Which silicone is suitable for potting sensors?
Sensors often measure very small signals. The potting compound must protect them from moisture, media and vibration without distorting the measurement. Soft, low-stress silicones are therefore ideal: they transmit hardly any mechanical force to the sensing element and stay elastic in both cold and heat.
Key points
- Low stress: soft gels and compounds with low Shore hardness protect pressure sensors, strain gauges and fine bond wires.
- Shrinkage-free curing: addition-curing silicones cure without by-products and with virtually no shrinkage – even in closed housings.
- Flowability: low viscosity ensures small cavities are filled completely.
- Transparency: clear compounds are recommended for optical sensors, LEDs and visual inspection.
- Adhesion and sealing: good adhesion to the housing prevents moisture from creeping along the interface.
Suitable products
- WACKER SILGEL 612 A/B – very soft, clear silicone gel (1:1), ideal for highly sensitive sensors.
- ELASTOSIL RT 604 A/B – crystal clear and very low viscosity, soft vulcanizate.
- ELASTOSIL RT 601 A/B – clear standard potting compound for sensors and PCBs.
- ELASTOSIL RT 745 A/B – soft, adheres to many substrates without primer.
- ELASTOSIL RT 625 A/B – translucent, cures quickly and without shrinkage, even in closed moulds.
Practical tips
- Prepare clean, dry and grease-free surfaces; use Grundierung G790 TF if required.
- Pour slowly from one side so that air can escape; de-aerate beforehand for tight geometries.
- Keep addition-curing compounds away from sulphur, amines and tin-containing materials.
- Higher temperature accelerates curing and shortens process time considerably.
Questions about choosing a product? Call us on +41 61 322 42 24 (Mon–Fri 08:15–12:00 and 13:30–17:00) or write to info@ameba.ch.