17 hours ago, Stray
My opinion - go cheap and see if you can salvage them first. Doesn’t look like the rust has penetrated deep, as others have observed.
My method is to rub with aluminium foil and phosphoric acid (or Coca Cola if you can’t get some - use diet to avoid stickiness). The Phosphoric converts rust into a honeycomb phosphate coating - this stuff is TOUGH. The tinfoil breaks off into microscopic bits that embed in the phosphate layer. Scrape any big rust lumps off with razor blade.
Make sure all rusty spots are blackened by phosphoric acid. If not, wash it with phosphoric acid (or Coke) again until it does. You can’t do this too much!
Then epoxy any deep craters (JB Weld works great) . Don’t worry if it sticks out - deal with that later. Once cured for 24 hours, use razor blade to scrape down bumps of epoxy until it’s all level.
Now rub fork oil over the surface. Phosphate coating absorbs and traps oil beautifully, making the repair waterproof.
Then, VERY fine sand (I used 2000) followed by grey scotchbrite pad. Use oil as lube rather than water. Epoxy is softer than steel so will wear down even. DO NOT SAND/BUFF UP-AND-DOWN! Do it sideways. As Magneto says, chuck the stanchions on a drill and spin it to buff. If you can’t do that, throw them on a broomstick and buff like a shoeshine. This helps create horizontal ridges that hold oil and stops cutting up seals. Same idea as cylinder honing. Aim for a 45* cut.
You’ll end up with slightly less mirror-like chrome and your stanchions will work great for years to come.
This works even on worse rust than yours. Give it a go before you spend any real money. Will cost you less than £5 ($7?) in kit and about 2 hours in work.
Good luck and post pics when you’re done!
Stray
What Stray says is quite true, Phosphoric acid will chemically turn Iron Oxcide (rust) into Iron Phospahate a hard black fairly inert substace that forms a barrier that then protects the Iron substrate.
I work on ships also, as crew, and we use it after we scape any rust away and wire brush the area. We brush it on and wait for it to dry, may take a day, then apply a primer then when ready a topcoat. Works the charm.
I'm a rigger and on the bridge, not a painter, but I use the it on stainless to remove rust and on my bikes for the same reason as Maine has salt on the roads 6 months a year.
Not sure what you do on ships, but grab a painter some day at the yard and ask them about Phosphoric acid. One of the trade names is Ospho. Readily available in any real Chandlery, or maybe they can give you a cup or so. I use it straight from the container, I mean the stuff is in Coca Cola so its not that awful. I think much like Citric acid (lemon Juice) is an acid, this is also, but fairly beniegn. Wear some nitrile gloves and have at it.
I'll try to include a picture.
Good Luck.