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  1. #1
    Senior Member matimeo's Avatar
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    Ammonia and a stuck seatpost- questions

    I have an aluminum seat post stuck in a chromoly frame and I am attempting to use the least invasive methods first for removing the post (I already hammered the seat crooked trying to break it free). I know that ammonia is supposed to loosen it right up, problem is I don't see any way how that ammonia is going to get down between seat post and seat tube to do the job. Is there a good way to apply ammonia in this particular case? I have used a spray bottle to get ammonia all over anything that might help but still no budging. I've done it several times and let it sit for some time and still no results. Can anybody enlighten me on HOW to use ammonia to get a seatpost off?

    note: I realize there have been lots of threads on this subject, but none seem to adress how to apply the ammonia

  2. #2
    biked well well biked's Avatar
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    Remove cranks and bottom bracket, put ammonia into the seat tube from the bottom side. I've never had to do it, I feel very lucky. I've always had success using your first approach, hammering the nose of the saddle. I actually have an old battered saddle I use for just such occasions-

    edit: You'd need to make sure the top of the seatpost is plugged or stopped up some way to make this affective, of course, so the ammonia doesn't run out-
    Last edited by well biked; 11-30-06 at 06:51 PM.

  3. #3
    crusty jbrians's Avatar
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    take the seat off the post.
    take the wheels off the frame
    carry what's left over to your well secured bench vice and clamp the head of the post in the vice
    using the frame as your lever rotate the frame around the post and when it breaks loose you can work it out.

    The reality is that ammonia can clean out oxide but only if there is space for the ammonia to get to where it's needed.
    I tried all of the suggested methods to remove one from a Kona frame I salvaged but only the brute force method worked.
    Around and around we go!

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    Use duct tape to build a dam around the top of the seat tube.

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    I just had the same issue...
    I ended up using Breakfree~CLP
    That was after the forementioned didn't work. Although just pour it around the post...

  6. #6
    Senior Member matimeo's Avatar
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    Has anybody ever actually removed the bottom bracket and poured ammonia into the seat tube?

  7. #7
    Senior Member matimeo's Avatar
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    Quote Originally Posted by day1si
    I just had the same issue...
    I ended up using Breakfree~CLP
    That was after the forementioned didn't work. Although just pour it around the post...
    I assume this was with an aluminum post stuck in a steel bike?

  8. #8
    Senior Member peripatetic's Avatar
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    Yes, the brute force method works--sometimes. When it doesn't, it doesn't, and no matter how many people tell you to do it, it still won't.

    The areas that are stuck together really need to soak, for several days, in the ammonia. I've not had the time to do it with my two frames, but I've tried everything else (do a search in the C & V forum under my name, you'll find six or seven pages of detailed and helpful suggestions.)

    So removal of the BB is certainly necessary, and then plugging one end. You might want to try using a foam stopper for lab equipment, or some other plug covered with some kind of silicon/plastic coating (make sure it won't get eaten by the ammonia). Then fill up the tube, so that the ammonia can slowly work its way down in between the seatpost and seattube.

    Should this not work, a consultation of my aforementioned thread will show you the next alternative, which, thankfully, will require you to keep the plug in place. Then you use lye to eat away at the aluminum. My understanding is that this process also take several days. Should you wish to take this route, make sure you read up on the hazards of lye (NaOH), b/c it's very noxious to human flesh, organs, etc. Good luck, and report back with any success--I'm anxious to hear a positive story.

  9. #9
    Senior Member TimJ's Avatar
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    Quote Originally Posted by peripatetic
    Yes, the brute force method works--sometimes. When it doesn't, it doesn't, and no matter how many people tell you to do it, it still won't.

    The areas that are stuck together really need to soak, for several days, in the ammonia. I've not had the time to do it with my two frames, but I've tried everything else (do a search in the C & V forum under my name, you'll find six or seven pages of detailed and helpful suggestions.)

