de-anodised an alloy seatpost?

fatfreddy
fatfreddy Posts: 332
edited February 2008 in Workshop
Ok - long shot.

I have an alloy seatpost which gives loads of layback - perfect - only trouble is that its black and for reasons of pure vanity - I'd like it in silver. Ideally shiny.

I can't find a silver seat post with enough layback, so would it be possible to remove the anodising and polish it? or paint it?

Any tips appreciated.

FF

Comments

  • rdaviesb
    rdaviesb Posts: 566
    I've just done the same with a couple of handlebar stems. Soak in a caustic soda solution for 2-3 minutes, until the anodising dissolves. Rinse well and leave to dry. Watch the soda solution - it's really corrosive stuff, so wear gloves and protective goggles. I don't touch the solution at all - use tongs to put pieces into it.

    The pieces look terrible when they come out of the solution, but fear not. When dry, get polishing. I use a variety of fine abrasives and buffers to end up with a really shiny finish. Time invested now is important - as is patience. I'm considering getting the pieces clearcoated to protect the finish, but will see how we go for a the rest of the year first.
  • fatfreddy
    fatfreddy Posts: 332
    Brilliant - this is really helpfull.

    What strength of solution did you use? Or does it advise on the label?

    I have an old seat post I can experiment on.

    Thanks again.

    FF
  • eteb
    eteb Posts: 32
    rdaviesb, I'd also love to know what strength caustic you used, and also where you get it from.

    A bit off-topic, but I'm trying to find some so I can try a Sheldon Brown solution on a siezed alloy seatpost. Seems it's v hard to track down.
  • rdaviesb
    rdaviesb Posts: 566
    I used a tablespoon of soda granules in three pints of water. It's better to have a weaker than a stronger solution to control the reaction, and the amount of ammonia is emitted. I'm pretty sure I got the caustic soda from a DIY store - it's often labelled as drain cleaner. I've had about a kilo of the stuff hanging around for years.

    For a seized seatpost you mught first like to try the cola trick. Remove bottom bracket, upend the frame and pour cola down the seat tube. Leave overnight - this often works and is less dangerous than working with caustic soda.
  • eteb
    eteb Posts: 32
    brill -- thanks. I'll be buying coke for the first time in many months tomorrow then. :)

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