Thread sealant: types, color, application, manufacturers, tips, photos, videos

Thread sealant is designed to make gas, heating or plumbing pipe connections as tight as possible. When choosing a suitable option, you should take into account all the features of thread sealants, navigate among the whole variety of types, keep in mind both old-fashioned sealing methods and the use of modern anaerobic gels.

Peculiarities

When undertaking a major overhaul, many people think about the tightness of the pipes as the last thing, but in vain. After all, it depends on how high the probability is that everything could be ruined by an unexpectedly occurring leak. This is especially true when pipes run close to expensive equipment: the damage to the family budget will be more than noticeable. However, many find the simplest solutions, using improvised means to seal the thread: tow, threads, plasticine. All this does not provide the necessary insulation. And now it’s time to pay special attention to professional thread sealants.

Professional materials include fum tapes, Teflon threads and anaerobic gels. It is worth dwelling on the latter in more detail. They have recently been used more often than others, as they provide an optimal level of adhesion to pipes, completely sealing the threads. Properly applied anaerobic sealant can withstand pressure of 50 atmospheres, not to mention vibration loads. In general, such a sealant is the best choice for household use, and it will work just as well on professional sites.

The main feature of anaerobic gel is that it begins to harden only when the nut or connection is tightened and the air access to the sealant is blocked. As a result, the connection turns out to be, one might say, monolithic, and practically no mechanical effort can break it. Only ultra-high temperatures help, which can only be achieved using special tools (for example, a hair dryer). It is safe to say that heating pipes can also be sealed using gel, and the durability of the joints will be excellent despite temperature changes.

If you apply anaerobic gel according to all the rules, it will last for 5 years or longer. If the technology has not been properly followed, then the guaranteed service life will be only a year. However, even a one-year warranty is more than you can expect when using unprofessional products and materials. Many people complain that anaerobic binders are too expensive (the average price varies from 1,500 to 2,000 rubles per 50 ml tube), but practice shows that such sealants are worth the money, because repairs if something happens will cost much more. In addition, the gel is economical, and it is quite possible that such a tube will be enough to seal all the plumbing and communication pipes in the apartment.

Thus, we can say with confidence that anaerobic sealants owe their popularity precisely to their characteristics.

Kinds

Based on their base, anaerobic sealants are divided into those whose composition is based on an oligomer, and those based on polymers of the acrylic group. Both have similar qualities: they can withstand high pressure, are not subject to the negative influence of mechanical loads, and so on. The difference is important only for professional chemists; construction specialists do not pay attention to this parameter when choosing.

It is much more important to separate sealants according to the degree of fixation. There are options for strong fixation, medium (universal) and low.

Low degree fixing agents are used when it is necessary to seal a small diameter pipe connection. The clamp does not tolerate vibrations and fluctuations, and the pipe itself can be easily untwisted using available tools. This makes the use of low-fix sealant an excellent choice when you need to connect pipes only temporarily, and you plan to dismantle them in the near future. This type can also be used for long-term use, but provided that during operation there will be no significant loads on the threaded connection.

Medium hold pastes and gels are most often used in everyday life. They are suitable for sealing heating systems, gas pipelines, water supply systems, and their use is absolutely harmless and does not change the quality of drinking water. That is why sealants of this type are called universal. They firmly fix the thread, but the joint can be dismantled in the future, only for this it will be necessary to use specialized equipment. The clamp can withstand the loads generated by batteries, water supply pipes and plumbing fixtures.

Strong fixation is not needed at home. Such sealants seal the pipes forever and further dismantling is impossible. They are usually used in industrial production: plants, factories, and in the construction of the city sewer network. These clamps are much more expensive than household ones and require special knowledge and skills when working with them, because you will have to act quickly and accurately. The connection is inextricable and in the future, if necessary, the joint will have to be sawn.

Frequently used medium-fix sealants are also classified. In this case, the classification category is the degree of viscosity of the drug. The smaller and more frequent the threads, the thinner the sealant must be so that it can optimally fill the entire air space of the joint. The maximum diameter of pipes for which anaerobic gels and pastes are produced is 4 cm. Large pipes are sealed in other ways.

