There are materials that have a higher shore durometer that are non memory forming. If you're having trouble with your enclosure leaking over time, it may do to find a thicker, softer material. The compression ratio will be higher and even if there is some memory, it will generally compress pat...
I am in a situation where I have a 40mm thick piece of Acrylic between two polarizers. My problem is that the acrylic turns birefringent at around 35 deg C, and optical performance is badly degraded. I have contacted Ineos about Perspex, but it is not available in the right thickness in the...