Dave,
All chrome has nickel under it. The electroplating process by nature requires various "steps" that electrons can jump from one element to the next. The gap has to be small enough for the process to work. Originally copper was required for the nickel to stick to. Then the chrome could stick to the nickel. What happened was that through chemistry the industry formulated a nickel compound that would bond to steel, thus eliminating the neccessity for the copper step. Most of what we call chrome plating is nickel; the chrome itself is only microns thick since at that point the process is about 3% effecient as compared to about (as I sort of remember) nickel which is around 30% and copper which is very effecient at around 70% or so as I recall. The nickel is the primary source of durability and gloss (or depth) of the chrome. I think that covers it for the basics.
Brian Baylis
La Mesa, CA
>
> Ah, yeah I guess I was asking if there was any benefit in a nickel and/or a
> copper layer under the chrome in terms of durability, or corrosion
> resistance, or lessening any weakening of the steel.
>
> DF
> ----- Original Message -----
> From: "Brian Baylis" <rocklube@adnc.com>
> To: "Diane Feldman" <feldmanbike@home.com>
> Cc: <classicrendezvous@bikelist.org>
> Sent: Wednesday, May 16, 2001 8:03 PM
> Subject: Re: [CR]A few words about chrome plating
>
> > Dave, I'm not sure what you're asking. Please clarify.
> >
> > Brian Baylis
> > >
> > > What about a nickel layer under the chrome? I remember Ten Speed Drive
> > > making a big deal about the multi-layer copper, nickel, and chrome on
> their
> > > frames in the 1980;'s. At least on the top of the line Ciocc and
> Tomasso
> > > frames, the plating looked great, but how did it last and did the nickel
> > > have anything to do with it?
> > >
> > > David Feldman
> > > ----- Original Message -----
> > > From: "Brian Baylis" <rocklube@adnc.com>
> > > To: <classicrendezvous@bikelist.org>
> > > Sent: Wednesday, May 16, 2001 12:12 AM
> > > Subject: [CR]A few words about chrome plating
> > >
> > > > Listmembers,
> > > >
> > > > There are a few key points regarding chrome plating that weren't
> > > > completely addressed, which I'd like to illuminate since the topic
> came
> > > > up.
> > > >
> > > > First, it is of prime importance to have a very good relationship with
> > > > ones' plater if one expects excellent results while avoiding the
> > > > pitfalls that can (but do not neccessarily have to) accompany a chrome
> > > > plating job. The problem of drainage is easily solved by one of two
> > > > methods. The best one is not to have any holes in the seat stays or
> fork
> > > > blades in the first place. The only safe way to accomplish this is
> > > > during the framebuilding process; filling the one vent hole in the
> fork
> > > > or stay just after brazing the final joint that encloses the tube
> while
> > > > it is still hot. Trying to fill a hole afterwards is risky and is a
> > > > pretty good way to insure that a small pinhole will allow plating
> > > > solution to enter and have no way to escape. So for resorations it is
> > > > best to make sure each stay and blade hace two holes at opposite ends
> > > > that are about 3/32" in diameter. Any GOOD plater can work with that
> and
> > > > give the owner of the frame the ability to introduce a rust inhibitor
> > > > AFTER the paint job is applied.
> > > >
> > > > Regarding polishing. Yes it is dangerous, providing the plater (which
> > > > includes all but the one I use) goes about it with the polishing
> lathes
> > > > that Jim described. The exceptional plater will have developed a
> > > > "secret" method to accomplish this task without risk to frame or human
> > > > body. As luck would have it, the polisher at my plater is a good
> friend
> > > > of mine (we have an interest in drums and drumming in common) and has
> > > > passed this trick on to me; which I can use myself if I'm so inclined
> > > > (which usually I'm not). But, it is quite safe and only requires some
> > > > time and effort to accomplish, along with a few special tools and
> > > > whatnot.
> > > >
> > > > Only a really careless or inexperienced plater can accomplish hydrogen
> > > > embrittlement on a frame. It's not easy to do. As far as I know, only
> > > > about a half an hour at 300 or so degrees is required to disipate the
> > > > effect. Maybe industrial (or "hard" chrome) requires 12 to 24 hours at
> > > > temp., but not decorative chrome like we use. Modern nickel
> formulations
> > > > take the place of the old "triple chrome" process and work perfectly
> > > > well. Like Jim said, copper is for heavily pitted parts these days. If
> a
> > > > frame is that bad off, it's probably best not to chrome (or maybe even
> > > > ride) it at that point.
> > > >
> > > > The chrome I get from my plater is mirrorlike; it's all in the
> polishing
> > > > and keeping clean tanks.
> > > >
> > > > As far as a completely chrome frame goes, OUCH! Costs a bit of money
> for
> > > > a good plater to do it; so there's no point in doubling it by sending
> it
> > > > to someone else to hand to a plater. Find you own guy and save the
> money
> > > > for a payment on your Ferarri, like Joe said. Good luck.
> > > >
> > > > Brian Baylis