How to properly connect a plastic pipe to a cast iron sewer? How to connect a cast iron pipe to a plastic one: do-it-yourself joining Approximate cost of work

Hello! Today I will tell you how to make the transition from a cast iron pipe to a plastic one.

This article will help you independently hammer out a cast iron sewer for repair. After which it will be possible to install a plastic pipe into the cast iron socket.

What are the difficulties in this task:

1. According to the diameter standard, a cast iron pipe is larger than a plastic one.
2. It is impossible to disassemble the connection without knowing the hardware. The joints look like a single whole.
3. A cast iron pipe breaks easily; you must work extremely carefully with a hammer.
4. The cast iron socket is caulked with sulfur or cement. For different mints, there is a different method of dismantling.
5. When minting sulfur, you will need a torch and a gas mask.

Diameter standards

Let's look at the situation using the example of a cast iron sewer tee to a bathroom. node

The fact is that it is this tee that is most often changed during repairs, even if it is in working order. It takes up much more space than plastic. And this is important, since with a plastic tee the toilet can be installed closer to the wall and further from the door. Well, that is, while sitting on the toilet you can read an encyclopedia.

Tool

The minimum we need:

1. Plastic cuff
2. Sealant
3. Lubrication
4. Hammer
5. Flat head screwdriver
6. In case of sulfur, burner and gas mask

Step 1. Chasing

The method of caulking a cast iron pipe depends on how it is assembled:

1. for cement
2. or "sulphur"

1. Cement

You need to take a small chisel or flat-head screwdriver and gradually, slowly, knock out a small piece of cement. We place the screwdriver in the space between the pipe and the socket. We beat in a circle.

Under the cement there is a heel. A heel is a strand of flax impregnated with oil, which prevents the flax from rotting. We pick out the heel as much as possible.

After this we try to move the pipe. In the case of a tee, it is quite simple to move it: we insert some kind of lever into the outlet of the tee: a block or a long key. If the tee still does not move, then knock out the cement further. Don't use a big lever to force it off. There is a high probability of breaking the socket into which they were going to install a new pipe. Be careful. The work is painstaking and cannot be rushed.

2. Sulfur

Warning: fire.

First, we need to ensure complete fire safety. You will be working with an open flame, remove anything around that could catch fire. Have water ready in case you do set something on fire. Air. Ensure the room is fully ventilated. Whether it’s winter or the heat of summer, open the window and door so that there is a draft. Otherwise there will be nothing to breathe. I recommend wearing a gas mask or at least a carbon respirator.

I assume that you can heat the bell with a hair dryer. The melting point of sulfur is approximately 450 °C.

After ventilation and fire safety are ensured, turn on the burner and begin to heat the bell evenly. I highly recommend not putting the burner in one place and leaving. If heated unevenly, the cast iron socket may burst. At least I try to avoid such experiments.

It is not necessary to wait for the sulfur to flow out. It is enough to simply soften it with heat. Insert the lever into the tee elbow and move the tee. As soon as it moves, turn off the burner and, shaking it back and forth, move it to the side.

In the case of cement caulking, the same thing: as soon as the tee moves, start loosening it. Before finally removing the tee, Immediately prepare a rag or other plug for the pipe.

They can drain water from above, and there’s no point in breathing in the smell of sewerage.

Step 2. Clean and install the cuff

After we have hammered out the cast iron pipe and removed the old section, we need to take care of the cleanliness of the socket.

We clean and wipe it dry so that no lumps remain.

Then we coat the cast iron socket with sealant and insert the cuff (sealant is not always needed).

I throw the cuffs into hot water for about 30 seconds. They become soft and easier to place! I shared vitalix1974

, in the comments on YouTube

Apply lubricant to the inside of the cuff.

Step 3. Insert the plastic pipe

And now all that remains is to insert the plastic pipe into the cuff.

in this case, you can lightly tap the plastic socket to force the pipe into our cuff. Use a board or plywood to distribute the load by tapping with a hammer. Do not tap directly on the plastic pipe. It can be broken that way.

Good luck with your transitions!

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.

Some are stopped by the financial side of the issue, others are unable to come to an agreement with their neighbors. It is in such situations that the need arises to connect plastic and cast iron sewer sections. There are several methods that allow you to carry out such work quickly, efficiently, and without the involvement of professional help.

