I like the look of bare aluminum, and picked up an old Diamondback Response SE with 7005 Al tubing that's ball-burnished. After stripping the bike to the frame and degreased it, upon inspection I found some deep gouges caused by the chain jamming into the chain stay. Also some deep scratches on the top tube and seat stays which can't be sanded out.

Is there a way to cosmetically 'fix' these and allow me to polish the frame to my desired finish?
I've read of of how custom body work and repair uses solder to fill in weld seams and damaged panels.
Can the same be done to fill and build up the damaged areas? Or will the frame act as too good a heatsink and not allow the surface to heat up enough? Or if I can heat it up, will the heat damage the 7005?

IMO, the solder should be easy to shape and polish to match the appearance of the Al.

Or is welding and building up the damaged areas with Al the only way?