About the buffing: Aargh. I'm sorry that I didn't step in quickly enough to warn you!
Unfortunately, that buffer is not suitable for buffing out paint finishes. It spins at 3450 rpm, which is way too fast. Plus, as the others have mentioned, those wheels are too stiff. With that combination, it will instantly apply too much heat to a small spot, and melt the paint right off. As you found out.
Even with softer wheels, 3450 is too fast. One of my bufffers is switchable between 1725 and 3450, and I've experimented with buffing at 3450 using 6" unsewn cotton wheel. Moderate success, but it was scary. Too easy to dwell a bit long and start melting the paint. And it wasn't really speeding things up. The faster the wheel spins, the more the centrifugal force holds it out in a circle. So, the contact area is less. Slower speed with a softer wheel and a bit more pressure buffs a larger area with less heat buildup.
What I recommend is to use 6" x 1/2" wide unsewn cotton or flannel buffing wheels, spinning at anywhere from 500 to 1200 rpm. That's a safe range that works quickly with minimal risk. It's still possible to burn through at sharp edges, but you have to try pretty hard.
The simplest way to get that speed range is with a handheld variable speed electric drill. Ideally, one with a keyless chuck. With a couple of wheels mounted on the little 1/4" shaft arbors, you can quickly swap them back and forth as you work around the instrument.
If you want to do stationary buffing (bench mounted buffing wheels, handholding the instrument) then you need to rig up an arbor shaft with pillow block bearings, with a belt drive and pulleys to get the speed down to around 1000 rpm. If you want to use larger wheels, like 8" or 12", then the shaft speed has to go even lower. More like 500 rpm for 12" wheels.
I get my buffing wheels from McMasters, but there are many other sources. Here's an 8" dia x 1" wide unsewn cotton wheel on Amazon as an example of the type of wheel that you want.
Extra Thick Loose Cotton Buffing Wheel, 8" (80 Ply) - Power Rotary Tool Buffing Wheels - Amazon.com
This is the type of arbors I prefer:
Heavy-Duty 1/2" Threaded Arbor Mandrel 1/4" Long Shank - Fits Wheels Discs to 1" Thick - Taiwan - Power Grinder Accessories - Amazon.com
The buffer that you bought is actually fine for polishing metal. As you are getting more into making your own custom metal hardware, you'll use it. For buffing aluminum parts, I normally use sewn cotton wheels (which are on there now) and just the black Emory compound. If you really want to get into metal polishing, you can use the various grades of compounds. But for generally shining up aluminum parts, Emory alone is fine.
Amazon.com: Enkay 140-BL 1-Pound Black Emery Compound, Carded: Home Improvement
One accessory that you should eventually get for your metal buffer is a Finishing Wheel. This is a semi-hard wheel that's halfway between a grinding wheel and a Scotchbrite wheel. It's semi-hard and porous, made for deburring, rounding edges, and smoothing scratches out of metal parts. A tremendous time saver when making metal parts. I use mine many times every day. They're not real cheap, but they will last many years. They are available in different grades and sizes, which can get confusing, but here's an example:
Amazon.com: 3M DEBURRING WHEEL GENERAL PURPOSE WHEEL 6x1x1 9S-FIN # 64900 CLEANING FINISHING (E 13) NOVELTOOLS: Arts, Crafts & Sewing