Linen thread

Using flax thread is the oldest method of sealing threads.
The only advantage of this product is its low price and constant availability. Even if no other sealants are on sale, flax thread will definitely be available. But the material has a great many disadvantages:

• Difficult to install on threads. If you don't have the skill, you're unlikely to get it right the first time. If a mistake is made during winding, such a joint will quickly unwind, nullifying all your efforts.
• Small operating temperature range. Linen threads practically do not tolerate heat, so they cannot be used to insulate batteries and radiators. They will quickly collapse, leading to leakage.
• Hydrophilicity. Linen thread absorbs moisture well, as a result of which it swells greatly during operation. This may cause the pipe connection to burst. Similar cases are possible when we are talking about pipes made of fragile materials, such as aluminum. However, flax thread is still used to insulate those pipes through which water does not flow.

Teflon or plumber's thread

Teflon or plumbing threads are in many ways similar to flax threads. In the same way, there is a need for correct winding, but this is the only drawback they inherited from their natural “predecessor”.

Teflon threads are impregnated with special compounds that make them universal. They function well both when insulating water pipes, gas pipes and others. Compared to the previous case, the plumbing thread guarantees a good fit and does not fall apart for a long time. It can withstand high temperatures without anything happening to it.

Teflon threads are absolutely safe. They do not release anything into the pipeline, so they are suitable for use on drinking water pipes. However, it is better to clarify this point further.

Some cheap samples are intended purely for technical use.

FUM tape

FUM tape is one of the most popular options, as it is easy to use and has a low cost. All you have to do is wrap a piece of tape around the threads and then tighten the nut or fitting tightly.

However, this is not the main advantage of the tape. It does not affect the thread. If other materials fall apart or stick, then the FUM tape can be easily removed completely by simply unscrewing the thread. At the same time, the tape is completely safe and is excellent for sealing water pipes.

Unfortunately, the tape cannot fix the connection, as they say, tightly. Vibrations or mechanical stress will weaken the joint until a leak inevitably appears. The only means of prevention is to periodically tighten the nuts. Due to this drawback, it should not be used to seal joints on those pipes through which water flows under high pressure.

Non-hardening

This type is relatively new for the Russian consumer. These compounds are produced in the form of a paste, with which you need to thoroughly process the thread, and then simply tighten the nut. It’s also easy to unwind it in the future.

The viscous substance does not glue the pipes together, but simply fills cracks and gaps, preventing water from leaking out. The composition is absolutely harmless to humans, so such sealants can be used in plumbing work.

Do not use sealant paste in cases where the water supply is under high pressure. Then the water will displace the sealant and a leak will form. Unfortunately, there are no means of prevention here, so you will simply have to refuse to use such a remedy, choosing some other, more suitable option.

Hardening

Such substances have high strength characteristics. The fixative sealant takes a long time to dry. Time may vary significantly from manufacturer to manufacturer. However, this is the only drawback of such products.

After applying and tightening this sealant, you must wait the time indicated on the packaging before starting testing and active use. This is especially true when water is supplied under high pressure. It is worth noting that the sealant tolerates prolonged exposure to water under high pressure, since it is almost impossible to displace it after it has dried.

There are products on the market with certain degrees of fixation.

It depends on the degree exactly how, if necessary, you will have to untwist the pipe: simply apply more force or break it.

Anaerobic

Today, anaerobic fixatives are the latest development, quickly gaining recognition. They are suitable for use by both amateurs and craftsmen. Sold in convenient 250 ml tubes and suitable for long-term storage.

The operating principle of anaerobic sealant is as follows. In the open air, it retains a liquid consistency, so it can be easily applied to the thread without fear that it will “set” ahead of time. After the nut is tightened, a chemical process begins, the sealant crystallizes, turning into plastic glue and making the joint completely monolithic. The full reaction time takes no more than 3 hours, after which full operation can begin.