The entire complex of work can be divided into four stages:

1. Preparing the work site and the necessary tools.
2. Dismantling of the old pipeline.
3. Installation of plastic pipes.
4. Connection of elements.

To make the connection between a plastic pipeline and a cast iron pipeline reliable and durable, you should prepare all the necessary tools and materials in advance:

• A special hammer with a rubber or wooden head. An ordinary iron hammer will not work here, since it can easily damage cast iron, which is so durable in appearance but very sensitive to impacts.
• Cutting tool. This could be a grinder or a hacksaw.
• Adjustable wrenches.
• Depending on the chosen connection method, you may need a hand press, thread cutter or welding machine.
• Plastic pipes of suitable size. To connect the toilet to the riser, you will need elements with a diameter of 110 mm; for laying pipes to the bathtub and sink, plastic with a diameter of 50 mm is best suited.
• Necessary adapters, gaskets, couplings, seals, sealing agents.

Note! Installation of a plastic pipeline must include inspection hatches. Neglecting this rule will significantly complicate repair work if the need arises.

Dismantling an old pipe

The cast iron pipeline must be dismantled very carefully to prevent chips or cracks.

When installing a new sewer system in an old house, you must make the transition from cast iron to 110 mm plastic. There are different reasons. The most common problem is that old cast iron products are unsuitable for further use. But complete replacement of vertical pipes (risers) often encounters resistance from neighbors. This is where you have to join new plastic structures with old and rusty cast iron ones.

How pipes are connected

Old cast iron sewer systems become unusable. 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 become clogged much less frequently;
• plastic is lightweight and easy to install;
• you can install it yourself;
• no special equipment is required for installation;
• Putties and sealants 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 approximately 50 years.

The disadvantages include:

• if you drain hot water for a long time (60°C and above), the pipes may warp;
• very low sound insulation 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. Let's consider the connection process using the example of a riser with sockets of 110 and 50 mm.

First, the sockets are cleaned. You need to remove all dirt and rust from them, lubricate the rubber cuff with sealant (photo No. 2) and connect the pipes. It is advisable to insert 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 occurs somewhat differently:

• 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 sleeves must exactly match the diameters of the pipes.

The connection can be made by caulking. This method requires linen winding. The operating procedure is as follows:

• the plastic pipe at the junction is wrapped in several layers of plumbing tape;
• use a narrow spatula or screwdriver to hammer the winding into the gap between the pipes;
• the cast iron product is coated with several layers of a polymer-cement composition made of water, cement, and 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 effective joining method. To connect pipes you need to perform the following operations:

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

It is not recommended to use the sewage system during drying.

Sometimes you have to combine several connection methods. If, when joining products, a gap of rather large size is formed, you can use rubber gaskets together with caulking. Corrugated plastic products are connected to cast iron using linen winding along with treating the joint with plumbing silicone. When 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 installed.

It's quite easy to bark. The most difficult thing in this matter is dismantling the cast iron system. When converting cast iron to plastic DN 110 with or without a cuff, it may be necessary to dismantle the riser. You may need a grinder for this job. But most often the riser is not touched, and only the pipes from the bathtub, sink, toilet and washbasin are replaced (photo No. 4). The joints between the pipes are treated with construction silicone. For work, you should purchase cuffs, sealant, press fittings, and plastic adapters. Everything can be done with your own hands. The main thing is not to rush and perform all operations carefully.

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

The need for such a transition arises:

• when replacing a cast iron sewer tee, which 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 “cut into” the central pipeline;
• when installing new or replacing old meters.

Advantages and disadvantages of such a connection

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

1. high technical characteristics of plastic products, lack of rust, lightness and ease of installation compared to cast iron pipes;
2. less labor-intensive joining process compared to joining cast iron products;
3. the ability to make the connection yourself;
4. a variety of methods for installing polymer pipes with cast iron, each of which brings reliable results;
5. no need to purchase expensive equipment, use welding, etc.;
6. large selection of connecting elements.

The disadvantage is the difference in heating temperatures of these materials. Plastic products heat up faster, and they begin to deform, which leads to loosening of some types of connections 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 a professional

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. Almost any man can make a plastic line from a cast iron channel to plumbing fixtures on his own.

