Re: [CR]Chrome Removal Danger

(Example: Books:Ron Kitching)

From: <"brianbaylis@juno.com">
Date: Tue, 30 Aug 2005 14:17:52 GMT
To: stevem@mail.nonlintec.com
Subject: Re: [CR]Chrome Removal Danger
cc: classicrendezvous@bikelist.org

Steve,

OK, let me explain how this can work. I've seen it a few times. It may be somewhat rare, but it does occur. There is no way to tell in advance what the bike has been going through in it's years previous to being replated, but here's the way it happens. Almost every Italian frame I've ever seen that has chrome on the forks or stays has only one heat release hole in the fork blade or stay (seat stay). When the part is originally chromed, when plating solutions enter the tubes, they are never completely flushed out and complete drainage is impossible with only one hole in the tube. So there is not neccessarily a large amount inside the tube and maybe only a small amount, but it is there and the acids can be activated with the introduction of any moisture. That's the beginning, the original plating job left some solution behind; not enough to eat through the tube at the time or even over time. BUT! When a bike is replated the first thing that happens is the part must be stripped of the old chrome. This is done by putting the parts in caustic solutions with reverse current. It will safely remove the old chrome and not harm the silver or brass brazed joints, if all done properly. But the old acids from imcomplete drainage are moistened in the whole plating process.

Before anything goes to the plater I make sure each tube has two holes in it so all solutions can drain completely and the plater does not drag chemicals from one tank to another while doing the job. This insures that nothing new is left behind, but I've seen a few occassions where about 6 months to a year after the new plating the tubes begin to rust through from the inside. There is very little that can be done from there short of either some serious repair work or tube replacements. One can see or even predict in advance that this may occur. There is a certain amount of risk in doing a restoration that involves chrome plating. Rely on experts with lots of experience with chrome to have the best odds of success. All of the chrome related problems I've seen involve either a plater who doesn't know how to do bikes properly or a customer who has taken matters into their own hands and caused a problem in some way, with the few exceptions being the latent acids. Technically, that is from plater error also. I've seen only 2 cases of this in the past 30 years or so, and I see LOTS of bikes in my business.

So, the word "nonsense" will only appear in my explaination in this sentence. It can happen, although rare. I hope this helps you understand how this can happen. Stripping old chrome, polishing steel, and replating old frames involves a fair amount of work and a lot of care. Each situation presents a challange unique to the part in question and the people who handle the work need to adapt to each case the best they can. Working with old parts, especially chrome parts that have become rusty, requires the ability to judge how to best do the job and where to draw the line before lugs or crowns get too thin. By far the most difficult typical part is the Masi sand cast Fischer fork crowns. They are very pitted deep into the casting and it's nearly impossible to remove some of the pits.

Brian Baylis La Mesa, CA Whe do lots of chrome and it's generally a pain in the ass.


-- Steve Maas wrote:


Here comes the resident evil-tempered curmudgeon and technological bluestocking again with more grumpy skepticism.

I recognize that my chemistry is not what it once was--but, f'hevvinsake, precisely HOW does rechroming "chemically reactivate acids"? With 1000+ list members, we should have a chemist or two among us. Maybe even one who is a plating specialist. I'd like to hear from one of them on this issue. (I suspect that the word "nonsense" will show up in their replies.)

The simple fact, however, is that things are replated all the time--motorcycle parts, car parts, household items, and so on--and I've never heard this kind of concern applied to them. Corrosion after replating does happen, of course, but is caused by inadequate cleaning, not some kind of "reactivation," whatever that might be.

Steve Maas Dublin, Ireland

Jonathan Cowden wrote:
> This from Vintage Cycle Studios:
>
> "in some cases, redoing existing chrome may chemically reactivate left
> over acids used as part of the original chroming process. These acids
> may cause severe internal tube corrosion that may lead to rust- through
> areas."
>
> Best regards, Jonathan Cowden Carpinteria, Ca
>
>>
>> Let me just comment that Waterford will not re-chrome. I learned this
>> when they were still Schwinn, when they repaired the frame on my
>> formerly all-chrome '65. Gave me my choice of colors and did a lovely
>> job, but not chrome.
>>
>> Last year, when I had the '38 repainted by Waterford, I believe I
>> noticed the same thing on the web site, or when I asked about redoing
>> what had been a chrome fork on that bike. Again, the answer was
>> negative.
>>
>> I suspect there is a reason...
>>
>> harvey sachs
>> mcLean va
>>
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