.
On the inside of the pipe is removed all rust. To do this, you can use a metal brush and large-sized sandpaper.

Then the special rubber liner is inserted inside. It will execute the functions of the seal. It must be reminded that before inserting the adapter, it is necessary to apply sealant.
After that, a plastic tube is inserted into the cuff, and at least 5-8 cm for the greatest reliability.

This method is relevant only if the pipe has a special expansion fool. If it is not, then a somewhat different way is applied.

The top of the pipe is cut with a grinder, after which the end will need to be treated with a file and sandpaper to remove all burrs.
Then there is a special adapter on the cast-iron pipe, on top of which a plastic fub is put on.
Next, the actions described above are repeated. The connecting element is inserted, which in turn plastic pipe is mounted.

Zackecan with linen plumbing winding

As another way of connecting pipes, you can mention a method with a sanitary winding zackecan. The way is simple, but requires experience.

First, a plumbing winding in several layers is wound on the plastic tube. As a result, the thickness should be obtained, approximately equal to the diameter of the cast iron pipe.
Plastic tube with winding is inserted into the cast iron.
After that, a slot of the winding is bought between the connected pipes. For these purposes, you can use, for example, a narrow spatula.
The rest of the slot space between the pipes must be filled with a special solution. For its preparation you need to mix the glue PVA and cement, diluing to the necessary consistency with water.

The resulting connection will be suitable for use in a day - two, when the mixture is finally dried. The described method is relatively simple to use and is available. It does not need any special tools for its use, and all the necessary materials are available. The pipe connected in this way for a long time remains tightness, and in the event of a leakage, it is always possible to bone some additional amount of winding or apply a solution.

Connection using silicone sealant

It is worth saying that the above-described method was widely used before the appearance of silicone fillers. Today, popularity has received a little modified option.

Before connecting the cast-iron pipe, you need to dry well and clean.
Then the pipe, wrapped with a plumbing thread, must be inserted into a cast-iron socket to a depth of 10 cm.
After that, in the remaining slot with the help of a special mounting gun, the required amount of silicone sealant is supplied.
The compound is then left for about a day to frost silicone, after which the water supply can be used.

The described method is much easier than the previous one and to some extent preferable, since Silicone is decomposed longer. This means that the place of the junction will be sealed longer.

Combined method

Each of the described methods has its own specifics and advantages, but nothing interferes when connecting pipes to use a combined method. For example, the pipe can be wrapped with a linen winding, but instead of the gap zackeck, fill it with silicone sealant. Here you can experiment, so everyone can find a method for themselves.

Compound press fitting

Another way to connect pipes from various materials is a compound with special connecting elements called fittings.

First, the cast-iron pipe (regardless of whether it has an extension or it without a squab) is cut off with a grinder. The cut ends must be treated with a file and sandpaper, in order to remove burrs.
Next, the outer surface of the metal pipe must be cooled with machine oil or solidol.
Then the external thread is cut with a special tool.
After that, a plumbing thread is wound on the thread, over which the connecting fitting is winding.
On the other hand, this connecting element is put on a plastic tube with a crimp cuff. It must be remembered that all sealing rings should be in place.
With the help of a special tool crimping the coupling.

This method is reliable, durable and durable. Its use requires certain efforts, but the result will be valid for quite a long time.

Note! Do not forget to take care of trifles and be sure to follow safety rules.

Video

If you are going to carry out the transition from cast-iron sewage to plastic, you will have to perform the decontamination of the fan tee. In this video, it is shown how to do it. You will also see how to combine plastic and cast iron pipes.