More complex work, including dismantling 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 pipeline segments and their complexity. Dismantling work is estimated by the number of linear meters. Removal of the cast iron tee will be assessed separately.

On average in Moscow, the price of work to replace a cast-iron sewer system (1 point) starts from 1,200 rubles. Dismantling of cast iron sewer pipes - from 380 rubles. per linear meter.

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 optimal solution would be a threaded connection through a polymer adapter, which will have a thread at one end and a socket at the other for connecting to a plastic hose.

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

Application of rubber gasket

If the cast iron channel has a socket, use a simple connection method 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 into the cross.
• Then the plastic input is inserted there until it stops, no less than 3 cm. The joint is treated again with sealant.

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

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

Using a plastic adapter with a rubber seal

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

1. Cut the end of the pipe straight with a grinder.
2. Put a rubber ring on it, then a cuff.
3. All this is coated with sealant.
4. Next, a plastic adapter is inserted.
5. 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 labor-intensive to execute. Its reliability is ensured by the threaded connection of the adapter coupling with the cast iron pipe. The transition coupling has a thread at one end and a socket at the other for a sliding connection with a polymer sleeve.

• A chamfer is cut 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 plumbing paste.
• Screw the adapter onto the thread by hand so that the fitting does not crack. Later, after the start of operation, they tighten it with a key.
• A plastic pipe with a crimping collar is inserted into the socket at the other end of this coupling and crimped using a special hand press.

This video demonstrates a threaded connection:

Embossing with linen winding

Caulking has long been used for socket connections of sewer pipes.

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

Currently, instead of cement mortar, silicone sealant is increasingly used, which, due to its plasticity, does not allow the connection to lose strength due to 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 whose size does not exceed two millimeters.

• The bell must be cleaned and dried, for which a hair dryer is used.
• The connected end of the polymer pipe is wrapped with plumbing thread, inserted into the socket and the cracks that form around it are sealed with silicone.
• The silicone must be pushed deep down to the very end of the plastic.
• It is better not to use the pipeline while the sealant dries (about 5 hours).

Flange connection

This type refers to detachable connections. It is used when working with large diameter pipes, where it is difficult to cut threads and use threaded couplings. If necessary, it will be possible to disassemble and make repairs.

The work order is as follows:

1. Use a grinder to cut the cast iron pipe straight.
2. Clean the welding area from nicks.
3. Weld a flange to the resulting pipe.
4. A special crimp coupling is put on the attached plastic part, the flanged part of which is bolted to the cast iron flange. A seal is placed between the flanges.

Which way is better

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

Easy to use are the connections on silicone and rubber gasket.

The flange connection is suitable for work with large pipelines, where detachable fastenings are more relevant.

GOSTs 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.

Each type of polymer, depending on the scope of application (sewage, heating or water supply), has its own GOST standards.

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

Diameter standards

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

The dimensions of external sewerage are determined by SNiP standards. In intra-block networks, a diameter of 150 mm is used, in street networks - 200, 250 mm.

Polypropylene products are produced in accordance with GOST 26996-86. The standard has not established a specific size for the sewer sector. 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. Its requirements: PVC pipes must have a Ø from 10 to 315 mm.

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

Step-by-step technique for connecting pipes with your own hands

The technology for performing the work includes the following stages:

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

At the first stage, the location of the connection is determined and the method of its implementation is chosen. Make the necessary measurements and determine the need for materials.

Required tools and materials

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

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

Select the necessary tool. It may include:

1. a set for dismantling the cast iron part - a hacksaw or grinder, a mallet, possibly with a rubber pad;
2. screwdriver;
3. spanners.

To cut the thread you will need a thread cutter.

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

Work progress

If wiring is to be done, all its sections are marked. In case of short wiring, mark the location of the cast iron cut.

Installation features

If you have to disassemble and remove the old part of cast iron from the socket, you should be careful: cast iron is a brittle metal and the socket can crack if hit with a hammer or by forcefully turning the piece being removed in it. Caulking may require the use of a blowtorch or torch if the joint is filled with sulfur. You cannot do without a respirator or gas mask here.

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

The wiring always starts from the riser.

