Removing stuck or seized seatpost?

http://goo.gl/7t52jr

Cheers! Might double up with blutac and cling film

Good shout. Cheers

How about carving a suitably shaped bung out of cork?

I am playing with Wilko Soda now for second day on two frames, first time.
Fuji Track - seatpost is almost dissolved, few more tries and it will be OK. Second frame - Specialized Langster - no matter how much I pour in, seatpost doesn't dissolve. Magnet doesn't work on it so it must be aluminium. Any ideas? Increase ratio of soda against water?

Titanium post perhaps?

This frame would not have deserved Ti seatpost. I probably need better ratio mixture and spend whole day pumping it.

Fuji's seatpost has been removed now. I haven't fully dissolved it but it was thin layer so just hit it out with screwdriver and then pulled it out. Original paint became more matte finish rather than shiny but planning to clean good and wax it. Seat tube it not that bad damaged or residue left inside.

Langster seatpost is getting thinner and thinner, by Tuesday it should be out. I have wrapped frame fully with film to protect paint (lesson learned from Fuji) so hope for best result. I have to increase soda water ratio (more soda) and use quite warm water (another lesson learned from experimenting with Fuji).

https://www.youtube.com/watch?v=iDzm-sIN47M

Sixteen minutes? I hope there's a plot twist - beard on fire or similar - and it's worth it.

Beard on fire, stumbles, knocks self out, dog arrives, pees etc.

Gents, just stumbled upon this video showing a contraption for extracting stuck posts. It's seems to be based around a large bearing puller, and personally I think it would only work on semi stuck posts, rather than when galvanic corrosion or full on rust has set in, but thought it might be of interest. Anyone up for the challenge of building one?

https://youtu.be/X-EfsLG8np0

Just spotted this, a guy using liquid nitrogen to freeze/shrink seatpost on the basis that alu shrinks more than the steel frame material. Not sure how easy it is to get a hold of LN?
https://www.crazyguyonabike.com/forum/board/message/?o=1mr&thread_id=792262&page=1&nested=0&v=h

I'm in stuck seatpost world right now, it consumes my waking thoughts. ebay 'bargain', nice spec vintage Saracen tange-tubed MTB, ritchey logic/deore dx kit, terribly listed, got it for just over £30. Asked about dents, cracks etc, and got the all clear, forgot to mention the seatpost. It's stuck fast and by my reckoning must have a good 30-40cm in the seat tube.

There's really not a lot to grip. Thinking a slide hammer might be the best option, but I could potentially get access to some liquid nitrogen. Hmmm?

Dont know how easy LN is to get a hold of but I've read elsewhere that plumbers freezing spray is worth a go, especially if you heat the tube as well. There's a guy on CTC uses a flat wood drill bit, slightly smaller than the ID of the seat tube, with an electric drill and "reams" them out. Not for the faint of heart!
I've got one out by drilling a hole through and putting a nut/bolt on it to get grip and then cracked it 4ft sash clamp and a few feet of scaffolding tube to increase the leverage.

There's a guy on CTC uses a flat wood drill bit, slightly smaller than the ID of the seat tube, with an electric drill and "reams" them out.

What could possibly go wrong?

I've got my liquid nitrogen contact on board with the scheme. Need to source a slide hammer now. Time to speak nicely to the mechanic at work.

@Scilly.Suffolk ha ha, I thought that as well. CTC guy reckoned that it was easy to tell when you had strayed off the alu, said you quite quickly got a "feel". I'd have a crack on a cheap frame.
@Tonts, heard of this guy? http://www.theseatpostman.com/home

Be very very careful with liquid nitrogen, wear wrap around eye protection and decent gloves, not marigolds something heavy duty.

Cheers. I appreciate it's dangerous stuff, but the chap who's helping me uses it daily so he's in charge.

@TheShipwright I did see him in another thread but 70 notes and postage on top for a bike I paid less than half for, seems a bit excessive.

https://youtu.be/Zas2EovN0wI?t=45

@tonts, good luck let us know how you get on

Will do. Anyone ever tried putting the seatpost in a vice and twisting the frame?

Dave yates told me this was the best method, but I'm afraid of twisting the frame in some way.

From my experience using heat rather than cooling has been more successful, although if all else fails I think this method is better than dissolving alu posts with caustic soda:

https://youtu.be/LJLZ9Ojtr80

Ive tried the seatpost in a vice twist the frame technique. Never worked in my case but its a good way increasing the leverage without tools and i guess spreading the stress across more of the frame.

It's a method of attack that's worked for me on steel frames.