Thanks for answers. I know that Evapo Rust and Frame Saver are great things, but to get enough to cover whole frame would probably exceed the value of frame itself. I don't have tools and containers for electrolysis, but Oxalic acid sounds pretty good. From what I know I should mix powder acid and warm water in 1:10 ratio, then pour it inside frame and wait for around 12 hours, then dilute the acid with mix of water and baking soda and clean the remaining with just water. Am I correct here?
Now, speaking of paint I am unsure what to use, I've heard that 2-ingredient epoxy paint with hardener or 2-ingredient reactive paint with hardener are best primers but those are pricy compared to some anti-rust/corrosion 2in1/3in1/"paint and forget" solutions. Are those mixed paints really that bad, because everywhere where I look people disdain them. Also, would pouring some of such pain inside frame work as anti-corrosion cover? As noted above, I could try linseed oil for that but boiled version also costs alot here. Perhaps linseed varnish would work, I could get it cheaply.
Finally, what about that lead paint which I could get. It's relatively cheap and I could mix it with linseed varnish to create nice priming solution like they did 70 years ago but is it worth possible health hazards?
Last edited by cuyd; 09-29-19 at 10:55 AM.