Astute On Anaerobics.
Although nearly a half century old, anaerobic adhesives are still misunderstood. Now, an educational campaign aims to help engineers properly use these compounds. Nearly 50 years ago, developers at Loctite Corp. created a liquid resin that hardened in the absence of air. It was the first anaerobic adhesive. Today, that technology has yielded a variety of adhesives that, while widely used, are still commonly misunderstood.
The two most familiar categories of anaerobics are threadlockers and retaining compounds. Threadlockers are used to fill and seal the voids in threaded assemblies to hold fasteners solidly in place. Retaining compounds are used to bond nonthreaded cylindrical assemblies, such as bearings on shafts, as well as augment and even eliminate shrink fits, press fits, and other mechanical methods.
Loctite has begun a campaign to educate manufacturers about the proper use and application of threadlockers and retaining compounds. At the foundation of the effort are two corresponding versions of a new adhesive training kit called the Solution Pak.
One version contains samples of low-strength, medium-strength, high-strength, and penetrating threadlockers, while the other includes retaining compounds for general purpose, fast-cure, and high-strength applications.
Both have a primer about last curing on inactive surfaces, a 24-page guide on selecting and applying adhesives, and an interactive CD with performance information and formulas to demonstrate how to design reliability into manufactured products.
Solution Paks are priced under $25.
More information can be found at www.loctite.com/solutionpaks, by calling (888) 334-1010, or by writing in 331 on our reader service card.
Facts To Stick With When Designing
Think you know all about threadlockers and retaining compounds? See if any of these important facts found in Loctite's Solution Paks are new to you.
* Anaerobic adhesives only cure in the absence of oxygen and contact with metal, forming a solid thermoset plastic. The result is a secure one-piece assembly that won't Loosen under stress.
* Threadlockers and retaining compounds fill all voids, providing 100 percent contact between parts. The typical press fit has 30 percent metal-to-metal contact; the typical nut-and-bolt assembly can have as little as 15 percent.
* By sealing the spaces between assemblies, threadlockers and retaining compounds keep out air and fluids that can cause corrosion.
* Threadlockers provide lubricity to improve torque control and reduce galling.
* Retaining compounds allow wider machining tolerances and can eliminate press and shrink fits, potentially eliminating machining steps and increasing production rates.
* Retaining compounds can augment press fits, doubling strength and eliminating fretting and Leakage.
* Any assembly fastened with anaerobic adhesives can be disassembled. Those secured with high-strength grades can be disassembled by applying heat.
* Most threadlockers and retaining compounds can be applied with manual, semi-automatic, or fully automatic dispensing systems.