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82 DESIGN007 MAGAZINE I AUGUST 2021 resin-encapsulated component that requires maximum protection against water ingress outdoors is the LED lighting unit; these resins are also optically clear and UV stable, making them ideal for the task. Electrolube was tasked with solving an underwater LED lighting application. is is a prime example where encapsulation resins are critical for long-term performance. Water naturally corrodes most metals due to electro- chemical oxidation; when a saltwater medium is used, the rate of oxidation significantly increases due to the presence of dissolved sodium and chloride ions. Technical Support swung into action to resolve the problem. e customer was already using an epoxy resin from a different supplier; this was causing deformations to the plastic housing due to the high exotherm and needed to be replaced. e resin had to withstand water temperatures between 5–40°C, as well as be flame retardant, and needed to be light blue for aesthetic purposes. Importantly, the unit required a flexible encapsulation resin that could resist attack from constant immersion in pool water. Critically, this water could be salt- water or fresh water. e unit to be potted was complex, with tiny gaps in the casing. It was essential the resin did not bleed through these gaps and cover the LED lens. e product used had a history of provid- ing protection in underwater applications. e only problem was the colour—black—and the fact that it is designed to flow through tight spaces. With a bit of lateral thinking, the logical solution was to increase the thixotropic nature of the resin, which would prevent the resin bleeding through the gap and simply change the pigment in the resin. e R&D team produced a material that was still very easy to mix and pour into the unit, with sufficient thixotropy to prevent flow through the gaps and over the LED lens, and altered to the desired colour shade. e solution worked extremely well. Importantly for this application, the resin can withstand both fresh and saltwater ingress and prevent the transmission of metal ions that could attack any metal present. e polymer used in the resin is highly resistant to water even at the high pressures experienced as water depth increases. is example dem- onstrates anything is possible when it comes to finding resin solutions that provide effective resistance to their end-use environments. If protecting components from mechanical shock and vibration are a concern, then a more flexible cured resin is likely to be the best solu- tion as it adds a level of compliance that helps to insulate the potted components against adverse mechanical movements. In addition to their moisture resistant properties, polyurethane resins also provide this desired level of flexibility and so they are oen the first choice for shock and vibration protection. Polyurethane resin finds use in Tyre Pressure Moni- toring System (TPMS) sensors; this tough moisture resistant resin easily passes accelerated life testing, critical to resin qualification for TPMS used in the automotive industry. Silicone resins also offer excellent flexibility and will tolerate even higher operat- ing temperatures. ere are epoxy resins that offer good moisture resistance, as well as