Interesting corrosion failure

http://www.yellowjersey.org/photosfr...t/failspok.jpg

2004 chinese Trek low end hybrid with low miles. Rider (est
120lb) says she took it out for the first time this year
and during first ride, spokes failed and wheel rubbed the brake.

The front wheel, fork, brake, handlebar are severely
corroded, perhaps from being parked in a garage with the
front closest to a car's daily salt splashes. 8 spokes
missing or broken. Spokes failed in the middle, not the
heads. A dozen or so green nipples are covered in white
efflorescence near the rim (assume these were at the bottom
when parked). The other nipples are dingy nickel.

Spokes do not respond to a magnet. Being 'stainless' or
'inox' doesn't mean a steel will not corrode, it just
succumbs more slowly.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Sunday, May 31, 2020 at 11:15:02 AM UTC-7, AMuzi wrote:
http://www.yellowjersey.org/photosfr...t/failspok.jpg

2004 chinese Trek low end hybrid with low miles. Rider (est
120lb) says she took it out for the first time this year
and during first ride, spokes failed and wheel rubbed the brake.

The front wheel, fork, brake, handlebar are severely
corroded, perhaps from being parked in a garage with the
front closest to a car's daily salt splashes. 8 spokes
missing or broken. Spokes failed in the middle, not the
heads. A dozen or so green nipples are covered in white
efflorescence near the rim (assume these were at the bottom
when parked). The other nipples are dingy nickel.

Spokes do not respond to a magnet. Being 'stainless' or
'inox' doesn't mean a steel will not corrode, it just
succumbs more slowly.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

I guess living all of my life in California despite being adjacent to the bay, I've been lucky. I've never seen stainless spokes corrode like that.

On Sun, 31 May 2020 13:14:54 -0500, AMuzi wrote:

http://www.yellowjersey.org/photosfr...t/failspok.jpg

2004 chinese Trek low end hybrid with low miles. Rider (est
120lb) says she took it out for the first time this year
and during first ride, spokes failed and wheel rubbed the brake.

The front wheel, fork, brake, handlebar are severely
corroded, perhaps from being parked in a garage with the
front closest to a car's daily salt splashes. 8 spokes
missing or broken. Spokes failed in the middle, not the
heads. A dozen or so green nipples are covered in white
efflorescence near the rim (assume these were at the bottom
when parked). The other nipples are dingy nickel.

Spokes do not respond to a magnet. Being 'stainless' or
'inox' doesn't mean a steel will not corrode, it just
succumbs more slowly.

It is difficult to tell from the photo but it looks almost as though
the spokes cracked, part way through, then corroded in the crack and
than broke the remaining portion. At least there seem to be small
shiny sections, as though freshly broken, and large corroded sections
at each break.
--
cheers,

John B.

On Sun, 31 May 2020 13:14:54 -0500, AMuzi wrote:

http://www.yellowjersey.org/photosfr...t/failspok.jpg

2004 chinese Trek low end hybrid with low miles. Rider (est
120lb) says she took it out for the first time this year
and during first ride, spokes failed and wheel rubbed the brake.

The front wheel, fork, brake, handlebar are severely
corroded, perhaps from being parked in a garage with the
front closest to a car's daily salt splashes. 8 spokes
missing or broken. Spokes failed in the middle, not the
heads. A dozen or so green nipples are covered in white
efflorescence near the rim (assume these were at the bottom
when parked). The other nipples are dingy nickel.

Spokes do not respond to a magnet. Being 'stainless' or
'inox' doesn't mean a steel will not corrode, it just
succumbs more slowly.

I know you said that the spoke corroded in the middle, but by any
chance were they corroded where the spokes cross over and touch other
spokes? One problem with stainless is that it can be both anodic and
cathodic to itself:
https://yarchive.net/metal/galvanic_corrosion.html
...remember that sometimes the above rules must be
bent a little for other reasons, and that corrosion
can be far more complex than just galvanic corrosion.
Look at the stainless steels for example. Most can
be both cathodic and anodic to themselves! Corrosion
while immersed in sea water can be quite different
than corrosion from exposure to pollutants in the
atmosphere.

