[old_tv_nut]

Yes, it has been tried at various times on various tubes. I bought a can of it for Scotty at Hawkeye to try on my leaky 21AXP22. He applied it to the metal/glass seals, but unfortunately the leak was a small ding in the metal/metal weld, which wasn't discovered until it was helium tested (which required necking the tube) at ETF. The tube is still at ETF waiting for someone to successfully set up a rebuilding facility, at which time Vacseal could be tried at the identified leak point.