seatpost with in a stuck seatpost, anyone done it?

[andyparle]

So. My old Sunn exact ti has a seatpost stuck in the frame.
Has anyone ever had a seatpost thats stuck (chopped off to the top of the seat tube) and then used a smaller daimeter seatpost inside it as though the remains of the old aseatpost is a shim?
please refer to this thread for my attempts and the bike builders for getting it out:

http://www.retrobike.co.uk/forum/viewto ... p;t=351380

 

[clubby]

Re:

Edit. Just read whole story, and what I've written below may be a load of bollocks for your situation, but I'll leave my tupence worth anyway. Edit end

Won't work. How you going to clamp the new post?
My mate was in a similar situation and managed to drift the old post downwards to the bb shell, then insert a new post. In tight so doesn't rattle at all.
All depends how long the seat tube is, and how much post is stuck in. You may also have to trim new post slightly if it's long.
You may also have to remove and trim any bottle bolts on the seat tube.

 

[andyparle]

Unfortunatley it wont shift down at all either. its fully bonded itself in there. the clamp will work just the same, the seat tube that is in there will have a slit cut in to it to match the seat tube split so the part of existing seat tube will hopefully work just the same as a shim would maybe. The bike builder its at has had it now for approx 8 months trying all kinds of methods when he has spare time and it just aint working so its a bit of a last ditch attempt.
Its far too nicer a frame to give up on it though and I guess a smaller gauge seatpost is better than non at all
Now who has a 22.2mm seatpost they want to sell haha

 

[integerspin]

And the frame builder can't remove it!
Send it to me.

 

[andyparle]

okay. And what would be your process for removing the remains of the offending seatpost?

 

[danson67]

Maybe try this guy in Chorley?..£60ish, but seems to have an excellent success rate:

http://www.theseatpostman.com/home

All the best,

 

[andyparle]

Cheers. sounds like he might be the chap for the job!

 

[Dale cannon]

Not read the whole thread but have you thought about or tried caustic soda?

Used it on a steel frame poured into the seat tube via the bb. It dissolved the post in less than 10 minutes, the only cost was the caustic soda at £2.50.

Apologies if you've already tried/discounted this method.

 

[integerspin]

Small exposed area of aluminium will probably make using caustic a bit slow,
it would work but I can imagine it taking weeks and you would probably have to
clean it out quite often.

Titanium isn't super hard, I think the hardest is around 40RC, HSS is <62RC.
I would get my trusty Cenger saw and cut a few slots in the post then pull
it out, or push it down. The shim I would slit into 4 or maybe use caustic.
The mill is always the last resort for things like this.

 

[andyparle]

Aye. I tried it before passing it on to the frame builder, and then he give it a go with both caustic soda and some other type of acidic dissolvent with not much joy. it goes; ti seat-tube bonded to alumimium shim bonded to ti seat post.