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Mirror finishing galvanized (galvannealed) steel

June 16, 2010

I have been stripping and polishing small satellite dishes to a mirror finish. They usually are what is referred to as paint grip galvanized and polish up nicely with buff and compound. This is for solar applications (mirror stainless ranks about 11, mirror aluminum ranks about a 3, this mirror galvanized ranks about a 9 for solar reflector usage). I'm wondering if there is an electropolishing process that can accomplish same without the buff and compound.
any advice appreciated- even a manufacturer.
I am looking into it as a less expensive alternative to polished stainless.

Mike Swayze
Hobbyist - Apex, North Carolina, USA

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June 18, 2010

Polishing might be only one aspect of this, as I assume you will want the finish to remain shiny (highly reflective)?
If so, galvanizing doesn't seem a great finish to use. Galvanizing is zinc, and that's reactive with air (and rain, and other things) causing zinc oxides and carbonates to form on the surface, resulting in a dull finish.
So even if you get it shiny, then it'll soon dull down.
Unless you put another coating on top of that to protect the zinc, and then you'd question why bother with the zinc?

What about powdercoating in a shiny silver, similar finish to mag wheels etc? Still cheaper than stainless, but lower corrosion resistance, though doesn't loose its shine like galv will.

Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK