This chair is proving to have amazingly strong bones once the excess paint has been removed to reveal its more subtle painted history.
Most of the rust on the bent tubular legs was very superficial. It could be brushed or shaved off with the rest of the excess paint. If this area is going to be weak, it will be at the stress points for the tube, where it bends, or where it is attached to the body of the chair.
All four connections to the body of the chair have rust like this. It is heavier than anywhere else, but not so bad as to effect the strength or the structure. I want to separate the two pieces so a protective layer of poly can be applied.
How to do this? My resident expert says that one would use two pairs of vice grips, and usually the rusty nut and bolt will break. This is what you want. Then you can clean up the rust and insert a new nut and bolt.
Above is an example of weakening steel to the point of breakage. More than once one of us has slowly floated ground-ward as weakening chairs finally bit the dust.
Above is a different chair that has been repaired. My husband used a high speed wire brush on an angle grinder to clean out all the weak rusty areas. With an oxy-acetylene welder, he took replacement steel in a flat sheet, and welded the new into place. He said that the act of using the welder will identify and destroy more of the rust not seen before. The heat of the welding will help you curve the plane of steel into the necessary tube shape. The final step is to apply something like Rustoleum to the new section to assure that what happened in the weather before will not happen again.
And remember those holes. I am going to add some to all my chairs that don’t have them. Water is the enemy!