In other words, two pieces of stainless steel will develop a
sufficient potential between them to produce galvanic corrosion. In
the galvanic table in the above URL, note that chromium-nickel-iron
appears twice, once as "active" and again as "passive" with quite a
large gap in potential between them. I may have seen this while
working on marine radios, but did not bother to investigate. In your
photo, the upper spoke did not break perpendicular to the axis of the
spoke, but rather broke lengthwise, as I would expect if the spoke
were under tension or torsion. However, the perpendicular breaks on
the other spokes seem to indicate bending, not tension. My guess(tm)
is that the wheel already had some broken spokes before the owner took
the bicycle for a ride.

The white powder(?) kinda looks like aluminum oxide, which is what I
would expect if something made from aluminum were leaned against the
spokes in a electrolytic (salt) atmosphere. Possibly contact with
another bicycle, aluminum rim, frame, rack, floor pump, aluminum bike
stand, aluminum bike rack, etc?

I'm doing quite a bit of guessing based on only one photo. If you
still have the remaining spokes, try match up pairs of several broken
spokes in a photo. I suspect I can extract some more guesswork from
how the spokes broke. I'm especially interested if they broke where
the spokes crossed over each other.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 6/1/2020 12:40 AM, Jeff Liebermann wrote:
On Sun, 31 May 2020 13:14:54 -0500, AMuzi wrote:

http://www.yellowjersey.org/photosfr...t/failspok.jpg

2004 chinese Trek low end hybrid with low miles. Rider (est
120lb) says she took it out for the first time this year
and during first ride, spokes failed and wheel rubbed the brake.

The front wheel, fork, brake, handlebar are severely
corroded, perhaps from being parked in a garage with the
front closest to a car's daily salt splashes. 8 spokes
missing or broken. Spokes failed in the middle, not the
heads. A dozen or so green nipples are covered in white
efflorescence near the rim (assume these were at the bottom
when parked). The other nipples are dingy nickel.

Spokes do not respond to a magnet. Being 'stainless' or
'inox' doesn't mean a steel will not corrode, it just
succumbs more slowly.

I know you said that the spoke corroded in the middle, but by any
chance were they corroded where the spokes cross over and touch other
spokes? One problem with stainless is that it can be both anodic and
cathodic to itself:
https://yarchive.net/metal/galvanic_corrosion.html
...remember that sometimes the above rules must be
bent a little for other reasons, and that corrosion
can be far more complex than just galvanic corrosion.
Look at the stainless steels for example. Most can
be both cathodic and anodic to themselves! Corrosion
while immersed in sea water can be quite different
than corrosion from exposure to pollutants in the
atmosphere.

In other words, two pieces of stainless steel will develop a
sufficient potential between them to produce galvanic corrosion. In
the galvanic table in the above URL, note that chromium-nickel-iron
appears twice, once as "active" and again as "passive" with quite a
large gap in potential between them. I may have seen this while
working on marine radios, but did not bother to investigate. In your
photo, the upper spoke did not break perpendicular to the axis of the
spoke, but rather broke lengthwise, as I would expect if the spoke
were under tension or torsion. However, the perpendicular breaks on
the other spokes seem to indicate bending, not tension. My guess(tm)
is that the wheel already had some broken spokes before the owner took
the bicycle for a ride.

The white powder(?) kinda looks like aluminum oxide, which is what I
would expect if something made from aluminum were leaned against the
spokes in a electrolytic (salt) atmosphere. Possibly contact with
another bicycle, aluminum rim, frame, rack, floor pump, aluminum bike
stand, aluminum bike rack, etc?

I'm doing quite a bit of guessing based on only one photo. If you
still have the remaining spokes, try match up pairs of several broken
spokes in a photo. I suspect I can extract some more guesswork from
how the spokes broke. I'm especially interested if they broke where
the spokes crossed over each other.




