Removing Rust without damaging the surface finish 1

[Luisfrom]

Hey everyone,

I have a steel counter plate cutting-die with parts of the steel plate surface and channel rusted. I'm trying to figure out a way of removing the rust without damaging the surface. I'm thinking of dipping the steel plate in vinegar, since I hear this is a good way of removing rust. However, I was told that by doing this I can damage the surface. Those any one have any suggestion on how to remove the rust. Any suggestion will highly be appreciated.

Thanks!

 

[Guest102023]

Oxalic acid is touted as being able to remove scale on steel. I have not personally used it for that, but a little googling might confirm it for you.
If the rust is more than superficial it may already have affected the surface finish.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[1gibson]

Have you seen the laser rust removal videos? Pretty cool stuff.

 

[MintJulep]

Electrilysis.

http://myweb.tiscali.co.uk/andyspatch/rust.htm

 

[JamesCKelly]

Phosphoric acid does remove rust, slowly.

A 5% solution of H2PO4 that is widely available is trademarked Coca-Cola. I'd use the regular, not the diet. Vaguely recall sugar helps modify things. Antique dealers have used a Coke soak to (slowly) clean up old iron stuff

If this is too ludicrous for your boss, then just get some commercial purity phosphoric acid and dilute it to somewhere around 5 or 10%

 

[mrfailure]

I've always thought a 5% solution of citric acid is a good mild cleaning agent that does no harm.

 

[racookpe1978]

Well, no, the citric acid is merely a mild acid which doesn't act against surface rust.

The phosphoric acid DOES react with the surface rust, and forms a stiff (hard) black deposit on the surface as the iron oxide reacts. But it does NOT "clean" the surface back to either a bright finish nor a smooth finish. The rust already damaged the surface finish with high spots (iron oxide) and low spots (where the rusted iron has flaked off already, or has spalled off.) The phosphoric acid DOES react with the rust so the surface is solid and will not continue rusting.

 

[Compositepro]

"250 mL of Coca-Cola provides 43 mg of phosphorus" according to Coca-Cola. That is far, far below 5%.