Had a paint job peel off a bumper I did 3 days earlier

I was stuck in the shop on a Friday night trying to finish up a 2015 Camry rear bumper for a customer who needed it by Saturday morning. Laid down the base and clear, let it flash like normal, but I guess humidity was way higher than I thought cause I didn't check the temp gauge. Monday rolls around and the customer's back yelling that the clear is flaking off in sheets. Had to strip the whole thing down to bare plastic and start over, cost me 4 hours and a whole can of clear. Turned out my booth's dehumidifier filter was clogged, nobody told me it needed cleaning. Any of you guys had paint lift because of something stupid like moisture?

2 comments

2 Comments

juliahall1mo ago

Actually it wasn't the humidity alone that did you in, it was probably more about the dew point being way off. I see people blame humidity all the time but the real killer is when the surface temp of the bumper drops below the dew point, then you get that invisible moisture layer sitting on top of your fresh paint. You said you didn't check the temp gauge, but did you use a dew point calculator or at least a temp gun on the plastic before you sprayed? Cause if the bumper was cold and the air was humid, that condensation formed right under your clear as it flashed. Also those clogged filters in the booth, that's a whole other beast, it turns your spray environment into a swamp even if the humidity numbers look okay on paper. I learned this the hard way on a Subaru bumper years ago, same exact flaking issue, and now I always run a digital temp/humidity meter in the booth plus check the dew point before any clear coat goes down.

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the_elliot1mo ago

Man, you just described my exact nightmare. I had a similar thing happen with a Honda Civic bumper a few years ago. I was so sure the humidity was fine cause I checked the gauge inside the booth but that thing was garbage. I was spraying clear and it looked great going on, then the next morning I had this weird haze and flaking near the edges. I finally broke down and got a cheap temp gun and a little dew point meter from Amazon. Now I check the bumper temp before I even mix the clear. If its more than a few degrees off from the ambient temp I let it sit longer or hit it with a heater first. Makes a world of difference.