Advertise on Bikeforums.net



User Tag List

Results 1 to 21 of 21
  1. #1
    Senior Member
    Join Date
    Feb 2012
    My Bikes
    1983 Trek 613 (new drivetrain), 1982 Trek 613 (fixie), 2011 Cannondale Synapse Carbon 5, 1997 Trek 930 MTB (singlespeed), Surly LHT
    Posts
    86
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    last resort for stuck seatpost, dissolve with lye or cut?

    I'm trying to salvage a Trek 613 frame, with one heck of a stuck aluminum (fluted) seatpost.

    I've tried bench vise (well the best I can given that the vise wants to rotate under very high torque no matter how hard i tighten the vise).

    I've tried ammonia for 30 hours.

    I've tried PB Blaster.

    I've heated it up the post with propane twice, my most recent effort I then stuck the hot post in the snow (its -16 Fahrenheit today) and then I immediately tried bench vise.

    Seems my next options are either cutting it out with a hacksaw blade (maybe finagled to a broom stick dowel) or to dissolve it out with lye. Which option would you chose?

  2. #2
    Senior Member Chris W.'s Avatar
    Join Date
    Jul 2008
    Location
    Nampa Idaho
    My Bikes
    76' Centrurion Pro-Tour, 81' Woodrup Giro-Touring, , 85' Trek 520, 86' Specialized Rock Hopper, 95' Rock Hopper Ultra.
    Posts
    917
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I had the same problem on a Trek 520. After exhausting all a Sheldon Browns tricks, I used lye. The lge worked, but the heat from the reaction ruined the paint. Use extreme caution when using lye, it can blind, and burn!!!

    Cheers,
    Chris

  3. #3
    Senior Member SJX426's Avatar
    Join Date
    May 2008
    Location
    Alexandria, Va
    My Bikes
    1972 Motobecane Le Champion (totaled), 1983 Colnago Superissimo, 1984 Trek 610, 1997 RockHopper, 1994 Burley Duet, 80's Pinarello Tre Cime, 88 Masi Gran Corsa (Frame), 1991 Pinarello Montello
    Posts
    2,712
    Mentioned
    9 Post(s)
    Tagged
    1 Thread(s)
    I had 6 inches of stuck (don't go there!). Used Kroil available only on the internet. hit it from both ends and let it sit for a couple of days. Broke free with a little heat on the post only. Took some effort.

  4. #4
    Senior Member bbbean's Avatar
    Join Date
    Jul 2013
    Location
    Missouri
    My Bikes
    Giant Defy Composite 0, Cannondale SuperX, Univega Alpina Ultima
    Posts
    572
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I had an old fluted seatpost stuck so tight the bike shop said it was permanent. Took the bike into the farm shop and a bigger vise and we got it, but it took some serious beating, extender handles, and 2 stromg guys working on it. As luck would have it it was a 1980s steel framed MTB. Wouldn't want to try that on an aluminum or CF frame bike.

    BB
    www.beancotton.com
    Formerly Fastest of the Slow Riders, Currently Slowest of the Fast Riders



    http://veloviewer.com/athlete/2615827/

  5. #5
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    40,102
    Mentioned
    28 Post(s)
    Tagged
    0 Thread(s)
    Know someone with a drill press? you can cut it off then bore out most of the post with a 1" drill.


    one of my friends broke the brazing of the seatstays twisting the frame,

    so then damage done got the torch out, frame red hot it came out,
    then he rebrazed the seatstay tips.
    Last edited by fietsbob; 12-30-13 at 12:13 PM.

  6. #6
    Can'tre Member 3alarmer's Avatar
    Join Date
    Nov 2010
    Location
    ,location, location...
    My Bikes
    old ones
    Posts
    6,971
    Mentioned
    105 Post(s)
    Tagged
    3 Thread(s)
    I know you've already tried heat, snow, and PB Blaster, but while you still
    have something to grab in a vise and twist on, get some CRC Freeze Off at
    an auto parts store, heat the post one more time, with a heat *** or torch
    (being mindful of the painted seat tube), and then hit the post at the insertion
    point and up and down the tube slot with the Freeze Off.

    You need a vise that will not slip, so before doing this, find one that will not move at all.


