Galvanic Corrosion?

alex222
alex222 Posts: 598
edited November 2016 in Workshop
I spotted some white bubbling around a bottle cage boss on my bike a couple of weeks ago. In a video posted on another thread last night galvanic corrosion was mentioned. So doing some research it appears this is what I have (hopefully I've managed to upload the photos correctly below).

I can't seem to find much information online though, so I was hoping some other forum members would be able to provide some advice. I was wondering whether this is something I need to get sorted (I assume at a carbon repairers)? Also whether this would be a warranty claim?

I've found some comments saying paint corrosion isn't covered by most warranties, but also elsewhere that modern frames shouldn't suffer from galvanic corrosion.

Bike is 2.5 years old, summer use only and has only ever been stored inside the house.

Photo%2022-11-2016%2C%2009%2047%2039.jpg
Photo%2022-11-2016%2C%2009%2047%2046.jpg
https://www.dropbox.com/s/eoq7ze6m3gm2r ... 9.jpg?dl=0
https://www.dropbox.com/s/cjm5q2obg0yx8 ... 6.jpg?dl=0

Thanks a lot

Comments

  • napoleond
    napoleond Posts: 5,992
    Wouldn't worry too much about it there tbh. Clean it up and ensure that the bolts are greased.
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  • alex222
    alex222 Posts: 598
    NapoleonD wrote:
    Wouldn't worry too much about it there tbh. Clean it up and ensure that the bolts are greased.
    Great thanks, was starting to get worried about it. Will just keep an eye on it.
  • ugo.santalucia
    ugo.santalucia Posts: 28,312
    Nope... galvanic corrosion needs intimate contact, so you would expect it to happen on the threads, rather than in the area around it
    left the forum March 2023
  • pbassred
    pbassred Posts: 208
    Nope... galvanic corrosion needs intimate contact, so you would expect it to happen on the threads, rather than in the area around it
    but carbon is conductive so it could be the path from another (more nobel) metal component via the carbon to the inserts. I don't know but its worth a thought. It also depends what the inserts are made of. Its an interesting science project but not mission critical.
    I wouldn't worry about it. As long as these is some grease on it, it should well outlast the bike.

    Edit:- Fancy a read ? https://www.corrosionpedia.com/2/1556/corrosion/galvanic-corrosion-of-metals-connected-to-carbon-fiber-reinforced-polymers
  • ugo.santalucia
    ugo.santalucia Posts: 28,312
    pbassred wrote:
    Nope... galvanic corrosion needs intimate contact, so you would expect it to happen on the threads, rather than in the area around it
    but carbon is conductive so it could be the path from another (more nobel) metal component via the carbon to the inserts. I don't know but its worth a thought. It also depends what the inserts are made of. Its an interesting science project but not mission critical.
    I wouldn't worry about it. As long as these is some grease on it, it should well outlast the bike.

    Edit:- Fancy a read ? https://www.corrosionpedia.com/2/1556/corrosion/galvanic-corrosion-of-metals-connected-to-carbon-fiber-reinforced-polymers
    Carbon fibre composite is a poor conductor... so poor that the Boeing 787 has to be clad in a copper mesh to act as a decent Farady cage.
    left the forum March 2023
  • Alex99
    Alex99 Posts: 1,407
    ugo.santalucia wrote:
    Nope... galvanic corrosion needs intimate contact, so you would expect it to happen on the threads, rather than in the area around it

    Isn't there an alloy insert for the bottle cage mounts? The galvanic corrosion would be betwen these and the carbon of the downtube. Basically, that's what it looks like in the photo.
  • hambini
    hambini Posts: 113
    Alex99 wrote:
    ugo.santalucia wrote:
    Nope... galvanic corrosion needs intimate contact, so you would expect it to happen on the threads, rather than in the area around it

    Isn't there an alloy insert for the bottle cage mounts? The galvanic corrosion would be betwen these and the carbon of the downtube. Basically, that's what it looks like in the photo.

    I'd agree. Usually the attachments onto the frame are attached using blind rivnuts. Where the nut expands on the inside, it can perforate into the frame material. The carbon can conduct and sets up a battery between the bottle holder and the frame.
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  • napoleond
    napoleond Posts: 5,992
    It definitely can happen there.
    Grease them bolts.
    If it does get worse then try the warranty route. If that fails contact either HQ Fibre or Fibrelyte.
    Insta: ATEnduranceCoaching
    ABCC Cycling Coach
  • sungod
    sungod Posts: 17,340
    galvanic corrosion of al in cf can be serious, the corrosion product takes up more volume which can allow more water to penetrate

    try warranty first, otherwise if things are still mechanically sound try treating the area with acf-50, it'll seep in and block further damage, re-apply every few months, only needs a few drops
    my bike - faster than god's and twice as shiny
  • sheffsimon
    sheffsimon Posts: 1,282
    ugo.santalucia wrote:
    pbassred wrote:
    Nope... galvanic corrosion needs intimate contact, so you would expect it to happen on the threads, rather than in the area around it
    but carbon is conductive so it could be the path from another (more nobel) metal component via the carbon to the inserts. I don't know but its worth a thought. It also depends what the inserts are made of. Its an interesting science project but not mission critical.
    I wouldn't worry about it. As long as these is some grease on it, it should well outlast the bike.

    Edit:- Fancy a read ? https://www.corrosionpedia.com/2/1556/corrosion/galvanic-corrosion-of-metals-connected-to-carbon-fiber-reinforced-polymers
    Carbon fibre composite is a poor conductor... so poor that the Boeing 787 has to be clad in a copper mesh to act as a decent Farady cage.

    As a chartered Electrical Engineer I'm unable to let that pass....it's Faraday :)
  • ugo.santalucia
    ugo.santalucia Posts: 28,312
    SheffSimon wrote:
    ugo.santalucia wrote:
    pbassred wrote:
    Nope... galvanic corrosion needs intimate contact, so you would expect it to happen on the threads, rather than in the area around it
    but carbon is conductive so it could be the path from another (more nobel) metal component via the carbon to the inserts. I don't know but its worth a thought. It also depends what the inserts are made of. Its an interesting science project but not mission critical.
    I wouldn't worry about it. As long as these is some grease on it, it should well outlast the bike.

    Edit:- Fancy a read ? https://www.corrosionpedia.com/2/1556/corrosion/galvanic-corrosion-of-metals-connected-to-carbon-fiber-reinforced-polymers
    Carbon fibre composite is a poor conductor... so poor that the Boeing 787 has to be clad in a copper mesh to act as a decent Farady cage.

    As a chartered Electrical Engineer I'm unable to let that pass....it's Faraday :)

    I agree... I think the a must have got caught ina short somewhere... :lol:
    left the forum March 2023

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