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I am that out of date



 
 
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  #181  
Old April 29th 21, 09:36 PM posted to rec.bicycles.tech
AMuzi
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Default I am that out of date

On 4/29/2021 12:53 PM, wrote:
On Wednesday, April 28, 2021 at 8:01:42 PM UTC-4, wrote:

The meterial is:
Zinc Yellow-Chromate Plated Steel
which is not compatible with carbon fiber. If you ever switch to
carbon fiber cranks, you'll have problems. I suggest you stick with
stainless steel washers.


What is it about zinc plated steel that makes it incompatible with CF?

Possible galvanic corrosion.

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


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  #182  
Old April 29th 21, 10:55 PM posted to rec.bicycles.tech
[email protected]
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Posts: 163
Default I am that out of date

On Thursday, April 29, 2021 at 4:32:12 PM UTC-4, wrote:
On Thu, 29 Apr 2021 10:53:34 -0700 (PDT), "
wrote:

On Wednesday, April 28, 2021 at 8:01:42 PM UTC-4, wrote:

The meterial is:
Zinc Yellow-Chromate Plated Steel
which is not compatible with carbon fiber. If you ever switch to
carbon fiber cranks, you'll have problems. I suggest you stick with
stainless steel washers.


What is it about zinc plated steel that makes it incompatible with CF?

Radically different galvanic potential voltage in the presence of an
electrolyte.
https://l-36.com/corrosion.php
Note that zinc is very anodic (-1.0V) while carbon is very cathodic
(+0.2V). Remember the carbon-zinc 1.5v flashlight batteries?[1]

If you look at the chart, the materials that are close together in the
galvanic series are fairly immune to corrosion while the materials
that are far apart are a problem. For example, carbon, titanium, and
stainless steel are fairly close together and therefore safe. However,
aluminum, copper, brass, cadmium and zinc are at the opposite end from
carbon and therefore need to be insulated from the carbon. Painting
the CF with an insulator can work but only until a tiny crack ruins
your day.

This is aluminum and CF (nobody makes zinc galvanized bicycle frames)
which should give you a clue what can happen:
https://www.bikeforums.net/road-cycling/992139-colnago-c40-carbon-fiber-corrosion-aluminum-guides-salt.html

Dr Barry L. Ornitz on galvanic corrosion:
https://yarchive.net/electr/galvanic_corrosion.html

"How to prevent galvanic corrosion in carbon composites"
https://www.youtube.com/watch?v=DPbToNbtubg (5:04)


I never studied metallurgy but recalling my physics classes it all makes sense. But gawd that video was painful. This one is much better https://www.youtube.com/watch?v=yRpMZaU8zKw


[1] Yes, you can make a carbon fiber battery:
https://newatlas.com/energy/carbon-fiber-structural-battery/
--
Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

  #183  
Old April 29th 21, 11:38 PM posted to rec.bicycles.tech
Tom Kunich[_4_]
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Posts: 2,196
Default I am that out of date

On Thursday, April 29, 2021 at 1:37:11 PM UTC-7, AMuzi wrote:
On 4/29/2021 12:53 PM, wrote:
On Wednesday, April 28, 2021 at 8:01:42 PM UTC-4, wrote:

The meterial is:
Zinc Yellow-Chromate Plated Steel
which is not compatible with carbon fiber. If you ever switch to
carbon fiber cranks, you'll have problems. I suggest you stick with
stainless steel washers.


What is it about zinc plated steel that makes it incompatible with CF?

Possible galvanic corrosion.


The corrosion that was on the C40 was probably someone running out of the proper pop-rivet and using a couple steel ones The top cable ends on a bike of that vintage were chromed bronze and the cables themselves high grade stainless.
  #184  
Old April 30th 21, 12:40 AM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default I am that out of date

On 4/29/2021 10:51 AM, wrote:
On Wednesday, April 28, 2021 at 6:38:21 PM UTC-4, Frank Krygowski wrote:
On 4/28/2021 4:22 PM, jbeattie wrote:


I've gotten pedal washers free from LBSs and bought a bunch off Amazon. I can't find any hardware store equivalents. If there is a cheap equivalent/common part, let me know.

These might do:
https://www.mcmaster.com/standard-wa...teel/od~0-734/

and be cheap enough. Not as cheap as some on Ebay, though.

I don't know about shipping. I'm lucky in that McMaster-Carr's warehouse
is within a couple miles of a route I drive weekly. I've ordered stuff
and picked it up myself.


--
- Frank Krygowski


McMsters shipping is top-notch. Usually next day and usually free. We regularly order from mcmaster at work, and I've used them almost exclusively for hardware for well over 20 years. Never had an issue with shipping, though once or twice I've had a quality issue with the product and the fact that they usually don't list the manufacturer of the product is annoying.


Miss those big yellow McMaster-Carr catalogs!

We have a great fastener store in Sunnyvale, Olander, that does
will-call. A few years back they instituted a $5 minimum per SKU because
they were getting tired of selling 25ΒΆ items to end-users.
https://www.olander.com/.

But if you're in no rush, you have a much wider variety of metric
fasteners on Aliexpress.

 




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