When operating heating systems, and chimneys in particular, periodically there is a need to get rid of cracks, gaps and cracks that have appeared. The owners of brick structures — fireplaces or stoves — often face similar problems.
In such cases, you risk not only an increase in fuel consumption, but also penetration of combustion products into the living room. Which, in turn, can cause severe poisoning, and sometimes even cause death. Therefore, the maintenance of heating systems must be approached with all seriousness.
Features of the chimneys
If you put quality ceramics or a sandwich in the chimney, then these problems are minimized. But not everyone can afford such expensive equipment, as well as expensive installation, so many have to use what is.
Normal operation of the chimney is possible in the absence of gaps, that is, the system must be airtight. Very often soot accumulates on the walls, and if it gets access to the air, it can easily catch fire. Given a local temperature of 1,500 degrees, the fire will easily reach the partitions and the roof. What will happen next is clear to everyone.
It is also worth noting that cracks in the chimneys are the cause of the attenuation of the flame in a gas boiler. In winter, when the winds are strong and unpredictable, you risk staying with the heating off. In the daytime, this is a completely solvable problem, but waking up at night from the cold and going to light the boiler is still a pleasure.
How to be
In this case, special sealants for chimney pipes act as a panacea. This, as a rule, is a ready-made and tubular consistency that resembles ordinary toothpaste. Sealants for chimneys are different both in composition and in the method of application. Therefore, the average consumer is very easy to get confused in all this diversity.
We will try to understand this issue and consider the features of sealants for chimneys: the characteristics, application and feasibility of buying in a particular case. Such compounds are sold in any hardware store, so there should be no problems with the purchase.
Types of sealants
The main component of the sealant is polymers. Moreover, different compositions are used, fillers are added, and the basic qualities of the final product depend on this. The packing of sealants for chimneys is also different: in tubes like toothpaste, under the mounting gun, or in very modest portions for single use.
There are also two-component compositions that must be mixed before use. Due to the stringent requirements and the choosiness of the product as a whole, such sealants for chimneys are recommended to be used only by professionals. Yes, they are cheaper, and they have a greater return, but for one-time and small work there is already a lot of trouble.
Specifically for chimneys, special compositions are used that can withstand high temperatures. But here there is a gradation, which you must pay attention to before buying. On sale you can find two categories of sealants - heat-resistant and heat-resistant. Depending on the temperature and type of work, an appropriate category is selected with its specific characteristics. Let's consider them in more detail.
Heat Resistant Compounds
Heat-resistant sealants for the chimney are made on the basis of silicones. The specific temperature regime can vary greatly and depends on the selected composition. For example, when iron oxide is added, the sealant tolerates heat up to 250 degrees with short-term peaks up to 315 ° C. Such compositions have a reddish-brown color and are perfect for stoves and fireplaces with a similar gamut.
It should also be noted that silicone sealants can be neutral or acidic. The latter are noticeably cheaper and give out acetic acid upon hardening. Therefore, such compositions are best eliminated when working with corrosion-resistant metals, as well as concrete and cement. Such a sealant for a chimney made of stainless steel will come in handy.
Neutral Compounds
When dried, the neutral compounds release only water and alcohols, therefore, they can be used almost everywhere, naturally, with an eye on the maximum temperature. They are resistant to direct sunlight, do not pass water and are characterized by good adhesion with brick, concrete, ceramics, wood and glass. You can also use a similar sealant for a stainless chimney.
Features of heat-resistant compounds
The curing speed of silicone sealants can vary from several hours to several days. Here, again, everything depends on polymers and fillers. In addition, the date of manufacture of the product plays a significant role. That is, the fresher the sealant, the faster it freezes.
The approximate cure rate should be indicated on the packaging. The optimal parameters for silicone products are temperatures around 25 degrees and humidity within 50%. Everything that is knocked out of these limits, one way or another affects the speed of hardening. Low temperature and high humidity - long hardening, and vice versa.
Heat Resistant Compounds
Heat-resistant sealants for chimneys, or, as they are also called, heat-resistant, are made on the basis of silicate. Such formulations can tolerate very high temperatures. For them, the normal working environment fluctuates around 1200-1300 degrees. Some heat-resistant sealants for chimneys can withstand a peak temperature of 1600 ° C. In this case, another characteristic is indicated on the package - “refractory”.
This composition is used where direct contact with fire occurs. That is, inside the chimney, and not outside, as is the case with synthetic sealants. Silicate compositions are excellent for removing gaps in masonry with kiln casting, sealing fireclay bricks, as well as for chimneys made of sandwich and stainless steel.
Heat-resistant compounds are recommended in all cases for internal treatment of chimneys. An exception may be condensing or pyrolysis boilers, in which the temperature of combustible materials at the outlet does not exceed a temperature threshold of 150 degrees. It is much more practical to use ordinary heat-resistant sealant.
Features of heat-resistant compounds
It is also worth noting that heat-resistant compounds are very well combined in an impressive list of building materials: stone, concrete, cement, metals, including stainless steel. Perhaps the only critical drawback is related to smooth surfaces. They do not hold heat-resistant sealants very well, unlike heat-resistant analogues, therefore, additional abrasive preparation is required here.
In addition, the composition is finicky to temperature during application. The best option is the upper limit of 40 degrees and the lower limit of 20. Otherwise, stability and quality of solidification are difficult to guarantee.
After hardening, the consistency of the heat-resistant sealant becomes stiff and inelastic. Therefore, this composition is best used in places where vibration is excluded or at least minimized. Otherwise, the sealant will simply crack. But this nuance has its advantages. It is much easier to apply paint to the solid composition, which will hold much better than on elastic heat-resistant sealants.
Stamps
Almost all popular and sought-after manufacturers write on their products that the sealant is designed for chimneys, so there should be no problems in a good half of cases. In addition, the detailed information on the label will allow you to navigate in temperature conditions, as well as in the composition belonging to one or another resistance class.
Among manufacturers, we can distinguish several of the most popular and well-established brands. Their products are enviable and have a lot of positive feedback on specialized forums from consumers.
Top Chimney Sealant Manufacturers
- Penosil.
- Soudal.
- "Titanium".
"Penosil" boasts the release of extremely high-quality heat-resistant sealants that can easily withstand temperatures of 1500 degrees. “Sudal”, as they say, ate the dog on heat-resistant compounds, and on its shelves you can see a huge assortment of silicone fillers for any chimney.
Titan for the most part offers versatile products. Its sealants can withstand temperatures up to 1300 degrees and have an attractive cost, compared with the compositions of the two previous brands.