Powdercoating is more durable than just about any paint provided the metal has the proper etch first. Not all abrasives are conducive to good "stickiness".
A small electrical charge is put on the metal piece which draws the powder into inaccessible spaces. However, if there is rust, dirt or residue in there the powder won't stick well. Just like in painting prep is everything.
We powdercoated a smashed race car's frame as an experiment to see how well the powder stuck to the inside of the fully-boxed frame. After cuttting the frame into a bunch of small pieces we found that every square inch was covered.
The only thing that I don't like about the process is that when chipping occurs you can't perfectly patch the area with paint - it won't match unless you paint the entire piece.
Other than that it's a great way to go - and cheap!
