Electrolytic steel derusting



I'm interested in finding out more about electrolytic derusting of automotive sheet metal. Specifically can anyone tell me the percentage of sodium cyanide to sodium hydroxide to use in solution and the voltage/amperage per square inch to use? Can a sodium hydroxide & sodium gluconate solution be used electrolytically without having the solution boiling? What are the best complexing and foaming agents to use?

Thanks in advance for any insight,

Jim Walters
- Victoria, BC, Canada



Jim,

I can answer some of your questions. Sodium gluconate + sodium hydroxide used with current is an excellent deruster for mild steel. No cyanide is needed. Main problem is that when the rust is removed there is a pit left in the surface. The derusted surface is not blemish free. The best I can recall of the operating conditions is: 8 oz/gal of sodium glucanate, 8 oz/gl of sodium hydroxide, 140 deg F and 5 Volts anodic.

Hope this helps,

Pat Mentone
Mentone Component Technology Corporation - St Paul, MN, USA