Aluminium Bolts + corrosion

JS200
JS200 Posts: 29
edited July 2013 in Workshop
Hello,

Wonder if someone can give advice. I've misplaced the aluminium bolts from my frame. I put steel bolts in my old hybrid aluminium frame, and they have corroded the frame itself. I don't want to have the same problem with my new aluminium framed bike so I'm looking at getting new aluminium bolts (not load bearing).

Questions:

1) Will any 'alloy' bolt do, or is there any risk of corrosion between aluminium and alloys?

2) What specific grease should I use in these (and any other) bolts in an aluminium frame. I have lithium grease, is this ok?

Thanks in advance!

Comments

  • keef66
    keef66 Posts: 13,123
    I'd have thought any aluminium alloy bolt would be an improvement on steel re galvanic corrosion. I'd say any grease would be OK, and periodically remove, regrease and reinstall them to make sure nothing nasty is happening.

    I'd stay well clear of anything alu alloy with a small hex socket though; far too easily rounded.
  • JS200
    JS200 Posts: 29
    Cheers for the reply...
    keef66 wrote:
    I'd stay well clear of anything alu alloy with a small hex socket though; far too easily rounded.

    Yeah, although only using these to 'plug up' the frame and wont be attaching any weight or tightening them too much. My main concern is to make sure, long-term, the frame doesn't corrode like it has on my old bike, which really surprised me when I recently saw how badly it had corroded with the steel bolts. To be fair it is quite old, but I'm now unable to sell it.

    The old bolts (on my new bike) were aluminium, judging by how soft they were. So just greasing the bolts should be enough to stop that galvanic process, and using an alloy bolt should significantly reduce the undesirable reaction between the bolt and the frame?
  • JS200
    JS200 Posts: 29
    In fact.... could I just plug up the hole with a nylon/plastic screw/plug, just to stop water getting in the frame. I'd use steel if I was going to attach a rack for touring anyway, and that would only be for a short amount of time.

    ... hmmmmm
  • freezing77
    freezing77 Posts: 731
    JS200 wrote:
    In fact.... could I just plug up the hole with a nylon/plastic screw/plug, just to stop water getting in the frame. I'd use steel if I was going to attach a rack for touring anyway, and that would only be for a short amount of time.

    ... hmmmmm

    Best of all worlds get some nylon screws.

    http://www.specialist-fasteners.co.uk/fasteners-small-components/plastic/screws-nylon-other-materials/hexagonal-head-screws-nylon/

    fasteners_165.jpg
  • JS200
    JS200 Posts: 29
    Perfect. That's brilliant thanks. Problem solved. I could probably even get some to match the colour of the bike.

    Cheers :)
  • Yossie
    Yossie Posts: 2,600
    Just use some copperslip like you should be using on every non rotating bolt on the bike. Moly for stuff that moves.

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