All of our wheel wells have vintage undercoating. This would be old hard and dried undercoating. I removed large patches with an air chisel but it didn't remove years of dirt and road grim. I dug out several air tools and I tried all of these discs.
This area would have been impossible to clean with a die grinder.
So I decided to sandblast. It's messy, it's dirty, but I knew it would work.
I like using Quikrete Commercial Grade Medium Sand because the granules are small enough to get through the nozzle yet large enough to do a good job of removing rust and paint. Play sand doesn't work in my blaster, it plugs up the nozzle.
The results are pretty spectacular. In fact, this wheel well is ready to paint.
But this is only 1 wheel well and it took 100 lbs. of sand. Three more of these are waiting plus the transmission tunnel.
Ty, you're missing out on all the fun!