Not a sign making application but thought this may be the best place to get good answers. We are having to CNC some sink/drainboard mold plugs for a concrete counter top. Was planning to CNC the 3D plugs out of 2" XPS. Once they are machined they will have to be sealed (spray) to help with the release (they will get spray release as well when they are cast). Does anyone have any experience with a good product to spray/seal XPS or ISO?

Thanks for any input.