The family of anerobic sealants are typically employed in purposes like threadlocking; retaining rigid, cylindrical assemblies; and sealing between flanges. They are commonly called machinery adhesives or mechanical adhesives.
In most purposes a liquid is employed. The viscosity will differ between the varying types of anaerobic glues, some will be more similar to a gel that will adhere to the metal and a few will be so thin they will wick or seep into restricted spaces.
What makes these types of adhesives unique is their capacity to cure. In the absence of air, and in the presence of metal ions the curing process begins. Powerful polymer chains are formed that create a tenacious bond between metals. As opposed to traditional glues that cure by way of mainly evaporation through the air, the air impedes anaerobic adhesives.
Though anaerobic purposes vary extensively, in many cases the adhesive gives high shear strength and exhibits very little flexing or peel forces. When anaerobic products are employed to lock threaded assemblies with each other, they prevent loosening and corrosion of the assembly. For example, when an anaerobic adhesive is sealed between a nut and a bolt on a threaded assembly, it rapidly cures to form a hard, crosslinked plastic with powerful adhesion to a lot of metals.
As the liquid threadlocker cures, it finds its way into each tiny imperfection within the threads. The adhesive totally fills the microscopic gaps between interfacing threads to lock and seal the assemblies, preventing lateral movement and corrosion that could result from moisture, gases, and fluids.
The sealing character of anaerobic glue tends to make it perfect for use as formed-in-place gaskets that provide a seal between flange faces. Simply because they permit you to create joints with a line-to-line fit between metal flanges, they remove the need for tightly controlled flange surface finishes and the issues related with compression gaskets, including compression set, bolt relaxation, and loosening.
For rigid, cylindrical assemblies, including joining a bushing to a shaft, anaerobic adhesives have replaced press fits and shrink fits in many assemblies. Press and shrink fits generally require tight manufacturing tolerances and pricey surface finish requirements. Because they usually entail cumbersome heating and cooling of components before assembly, the assembly can actually be distorted.
In manufacturing operations in which application of the liquid threadlocker is not desirable, adhesive manufacturing companies have developed pre-applied dry threadlockers that cure once the threaded device is assembled.
Through adhesive technology new glues are being developed and traditional ones being enhanced, but possibly this kind of adhesive, anaerobic, will always have the most interesting curing mechanism.
For more information about Adhesive System's structural adhesives or any other adhesives please contact us at 877.740.1250 x20. You can also send us an email at asisupport@instantca.com. If you don't find exactly what you're looking for, tell us about your application and we'll help you find something that will work, or customize something specific for you.
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