Dismantling is carried out using heat: you need to thoroughly heat the joint, after which you can unscrew the nut.

This method does not work with strong-hold sealants.

Sealing gel

Thread sealants from this category are rarely used in everyday life. Basically, they have found application in the automotive industry, since it is convenient for car enthusiasts to carry sealant in the form of a gel with them, so that, if necessary, they can quickly fix a broken part.

The main purpose of gels is not sealing, but strengthening joints. They make them more durable and resistant to vibration and mechanical stress. This is why many people encounter such difficulties when naively trying to unscrew any bolt on the engine: even at the factory they are treated with a sealing gel.

The only way to deal with a joint treated with such a product is to heat it well.

Otherwise, you may waste your energy without achieving the desired result.

Using the spectral analysis method when calculating safe load

The technique for overcoming fatigue wear is well known to designers. With proper design and installation, the connection structure functions in such a way that the resulting forces cannot reach values ​​that can cause fatigue failures. The problem becomes obvious when studying the spectrum of acting forces. Figure 31 shows a small segment with strain gauge readings obtained during testing of one of the aircraft components. (Spectrum of fatigue loads for the studied fighter parts)

Rice. 31: Load spectrum view.

The question inevitably arises: how to determine the design load of a connection? We know that in connections tightened with forces exceeding the loads acting on them, cyclic loads on the bolts do not occur. Is it possible that the compressive force is so high that the magnitude of the bolt load cannot exceed a failure value of 4450 N (1 klb F), or is it possible that the probabilistic risk could reach several hundred maximum values, which, of course, cannot cause fatigue failure if they do not exceed the fatigue limit? It is difficult to answer this question unambiguously. Firstly, it is necessary to conduct a spectral analysis in order to determine the probability of the formation of peak loads. The results of such an analysis are shown in Figure 32.

Rice. 32: Spectral addition.

Secondly, it is necessary to consider another aspect of the problem, which is no less important than the issue of fatigue. The process of self-unscrewing of fasteners can occur as a result of overload of the connection. So, with 50 displacements of a bolted connection to the side, 20% of the tightening force will be lost. Due to the decrease in this force, more frequent and weaker loads will cause slipping and a fairly rapid failure of this connection. Thus, the designer, along with choosing the size of the bolt, also needs to decide on the method of its fixation. Different fixation methods have different effects on both the compression force and the possibility of self-unscrewing of the connection. If the bolt is secured, protecting it from self-unscrewing, then even a very large number of overload cycles will not affect its operation. The design load can be a fraction of the peak load with obvious weight and cost savings. Loctite thread lockers are the most effective means of preventing self-loosening of a connection and maintaining a constant clamping force.

Colors

The most important criterion by which one can immediately draw a conclusion about what the sealant is used for and what properties it has is color. Anaerobic thread sealants are produced in several colors.

Blue

Typically, blue anaerobic sealants are only suitable for metal pipes and parts. The joint turns out to be resistant to all kinds of influences, be it water, gas, antifreeze, gasoline and the like. The blue retainer is a high-quality seal that has only recently begun to be used in domestic conditions. Previously, it was only available in industrial production, for example, in the construction of defense structures, rockets, and spaceships. Application is limited only by the diameter of the pipes: it should not exceed two centimeters. Dismantling can be carried out without special equipment by applying medium mechanical forces.

Red

Red sealants are needed to seal worn, worn out threads. Red sealants are also used to seal joints of ferrous metal pipes. Red fasteners set faster than others, but this does not in any way affect their strength properties. They are resistant to high pressure and temperature changes. The diameter of the pipes that can be sealed with this anaerobic gel is no more than 3 cm. Dismantling will necessarily require heating the joint. When repairing, it is not necessary to remove excess sealant from the threads; you can apply a new layer directly on top of them.

Green

Green sealant is a low-strength variety. It is suitable for temporary connections of both plastic and metal pipes. When dismantling it, no effort will be required: it will be enough to unscrew the connection as usual. Manufacturers claim that the difference between the blue and green options is small, but this is not the case. Blue is resistant to all kinds of influences and vibrations, which cannot be said about green. The green sealant can be used to seal pipes up to 3.81 cm (1.5 inches) in diameter. The important point is that the threads must not be damaged.

