Case plating?
Tech Contributor
Joined: Aug 1999
Posts: 14,373
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From: At my Bar drinking and wrenching in Lafayette Colorado
It's plain, simple, cheap cold galvanized. Cad plating does not erode, scratch, or rust the way those panels do in an interior environment. Just look at it. Cold galvanize is the cheapest coating you can apply to something that's used in a non-cosmetic interior application, and requires no special tools or processes. Cad plating (Type II and Type III) is sealed with a dichromate or phosphate coating, which means it's either a bright silver ("blue dichromate"), a yellowish-gold ("yellow dichromate") or black semi-gloss finish as a result of the sealer. It's fairly durable for exterior applications, and is used when a wear-resistant surface is required. Cold galvanize is a spray-applied zinc finish which comes out slightly dull and grey-ish looking. It scratches easily, and will exhibit corrosion under old fastener locations as your panel does. You can clearly see that the finish on your panel is not at all "wear resistant." Cad won't do that, and cad is too expensive to apply to a cheap, hidden housing like that. If you want to verify, just take a razor blade and start scraping it away like you'd strip paint - you'll hit bare metal with just a little scraping. You won't remove cad with a razor blade.
Last edited by lars; Sep 6, 2022 at 09:57 PM.
