Stuck in seatpost

[fouronethreeoh!]

Ive been wrestling all day with a seized in aluminium seatpost in my t1 barcode frame.

Jeez, ive tried everything, soaked it in lube for several days, frozen it in liquid nitrogen, had 10 tonnes on it in a press and the little blighter still wont shift. Ive buggrrd the post now anyway so it looks like im gonna have to drill it out.

I think the problem is that there is about eight inches of post in the frame 

I will not be beaten though 

[harris]

costic soda will eat the alloy away until it vanishes ,dont inhale the fumes its bad

[jT Racing]

costic soda will eat the alloy away until it vanishes ,dont inhale the fumes its bad

good thinking batman       

[fouronethreeoh!]

Yeah im liking that, good thinking batman.

   

[CoolHands]

I think he means caustic soda (Sodium hydroxide) if you're searching for the stuff.

[jT Racing]

nice first post. your gonna be popular

[CoolHands]

just thinking about this. How would you apply the caustic soda to dissolve the seat post? Presumably it'd be tricky to find a container big enough to suberge the whole frame.

Or could you block up the seatube (if it has a hole in the bottom) and try & fill it up with solution?

[harris]

yep plug up the holes and fill the seat tube,its been done before.
you can get a container and just put the seat post part in tricky but it does disolve where it reaches.

[trasher]

how about the old toy arrow with the sucker on the end
push it down past the bottom of the  seat tube ,,,then pull it up slightly to form a seal
then pour in desired amount of caustic ,,,well you get the idea ,,,,

or should i get my coat 

[stfc]

depends on whether you are going to repaint the frame here but,  if you get a gas lamp/oxi and run it along the seat post tube on the frame  and then twist the post with a good pair of mole grips or similar it will come out, repeat obviously until it frees, alloy contracts and expands at a different rate to steel etc so that will do the trick, but will fook your paint, failing that soak it in diesel... failing that chuck it in a skip...

[Juju]

If its an ali frame, then anything with ammonia is meant to be good.

In roadie circles, this man was a legend and he virtually wrote the book on stuck seatposts. -

http://www.sheldonbrown.com/

and for you...  this link is the cats clit !

http://sheldonbrown.com/stuck-seatposts.html

all credit to the master of bike repair!

[fouronethreeoh!]

Was just trying to say how stuck in my post is.
Its well stuck, i froze it to -192c in liquid nitrogen to shrink it but it was still solid.
Had it up to 10 tonne in a press but still no movement.
So im going to try caustic soda to see if it will free it up a bit, its a steel frame so no probs there.

[hunterdubber]

I wouldn't buy a frame with a seatpost stuck again done it twice and both times was a nightmare
with both combinations , Alloy frame and cromo post ,,,cromo frame and alloy post

Did the press , ammonia , weld another bar to it , to twist it out , ,soak in WD40 for days,,,,etc etc
tried em all

heat actually did work on the cromo framed one in the end

but the alloy framed one I had to get my brother in law engineer to drill down the seatpost tube vertically as far as possible so the old post was removed
He said never again ,,they had 3 holding the frame under a stand drill , so it wouldn't whizz 'em round the room   


Good luck

[80sdave]

Dude get yourself a handheld gas torch from homebase and gently heat the frame (seat tube section) keeping the flame constantly moving dont concentrate on one spot. We do it on bikes that come in to us for the same problem, might loose a decal or two and if you stay in one place to long you will risk bubbling the paint but usually takes 3-5 minutes tops then straight away with seatpost in vice get twisting using the frame as leverage rather than trying to turn the little seatpost and that should sort it.

[Rombloke]

caustic is the way to go on the chromo frame alloy post scenario...i think phil fruit has pics

Dave

[jT Racing]

i usually try to get ali posts knocked into the frame first to get some kind of movement before using the vice. cro-mo posts though are weaker and shouldn't be bashed. first you will need a piece of metal to place inside the end of the seatpost to prevent crushing in the vice then twist. Cro-mo in ali, no idea, never had one like that.

[MartyC]

Cro-mo in ali, no idea, never had one like that.

I'd say drilling would get it out or a reamer