On 22 Feb 2007 10:01:01 -0800, "Sheldon Brown"
<
[email protected]> wrote:
>Quoth Carl Fogel:
>
>> Browse aroundSheldon Brown'ssite for lots of interesting articles:
>>
>> http://sheldonbrown.com/articles.html
>>
>> Sheldon mentions the shake-it-in-a-pop-bottle-with-Simple-Green method
>> of chain cleaning:
>>
>> "I used to use a parts cleaning tank and a toothbrush to clean chains,
>> but Zaven Ghazarian, an excellent mechanic I used to work with came up
>> with a better system: drop the chain into a plastic Coke bottle with a
>> couple of ounces of un-diluted citrus degreaser, cap it, and shake
>> thoroughly. Fish the chain out with a spoke, rinse in water, and you
>> are all set!"
>>
>> http://sheldonbrown.com/chains.html
>
>Actually, that's not quite correct. I do recommend using a Coke
>(never Pepsi!) bottle, but I do NOT recommend Simple Green.
>
>There have been many credible reports of chains damaged by Simple
>Green. I'm not a chemist, and don't understand the mechanism
>involved, but there have been too many cases of this to ignore.
>
>Sheldon "Citrus" Brown
>+------------------------------------------------------------------+
>| Honestly, I think we should just trust our president in every |
>| decision that he makes and we should just support that. |
>| -- Britney Spears, September 4, 2003 |
>+------------------------------------------------------------------+
>Harris Cyclery, West Newton, Massachusetts
> Phone 617-244-9772 FAX 617-244-1041
> http://harriscyclery.com
> Hard-to-find parts shipped Worldwide
>http://captainbike.com http://sheldonbrown.com
Dear Sheldon,
Sorry for the mistake.
It could be that Simple Green and similar cleaners are somehow both
worthless for cleaning crud off chains (a common comment) and yet
powerful enough to crack steel links (frequently the next comment).
But a quick look at the archives suggests an alternative explanation,
namely that someone takes a _rusty_ and filthy chain, cleans it, and
then discovers numerous cracks in the chain, probably caused by rust
expanding inside the chain.
In other words, the cleaner gets the blamed for the rust's dirty work.
The cracks caused by the rust could be pre-existing and invisible
under the crud until the chain was cleaned . Or the cracks could be
caused by rust expanding inside the links during the actual bath:
"Now that I think about it, I do recall hearing noises apart from the
bubbling while it [rusty 14-year-old-chain] was soaking [in dilute
phosphoric acid] which may have been the links fracturing. How could
being immersed in dilute H3PO4 have cause failure in this form?"
http://groups.google.com/group/rec...."simple+green"+chain&rnum=10#7976ca9a1b17cd21
or
http://tinyurl.com/2bcwd2
There's a nice picture of the cracked chain:
http://www.flickr.com/photos/85942209@N00/76768811/
In the same thread, Mike DeMicco pointed out that Simple Green isn't
even acidic, though it got blamed for the phosphoric acid bath
results:
"Simple Green seems to be much maligned. If you look at the MSDS
sheet, concentrated it has a pH of 9.5 (mildly basic). It should be
diluted anyway, which will reduce the pH. As long as you leave a chain
soaking in it for about a half an hour, and remove by flushing with
water, I don't see how it could cause damage to the chain. I've been
using it for years and have not had a problem. I would not leave a
chain soaking in it overnight; nor would I leave a chain soaking in
water that long either (unless I wanted a rusty chain)."
And Werehatrack mentioned that he's seen rusty chains crack:
"I've seen this kind of cracking (though not as extensively) in
corroded chains that had not been run through a corrosion removal
bath, so I suspect that at least some of the cracks were there before
it was soaked. OTOH, the acid etches the surface of the metal as well
as removing the oxide, particularly with certain alloys. I would not
be surprised if the failure was aggravated by the acid bath, but I
think the chain was likely junk before it was dipped."
So far, a cheap chain subjected to half a dozen cleanings using Simple
Green in an ultrasonic cleaner during some cleaning tests hasn't
cracked.
Like most chains, it's likely to be replaced long before any subtle
chemically-induced cracks can appear.
Cheers,
Carl Fogel