FALL 2024

92 THE DISTRIBUTOR’S

92 THE DISTRIBUTOR’S LINK BRUNO MARBACHER LIQUID THREAD LOCKERS PREVENT ROTATIONAL LOOSENING from page 12 A locking adhesive fills up all the empty spaces between the thread flanks, which eliminates thread play and consequently wobbling. As a result, we maintain friction in the thread and therefore preclude rotational loosening. Before the application of a threadlocker, the male and female threads should be clean, dry, and free of corrosion. Some adhesives have a higher oil tolerance, so they will bond, but best results are obtained with clean substrates. Liquid locking adhesives are applied during assembly. The thread can also be pre-coated with adhesive in microcapsules (Precote, 3M etc.). Anaerobic Threadlockers In this article focus is put on liquid anaerobic threadlockers which cure to form a hard bond. These are the ones preventing wobbling. Anaerobic” is not a common word, but it means that it “dislikes air,” and the adhesive only hardens when the air (oxygen) is blocked. As long as air can reach them, the adhesives remain liquid. That is why the supplied bottles are never completely full. Along with “blocking the air,” there is another essential condition for anaerobic adhesives to harden. This condition is “contact with metal.” In other words, it will not cure without metal. Also, engagement length is critical, jam nuts are not suitable for anaerobic threadlockers. Certain materials or surfaces can adversely influence the curing process such as stainless steel, hot dip galvanized steel, nickel, or chromium plated surfaces, aluminum, and many plastics. Primer (sold separately) cleans the surface and decreases the time it takes to reach full strength. It is recommended when working with aluminum, stainless steel, titanium, black oxide finishes and zinc coatings. Also, locking adhesives function different from jamming locking feature such as nylon patches, they are not interchangeable with those elements. Since the thread play in small diameter screws is smaller than in larger diameters, thread locking liquids are thinner than those used for larger screws. The frictional coefficients of thread locking adhesives are often higher than with other coatings which must be considered when determining the tightening torque. However, apart from securing against loosening, threadlockers offer an excellent safeguard against parts falling off. Chemical thread lockers are also the only possible locking method against loosening of very hard clamped parts. Serrated locking features cannot dig into these parts, meaning there is no locking effect. Also, Taptite screws cannot form threads in such materials. Criteria To Choose Locking Adhesive Thread size, oil tolerance, locking effectiveness, ease of removal, heat resistance, adhesive strength, material it’s applied to, and availability are all determining factors for choosing. In this article we cannot address as to which thread locker is best for a given application. We merely describe how they work, where and how they are used etc. Detailed information must be evaluated based on company literature. Strength Threadlockers are available in a variety of strengths. Each strength is denoted by a color. Low strength threadlockers are purple or have a purple stripe on their bottle. Medium strength is typically blue and high strength is red. Users often refer to their desired product by color rather than strength, grade number, or even brand. ¤ Low Strength: Ideal for fasteners