John,
Those bumps sticking up are most probably blisters of corrosion under the
plating - pushing out the chrome skin, after having eaten into the base
metal. After removing the skin, you'd undoubtedly find pits everywhere
there is a bump.
Most platers will not guarantee their work if they aren't the ones doing the
prep work. A quality job will include stripping the old chrome, an acid
bath to clean the metal, and a bath to neutralize rust and corrosion.
Plating begins with copper, with thickness built up to fill any
imperfections. Sometimes brass will be applied to fill deeper flaws prior
to copper. This layer is finished and buffed, repeated if necessary, to
yield a perfectly smooth surface. You could liken this to the primer/filler
stage in a paint job. Any imperfections here will show in the final finsh.
Then nickle to seal the softer copper and provide a hard base for the
chrome, then chrome.
As with anything else, you get what you pay for. Most of the cost of a
really good plating job is in the prep and copper finishing stages, where
the work is all highly skilled manual labor. After all, if you put a
reflective finish on a bumpy, wavy part you get a bumpy wavy mirror........
Mark Sedlack
ZROC
Cuyahoga Falls OH
66 1600 http://www.mildevco.net/chevypowereddatsuns/
77 280Z http://www.mildevco.net/chevypowereddatsuns/
----- Original Message -----
From: "John Roper" <john@roper-photo.com>
To: <datsun-roadsters@autox.team.net>
Sent: Wednesday, January 04, 2006 1:13 AM
Subject: RE: windshield frame refinishing
> Well the spots on my chrome appear to be external, not internal. Thus I'd
be
> grinding them "off", not grinding the surrounding area down to match.
>
> Make sense?
> -----Original Message-----
> From: Keith0alan@aol.com [mailto:Keith0alan@aol.com]
> Sent: Tuesday, January 03, 2006 9:46 PM
> To: john@roper-photo.com; datsun-roadsters@autox.team.net
> Subject: Re: windshield frame refinishing
>
>
> I think so, but, that's just my opinion. Another option is to braze or
> silver solder to fill the pits. I'd check with my plater first to make
sure
> they are comfortable plating over that type of repair. The reason they
like
> to grind out the pits is that it is fast and cheap, not because it's the
> best thing to do to classic car parts.
>
> keith
>
> In a message dated 1/3/2006 6:01:30 P.M. Pacific Standard Time,
> john@roper-photo.com writes:
> >The problem with grinding all the pits out is that the parts
> >end up really thin. Especially things like headlight trim.
> >The best answer is to have lots of copper plated on and
> >buffed to fill the pits. BTW, does any remember seeing the
> >little chrome dimples on my car? I don't think many will notice.
>
> I was planning to grind the pits off myself with a Dremel. Bad idea?
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