The spokes failed about 1/3 from the rim not at the cross (a
known issue but not applicable here). Yes, the aluminum rim
and the brass nipples appear to have been galvanically engaged.

The shiny spots seem to be from riding with spokes flappng
around and striking each other and the fork.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Mon, 01 Jun 2020 08:06:56 -0500, AMuzi wrote:

The spokes failed about 1/3 from the rim not at the cross (a
known issue but not applicable here).

Thanks. So much for my self corrosion theory.

Yes, the aluminum rim
and the brass nipples appear to have been galvanically engaged.

With severe corrosion only the front part of the bicycle, your
observation that the electrolyte (salt) was delivered in the garage by
the nearby parked car is probably correct. I wonder if the metal
parts on the car were also corroded?

Is the local road salt NaCl (sodium chrolide), or one of the
alternatives listed?
"CURRENT DEICING PRACTICES AND ALTERNATIVE DEICING MATERIALS"
https://www.michigan.gov/documents/ch2-deice_51438_7.pdf
We don't have road salt problems on the left coast, so this is all new
to me.

Was there a bank of batteries charged by solar panels or wind nearby?
We have such an arrangment in our ham radio repeater building. Despite
adequate ventillation, we still manage to get some metal corrosion in
the building:
http://802.11junk.com/jeffl/crud/k6bj-batteries-02.jpg
Putting a bicycle in the battery room would be a really bad idea.

The shiny spots seem to be from riding with spokes flappng
around and striking each other and the fork.

So much for my aluminum contact corrosion theory. I should have known
better since other parts of the bicycle were corroded without contact
with aluminum.

Yes, stainless steel will corrode:
"Metallurgy for Dummies - Corrosion Stainless Steel"
https://metallurgyfordummies.com/corrosion-stainless-steel.html
More examples:
https://www.google.com/search?q=stainless+steel+corrosion&tbm=isch



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Monday, June 1, 2020 at 9:30:07 AM UTC-7, AMuzi wrote:
On 6/1/2020 12:40 AM, Jeff Liebermann wrote:
On Sun, 31 May 2020 13:14:54 -0500, AMuzi wrote:

http://www.yellowjersey.org/photosfr...t/failspok.jpg

2004 chinese Trek low end hybrid with low miles. Rider (est
120lb) says she took it out for the first time this year
and during first ride, spokes failed and wheel rubbed the brake.

The front wheel, fork, brake, handlebar are severely
corroded, perhaps from being parked in a garage with the
front closest to a car's daily salt splashes. 8 spokes
missing or broken. Spokes failed in the middle, not the
heads. A dozen or so green nipples are covered in white
efflorescence near the rim (assume these were at the bottom
when parked). The other nipples are dingy nickel.

Spokes do not respond to a magnet. Being 'stainless' or
'inox' doesn't mean a steel will not corrode, it just
succumbs more slowly.

I know you said that the spoke corroded in the middle, but by any
chance were they corroded where the spokes cross over and touch other
spokes? One problem with stainless is that it can be both anodic and
cathodic to itself:
https://yarchive.net/metal/galvanic_corrosion.html
...remember that sometimes the above rules must be
bent a little for other reasons, and that corrosion
can be far more complex than just galvanic corrosion.
Look at the stainless steels for example. Most can
be both cathodic and anodic to themselves! Corrosion
while immersed in sea water can be quite different
than corrosion from exposure to pollutants in the
atmosphere.

In other words, two pieces of stainless steel will develop a
sufficient potential between them to produce galvanic corrosion. In
the galvanic table in the above URL, note that chromium-nickel-iron
appears twice, once as "active" and again as "passive" with quite a
large gap in potential between them. I may have seen this while
working on marine radios, but did not bother to investigate. In your
photo, the upper spoke did not break perpendicular to the axis of the
spoke, but rather broke lengthwise, as I would expect if the spoke
were under tension or torsion. However, the perpendicular breaks on
the other spokes seem to indicate bending, not tension. My guess(tm)
is that the wheel already had some broken spokes before the owner took
the bicycle for a ride.

