Re: [CR] Re: Repainting full chromed framesets

(Example: Bike Shops:R.E.W. Reynolds)

Date: Sun, 21 Jan 2007 13:58:32 -0800
From: "Rich Pinder" <rpinder@usc.edu>
Subject: Re: [CR] Re: Repainting full chromed framesets
In-reply-to: <d3d.685c99.32e53a18@aol.com>
To: classicrendezvous@bikelist.org
References:


Just recently Greg Softley posted an interesting idea on this theme - check it out. (His was about clear coating chrome - but same product/system he described ought to work for repaint - as it's all about chemically modifying the slick chrome before coating)

Search the archives for the following subject, posted on last December 21

[CR]Clear and tinted finishes over chrome]

Rich Pinder Van Nuys, ca

Stronglight49@aol.com wrote:
>
>
> Regrettable, but if you paint over previously chromed finishes, you should
> scuff the surfaces with sandpaper to ensure best adhesion. This is why the
> fork blades on a couple of my French bikes with fully chromed forks beneath
> their original paint have been progressively shedding large flakes of paint and
> primer from the upper portions of the blades. There is inevitable going to
> be some degree of over-plating on any bikes where one or more layer has
> applied beyond the areas which were intended to be exposed chrome - as on chromed
> half-stays and forks.
>
> Perhaps some more modern paint under coats and primers are now better for
> holding against the slick virtually non-porous chrome finish. It would be
> worth looking into before damaging any existing chrome with manual abrasion. I
> recall a recent thread about a current translucent paint which someone had
> applied directly over chrome with very good results. I hope one of the
> Professional painters can offer some good advice here.
>
>
> Good Luck
>
> Bob Hanson, Albuquerque, NM, USA
>
>
> ____________________________________
>
>
>
>
>
>
> In a message dated 1/21/2007 2:07:30 P.M. Mountain Standard Time,
> bikes@msu.edu writes:
>
> Bob,
>
> Since you certainly know the ins and outs of plating, could you pls. offer
> your advice on the best way to go about repainting a frameset that has paint
> over full chrome? Your information seems to only apply to metal that
> hasn't been previously chromed. I have a couple frames like this that I'm
> considering getting repainted and just want to make sure that I understand
> what I'm getting into.
>
> Many thanks,
> Tim Potter
> Okemos, MI
>
> -----------
>
>
> Date: Sun, 21 Jan 2007 14:26:36 EST
> From: Stronglight49@aol.com
> To: lowiemanuel@yahoo.ca
> Cc: classicrendezvous@bikelist.org
> Subject: [CR] Re: fully chromed frames
>
>
> Chrome is a very durable finish and definitely useful for potentially
> high-abrasion areas like lower stays and fork blades. The added weight of
> a
> chrome
> finish was probably why we did not often see this on the highest level
> pro-quality racing bikes since the 1960s.
>
> There are several other reasons why we seldom see chromed framesets today,
> but they are not entirely extinct. You will still see relatively
> inexpensive BMX/Freestyle bikes and Low-rider bike frames in full chrome.
> However,
> because OSHA has deemed the process to be very hazardous to health and the
> EPA
> has very realistic concerns about the final containment of all the highly
> hazardous chemicals used, these bikes are generally made in third world
> countries
> where both workers and the environment may be shown little regard.
> Regardless of the risks, the companies which do commit to plating OEM
> frames
> generally do a good job because they are familiar with working with bike
> frames and
> their livelihoods depend on producing consistently good quality output.
>
> Most of the reputable large commercial after-market platers in the US have
> now removed chrome plating from their offerings. Nevertheless, there are
> some fine smaller companies which will still chrome plate anything from
> auto
> bumpers to bike frames, but you should be sure that they are very familiar
> with
> the particular needs of hand brazed bicycle frames - which are not the same
> as plating simple flat sections of steel.
>
> One of the issues (and I may have read this in the CR archives) is the
> potential for weakening the bottom bracket if certain precautions are not
> taken
> when cooling the finished frameset (a lot of heat is generated during the
> plating process).
>
> Also, the entire frameset must be completely cleaned by several processes.
> Organic solvent degreasing, alkaline cleaning, and then finally acid
> dipping or "pickling" - where the metal is dipped in an acid bath to remove
> any
> surface oxides or "smuts" remaining on the steel before plating. And any
> acid
> salts which have entered the frame tubes, including through any of the
> small-heat release holes originally drilled into the stays and fork blades
> during
> brazing, will later have to be neutralized.
>
> It is also very expensive to complete a proper triple strate plating
> process which will commonly consist of first a layer of copper, then nickel,
> and
> then finally chrome, and perhaps more than one layer of chrome for a good
> show
> quality "wet look" finish. Enamel can hide a lot, but because any
> imperfections will be very evident and may even be more pronounced when
> seen
> through
> the plating, it is best to wet sand or even polish the base layer of
> copper,
> sometimes more than once, before moving on toward the final finish layers.
> So, it really is a lot of work, especially if you want a visually flawless
> chromed frameset. And I would not begrudge what may seem like an excessive
> cost
> - so long as your plater does a good job.
>
> Bob Hanson, Albuquerque, NM USA
>
>
>
> **********************
> Tim Potter
> Coordinator
> MSU Bikes Service Center
> Bessey Hall Auditorium, Lower level
> At the River Trail & Farm Ln. Bridge
> 517/432-3400
> bikes@msu.edu
> http://www.bikes.msu.edu