# Galvanic corrosion prevention on a bike frame



## Midle Age Warrior (Nov 13, 2006)

Hy guys
I had a chat last night with a friend who works with boats and outboards engines while we where taking care of a friend bike with some corrosion around the water bottle bolts, he also commented something about the increment of galvanic corrosion due to static produced by the moving parts at the end we where debating about the benefits of using some kind of sacrifice anode on the alloy bikes.
Any one have a thought about it, any comments??


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## flynfrog (Feb 4, 2011)

read up on MIL and FAA specs for prevention. I usually involves wet installing fasteners with a galvanic primer. I don't think an anode will do you any good.


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## flynfrog (Feb 4, 2011)

also it has nothing to do with static. Its basically tuning your frame into a battery Galvanic corrosion - Wikipedia, the free encyclopedia


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## Midle Age Warrior (Nov 13, 2006)

flynfrog said:


> also it has nothing to do with static. Its basically tuning your frame into a battery Galvanic corrosion - Wikipedia, the free encyclopedia


Galvanic corrosion
From Wikipedia

"...Dissimilar metals and alloys have different electrode potentials and when two or more come into contact in an electrolyte a galvanic couple is set up...", "...The electrolyte provides a means for ion migration whereby metallic ions can move from the anode to the cathode. This leads to the anodic metal corroding more quickly than it otherwise would; the corrosion of the cathodic metal is retarded even to the point of stopping..."

As we see in the description we need two different metals and a solution that provides an ion path, that is why I thought the corrosion we can find in a water bottle cage bolts can in some manner be reduced by the use of a pice of a less electrode potential than the alloy used in the frame.
I am so far to be an expert or even a average knowledge person in this particular object I am curious if an sacrificial anode placed on the frame could help


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## Danke (Sep 19, 2005)

You would have to get that anode in the circuit. 

You get Galvanic corrosion in spots like a seatpost and frame where moisture is trapped, or water bottle bolts, headset races etc.

Having an anode on the tube won't cut it. You can do that on a boat since the whole hull is in the electrolyte solution. 

On a frame the prep or anti seize compounds are the simple solution. If you want to get fancy you can reference the table when choosing materials and re-plate them etc. but that seems excessive.


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## Bill in Houston (Nov 26, 2011)

It would be easy to put a galvanized washer on the bottle mounting bolt. The zinc on it ought to protect it well. Try it and see if it works? It would cost about 30 cents to try.


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## Midle Age Warrior (Nov 13, 2006)

Danke said:


> Having an anode on the tube won't cut it. You can do that on a boat since the whole hull is in the electrolyte solution.


That is the point, will not work in a frame due to the lack of electrolyte around it.
Thanks for the input, I just was guessing.


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## Midle Age Warrior (Nov 13, 2006)

Bill in Houston said:


> It would be easy to put a galvanized washer on the bottle mounting bolt. The zinc on it ought to protect it well. Try it and see if it works? It would cost about 30 cents to try.


It is a cool idea, i will give it a try, let see what happen in an long term.


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## Bill in Houston (Nov 26, 2011)

if you had galvanic corrosion already, then the anode will work. you are just transferring the corrosion to the zinc on the galvanized washer rather than your bike parts. if what you had was not galvanic corrosion, then you still get to enjoy the geek factor of trying it out.


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## sonic reducer (Apr 12, 2010)

what are the reasons one would consider galvanic corrosion to be an issue on a bike frame?


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## esilvassy (Jul 25, 2006)

sonic reducer said:


> what are the reasons one would consider galvanic corrosion to be an issue on a bike frame?


Aluminum seat posts in Steel frames is a common seizing issue. One of the modes for the post getting seized is galvanic corrosion due to the dis-similar metals and lack of lube or anti seize.


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## Francis Buxton (Apr 2, 2004)

How about just putting some lube on the seatpost and/or cage bolts? This puts a layer between the tow having direct contact, and it also allows you to tighten your bolts better due to the reduced friction at the threads, meaning your cages won't come loose as quickly and create your static friction. Seems simple enough to me. I've never had a problem with galvanic corrosion on a bike. It's not like it's a water main.


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## Iridethedirt (Jan 20, 2008)

yep. grease and anti-sieze are the accepted methods depending on the specific application. Ti bolts should always get anti-sieze. most any metal/metal contact on a bike fame anywhere should have grease or anti-sieze with very few specific exceptions.


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## Yogii (Jun 5, 2008)

Use nylon bolts for the water bottle cage.


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## Bill in Houston (Nov 26, 2011)

Iridethedirt said:


> most any metal/metal contact on a bike fame anywhere should have grease or anti-sieze with very few specific exceptions.


Yup. I always heard that every bolt/screw should either have antiseize, or loctite. You either want it to come undone someday, or not. With blue loctite, you get sort of an inbetween setting.


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