The white powder(?) kinda looks like aluminum oxide, which is what I
would expect if something made from aluminum were leaned against the
spokes in a electrolytic (salt) atmosphere. Possibly contact with
another bicycle, aluminum rim, frame, rack, floor pump, aluminum bike
stand, aluminum bike rack, etc?

I'm doing quite a bit of guessing based on only one photo. If you
still have the remaining spokes, try match up pairs of several broken
spokes in a photo. I suspect I can extract some more guesswork from
how the spokes broke. I'm especially interested if they broke where
the spokes crossed over each other.




The spokes failed about 1/3 from the rim not at the cross (a
known issue but not applicable here). Yes, the aluminum rim
and the brass nipples appear to have been galvanically engaged.

The shiny spots seem to be from riding with spokes flappng
around and striking each other and the fork.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

Isn't that thed area where the butted spokes narrow?

On 6/1/2020 12:52 PM, Jeff Liebermann wrote:
On Mon, 01 Jun 2020 08:06:56 -0500, AMuzi wrote:

The spokes failed about 1/3 from the rim not at the cross (a
known issue but not applicable here).

Thanks. So much for my self corrosion theory.

Yes, the aluminum rim
and the brass nipples appear to have been galvanically engaged.

With severe corrosion only the front part of the bicycle, your
observation that the electrolyte (salt) was delivered in the garage by
the nearby parked car is probably correct. I wonder if the metal
parts on the car were also corroded?

Is the local road salt NaCl (sodium chrolide), or one of the
alternatives listed?
"CURRENT DEICING PRACTICES AND ALTERNATIVE DEICING MATERIALS"
https://www.michigan.gov/documents/ch2-deice_51438_7.pdf
We don't have road salt problems on the left coast, so this is all new
to me.

Was there a bank of batteries charged by solar panels or wind nearby?
We have such an arrangment in our ham radio repeater building. Despite
adequate ventillation, we still manage to get some metal corrosion in
the building:
http://802.11junk.com/jeffl/crud/k6bj-batteries-02.jpg
Putting a bicycle in the battery room would be a really bad idea.

The shiny spots seem to be from riding with spokes flappng
around and striking each other and the fork.

So much for my aluminum contact corrosion theory. I should have known
better since other parts of the bicycle were corroded without contact
with aluminum.

Yes, stainless steel will corrode:
"Metallurgy for Dummies - Corrosion Stainless Steel"
https://metallurgyfordummies.com/corrosion-stainless-steel.html
More examples:
https://www.google.com/search?q=stainless+steel+corrosion&tbm=isch


"I wonder if the metal parts on the car were also corroded?"

Is that a joke? We're in Wisconsin.
https://duckduckgo.com/?q=wisconsin+...es&ia=ima ges

Mostly NaCl but various counties, townships, cities and
towns experiment with everything and anything (soy sauce
tailings from Kikkoman, cheesemaking and pickle brines and
beet juice among the more exotic)


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 6/1/2020 1:17 PM, wrote:
On Monday, June 1, 2020 at 9:30:07 AM UTC-7, AMuzi wrote:
On 6/1/2020 12:40 AM, Jeff Liebermann wrote:
On Sun, 31 May 2020 13:14:54 -0500, AMuzi wrote:

http://www.yellowjersey.org/photosfr...t/failspok.jpg

2004 chinese Trek low end hybrid with low miles. Rider (est
120lb) says she took it out for the first time this year
and during first ride, spokes failed and wheel rubbed the brake.

The front wheel, fork, brake, handlebar are severely
corroded, perhaps from being parked in a garage with the
front closest to a car's daily salt splashes. 8 spokes
missing or broken. Spokes failed in the middle, not the
heads. A dozen or so green nipples are covered in white
efflorescence near the rim (assume these were at the bottom
when parked). The other nipples are dingy nickel.

