[Rolf S. Ask]

Have been an industrial painter/sandblaster for many Years on oil rigs, new and old ones.... there is one thing to remember, the sand (and sanddust and old paint and rust) gets in everywhere. If you are blasting an axelhouse make _sure_ you have masked the parts that don't like sand extreemly good. And blasting a frame will blast places you will have problems getting paint into after.
And make sure you have removed/cleaned everything for old oil before blasting, otherwise you just blasts the oil in to the steel and it will be swetting oil after you have painted it. And if you have blasted I recommend using a zincbased paint. But remember, the zinck is not air-/waterrproof, you need another coating on top of it.
And save the expensive zinckpaint if you don't have sandblasted. The zinck requires ruffnes in the steel to fasten good. If the steel don't have any ruffnes there are many paints that are meant to be used as a etch (?) primer.
I never use sandblasting on cabsheatmetall or other thin parts. What I like the best on such items are the grinder with a sandpaper covered disk (lamels???), or the rotating steelbrush.
And then if there are any rust caves left, the best thing is acid. But the welding pick can also be of good use.
And there are many compunds to use that will penetraite rust and seal it.

Rolf