Found out paint thickness gauges can be fooled by metallic flake

I was reading a thread on a detailing forum last night, and someone mentioned that metallic flake in certain paints can throw off magnetic paint gauges by up to 20 microns. I always trusted those things blindly. I had a customer bring in a 2018 silver F-150 with a repaired quarter panel I didn't catch because the gauge read normal. Turns out, if the flake is heavy enough, it messes with the sensor. Has anyone else seen this happen on pearl or metallic jobs?

3 comments

3 Comments

fiona_kim978d ago

Gotta disagree a bit with @linda_reed on the GPS comparison, those things are actually way more reliable than paint gauges when it comes to metal flake. GPS gets confused by tunnels and tall buildings, sure, but a paint gauge getting tricked by flake is a known physics thing not just bad luck. The magnetic field literally gets disrupted by the aluminum or mica particles in metallic paint, so it's not like the tool is just being finicky. I've had a 2015 Honda Pilot in a dark silver metallic read 250 microns on a door that was clearly original paint from the factory, just because the flake was super heavy in that specific batch.

bailey.jennifer8d ago

Guess I've been lucky then. I've used one on all kinds of silver and gray metallics and never noticed it being off. Feel like 20 microns is splitting hairs for most real world work unless you're painting a museum piece.

linda_reed8d ago

Jump right in and check your reading on a couple different spots on the panel before you trust it. Honestly I've noticed this is just one more thing in life where we assume a tool is perfect when it's really not. Think about how many times people trust their phone's GPS even when it's clearly wrong about traffic or a shortcut. We put so much faith in little gadgets and forget they can be tricked by stuff like metal flake or even a radar gun getting confused by a big truck. Ngl that 20 microns is a big deal if you're trying to match a factory clear coat that's only 100 to 150 microns thick. So yeah I'm not tossing my gauge but I'm definitely double checking my readings on anything with heavy flake now.