    Otherwise, if this fails if the post is not in too deep the hacksaw method works.
    (You attach a small washer to the free end so that it can ride along on the seat tube
    past the post bottom and not cut into the frame tubing.)

    If you can find a frame guy and talk nicely to him, you might find someone willing
    to ream it out for you. I've never tried that one, myself.

    The hacksaw thing is a method for the patient and methodical, and is quite laborious.
    Quote Originally Posted by The Australian Book of Atheism
    There is only no god, and Cyclaholic is his prophet.

  7. #7
    Senior Member
    Join Date
    Sep 2004
    Location
    boston, ma
    Posts
    2,806
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by 3alarmer View Post
    I know you've already tried heat, snow, and PB Blaster, but while you still
    have something to grab in a vise and twist on, get some CRC Freeze Off at
    an auto parts store, heat the post one more time, with a heat *** or torch
    (being mindful of the painted seat tube), and then hit the post at the insertion
    point and up and down the tube slot with the Freeze Off.

    You need a vise that will not slip, so before doing this, find one that will not move at all.


    Otherwise, if this fails if the post is not in too deep the hacksaw method works.
    (You attach a small washer to the free end so that it can ride along on the seat tube
    past the post bottom and not cut into the frame tubing.)

    If you can find a frame guy and talk nicely to him, you might find someone willing
    to ream it out for you. I've never tried that one, myself.

    The hacksaw thing is a method for the patient and methodical, and is quite laborious.
    i have used freeze off on a thin thomson masterpiece and got it out. ripped the top of the post twice but did not need to cut it out. frame was a semi custom steel. freeze off is good stuff. the hacksaw always works though

  8. #8
    Senior Member Kopsis's Avatar
    Join Date
    Apr 2008
    Posts
    455
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    They lye approach is effective but can take a considerable amount of time to do it safely. When I went that route on an old SR seatpost (installed deep enough that the flutes funneled water into the top of the seat tube), a week of lye solution still only dissolved about half the wall thickness. But it was enough that going at it with a hacksaw blade after that was a much more manageable operation.

    If you go the lye route, I recommend mixing the lye solution in a 1 qt Pyrex measuring cup immersed in a water bath for cooling. Dissolving pure NaOH in water releases a lot of heat, even before it comes in contact with Al. Wait until the solution is completely cool before adding it to the frame. Start with a relatively low concentration solution so you can get a feel for how much heat it's going to generate in the frame. As you replace with fresh solution (a couple times a day) you can gradually up the concentration until you hit a point where the seat tube is about 150 deg F. Higher concentrations will work faster, but you risk paint damage from the heat.

    Be very careful working with the solution -- gloves, goggles, lab apron, etc. NaOH burns are no joke. Also make sure you have good ventilation and that if the seatpost lets go or the lye dissolves through it, you have something safe to catch the mess that drains out.

  9. #9
    Lover of Old Chrome Moly Myosmith's Avatar
    Join Date
    May 2011
    Location
    NW Minnesota
    Posts
    2,544
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    I removed an aluminum seat post that was seriously stuck in a Giant Yukon steel frame by using a long dull demolition saw blade. I cut the post off just 3-4 cm above the seat tube and inserted the blade which was sharp enough to cut the aluminum but dull enough to be very slow to cut steel. I made one cut completely through the side of the post and then three more nearly through. I used a large water pump pliers (aka Channel Lock Pliers) to crush the post in on itself and twisted. It still took some work but after the first two sections of post were free the whole thing finally popped out. The only damage to the frame was some minor scratching inside the seat tube. The whole process took about 30 minutes as I cut through the stuck post very carefully stopping frequently to inspect with a flashlight to make sure I was only cutting aluminum.
    Lead, follow or get out of the way

  10. #10
    Senior Member
    Join Date
    Sep 2007
    Posts
    354
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    i agree try the freeze off: broke free a super stuck seatpost outta my friends bob jackson using freeze on the seatpost and boiling water on the seattube several times + spraying liquid wrench / tapping with mallet. took two guys turning the frame to get it to break free and twist it out of the frame

  11. #11
    Senior Member surreal's Avatar
    Join Date
    Mar 2002
    Location
    NJ
    Posts
    2,892
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    As a guy who makes soap, I have a lot of experience with lye and lye solutions, and I'd never put the stuff anywhere near a frame I cared about. I'd definitely try Kroil, freeze-off, and using a stronger vice before I resorted to something that caustic. This is juts my opinion, coming from a guy who has lye experience, but has never used lye on a seatpost at all...

