Wednesday, April 2, 2014

How much do you want it... the stuck seatpost edition

The remains of an aluminum seatpost.
This post is over a month tardy but I had to get around to it... I think I'm only now emotionally ready to discuss it because the process of removing the horribly corroded aluminum seatpost from my steel 1993 Bridgestone XO-3 was way more complicated than it should have been.  I realized the post was stuck the day I bought it but figured that some elbow grease and maybe some lubrication would do the trick.  As it turned out I ended up bending the rails on the saddle and not budging the post after much grunting and swearing.  Next up was the fairly obnoxious use ammonia to try and dissolve the aluminum - steel corrosion. Of course to get it in there I had to remove the crank and bottom bracket, hang the bike upside down and fill the seat tube with ammonia.  I did that for 9 days!  The seatpost didn't even blink.  Next in the problem solving process I took the drastic step of hacksawing the seat post at 1" above the frame and attempted (hardheartedly) to use a hacksaw blade to saw through the now hollow tube enough to break it loose.  This may have worked if I'd given it much more time and effort. But even then I'm not sure as my eventual success would prove the corrosion was incredibly complete.

I threw in the towel on hard labor with the promise of good living through chemistry...

(not my video obviously)  The picture up at the top of the post shows the results, a couple notes about the process. I ended up using 4 lbs of lye (sodium hydroxide) purchased first through Amazon and then at the local hardware store when I blew through the first 2 lbs in no time.  The reaction, at least for me was way less catastrophic than I had anticipated. I ended up spending over 4 hours with the chemicals, it was a huge mess, I ended up with  minor skin irritation on my face (probably wiping my cheek w/ my gloved hands).  The frame was a mess, I thought I had ruined it to be honest but I just got fed up w/ the process and was sloppy towards the end.  The frame finish was already really rough so once I wiped it all down the next day it was really no worse the wear.  The truly disappointing part to me was that even with the application of so much time and chemicals I still had to use a hammer and screwdriver-chisel to remove the ribbons of seatpost painstakingly.  I was so rough with the frame I thought for sure I'd deformed the seat tube for good.

As it turns out the Bridgestone took that walloping, took the chemical burns and spat it out like nothing. The bike now has a completely adjustable seatpost as was intended and I'm glad the project is over with!  I'd be happy to answer any questions, the use of the lye is a tool in the tool box but I'll be attempting to never do it again.

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