I just finished using oven cleaner to strip the factory finish from an HFC M712.
1. Get a zip-lock freezer bag (large size)
2. completely dis-assemble the M712 and clean it thoroughly to remove the factory applied silicon oil lubricant (plain old liquid dish soap works well)
3. put on safety glasses, an organic chemical respirator/mask, nitrile gloves (or something simlilar), work in a well ventilated area and wear old clothes or a pair of coveralls (just in case)
4. place a part in the zip-lock bag
5. spray the part (while in the bag) ensuring complete coverage of all surfaces from which one wishes to strip the paint
6. close the bag
7. wait for a few hours (I left it in my garage for an afternoon while I ran some errands) ... when it is ready when you can rub a part with your GLOVED finger and the paint should easily lift off
8. put on the safety gear listed in step 3 and remove the part from the zip-lock bag and wash thoroughly with water and dish soap - use an old toothbrush or scrub brush to help remove gunk from any crevices
9. dry with a towel and then really dry it off with a heat gun (on low) or a hair dryer
10. optional: use a wire wheel in a Dremel on LOW SPEED using light pressure to remove any remaining paint (there is likely to be a few bits here and there) - too much pressure or too fast a speed setting will damage the aluminum
11. sand to a smooth finish using wet-dry sandpaper in progressive grits (I used 320, 400 and then 600)
12. optional: polish to a mirror finish with a buffing wheel and polishing compound (not necessary in my humble opinion)
I can't stress the use of the safety equipment enough. Oven cleaner can emit nasty fumes which you definitely do NOT want to inhale. It can also be quite corrosive so chemical burns for unprotected skin or eyes is a real possibility.
Monsterpartyhat, would it be possible to have this gun sand blasted to remove the factory paint? Or would that be too harsh a treatment for this type of metal? I would like to do the Aluminum Black treatment to this blaster but the thought of the sanding is a huge deterrent.