Chemical polishing prior electropolishing

"because electropolishing ... generates a finish like ocean swells whereas a mechanical finish, no matter how fine, resembles a plowed field".

Ted,

Would you consider the mirrored finish stainless steel backs of Apple's iPod as "plowed field" or "ocean swells"?

Would you know if the mirrored stainless surface is electropolished or chemically mechanically polished?

Hi, Mike. Whatever the finishing method for the back of an iPod, it looks very good. I love the way the lettering is etched into it. I wouldn't know by eye how the polish was achieved, only by microscopic examination.

But when it comes to pharmaceutical and food handling surfaces, as opposed to music players, I wouldn't go by looks; I would want material that was smoothed by dissolving away the outer surface rather than by gouging abrasive plow tracks into it :-)

Regards,

Ted,

I find it interesting, polishing of semiconductor wafers are done through chemical mechanical polishing and not electropolishing. How's that for "plowed fields"? ;-)

Silicon is a different material than stainless steel and perhaps it doesn't develop clods.

I realize you don't like this "plowed field" analogy, but it was not my invention, it is quoted from books and micrographic photos. Just as fractal analysis tells us that the fractal degree of a seacoast remains the same at any degree of magnification, in the same way, regardless of the fineness of the abrasive grain utilized, a mechanically polished surface always retains the same "plowed field" look when we examine it at a magnification commensurate with that abrasive grain size. It doesn't matter if the final abrasive step is India Ink ... examine it at the appropriate magnification and it will look just like a surface abraded with coarse sandpaper looks at low magnification because it's the same process but with a smaller abrasive grit.

Nobody here is opposed to mechanical polishing of stainless steel, which is appropriate to the vast majority of applications. But if someone claims that there is no reason nor need for electropolishing, they're simply incorrect.

Regards,