Anaerobic adhesives equipment

Polyester resins and anaerobic adhesives and sealants have also exhibited high radiation resistance. Anaerobic adhesives have several years of long-term exposure in radiation environments due to their use as thread locking sealants in nuclear reactors and accessory equipment. 

Vernon Krieble, then a professor at Trinity College in Hartford, Connecticut. Their first use was as threadlocking sealants, to lock nuts on threaded fasteners as a replacement for metal lock washers, and to lock threaded fasteners in tapped holes in metal parts. They were the first products termed sealants to have a viscosity lower than that of water. Today, such anaerobic adhesives and sealants are used in almost all mechanical equipment that is subject to vibration. 

Anaerobic adhesives offer an additional advantage in being available in a specific range of strengths based on the requirements of the MoD s DTD 5629-33 inclusive. So bonded assemblies may be made suitable for disassembly using conventional workshop equipment, or made permanent. 

Nuts locked with the correct grade of anaerobic adhesive can readily be removed with conventional tools and, where equipment is used in very severe environmental conditions, anaerobic adhesives are frequently employed to prevent corrosion. 

Most anaerobic adhesive formulations are based on oligomeric acrylic esters, inherently low-toxicity materials. Various formulations contain additives such as adhesion promoters or cure components, and after excessive or repeated skin contact may cause skin irritation in sensitive persons. Adhesives should be washed away with water after skin contact. Nonaque-ous hand cleaners assist in removal of adhesive. Skin contact should be avoided by the use of appropriate application equipment. 

Obviously, successful application equipment design is contingent upon incorporation of materials compatible with anaerobic adhesives. Components or fittings should be fabricated from materials which do not contain destabilizing components. 

As with the anaerobic adhesives, moisture-curing adhesives, such as cyanoacrylates, are typically applied using bottles, cartridges etc., made for specific applications. Since moisture exclusion is imperative for premature polymerization, metering and dispensing equipment is designed specially to prevent contact of moisture-curing adhesives with air, prior to use. 

It is now common for anaerobic adhesives to be formulated to meet the specific needs of both the application and the equipment required to apply it — a process which has now resulted in several new and significant product developments. 

Many small-volume users dispense adhesive directly from the manufacturer s bottles and tubes, which are specifically designed for this purpose, but when mechanical application is required the anaerobic nature of the adhesive demands equipment which will not cause spontaneous curing within the apparatus. This must be obtained from the adhesive manufacturer. However, it may be coupled with a variety of supplementary mechanisms ranging from simple guidance systems to fully automated, self-checking dispensers. The ingenious methods often used to apply these adhesives have led to the development of some of the sophisticated equipment to be found in the adhesives field. 

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