Switched from water-based to a polyurethane clear coat for my garage signs and the difference is night and day

Water-based was peeling up in the humidity after just 3 months, but the poly has held solid through a whole summer of 90 degree heat. Has anyone else found a clear coat that doesn't yellow over time?

2 comments

2 Comments

baker.phoenix14d ago

I’ve actually gone the opposite direction after trying polyurethane on a batch of signs a few years back. I had it yellow pretty badly within about 18 months on a set of outdoor address plaques in southern Arizona. That 110 degree sun seemed to bake the yellow right into the finish. Ended up stripping them and going back to a water based acrylic with UV blockers, and those have held up for four years now with zero yellowing. Maybe it depends on your local climate or the brand you pick, but I wouldn’t call poly the automatic winner. Not all water based coats are equal either, the cheap stuff definitely peels, but the better ones hold their own.

campbell.nora14d ago

Must say I had pretty much the same experience with poly here in Texas... that sun just destroys it after a year or two. Switched to a marine grade spar varnish for outdoor stuff and it's been way more forgiving, even with the UV beating down on it. Water based acrylics with good UV blockers have never let me down either, just gotta spend the money on the decent brands.