Not very long at all. All I know is that the local graphics business guy said they use this stuff, and its ONLY use is to protect decals. My thinking is that if they used this and it didn't work as claimed, then people would be coming back to him raising h*ll, and he'd be sued, and go out of business. He's been in business for 10 years or so. But from my own personal experience, I can't say, because its only been on for 2 weeks. The REAL QUESTION is why nobody has apparently known (or posted) about this stuff. Why?
Why don't you contact Keystone and ask them about Clearshield, and tell me what you find out? Being paranoid, maybe this isn't common knowledge because they want your decals to rot off. Dunno.
