Model72,
Yeah I feel your pain here, sucks to try to remove material from an outer diameter surface like this. Sand paper isn't real effective on metal, think your better with some kind of small flat grinding wheel, maybe 4" or 6" dia, preferably something with a lot of control. (Throw your dremel away, I hate those things!). I find it good to have another job going while I work on something like this, work on it until your patience is gone, then come back later and try again! Sometimes it's handy to put masking tape on the outer surface so you can see where your hitting / not hitting, helps target your grinding when you get close to right.
Can't help with the powder coating globe issue, never seen that but it makes complete sense the powder coat would build up too much. You probably could get some smaller diameter stainless wire and make your own ring. That diameter is small enough that you can free hand bend it around something cylindrical pretty easy. You can use the rings you have as the shape you want. You could also grind the back side of the rings you have slightly, effectively making it smaller diameter so it fits better, maybe.
Last edited by Paul Bell; Tue Apr 21 2015 01:58 AM.