Seat post stuck in 1984 Colnago steel seat tube

[MarkFHarrison]

I have had this gorgeous bike for a while but have never been able to budge the seat post. I have tried all reasonable recommended measures and I think the previous owner might have had a half-hearted go at it with a blow torch with minor discolouration of the paint work. Is there anyone out there who can unstick it without damaging the frame?

[rjb]

Have a read of these posts.
You should find something there to suit you.
viewtopic.php?f=5&t=16716

[avalonian]

Try
http://theseatpostman.com

[MarkFHarrison]

I have tried most of the methods described in rjb's kind response and none of them have worked, including the PlusGas that was eventually appropriated by some builders who were renovating my house and had an attachment stuck on their JCB. It worked for the JCB but not my Colnago Perhaps I am being too timid.
The post is aluminium based and the frame is Columbus steel. I'm prepared to sacrifice the post but not the frame, which has seen me through a few vintage events. I am hoping to gradually bring it up to concours standard. I like the sound of avalonian's service apart from the prospect of having to deliver it to an Athurian island, although I do get the clever reference to extracting Excalibur

[Mick F]

Do you have a nice big well-secured bench vice?

Have you inverted the frame and clamped the seatpost in tight, and poured in lots of Plus Gas down the seat tube and left it for a week or more, then tried to twist the frame?

I know you've tried most of the methods.
Have you actually tried it properly? .......... as you don't say you have.

[pwa]

I have removed a couple by sawing off the top of the post then using a hacksaw blade with improvised handle (tape or rag, etc) to cut two grooves through the post wall. Needs care and a steady hand in the final stages. And it takes ages. Best to do ten minute stints when you can be bothered, possibly over the course of a week. For a particularly precious frame I would think about measures to prevent over cutting into the steel of the frame.

[Vetus Ossa]

Do you have a nice big well-secured bench vice?

Have you inverted the frame and clamped the seatpost in tight, and poured in lots of Plus Gas down the seat tube and left it for a week or more, then tried to twist the frame?

I know you've tried most of the methods.
Have you actually tried it properly? .......... as you don't say you have.

As above but instead of Plus Gas which won’t do anything use ammonia.
If you’re old enough to remember nappy buckets you will remember that it is a tad smelly so best done outside the house.

[nigelnightmare]

I have removed a couple by sawing off the top of the post then using a hacksaw blade with improvised handle (tape or rag, etc) to cut two grooves through the post wall. Needs care and a steady hand in the final stages. And it takes ages. Best to do ten minute stints when you can be bothered, possibly over the course of a week. For a particularly precious frame I would think about measures to prevent over cutting into the steel of the frame.

+1
BUT leave about 2" sticking out to grab onto.
Also try a padsaw for plasterboard as it has is less likely to damage the Steel frame but will still cut the Aluminium seat post.+ it has a handle.

[alexnharvey]

Cutting it out seems like the method most likely to result in damage to the frame to me.

Cooling the seatpost drastically to shrink it (using liquid nitrogen, dry ice pellets or plumbers freeze spray), or chemical attack of the corrosion or seatpost itself (ammonia or caustic soda) are much less likely to damage the frame. Combined with inverting the frame and clamping it in a large vice attached to a sturdy object of course.

Curious to know if these are considered unreasonable methods by the op since they say they have tried all the reasonable ones!

[Vetus Ossa]

Re ammonia. I do know this works as I have used it on an aluminium seatpost that was stucker than stuck in my steel Cougar.
No paint damage and the seatpost was even usable after as it had nice flat sections I could grip in a friends vice.

[gazza_d]

I would second the suggestion to use John the Seatpost man.
He removed a stuck post from a much loved Moulton frameset for me a couple of years ago.

[fausto99]

Re ammonia. I do know this works as I have used it on an aluminium seatpost that was stucker than stuck in my steel Cougar.
No paint damage and the seatpost was even usable after as it had nice flat sections I could grip in a friends vice.

+1 for ammonia for an aluminium post in a steel frame. Worked for me after the ammonia had been in overnight. Nonetheless there's a lot to be said for giving the job to someone who does it all the time - I'd not heard of the seatpost man.

[geocycle]

Try
http://theseatpostman.com

Amazing to think this happens enough to support a specialist! I wonder if there is a pedalman as well, mine are well and truly seized?

PS. Worth reading his website for tips and pitfalls

[Mick F]

One method I would favour is to undo the clamp and then carry on riding. Eventually, it may start to slip.
Make sure you take the tools with you to tighten it up again if it does eventually start to slip.

[fastpedaller]

Try
http://theseatpostman.com

Amazing to think this happens enough to support a specialist! I wonder if there is a pedalman as well, mine are well and truly seized?

PS. Worth reading his website for tips and pitfalls

I wonder how he does it (and apparently so quickly) - only clue is 'special tools' so my guess would be a 'slide hammer' type arrangement, but how to do it without damaging the seatpost? Fair play to him for seeing the market, and it appears he does a great job.