Grinding welds, what do you use?

[lyrikz]

Lately i have been using a 4 inch grinder to get the welds down, then a sanding disk on an air wheel to get it smooth.. Only problem i seem to run into is that i hit the surrounding metal quite a bit and im sure its thinning it out. Thinning out already thin metal isnt very good....

I was thinking what if you used a dremel with a little metal bit on it... That work better? IM open for all suggestions on what you guys use...