  12. #12
    Banned
    Join Date
    Dec 2013
    Location
    none
    My Bikes
    '78 Raleigh rebuilt to 21C...Redline Monocog cyclocross in steel redone to 8 spped trekker
    Posts
    101
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    AND THE WINNER IS

    MYOSMITH !

    add a broad flame oxygen/map gas torch followed with seting the tube into a dry ice trench ...dry ice/Al foil/DIY cardboard box.

    I have serious reservations on what this does to tubing strength.

    what happened in there is an addition of water and oxygen molecules to the surfaces/lubricants in space not large enough for those molecules. The molecules packed in and packed in until their packing in strength forced the tubing apart from the as newly back then inserted position.

    The molecules continued packing in...until t he Universe began expanding....almost right ?

    Worser, these dang molecules packed so tightly they formed an almost metallic strength INSOLUBLE compound you now attempt to mine.

    if not insoluble then how would it form in the first instance ?

  13. #13
    Senior Member clasher's Avatar
    Join Date
    May 2009
    Location
    Kitchener, ONT
    Posts
    1,503
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I've done the lye thing before (outside, with full rubber suit and faceshield) and wouldn't really recommend it unless you've worked with chemicals before. It boggles my mind that I can walk into any store and buy lye and other crazy strong chemicals without any questions asked. I did mine outside in the winter to alleviate the heat issues a bit. I'd plug any holes from the bottom bracket and stick a funnel at the top of seat tube sealed up nicely with some caulking to try and keep the foaming lye off the frame.

  14. #14
    Senior Member Thumpic's Avatar
    Join Date
    Dec 2007
    Location
    The Sunny South
    Posts
    1,534
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I took a frame with a stuck post to a diesel truck shop on a Friday afternoon.....I'd never been there before, but this is the old civil south.....

    "A friend of mine said you guys could probably get this out, but I don't know....." 20 minutes later, after applying something vile from a spray can and employing a vise as big as an outboard motor; the stuck post was out....

    You need more vise in your life......
    Thumpic....

    Green is the new "CHEAP"

  15. #15
    Senior Member
    Join Date
    Nov 2003
    Location
    Minneapolis, MN
    My Bikes
    2x Bianchi, 2x Specialized, 3x Schwinns
    Posts
    303
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ppg677 View Post
    I'm trying to salvage a Trek 613 frame, with one heck of a stuck aluminum (fluted) seatpost.

    I've tried bench vise (well the best I can given that the vise wants to rotate under very high torque no matter how hard i tighten the vise).

    I've tried ammonia for 30 hours.

    I've tried PB Blaster.

    I've heated it up the post with propane twice, my most recent effort I then stuck the hot post in the snow (its -16 Fahrenheit today) and then I immediately tried bench vise.

    Seems my next options are either cutting it out with a hacksaw blade (maybe finagled to a broom stick dowel) or to dissolve it out with lye. Which option would you chose?
    Here is my seatpost adventure from last fall. Cut it out sucessfully.

    http://www.bikeforums.net/showthread...=#post16018389
    Last edited by loky1179; 01-01-14 at 11:10 AM.

  16. #16
    Senior Member
    Join Date
    May 2010
    Location
    Madison, WI
    Posts
    1,094
    Mentioned
    1 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by Kopsis View Post
    They lye approach is effective but can take a considerable amount of time to do it safely. When I went that route on an old SR seatpost (installed deep enough that the flutes funneled water into the top of the seat tube), a week of lye solution still only dissolved about half the wall thickness. But it was enough that going at it with a hacksaw blade after that was a much more manageable operation.

    If you go the lye route, I recommend mixing the lye solution in a 1 qt Pyrex measuring cup immersed in a water bath for cooling. Dissolving pure NaOH in water releases a lot of heat, even before it comes in contact with Al. Wait until the solution is completely cool before adding it to the frame. Start with a relatively low concentration solution so you can get a feel for how much heat it's going to generate in the frame. As you replace with fresh solution (a couple times a day) you can gradually up the concentration until you hit a point where the seat tube is about 150 deg F. Higher concentrations will work faster, but you risk paint damage from the heat.