Frequent connection problems and errors

Often they try to insert rubber seals into the socket without proper preparation of its interior. You must understand that any bump on its surface can cause a leak. The inlet part of the cast iron must be thoroughly cleaned mechanically.

Insufficient drainage slope 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 basic lubrication, an insulating layer, or a loose or overtightened threaded connection.

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

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

The plastic channel does not provide complete sound insulation. The problem can be solved by installing an additional protective box.

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

A combination of several pipe joining methods

To guarantee protection from leaks, a combination of several connection methods is used.

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

Today, many people want to replace the old ones with plastic ones. Is this necessary, 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 this for?

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

• during the construction of a private house, when it is necessary to “cut into” the central pipeline;
• with a complete update of communication systems, if a major renovation of the home is being carried out;
• when installing new or replacing old meters.

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

But before you begin installation, you need to consider that:

• cannot narrow in the direction of movement of the filling medium;
• the presence of protrusions and 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 expansion.

Table. Dependence of price on linear parameters of plastic pipes

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

		Length, mm	Price 1 piece, USD
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 range of materials plus GOSTs

To create high quality 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 about quality indicators and the scope of application of polypropylene pipes is reflected in regulatory documents, the main one of which is, which came into force in 2003.

Important!

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

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

1. duration of operation;
2. pressure;
3. temperature range of application;
4. safety factor.

Cuff diameter 110 mm

There are several ways to switch from cast iron to plastic with a diameter of 110 mm. The simplest and cheapest is the transition with a cuff. Preparations for work should begin by dismantling 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, you should wear goggles and a respirator before work.

Approximately from the middle of the pipe, then try to rotate it around its 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 the space for the new plastic riser. After this, begin cleaning the outer and inner parts of the socket from the possible presence of rust, old sealant, and hardened pieces of cement mortar. After this, using coarse sandpaper, polish as much as possible the inside of the bell, dry it, remove unnecessary dirt and dust, and degrease it.

Important!

You should remember that cast iron is fragile, so cleaning must be done very carefully so as not to damage the socket. Now you can start installation.

To do this you need:

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

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

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

The minimum price of this method of connecting cast iron and plastic pipes is the main advantage of this relatively easy technical operation.

Using a coupling

If you want to connect cast iron and plastic of the same diameter, then use it 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 and rust, and then sand it with coarse and fine-grained sandpaper. Then connect the pipes, and for greater security, tighten the edges of the coupling with clamps. If the pipes are of different diameters, then you can use a taper or a transition coupling.

Transition with and without bell

Let's consider 2 cases of how you can qualitatively connect a plastic pipe to 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 bell from dirt and remnants of old embossing, 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 pipe into the cuff.

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

If there is no socket, you should carefully cut the pipe, clean and align the end. In order to carefully insert a cast-iron riser into plastic, an adapter pipe made of plastic with a larger diameter than in a cast-iron product is often used.

The work is carried out in the following sequence:

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

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, clean the cut end well with coarse sandpaper, straighten it with a file, and then spread it with grease or mineral oil.

After this, you need to cut a thread (4-5 cm wide), onto which you wind a special thread for plumbing work. Then take a press fitting (), and without much effort screw it to the ends of the plastic and cast iron pipe. 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 any problems, you need to follow the practical advice and recommendations of experts.

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

It should be remembered that:

• The easiest way to dismantle old cast iron pipes is with a grinder;
• you cannot break off an old cut pipe, since you cannot foresee how it will break off;
• to avoid chipping, strike the pipe with a wooden or rubber hammer;
• it is necessary to equip an inspection hatch;
• to avoid paying twice, do not use cheap, not always high-quality, Chinese fittings;
• You can get rid of cracks using silicone;
• when using silicone, avoid mechanical impact on the joints for 4-6 hours until the polymerization process 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 old sulfur filling using a blowtorch or gas torch. Doing it carefully in any other way will not work. Remember that sulfur vapor is toxic, so it is best to wear a gas mask when performing work;
• To prevent damage to plumbing fixtures, it is better to disconnect the bathtub, toilet, and washbasin from the system. If a cement base is also used to secure the toilet, then it is better to immediately break it and remove it in parts, since it is unlikely to be able to be carefully removed;
• During installation, do not forget that there is a big difference in the coefficients of thermal expansion between cast iron and plastic.

