Removing stuck or seized seatpost?

Thought I'd revive this post and embarrass myself. A fair while back I greased a USE alien carbon post before I stuck it in my alu frame. Yes I am a fool. But up until now it's stopped people nicking my seating.

Ahhh !! grease will delaminate carbon !

Trouble is I'm now thinking of powdercoating/ selling it, for which I imagine I'll need to unseize it. Any thoughts on how to deal with this? Someone told me if you try cutting and reaming carbon it makes a horrible toxic dust. Would try the above mentioned broom into saddle rails and twist approach, but I think the dainty alien clamp arrangement would give before the post.

Drill a hole through the post perpendicular to the post's axis stick in a screwdriver and use that to turn the post.

Use a dust mask and do this outdoors.

just bought a new bike , got home and relised it has got a extremly baddly seized seat post, ive read all the previous threads about removing stuck seat posts and have tried everything but nothing seems to work , has anyone had any experiance and any advice for removing the post
thanks

what are the ones you have tried tony?

hitting, twisting ,clamping, wd40 , lubeing, heating and hacksawing- so now i havnt got much of the post left to hold onto.

Steel frame? Alu post?

Melt the post out, heat the steel tube until the post starts dripping out.
Then clean up the inside followed by a fluch through with a reamer.

Will leave scortch marks and burn some of the paint off though.

alloy post, steel frame = caustic fucking soda FFS

melting point of aluminum 2000°c
melting point of brazing filler metal 425°c

if your frame is tigged not lugged then you may be o.k but i would not want that much heat near a weld post heat treatment.

What bike is it?

steel frame with aliminum post , ive hacksawed the post so about 1 cm of leaverage , but think its some how welded itself togerher. i will try the caustic soda and was wondering where to get the stuff

try your local DIY emporium, they usually have some.

B.

Melting point of aluminium 660C
Agree on the braze 425 - 450C.

However heating the frame to melt the alu will probably screw the frame tube heat treatment.

Caustic disolves alu, so go with the caustic soda (100% sodium hydroxide)(NaOH)

See this: YouTube

But for gods sake wear proper gloves and goggles, this shit will eat your flesh.

Do it outside on a dry day, mix a saturated solution and pour it into the seat tube (remember to bung up the vent hole at the bottom bracket end).
I have used this method and it works in a spectacular fashion.

Oh and I should just mention that the reaction liberates LOTS of hydrogen, which is explosive.

Toodle pip

maybe if you have enough post you could drill through it and get some sort of bar in there that you could get plenty of leverage on. There is something else you can spray on, not wd40, i forgrt the name but i think it's a proper release agent. Called something like 'pro gas' cause i always thought people were talking about a propane gas torch or something when they refered to it.

B.

alloy post, steel frame = caustic fucking soda FFS

This is a joke, right?

maybe if you have enough post you could drill through it and get some sort of bar in there that you could get plenty of leverage on. There is something else you can spray on, not wd40, i forgrt the name but i think it's a proper release agent. Called something like 'pro gas' cause i always thought people were talking about a propane gas torch or something when they refered to it.

B.

It's Plus Gas. And it's less likely to kill you and those near to you than caustic soda.

Hacksaw across near the seat tube, then padsaw vertically through the stump.

It's Plus Gas. And it's less likely to kill you and those near to you than caustic soda.

Agreed, but its much less fun.

Toodle pip

This is a joke, right?

no, it's not a fucking joke, it's the way to remove a fucked alloy post from a steel frame.

believe me, I've had experience in these matters.

and yes, do it outside.

google or whatever, there's plenty of info on it.

cheers all, i will try all the methods and hopefully it will pop out

cheers all, i will try all the methods and hopefully it will pop out

If you use the caustic method it won't "pop" out, it will dribble out in a bubbling slurry. Wash it down with LOTS of water.

Good luck.

Toodle pip

the toodle pipper is right.

but you shouldn't have sawn it off, really.

saw an interesting technique the other day which involved spraying the seat post with butane lighter fluid until it is basically frozen, and then it will twist off as it will shrink due to the cold, It seemed to work well but used a whole can of butane gas

if you want caustic, nip along to a plumbers merchants and ask for "spirit of salts". tell them your'e unblocking a drain rather than the real reason, unless you want every fucking plumber in london pointing at you

yeah, it's commonly sold as drain cleaner in hardware shops

ER. whilst writing the above, Guerillaphoto gave us a plan B. Go to a plumbers merchant and purchase a pipe freezing kit. this it a can of liquid CO2 and a cuff.