    Be very careful working with the solution -- gloves, goggles, lab apron, etc. NaOH burns are no joke. Also make sure you have good ventilation and that if the seatpost lets go or the lye dissolves through it, you have something safe to catch the mess that drains out.
    Just don't keep lye in the measuring cup - it dissolves glass, given enough time. Pyrex-branded kitchenware is also not generally made of pyrex glass anymore (1998 on), and can shatter from thermal shock.

    The stuff bubbling out of reacting lye is hydrogen, and very very flammable. Do this someplace well ventilated and away from flame/spark/etc.
    Last edited by Nerull; 01-01-14 at 08:24 AM.

  17. #17
    Senior Member
    Join Date
    Feb 2012
    My Bikes
    1983 Trek 613 (new drivetrain), 1982 Trek 613 (fixie), 2011 Cannondale Synapse Carbon 5, 1997 Trek 930 MTB (singlespeed), Surly LHT
    Posts
    86
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by 3alarmer View Post
    I know you've already tried heat, snow, and PB Blaster, but while you still
    have something to grab in a vise and twist on, get some CRC Freeze Off at
    an auto parts store, heat the post one more time, with a heat *** or torch
    (being mindful of the painted seat tube), and then hit the post at the insertion
    point and up and down the tube slot with the Freeze Off.

    You need a vise that will not slip, so before doing this, find one that will not move at all.


    Otherwise, if this fails if the post is not in too deep the hacksaw method works.
    (You attach a small washer to the free end so that it can ride along on the seat tube
    past the post bottom and not cut into the frame tubing.)

    If you can find a frame guy and talk nicely to him, you might find someone willing
    to ream it out for you. I've never tried that one, myself.

    The hacksaw thing is a method for the patient and methodical, and is quite laborious.
    Thanks for the tip! CRC Freeze Off worked!!

  18. #18
    Senior Member
    Join Date
    May 2005
    Location
    IL-USA
    Posts
    1,607
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Ummm.... Just for future reference: aluminum has a greater thermal expansion than steel.

    When the two are heated, aluminum expands more than steel. And when the two are cooled, the aluminum contracts more than steel.

    If you have an aluminum part stuck in a steel hole, you don't heat the whole thing because that makes it stuck even worse. You have to chill the whole thing, and the aluminum will shrink more than the steel does.

  19. #19
    Senior Member
    Join Date
    Feb 2012
    My Bikes
    1983 Trek 613 (new drivetrain), 1982 Trek 613 (fixie), 2011 Cannondale Synapse Carbon 5, 1997 Trek 930 MTB (singlespeed), Surly LHT
    Posts
    86
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Doug5150 View Post
    Ummm.... Just for future reference: aluminum has a greater thermal expansion than steel.

    When the two are heated, aluminum expands more than steel. And when the two are cooled, the aluminum contracts more than steel.

    If you have an aluminum part stuck in a steel hole, you don't heat the whole thing because that makes it stuck even worse. You have to chill the whole thing, and the aluminum will shrink more than the steel does.
    The idea of heating the seatpost and then cooling it is an attempt to break some bonds. Moreover when you heat up both the seatpost and the seattube, the steel seattube doesn't dissipate its heat nearly as quickly as the aluminum when cooled.

  20. #20
    Can'tre Member 3alarmer's Avatar
    Join Date
    Nov 2010
    Location
    ,location, location...
    My Bikes
    old ones
    Posts
    6,971
    Mentioned
    105 Post(s)
    Tagged
    3 Thread(s)
    Quote Originally Posted by ppg677 View Post
    Thanks for the tip! CRC Freeze Off worked!!

    ....another unsolicited testimonial from a satisfied consumer.
    Quote Originally Posted by The Australian Book of Atheism
    There is only no god, and Cyclaholic is his prophet.

  21. #21
    Senior Member
    Join Date
    Nov 2003
    Location
    Minneapolis, MN
    My Bikes
    2x Bianchi, 2x Specialized, 3x Schwinns
    Posts
    303
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ppg677 View Post
    Thanks for the tip! CRC Freeze Off worked!!
    Well shoot. Now I want a do over.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •