depends on what you use, I have G3 which I've used by hand and it sorts a large amount of scratches and paint mess, it's nickenamed T-cut on steriods, the liquid is clear but turns colour of the paint, thats how much it works, needs to stay wet and moved so a buffer is more useful tha the arm.
sanding?
Polishing, i'm too cheap to get a re-spray so just gonna use G3 on it, I'm good at polishing things so much that they shine, you should see Dusks shlong, bling bling
Variable speed grinder is highly recommended! Ed i think used 3M cutting compound when he did my car last year, worked a treat. Dont forget to polish it up afterwards tho!
Thats the plan, got most the chemicals I need, just need a decent buffer now, looking forward to it cause I got some spare wings looking nice aftre 10 mins hand buffering so what will it look like after 30mins at 3000rpm+
Bought me one of these
and spent the good part of 4 hours really working on the car with G3 then Tcut wax and I gotta say I the pics don't do it justice!
ALL scuffs and light scratches are gone, bad ones are better looking and the paint is so shiney I was able to do my hair in the reflection