Was able to clean up the tank a bit today. My first mistake when the gas ran over the paint was to try and wipe it down with a rag. I think I would have been better off hosing it down with water. So I took a putty knife to it and scraped off the nasty part of the smears, which made it look quite a bit better. All right, maybe there's still hope to salvage it? I pulled out the rubbing compound and the drill and worked over the spots for awhile. Certainly not pristine, but from 20 feet back you can't see it any more. Considering how bad it looked, I'll take that as a win!
The new turn signals are scheduled for delivery on Monday, then I'll be fully functional again. I've been doing some reading on welding aluminum and it seems like argon gas is pretty much required. I never needed it for steel, but it appears to be time to pick up a bottle now. Fortunately I got the welder with the kit for using gas so I just need to break out the regulator. In the meantime I've been looking over this meter bracket and noticed the mounting tabs bend back almost onto the body of the bracket. I'm thinking once I have the tabs welded back in place again I can really beef of the strength of the bracket by adding short supports between the tabs and the bracket body, which should eliminate any vibration through the welds.
I'm starting to reconsider making a new bracket from steel...