I just found out that paint thickness can vary by 40% between panels on the same car

I was reading a thread on a paint forum and someone posted data from a thickness gauge they used on a 2019 Honda Accord. The hood read 120 microns but the driver door was only 85 microns. That's a huge difference from the factory. Has anyone else checked panel thickness on newer cars and seen this kind of variation?

3 comments

3 Comments

jadej501mo ago

Wait do you think the weight thing is actually a big factor though? Because I checked my 2018 Camry after reading that same forum thread and found my driver door was 95 microns while the rear passenger door was 130. That seems way too random for it to be some smart engineering choice... I always figured they just had bad days at the factory or ran out of paint on some cars. What really helped me was taking my cheap gauge to a body shop I trust and having them check my readings. They told me that as long as the difference is under 50 percent you're usually fine for normal driving, but if you're planning to repaint you gotta mix your primer and paint to match the thickest panel on the car. I messed up my first touch up job because I went by what the hood measured and then the door came out too thin and chipped within a year.

michaelgrant1mo ago

Hold your horses a second though. That 40% difference might not be a defect, it could be a deliberate engineering choice. Think about it, the hood is a big flat panel that gets hit with rocks and bugs all the time, they probably spray it thicker to handle that abuse. The door gets opened and closed all day, so making it thinner saves weight on a part that moves. I checked my 2015 Mazda 3 a while back and the roof was way thinner than the front fender, like 90 versus 140 microns. It makes you wonder what panels are designed for what sort of punishment.

cole_flores441mo ago

Yeah that 40% difference you mentioned reminded me of when I had to repaint a door on my old truck. The factory coating was way thinner than the hood, like it was a different car almost. When I sanded it down it was barely there compared to the hood which had this thick almost rubbery layer. I learned the hard way that if you're doing touch up or repainting you really gotta measure each panel separate. Don't assume they're all the same because they definitely aren't. I use a cheap paint thickness gauge from Amazon and it's been a lifesaver for matching up repairs.