Strength and viscosity
Both the viscosity and the strength of the adhesive material used in an application are directly relevant to the fastener size that is used. Threadlocker which has low-strength are commonly used in screws that are at least 1 quarter of inch in diameter. Examples of this are calibration screws, gauges, meters and other fasteners. Medium strength adhesives are used for materials that are up to ¾ of an inch in its diameter which are used in presses and machine tools, compressors, mounting bolts and pumps. The high strength threadlockers are best suited for use in fasteners that is up to one inch in diameter. These are found in assembly applications which are permanent like heavy equipment and in different mounts. There are also penetrating threadlockers which have low viscosity and are available to easily wick fasteners which are pre-assembled.
The operating conditions when using the threadlocker are considered. There are many new technological examinations that offer advantages that were previously unavailable including high temperature formulations, surface insensitivities, formulations engineered to endure extreme vibrations and chemically resistant materials.
The type of metal that is used as the fastener is also vital to the efficacy o the adhesive material. If the fastener is made up of two metals which are inactive like the magnesium, cadmium, stainless steel, zinc, titanium or anodized aluminum, you may be required to use a primer in order to speed up the curing process. If there is only one inactive metal in the bonding, then it is safe not to use a primer.
When you apply the threadlocking adhesive, the adhesive should be able to wet the entire length of the area where it is to be applied. The size of the thread will influence the proper wetting as well as the viscosity of the adhesive material and the geometrical shape of the parts. If the parts to be connected are large, you need to ensure that both faces of the material are wetted in order to ensure reliability of the application.