Sealing outdoor enclosures presents unique engineering challenges, especially when a product must operate reliably in harsh climates and maintain strict ingress protection like IP66.
When a transformer monitoring device manufacturer sought a silicone sealing solution for both the lens and main enclosure, they initially requested solid extrusion profiles for both areas. However, as the project progressed, hands-on trials and collaborative testing with Silicone Engineering revealed a smarter path forward.
To support the design process, a full unit of the device was forwarded to Silicone Engineering, allowing our materials team to test, fit, and recommend the best sealing solution for each part of the enclosure.
Lens Gasket Solution
The lens section required a gasket that would seat firmly within a pre-cut channel, compressed securely by a bezel clamp. Our engineering team recommended suraSil™ GP60, a solid silicone rubber extrusion with a 60 Shore A hardness.
The profile was tailored to include locator pips to aid assembly and keep the gasket firmly in position during and after installation. The first samples were manufactured and tested by the client, and approved with no revisions required.
The GP60’s firmness, UV/weather resistance, and compression characteristics made it ideal for ensuring long-term sealing around the display window.
Enclosure Gasket Evolution
Initially, the enclosure gasket was also designed using a solid silicone extrusion. However, during assembly trials, the client identified excessive resistance at the hinge points, which made it difficult to fully close and latch the unit. Recognising that the solid profile was over-specified for this area, our team proposed a more compressible alternative: expanSil™ GP400, a closed-cell silicone sponge extrusion.
With a medium density and excellent recovery characteristics (compression set ~3.0% @ 70°C), GP400 offered the ideal balance of flexibility and sealing performance. Samples were produced and trialled in the real enclosure, and this time, the fit was perfect. The sponge gasket allowed the cover to close smoothly while maintaining full IP66 sealing integrity.
Outcome
Both suraSil™ GP60 and expanSil™ GP400 are now fully specified in the client’s technical drawings. The dual-material strategy not only solved two different sealing challenges but did so with precision and practicality. This project reflects the value of collaborative development, where hands-on testing and materials expertise come together to deliver optimal sealing performance in demanding real-world applications.