A heat-resistant adhesive should ensure secure connections where other adhesives have long since given up and can no longer be used. It is a professional adhesive and connection material that is extremely resistant to temperature fluctuations and ages only slowly. Heat-resistant adhesive can also protect against corrosion.
There are numerous areas of application where conventional adhesives fail. Unfortunately, it is the case that high temperatures in particular can affect the processing of the adhesive and its properties in the dried or bonded state. Many commercial adhesives fail at high temperatures. Either they melt and can no longer establish a secure connection, or they become porous and thus do not serve their purpose either. Special and heat-resistant glue is used here. Even high temperatures of several hundred degrees Celsius do not bother him. It can also be used in the oven, for example, if an oven pane needs to be glued.
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Bonded joints and the influence of temperature on their properties
One of the most important factors when using adhesives is the temperature. It influences the curing time and the viscosity of the adhesive. Other factors also depend on the temperature, such as the subsequent hardness of the adhesive bond or its strength and resistance to aging processes. However, the temperature also plays an important role in the actual processing of the surface to be processed. The heat-resistant adhesive is made for room temperature processing, but also offers stable adhesive bond properties at high temperatures.
Adhesive for high temperatures
Select the correct adhesive for the selected temperature range
It is very important to choose the right adhesive for each application and for the corresponding temperature range of the future connection point.
The following things play a role here:
- the curing time and the viscosity of the adhesive
- the hardness of the subsequent connection
- any temperature fluctuations that may occur at the future connection point
- possibly mechanical effects on the splice, which can occur during later use
- the materials used in the splice
- possibly other environmental conditions such as humidity or even wetness
- optical impairments, which can be caused by the splice and could later be annoying
So there are a lot of things that go into choosing the right glue. Here are a few more tips to help you choose a topic:
Tips for choosing
… the right glue
- The technical information sheet or the safety data sheet that comes with heat-resistant adhesive usually provides reliable information about the technical properties and the factors that have just been mentioned.
- Some adhesives should only be processed within a certain temperature range.
- High temperatures often significantly reduce the adhesive strength.
- Only heat-resistant adhesive offers ideal properties even in high-temperature ranges.
- High-temperature adhesive or heat-resistant adhesive is usually marked as such (e.g. by clearly visible temperature information on the packaging). (Possible image: temperature information on packaging for heat-resistant adhesive)
- The materials of the surfaces to be bonded also play a role and should match the specifications of the preferred adhesive.
Products & Prices
Some high-temperature adhesives from well-known manufacturers and their prices
Many well-known manufacturers offer high-temperature adhesives. Here are some examples with prices:
|UHU 46735 high-temperature silicone||Sealing and bonding of gaps, joints and cracks||permanently up to 180 °Cbriefly up to 300 °C||€9.00 for 80 ml|
|Thermic 1100 °C||Chimney Adhesive for sealing stoves and chimneys||heat resistant up to 1100 °C||€8.90 for 20g|
|Fermit Thermocoll||Adhesive for seals||heat resistant up to 1100 °C||€4.99 for 17 ml|
|UHU Plus Endfest 2-component adhesive||Metals, stone, concrete, wood, porcelain||heat resistant up to 100 °C||€7.35 for 24 ml|
|Henkel Loctite 5366 silicone adhesive||Permanently elastic sealant for glass, metal, plastics and ceramics||heat resistant up to 150 °C||€14.95 for 310ml|
|E-Coll 2-K-Epoxykleber||high-strength bonding and filling compound for earthenware, ceramics, wood, glass, concrete, metal||heat resistant up to 100 °C||€5.54 for 50g|
|JB Weld HighHeat Epoxy Metal Putty||Exhaust pipes, silencers, engine blocks||permanently up to 235 °Cbriefly up to 260 °C||€14.95 for 50g|
In principle, larger containers are usually cheaper than small tubes, for example. If large quantities of glue are required regularly, it is best to buy larger containers.
Possible areas of application for high-temperature adhesives
Most heat-resistant adhesives are suitable for both short-term and long-term use in high ambient temperatures. However, there are some differences. For example, certain adhesives are also suitable for use with strong temperature fluctuations. Such special adhesives are often used in the following areas:
- Combustion engines and electric motors (e.g. as sealants)
- Connections in industrial plants
- ovens and stoves
- fireplaces and stoves
- Connections in heating and exhaust systems
Adhesives are often used as sealants
Many adhesives also serve another purpose, namely to seal individual components in the machines or on other devices such as closures. When choosing the right glue, it is therefore very important that heat-resistant glue is used that can also fulfill this important function. Not all high-temperature adhesives are suitable for double use as a sealant. (Possible image: machine parts with sealing surfaces)
Heat-resistant adhesive as a special agent for high temperatures
The heat-resistant adhesive must also show certain properties at extreme temperatures, even with a variety of different materials or material combinations such as the following:
- metals of all kinds
- Ceramic fabrics
- mineral substances
- stone materials
- glass and many more
Special high-temperature adhesives also include adhesives that harden very quickly, such as superglue or special component adhesives and contact adhesives. Of course, all of these adhesives have their prices and some are optimized for use at higher temperatures. They therefore perform significantly better than conventional adhesives. Some of these adhesives can even be used for temperatures of up to several hundred degrees Celsius, sometimes even for extreme applications at temperatures around 1000 degrees Celsius.
For strength or tensile strength
An essential factor when using a heat-resistant adhesive is the subsequent strength of the connection, which is usually specified for an adhesive surface of one square centimeter. In the best case, this tensile strength reaches values of several hundred kilograms per square centimeter. An adhesive with such a strength can even be used when an adhesive connection is to be used instead of, for example, welding, soldering or even screwing. (Possible image: screw or splice)
For further processing of the splice
Many connections made with special glue can later be painted over or varnished. It is often also possible to further process the connection point mechanically, such as grinding or sanding. If this is desired, the corresponding information should be available for the adhesives used. These properties are often only given at a certain mixing ratio (in the case of multi-component adhesives). These special properties sometimes also affect the prices for the adhesives to be purchased.
1. Before using the adhesive, the processing instructions on the packaging should be carefully studied. A very important specification is, for example, the processing time, i.e. the time in which the adhesive should be processed before it hardens. The times may vary greatly and are also dependent on the respective ambient temperatures.
2. That brings us to the next important factor: temperature. Not only the subsequent application temperature for the connection point is important, but also the processing temperature. Adhesives can often only be processed properly within certain temperature ranges and only guarantee the subsequent quality of the connection made within these ranges.
3. It goes without saying that the surfaces to be bonded should be thoroughly cleaned before the adhesive is applied. Good preparation of the adhesive surfaces is already half the battle.
4. The splices should be bonded together exactly according to the manufacturer’s instructions for the adhesive used. The contact pressure often plays an important role here. Many adhesive bonds only achieve the desired strength if there was sufficient contact pressure during processing.
5. Once the adhesive bond has been made, the bond should be allowed sufficient time before being subjected to mechanical stress or exposure to high temperatures. (Possible image: still fresh splice)