It is all about preparation:
a) Disassemble, to the extent possible. Screws, nuts, bolts, and so forth.
b) Remove all existing coatings. With chemicals, if necessary.
c) Remove all existing rust. By chemical or physical means.
d) Rent or borrow an electrostatic painting device, purchase the appropriate paint. This is NOT a powder-coat.
e) Paint per the directions. Include the fasteners if not already plated, or replace the fasteners with stainless steel.
f) Obtain magnesium washers ILO those supplied, and use them during the reassembly.

Should give you at least another 20 years.

Peter Wieck
Melrose Park, PA