Spokes do not respond to a magnet. Being 'stainless' or
'inox' doesn't mean a steel will not corrode, it just
succumbs more slowly.

I know you said that the spoke corroded in the middle, but by any
chance were they corroded where the spokes cross over and touch other
spokes? One problem with stainless is that it can be both anodic and
cathodic to itself:
https://yarchive.net/metal/galvanic_corrosion.html
...remember that sometimes the above rules must be
bent a little for other reasons, and that corrosion
can be far more complex than just galvanic corrosion.
Look at the stainless steels for example. Most can
be both cathodic and anodic to themselves! Corrosion
while immersed in sea water can be quite different
than corrosion from exposure to pollutants in the
atmosphere.

In other words, two pieces of stainless steel will develop a
sufficient potential between them to produce galvanic corrosion. In
the galvanic table in the above URL, note that chromium-nickel-iron
appears twice, once as "active" and again as "passive" with quite a
large gap in potential between them. I may have seen this while
working on marine radios, but did not bother to investigate. In your
photo, the upper spoke did not break perpendicular to the axis of the
spoke, but rather broke lengthwise, as I would expect if the spoke
were under tension or torsion. However, the perpendicular breaks on
the other spokes seem to indicate bending, not tension. My guess(tm)
is that the wheel already had some broken spokes before the owner took
the bicycle for a ride.

The white powder(?) kinda looks like aluminum oxide, which is what I
would expect if something made from aluminum were leaned against the
spokes in a electrolytic (salt) atmosphere. Possibly contact with
another bicycle, aluminum rim, frame, rack, floor pump, aluminum bike
stand, aluminum bike rack, etc?

I'm doing quite a bit of guessing based on only one photo. If you
still have the remaining spokes, try match up pairs of several broken
spokes in a photo. I suspect I can extract some more guesswork from
how the spokes broke. I'm especially interested if they broke where
the spokes crossed over each other.




The spokes failed about 1/3 from the rim not at the cross (a
known issue but not applicable here). Yes, the aluminum rim
and the brass nipples appear to have been galvanically engaged.

The shiny spots seem to be from riding with spokes flappng
around and striking each other and the fork.


Isn't that thed area where the butted spokes narrow?



They are straight gauge spokes.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Mon, 01 Jun 2020 16:16:59 -0500, AMuzi wrote:

On 6/1/2020 12:52 PM, Jeff Liebermann wrote:
"I wonder if the metal parts on the car were also corroded?"

Is that a joke? We're in Wisconsin.
https://duckduckgo.com/?q=wisconsin+...es&ia=ima ges

Sorry. I didn't mean to insult Wisconsin by suggesting that it might
be lacking in rust.
https://en.wikipedia.org/wiki/Rust_Belt

Mostly NaCl but various counties, townships, cities and
towns experiment with everything and anything (soy sauce
tailings from Kikkoman, cheesemaking and pickle brines and
beet juice among the more exotic)

Ummm... thanks. To preserve my sanity, please forgive me for not
researching the relative merits of these food waste products. All
seem to be edible, if that's considered a benefit. They probably reek
badly if left on a warm road to rot.

Egads. I thought you were joking:
"Pouring Cheese on Icy Roads in (Where Else?) Wisconsin"
https://www.nytimes.com/2013/12/24/us/wisconsin-finds-another-role-for-cheese-de-icing-roads.html
Added to rock salt, it produces a mixture that
sticks to roads better, freezes at a lower temperature
and saves money.

https://en.wikipedia.org/wiki/Freezing-point_depression
...NaCl becomes ineffective and other salts are used,
such as calcium chloride, magnesium chloride or a
mixture of many. These salts are somewhat aggressive
to metals, especially iron, so in airports safer
media such as sodium formate, potassium formate,
sodium acetate, potassium acetate are used instead.

That's better. I'm into better living through chemistry.
https://en.wikipedia.org/wiki/Better_Living_Through_Chemistry


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558