Purpose of thread sealant

Sealants for threaded connections are constantly being improved, new products with improved characteristics are appearing to ensure high-quality sealing of pipes for a long time. Without sealing around the joints, there is a high risk of leakage, which is why choosing the appropriate sealant is of utmost importance.

Undesirable phenomena cannot be prevented solely by washers and strong tightening. Threads and tapes are often used for sealing; their task is only to seal; they cannot protect against negative influence factors. It is being replaced by modern thread adhesive in the form of gels and anaerobic compounds.

How to Unscrew a Thread Locker

An option for unscrewing bolts that were locked using clamps is temperature exposure. For different fixation levels you will need different temperatures: for red – 200-250 degrees; for blue – 100 degrees; the green type can unscrew at lower temperatures. The heating tool is a soldering iron or a hair dryer.

An option for unscrewing bolts that were locked using clamps is temperature exposure.

Thread adhesives provide a high level of thread bonding and can withstand varying degrees of stress. When choosing, take into account the operating conditions in order to use a type of product that is sufficient in terms of adhesion force.

Characteristic properties

To work with sealant, you need to know its characteristic features. This will allow you to choose exactly the composition that is suitable in a particular case.

All sealants differ in the following technical features:

• Fluidity or viscosity. For sealing small joints, mixtures in the form of a paste are best suited. When you need to seal a large seam, then you should use a liquid sealant. The greater the width, the thinner the composition. The mixture will flow into all gaps, completely sealing the joint.
• The strength or force required to separate a joint. Maximum fixation sealants cannot be unscrewed, you will only have to break them. A low-strength composition will allow you to do this with little effort. With medium fixation, you can unscrew it using additional tools.
• Temperature, that is, the maximum limit that the composition can withstand without losing its properties. It varies greatly for different sealants. Most compounds can withstand from -50 to +150 degrees. For extremely low and high temperatures, you need to buy a specialized thread sealant.
• Hardening speed. It is usually indicated on the packaging of the sealant. The rate of hardening depends on many factors, including the quality of the composition itself and the conditions under which sealing is carried out. The pipes can be used after this period has expired, otherwise depressurization will occur.
• Scope of use. There are many sealants available, but not all are suitable for water pipes or pipes that carry gas. It is necessary to select a mixture in accordance with the possibility of its use for individual jobs.

About bolt selection

To obtain the required clamping force F, the designer needs to select a suitable fastener. The clamping force, which is related to S (bolt tension), can be represented as the following equation:

S = F/A,

in which A is the cross-sectional area of ​​the bolt used or, as a rule, the sum of the areas of all bolts used in the connection. If the material of the bolt is known in advance, then the most optimal value of the bolt tension S is considered to be 75 percent of the permissible load and, accordingly, the value A can be calculated. Next, using the equation “tightening torque - voltage”, it is easy to determine the number of bolts and their diameter:

T = kDF

The shear torque will produce a compressive torque. If this value exceeds the permissible bolt load, the number of bolts used must be increased so as to reduce the maximum load for each fastener. The procedure can be done in reverse: if fewer bolts are used, the load limits must be increased, so the above equation can be applied to determine the most suitable bolt material. As practice shows, the value of k depends on the use and for each situation should be determined empirically. The equation (Fig. 30) can only serve as a guide. The most reliable values ​​are obtained through experiments.

Advantages and disadvantages

Each type of thread sealing has its pros and cons. Previously, threads and FUM tape were actively used for this purpose, but now they are significantly inferior to modern sealants. And there are many reasons for this.

