Metal finishing Q&As since 1989

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Improve on Electro Polishing Process on S/S

2000

Can you please send us information on electro-polishing solution mixtures and additives to minimise sludge for a typical electro polishing bath to polish bend 300 series s/s tubing 63 dia. as well as deburring mild steel.

the ep plant already exists, but we would like to improve on our production time and quality.

kind regards

Gerwald Erber
- johannesburg, South Africa

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Sludge is a nasty byproduct, but a necessary one. If you electrochemically remove burrs or surface material and did not form a sludge, you would have a rapid decrease in the effectiveness of the solution because of all of the metal ions in it.

My opinion is that you need to develop an effective and practical method of removing the sludge. Constant filtration is one, but you do not want it to induce solution movement in your tank. Mechanical agitation and filtering after hours seems practical. The old stand by is to hoe it out every night, putting the drippings back in the tank and let it settle overnight. Unless you have a bottom heater or have huge wave action from parts going in or out, you can probably get by with clearing the tank on the weekends. Undisturbed sludge is not good, but it is not terrible.

James Watts
- Navarre, Florida
2000