How to Select Potting Compound for Liquid‑Level Sensors? “Water‑Resistant” Does Not Equal “Oil‑Resistant”

When selecting potting and sealing materials for liquid‑level sensors, the primary question shall be: What medium will the sensor be immersed in long‑term? Instead of simply asking: “Is this adhesive waterproof?” Water, engine oil, fuel, coolant, brake fluid and other industrial media exert completely different effects on polymer materials. ELAPLUS industrial sensor solutions treat oil‑resistant sealing as an independent application category, separate from bulk potting, pin sealing and substrate fixation. Six Conditions to Confirm Before Material Selection for Liquid‑level Sensors Condition Rationale Medium name Determines chemical compatibility of material Medium temperature High temperature accelerates material aging Immersion duration Short‑term exposure ≠ long‑term immersion Presence of pressure Affects medium penetration at interfaces Housing material Influences bonding performance Chip‑to‑adhesive contact status Determines stress‑related material requirements Why 24‑hour Immersion Test Is Not Sufficient for Final Conclusion Materials may suffer liquid absorption, swelling, softening, hardening or bond strength degradation in contact with media. Many of these changes do not fully occur within 24 hours. For long‑service‑life liquid‑level sensors, performance comparison shall cover: before aging → during aging → after aging. Key Inspection Items for Media‑Resistance Test Test Item Observation Points Appearance Cracking, blistering Mass Liquid absorption Volume Swelling Hardness Softening / hardening Bonding Interface degradation Resistance Insulation property shift Sensor output Functional variation Industry Pitfall A typical engineering mistake: passing water‑immersion test and then claiming general media resistance. This is insufficient for real‑world applications. Valid evaluation must adopt customer’s actual working medium and operating temperature. Scenario‑based Adaptation Fuel‑level, engine‑oil‑level, coolant‑level, water‑tank, urea‑level and industrial chemical liquid‑level sensors shall all be validated against real service media. FAQ on Potting Compounds for Liquid‑level Sensors Q1: Does water‑resistant silicone guarantee engine‑oil resistance? A: No direct inference can be drawn. Validation with target medium is mandatory. Q2: Are oil‑resistant materials automatically suitable for fuel exposure? A: Not necessarily. Oil…