Questions and answers (FAQ)

How to properly connect a cast iron pipe to a plastic product?

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 to each other, you must:

• accurately select parts in diameter and length;
• depending on the gap between the elements being connected, choose the joining method;
• determine the materials needed for sealing;
• maintain the period of time necessary for the final hardening of the sealant, glue, weld;
• adhere to the algorithm for performing pipe connection work.

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 can the plastic product and the cast iron pipe be properly connected.

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 make a cast iron-plastic transition. This is due to the fact that many apartments and private houses use old cast iron systems, 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 we can highlight connections using:

1. Press fittings

When switching from cast iron to plastic 50, a press fitting is used in the form of a coupling with an internal thread at the socketless end. This connection is quite reliable, since the thread ensures complete sealing of the seam.

Sequence of work:

• trimming the edges of a cast iron product with an angle grinder;
• chamfering around the perimeter of a metal part, lubricating this part of the riser with grease, lithol or mineral oil;
• cutting threads 40-50 mm long using a die or thread cutter of the appropriate diameter;
• applying a sealing material to the threads (fum tape, plumbing paste or silicone with tow);
• screwing the press fitting. It should be noted that during this procedure you do not need to apply special force, since cast iron is a brittle metal.

Important! To ensure reliable connection, it is advisable to re-tighten the threaded connection after 10-15 days.

2. Rubber seals

If, during the process of dismantling the old section of the system, the remaining part of the pipe is smooth and there are no chips or cracks on it, then this joining 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 and dirt. After this, the rubber part is inserted into the socket extension, and a PVC pipe is inserted to a depth of 45-75 mm. If there are sinks, they must be sealed with sealant.

If there is no socket, use a plastic adapter. Cleaning the edges with a grinder and removing rust and dirt is done in the same way, after which a rubber seal and 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 cross-section of 50 mm, embossing is often used. This method is optimal if the connection is of the “pipe-socket” type.

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

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

Important! The pipeline will be ready for use in 24 hours. This is exactly how long it will take for the sealing compound to completely harden.

4. Silicone sealant

If the riser is in good condition, and the gap between the joining elements does not exceed 2.0 mm, then they can be connected to each other using sealant. It should be remembered that the connecting parts must be dry and clean at the joint, and the silicone should be applied under pressure, since this method ideally fills possible cavities and voids.

Important! Operation of the connected parts is possible after complete polymerization of the sealing substance, which occurs after 4-5 hours.

You can also find adhesive connections between plastic and cast iron, joining 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, a non-standard method is often used. Its essence is as follows:

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

B) Using your hands (wearing gloves), slightly stretch the heated part to form a kind of socket.

C) Place the stretched pipe element onto the cast iron pipe, making sure that the plastic is evenly placed on the riser along the entire circumference.

After cooling, the connection cannot be removed from the cast iron either by hand or with a hammer. Simple, universal, reliable.

Traditional docking methods can also be used.

How to switch from cast iron to plastic without a socket

If there is no socket, use a plastic adapter. They work according to the scheme:

• level the cast iron edge with a grinder;
• an adapter is placed on the flat end;
• the “dressed” part of the part is coated with silicone sealant;
• A plastic adapter is placed on the pipe surface, having previously been lubricated with a sealing substance.

General view of the plastic adapter

1- PVC pipe socket

2 – rubber seal

3 – adapter element

4 – rubber cuff

5 – second rubber seal in the form of a ring

6 – socketless riser made of cast iron.

How to switch from cast iron to plastic 110 if you can’t get a cast iron pipe

When replacing a metal product, it is best to cut off a section of the old pipe where it transitions into the socket. With this dismantling option, joining the old cast iron product with a new plastic pipe will take the minimum amount of time and use the least amount of effort.

Important! The optimal 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 splitting of a given area cannot be predicted.

When it is not possible to get the pipe out of the socket, then you need to use a grinder to make cuts around the entire circumference every 20-25 mm along (not across!!!) the pipe, reaching the expansion. After this procedure, all unnecessary remains of the risers are removed very easily.

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 the cast iron and plastic riser can be connected using special adapter couplings of appropriate diameters. You can purchase them at any plumbing store.

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