Re: Tinsmith's in frame gas tank for cantilever Schwinn.
nice work sb!
i use the sanding discs with the dremel. they usually last for about a minute and then disintegrate, so i take sandpaper, put masking tape on the back, and cut out a quarter sized circle and make my own.
you don't have to be all precision and make a perfect circle. i just cut them out freehand.
320 grit cuts right through the solder. it'll scratch the copper, but if you're not heavy-handed about it, you won't do any damage you can't polish out.
i use a fine 3M finishing wheel (remember those from the rusto builds?) to take out big scratches, and a worn down fine wheel will polish it pretty good, too.
as far as the look you're searching for, you can leave it natural and watch it age, and if you don't like it, polish it up later.
you can also let it darken up, then clear coat it when it gets to the color you want.
i've done all of those things, and i like the natural look the best. it seems to age with the bike. i mean, i haven't got to the point where it's 50 years old and green and crusty yet, obviously, so it might look weird in 5 years or so...
the biggest thing is to keep fingerprints off of it. all the other little stains from fuel, dirt, etc, look cool, but to me, fingerprints look bad.