Benefits of using thread sealant:

• Preservation of properties during temperature fluctuations. Does not affect the quality of sealing.
• Resistance to mechanical influence factors. It will not be possible to unscrew the nut without effort; to do this you will have to make an effort or use additional tools. This is an important condition, because water passing under pressure creates vibrations, which cause gradual unwinding.
• Penetration into hard-to-reach areas. The mixture fills all the cracks, the parts fit tightly to each other, creating complete tightness.
• Ease of use. Anyone can figure out thread sealants. They come with detailed instructions and tips.
• Low consumption. Use sealants sparingly; you only need a small amount of the compound to treat several pipes. For example, one bottle is enough for an average apartment.

But we should also dwell on some of the disadvantages of using sealing compounds. Such a plus as reliable grip turns into a minus when it is necessary to carry out repair work and uncouple the pipes. After using a high-strength sealant, the only way to disconnect is by breaking. Price also matters. The use of sealants will be more expensive than traditional thread sealing options.

Sealants are not suitable when repairs need to be carried out quickly, restoring the operation of pipes as soon as possible. The system can only be used after the mixture has completely hardened. There are not many disadvantages to sealants; they are becoming increasingly popular.

Application area

Thread sealant is used in many areas of human activity. It is used to seal water pipes in apartments and private houses. But such materials are not suitable for insulating street pipes due to the fact that they have large diameters. Also, sealant for threaded connections of water supply pipes can be used for joints of sewer pipes.

In plumbing, a special plumbing compound is used. Its feature is resistance to temperature changes. This is especially important when connecting a washing machine. But, at the same time, the material should be selected so that it has adhesion to the plastic, otherwise special activators will have to be used.

To seal threads in heating systems, a composition that is resistant to temperature changes is also needed. Gas pipelines should use materials that are resistant to aggressive environments.

Thread sealants are also used in machine tool industry, automotive industry, aviation, water transport, medicine, construction, etc.

Application

During production, anaerobic sealants are packaged in plastic bottles of varying volumes. The dropper on the bottle allows you to quickly and conveniently apply the sealant to the surface.

Stages of applying glue:

1. Degrease the areas to be joined and first remove dirt from them. Dry the surfaces thoroughly before applying glue.
2. Shake the bottle well so that the composition inside becomes homogeneous.
3. Apply glue to the surfaces to be joined and fix them in the desired position.
4. Remove excess product with a rag.
5. The composition hardens within 15 minutes.

The curing time depends on the size of the joint, the characteristics of the material and the room temperature. The gluing result will be of the highest quality if the sealant is applied to the entire bonded area of ​​both parts, evenly distributed.

Tip Heat the parts to be glued if the temperature is below +15˚ C to speed up drying. At low room temperatures, the composition hardens slowly.

Even the most modern water pipes have threaded connections, as they also require high-quality sealing.

In the recent past, tightness was achieved using sealing threads, flax strands, and FUM tape.

The anaerobic sealants that replaced them protect metal surfaces from corrosion and provide excellent air and water tightness of threaded connections.

Many companies produce sealants; when choosing an adhesive composition, you should pay attention to some factors:

• what joint strength should be obtained as a result of gluing;
• the conditions under which the joints connected by the composition will be used;
• Will the part need to be disassembled later?
• thread characteristics.

Loctite sealant

The most popular anaerobic sealants on the Russian market are:

1. Loctite (Loctite). Liquid compounds and sealing threads are produced under this brand. They are able to prevent gas or liquid leaks, increasing the strength of pipes several times. The cost of sealants from this manufacturer depends on their area of ​​application and composition characteristics. For example, 50 ml of Loctite 577 universal glue costs on average 1,750 rubles, a 50 ml bottle of Loctite 542, used for small carvings, costs 1,784 rubles.
2. Santekhmaster is a domestically produced glue from. The composition is resistant to antifreeze, gasoline, alcohol, and does not lose properties at elevated pressure and temperature. The product is used to seal threaded metal and flange connections, it is non-toxic and has no unpleasant odor. Prevents corrosion. A 15 g tube will cost at least 145 rubles.
3. Anatherm is used to seal pores and cracks, fix threads when assembling parts and welds. As well as durable and very fast gluing of parts, repair and restoration of components and mechanisms. The cost of a 200 g bottle starts from 2400 rubles.

