When it comes to automotive assembly, sometimes a one-solution-fits-all approach is the best one. Just ask the designers and assemblers at Local Motors, an American motor vehicle company located in Phoenix.
Since its founding in 2007 by John B. Rogers Jr., the company has focused on low-volume manufacturing of vehicles using co-creation (publicly shared design information) and multiple microfactories (small regional shops set up for flexible, small-batch production). Its current product lineup includes the Rally Fighter, Strati, Swim and Olli, an autonomous electric-powered shuttle bus.
“My vision is to bring technology to the vehicle world as fast as possible,” says Rogers. “Co-creating and micro manufacturing offer this by changing the way that vehicles are designed and built.”
In 2017, company engineers looked into ways to increase the vibration resistance of fasteners on the Rally Fighter and Strati, two totally different types of vehicles. For both, Local Motors turned to Loctite threadlockers made by Henkel Corp.
The Rally Fighter is a high-performance, off-road vehicle with thousands of parts. Loctite enables its nuts and bolts to withstand jarring bumps and racing in extreme conditions without constant tightening and maintenance.
The Strati, in contrast, is an electric car with only 49 parts. This small number of parts makes every one more critical than usual and more dependent on fasteners that are always tight and secure, according to Rogers. Loctite threadlockers not only provide both benefits, they enabled Local Motors to go from conceptualizing the Strati to driving it in four months.
“One thing we’re learning is we need to rely on adhesives to be able to make disparate surfaces mate,” explains Rogers. “Many Loctite products have empowered us to take this important step and create a new flexibility in our design.”
Available since the late 1950s, Loctite threadlockers completely fill thread roots on a fastener to prevent its side-to-side movement and increase the reliability of threaded assemblies. Local Motors uses three specific formulations: Threadlocker 243 on the Rally Fighter, and the 242 and 262 on the Strati.
Loctite 243 is a medium-strength adhesive, blue in color, that seals and secures metal fasteners. It is a general purpose threadlocker that provides a good bond on all metals, including passive substrates such as stainless steel, aluminum and plated surfaces. The product permits disassembly with hand tools for servicing and comes in 0.5-, 10-, 50- and 250-milliliter bottles.
Also medium in strength is blue Loctite 242, which is for metal thread sizes up to M36. The product is a medium-viscosity adhesive with a methacrylate base. It provides fixture times on steel, brass and stainless steel of five, 15 and 20 minutes, respectively. The product is also thixotropic to prevent migration after application and is intended for fasteners that require normal disassembly with standard hand tools.
Another formulation used extensively on the Strati is Loctite 262. Red in color, this threadlocker offers medium to high strength in a thixotropic methacrylate-based adhesive that also fluoresces under UV light to allow monitoring. Fixture times, respectively, are 180 minutes for stainless steel,15 for steel and eight for brass. Suitable for all metal fasteners, formulation 262 is ideal for applications where any adhesive migration must be prevented.
For more information on threadlockers, call 800-562-8483 or visit www.henkelna.com.