[CZroe]

Originally Posted by DannoXYZ

For rusty tanks, pre-gen ones are especially thin. So I'm scared of anything that has mechanical scrubbing & impact or removes more than just rust (most acids). Only acid I've found that removes only rust and stops at good metal is phosphoric acid, active ingredient in Naval Jelly. Also leaves midly-protective phosphate coating.

I think even better is electrolysis:

https://www.instructables.com/Electr...-Rust-Removal/
https://www.motorcyclezombies.com/re...rust-gas-tank/
http://www.secondchancegarage.com/pu...cleaning-1.cfm <-- a lot of geezers with pre-war classics use this process

Afterwards, DON'T use any kind of thick sealing stuff, they end up peeling off after while. Just POR-15's tank-treatment as it's chemical conversion for surface rather than coating on top.

Yeah, I was already looking into electrolysis after seeing this video:
https://youtu.be/ICW01HFbaxc

The plate inside the fuel filler neck makes it more difficult to isolate the sacrificial anode but I have a 1.5” #9 rubber (neoprene) stopper that fits the fuel filler neck perfectly. If I don’t drill perfectly straight I’ll stick a rubber grommet in the oval opening below. There doesn’t seem to be a good unpainted grounding point since the place he clamped to is painted and had rubber isolators, but I’ll screw some raw bolts in some place if I have to. I still need to find a stopper for the 30mm fuel sender hole but Lowe’s had several smaller sizes that’ll probably cover me.

Thanks!