How to delete

It may be necessary to remove glue from threaded connections immediately after gluing or after the composition has completely hardened. In the latter case, you will need a hair dryer and a wrench.

Sealant removal steps:

1. Turn on the hair dryer and direct a hot stream of air to the joint.
2. Gradually the adhesive will begin to crumble, then remove the remaining sealant with a rag.
3. Disassemble the connection using a wrench.

There is no need to completely remove the remaining adhesive; a new layer of sealant is placed on top of the old one without loss of effectiveness.

About fatigue strength

There are two ways to determine the fatigue strength of bolted connections: fatigue of the bolted material and fatigue of the bolt. The fatigue of a normally tightened bolt will not affect a rigid connection. The initial bolt stress will remain relatively constant until the external load on the joint exceeds the bolt load. When the operating loads on the bolt are lower than the design loads based on the preload force, the bolt will function with subtle voltage fluctuations or without it at all, and bolt fatigue will not affect the reliability of the connection, regardless of the number of load cycles.

Increasing the flexibility of the connection will increase the alternating stress in the bolted or screwed fasteners. If there is too much flexibility, the alternating loads present can become quite severe and, regardless of the initial preload on the fasteners, lead to fatigue failure of the fasteners.

The most important condition to prevent cyclic stress fluctuations caused by cyclic loading is proper prestressing or preloading of the fasteners. Test results show that connecting rigid parts with relatively elastic bolts is the best way to prevent failures caused by fatigue.

The use of Loctite thread lockers guarantees increased reliability of connections. The glue fills all the gaps in the thread, leaving absolutely no room for moving fasteners.

Manufacturers

You can argue for a long time about which manufacturer is better, so the simplest thing is to turn to reviews. Several brands receive the most positive ratings.

• Loctite. Universal glue from a Chinese manufacturer, however, many users noted that constant care of the cap is required.
• Sealup. Products from Italy are of high quality and easy to use. There is a guarantee seal, which stands out as an advantage, since it is possible to check how hermetically sealed the packaging is.
• Abro. One of the few sealants that can be used at negative temperatures - down to -20 degrees.

• Mannol. This option has one of the longest shelf lives, but it is impossible to work with it in a confined space due to the pungent odor.
• Wurth. This German-made fixative is considered to be of the highest quality. Despite the high cost, it is popular.
• Tangit Uni Lock. Manufacturer from Belarus. Specialized gels are produced for both plastic and metal.
• Siseal. Anaerobic gels of this brand are often used. Sold in containers of 100 g.

Tips and tricks

Professional craftsmen share several recommendations on how to make sealing threaded connections as simple and durable as possible.

• Do not be afraid that uncured sealant will come out from the inside of the pipe. It will not harden and during the operation of the water supply it will simply be washed off with water. Anaerobic gels are absolutely harmless, but it is still better to leave the tap open for a while so that excess sealant is completely removed.
• When screwing connections treated with thread sealant, there is no need to tighten the threads with wrenches. Maximum hand effort will be enough, but you really need to wrap with all your might.

• ​If the pipe is fragile, then there is no need to try to unscrew the joint treated with sealants. Heat must be used immediately. 170 degrees will be enough.
• If possible, it is best to avoid using sealants for temporary installations. Disassembling connections will require a lot of time and effort, which is not fully worth it. It is best to resort to using sealant threads or flax for temporary use.

For information on the features of thread sealant, see the following video.

Fixation by deformation:

In this case, the increased elasticity of the connection will be compensated by subsidence after assembly. This will maintain the prestressing force and make it more difficult to loosen the threaded connection. However, this method will not prevent self-unscrewing of the connection in the case where there are relative vibrations between stressed parts. High-stiffness disc springs and conical spring washers are examples of the deformation method. The locking effects of threaded connections obtained by using other elements, such as spring washers, fan washers, elastic washers and serrated washers, are not adequate. These types of washers are not recommended for use on bolts rated 8.8 or higher (the US equivalent is Grade 5).

Rice. 25: The engine crankcase is fitted with a Loctite threadlocker bolt.