i would agree with the Scotch Brite idea. I refinished my AGI from polished to brushed, it's hard to tell with my crappy pics but should give you some idea, the drip tip and the PV's tube are "factory" brushed finish for comparison. There are a few scuff marks on the AGI but those happened after I refinished it, pocket with keys and all that:
I know Scotch Brite may sound like a ghetto way of doing things, but it's quite common in industry. I used to work for a place that supplied high-end (very very expensive) stainless steel pressure cylinders to companies like Dow Chemical, guess how they gave their cylinders a brushed finish? They would
buy Scotch Brite by the short pallet, the red pads specifically.
I figure if it's good enough for an $8,000 cylinder the size of a 2-liter pop bottle, it's good enough for
vape equipment. The key to getting a good finish is even application of pressure, and making sure to keep the grain straight. A lathe makes this incredibly easy, but a drill also works.
For stuff like top caps or anything that's hollow with a larger diameter, you can simply put any sort of rod into the drill's chuck, take some fabric scraps and wrap them around the rod thicker than the inside diameter of the cap, wrap some duct tape around the fabric, then friction fit the object over the cloth. This will allow you to spin the item and get a good even finish.
The poster above mentioned holding the pad steady and rotating the part inside the pad. If you don't have a drill this will also work, using a large pad just hold the item between the pad, then with your other hand spin the item. Don't spin back and forth, remove your hand from the part and reposition it so you can continually spin the part in one direction.
While repositioning your spinning hand, increase the pressure on the pad and part so it keeps the same position and you don't get any grain marks that go in odd directions because the part slightly shifted in the pad. You just want one long continuous spin of the part.
You can start of getting the grain going and removing the polish without paying too much attention to getting the grain perfectly straight. This makes the whole job quicker, and as long as you finish up with some perfectly straight passes, the initial grain lines won't matter.
