Hi,

I am working on a product that uses a backing made from clear semi-rigid plastic. I can use either PET or PVC. The product will have some electronics on the plastic backing, and I need a clear, flexible sealant to cover the electronics and waterproof the whole thing. It will be used outside.

I've tried a rubberized coating - Rustoleum LeakSeal Clear - but it is perhaps too flexible. If you begin peeling it, you can easily peel it all off.
I've also tried an oil based polyurethane intended for outdoor use. That may not be durable enough. I can scrape it off with a fingernail.

Ideally, I'd like to find something that is flexible enough to bend with the backing, can be applied with a paint sprayer, is durable, can handle temperatures down to -40F, and is not too expensive.

I'm also going to try acrylic enamel. Don't know if that will be flexible enough.

Thanks to anyone who can help.