‘73 1800ES - I’ve got a few original steel wheels that I’m slowly getting around to stripping the old tires off of, sand blasting, repainting, and mounting new tires on. I found a couple of the old wheels to have inner tubes, making me think a previous owner may have installed them due to leaking rims. I know from personal experience that the spot welds can be a source of leakage. I prefer to not have to use inner tubes with the new tires, so I’m in search of a sealant that I can apply to the inside of the rims, over the spot welds. Someone suggested applying Flex Shield over the spot welds which “sounded” like a good idea but I’m not sure if that’s a good plan or not. I don’t want to have to remove the tires if the Flex Seal turns out to be a bust. Is there a particular sealant that is known to work well for this purpose?