Owner has a bead-blast cabinet which he uses on his machinery reconditioning - but it doesn't work too well if the parts are highly "greasy." Instead in those case he uses "electrolytic" removal of rust first.
It's a dilute caustic bath. Online recommends "washing soda" mixed with water, but Owner finds a dilute solution of lye works just as well.
The metal part to be cleaned is connected to the black (-) clamp of a battery charger. An electrode (any spare piece of steel) is used which is connected to the red (+) clamp. Both parts are in the bath and the relative position of the parts in the bath determines how many amps the charger runs at. It doesn't have to be to the capacity of the charger - but lesser amps just takes longer.
He'll typically leave a part in the bath for a minimum of two days. Perhaps after one day he'll pull the part out and wire brush it on a wire wheel or even by hand. By then the grease is gone but the paint may be still adhered.
The bath removes any paint, oil, rust, or even galvanizing on parts - so you want be sure you want bare metal. In the process the electrode is consumed so use a piece of scrap metal for this. Tin cans will work if the metal is not coated. (Many are.)
The process converts the red rust - which can't be painted over - to "black rust" which can.
Sometimes he'll use the bead blaster to "really clean" the part before painting - but I think he does this to "roughen" the surface so paint holds better. More often he'll use Kleen-Strip "Prep & Etch" which is a phosphoric acid product made for this purpose - it "neutralizes" the metal and makes for a better longer lasting paint attachment. And the part will go longer before the insidious rust begins before painting.
The downside of the electrolytic process (besides the labor) is it leaves the metal in a chemically PERFECT condition to re-rust - even from the moisture in the air. Hence the bath/blast/paint, or bath/Prep & Etch/paint - which you don't have to paint immediately.
But - if you're doing cooking grilles perhaps you don't want to paint anyway? Maybe a coat of cooking oil will hold it until you get some steak grease on it?
Electrolytic Rust Reversal link at
Every Thing You Always Wanted to Know About Electrolytic Rust Removal
Owner frequently consults online sources as he forgets which clamp (red/black) to connect to what.
A dilute caustic solution, Owner will reach into the bath with his bare hand (current off) to reposition. He says his hands come out "whistle clean" - although he confesses to using lotion on his hands that night - the bath is VERY DRYING to the skin.
Dobbin