    So removal of the BB is certainly necessary, and then plugging one end. You might want to try using a foam stopper for lab equipment, or some other plug covered with some kind of silicon/plastic coating (make sure it won't get eaten by the ammonia). Then fill up the tube, so that the ammonia can slowly work its way down in between the seatpost and seattube.

    Should this not work, a consultation of my aforementioned thread will show you the next alternative, which, thankfully, will require you to keep the plug in place. Then you use lye to eat away at the aluminum. My understanding is that this process also take several days. Should you wish to take this route, make sure you read up on the hazards of lye (NaOH), b/c it's very noxious to human flesh, organs, etc. Good luck, and report back with any success--I'm anxious to hear a positive story.
    So you haven't done the lye yet?

    And re: the original and follow-up questions, I had a stuck stem (a little easier to deal with) and let it soak in ammonia for days and it didn't do anything. I also tried freezing the aluminum to get it to strink a bit. Freeze and unfreeze the whole fork thinking the seal might break with swelling, and also brute force which didn't work (I had enough leverage to completely ruin the stem's thick clamp and it never budged). I ended up having to melt it away with lye.

    Couple things- don't use wd-40. I had a pretty-darn-stuck stem that would budge just a little with all my strength, so I did a test. I put some wd-40 in there to see what would happen and it made it worse. I put ammonia in there and it loosened right up.

    Try the ammonia for a couple days then try getting some leverage on it and see if it will twist. If it won't then I would bet it simply will not come out without melting it out with lye. I don't know what it does chemically speaking, but in my case the stem and fork where seriously, chemically bonded together. Even when it was done melting out with the lye there was a sliver of aluminum still stuck in the steerer tube and it was stuck fast like it was lightly glued on. Good luck and hopefully you won't have to lye it.
    fun facts: Psychopaths have trouble understanding abstract concepts.
    "Incompetent individuals, compared with their more competent peers, will dramatically overestimate their ability and performance relative to objective criteria."

  10. #10
    Senior Member KLW2's Avatar
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    After you use ammonia or lye, be sure to rinse throughly with water (then vinegar if you use lye, to neutralize the lye) both are corrosive, especially lye which can dissolve aluminum and steel before your eyes.

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    Ive never encountered this problem but why cant you put a propane or mapp gas torch on the post get it nice and hot then put a pipe wrench on the post and break it free. Spin it till it spins freely. Then it should slide right out

  12. #12
    Senior Member matimeo's Avatar
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    Quote Originally Posted by TheMow
    Ive never encountered this problem but why cant you put a propane or mapp gas torch on the post get it nice and hot then put a pipe wrench on the post and break it free. Spin it till it spins freely. Then it should slide right out
    Aluminum expands faster than steel- it would just make it more stuck.

  13. #13
    Senior Member TimJ's Avatar
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    Quote Originally Posted by KLW2
    After you use ammonia or lye, be sure to rinse throughly with water (then vinegar if you use lye, to neutralize the lye) both are corrosive, especially lye which can dissolve aluminum and steel before your eyes.
    Lye doesn't do anything to steel. It will remove paint but it doesn't touch steel, or plastic.
    fun facts: Psychopaths have trouble understanding abstract concepts.
    "Incompetent individuals, compared with their more competent peers, will dramatically overestimate their ability and performance relative to objective criteria."

  14. #14
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    Do the Ammonia thing first by pouring down the frame when you remove the bottom bracket, and let it soak for several days; but do this outside in a garage so you don't kill everyone in your home with the odor.

    In the future apply grease liberally (but do not apply grease to carbon fiber), this will not only prevent the corrosion but it will also prevent water from dripping down the seatpost and into the frame. I apply a thick dab of grease to the inside of the frame and spread it around the tube, and then apply some to the seatpost before insertion. Then just wipe off the excess that oozed out.

  15. #15
    Senior Member peripatetic's Avatar
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    Quote Originally Posted by TimJ
    So you haven't done the lye yet?
    Nope. Had to move apts. Have no workplace for nasty chemicalsor rusty old frames. Still plan to do so, however.

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