Rust Removal from Precision Cast Iron Surfaces in 2020: techniques and when to stop

[Bill Dufour]

EDTA in water will neutralize rust. That the basic formula for evaporust minus some propitiatory ph adjusters. EDTA is safe enough that some people eat it for their health.
Bill D

[Alan Lightstone]

EDTA in water will neutralize rust. That the basic formula for evaporust minus some propitiatory ph adjusters. EDTA is safe enough that some people eat it for their health.
Bill D

Does EDTA leave the same discoloration as Evaporust? Oh, and what is that discoloration? I seem to remember a dark residue left after using it. And, lastly, where does one get EDTA. And yes, it's in many processed foods.

[Bill Dufour]

I bought edta from ebay. It turns the iron gray. must be submerged or a waterline stain will appear. Like all derusting processes it will not affect the carbon in the iron. Unlike electrolysis there is no chance of hydrogen embrittlement and it can be run forever with no chance of eroding good metal. I believe it is safe for wood, aluminum and paint.
Bill D

[Keith Outten]

Sold my company van a couple of months ago and I had to remove the vinyl signs on the sides of the van. I ended up using a polisher and 3M 06060 Perfect It 3000 extra cut rubbing compound with a foam pad. The paint on the van looked factory smooth shined like a new penny.

I have been thinking about using the same technique on the cast surfaces in my shop. I expect that this technique will restore the cast surfaces to a mirror level finish but I can't say for sure until I give it a try. I used this same technique recently on a very old wooden table top with a Formica insert and the results were fantastic, looked just like a new lacquer finish smooth as glass. This table came from the old cafeteria at CNU, it had been abused by students for over 20 years.