Two-in-one locking and sealing advancement 17 February 2014

ND Industries® continues to be a leader in the field of pre-applied fastening technology, bringing powerful advanced locking and sealing products to the industry. One of ND’s unique offerings in microencapsulated locking and sealing technology is Expand-A-Seal®.

Fasteners with ND Industries Expand-A-Seal®

Developed by ND’s research and technology experts, Expand-A-Seal® is a pre-applied, epoxy thread locking solution that provides a total airtight and watertight seal – even under extremely high pressures.

Expand-A-Seal utilises a microencapsulation process, whereby an epoxy-type resin and expanding agent are contained within microscopic spheres – which are suspended within an epoxy hardener. This liquid slurry mixture is then applied to the threads of a fastener.

Expand-A-Seal is added to only one of the two mating parts and can be used on internally or externally threaded fasteners of any size. Once Expand-A-Seal has dried on a fastener, it can be safely handled. Only when the coated fastener is mated with its corresponding part do the microscopic spheres break open, activating the locking power of the adhesive agents.

Due to Expand-A-Seal’s low installation torque, fasteners can be easily assembled with common hand tools. However, ND Industries mentions that the chemical reaction that takes place upon mechanical fastening is so rapid that exceptional breakaway torque values are achieved before full cure, even within as short a time as one hour. No heat curing is required for fasteners coated with Expand-A-Seal, with full cure achieved within 24 hours at room temperature. As a locking agent, fully cured Expand-A-Seal creates a bond comparable in strength to most epoxy threadlockers.

ND Industries Expand-A-Seal®

The thread gaps are filled in with Expand-A-Seal®

“Expand-A-Seal exhibits phenomenal sealing action. Although some threadlockers do have limited sealing capabilities, even the most formidable bonds created by threadlockers leave miniscule spaces within the threads of a seated fastener, allowing for gas and fluid leakage. Such leakage can become a particularly difficult problem at fastening points when subjected to high pressure conditions, such as in compression tanks or air brakes. However, with Expand-A-Seal concerns about leakage become a thing of the past.”

When its chemical locking agent is activated, Expand-A-Seal expands volumetrically 20% – 50%, filling any gaps and voids within the fastener threads and creating a positive seal against air and most automotive fluids. Expand-A-Seal will even effectively fill gaps resulting from the use of oversized fastener threads or fastener deformation that occurs during welding.

When fully cured, Expand-A-Seal’s locking and sealing power is unaffected by exposure to foreign substances such as oil, gasoline, salt spray, acids, solvents, or water. In addition, its cross-linked molecular structure makes it one of the most resistant types of fastener adhesives available.

This means that Expand-A-Seal can be used to lock and seal almost any critical application where shock, vibration, and fluid or air pressure could cause a fastener to loosen or a joint to leak. Typical applications include engine pipe plugs, air filtering connectors, compressor fittings, cooling connectors, and many more.

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.