Stuck carbon seatpost in alloy frame. HEEEEEELP!!!!

[Mike Muz]

Hi folks,

picked this up from the tip at the weekend, thought it would be ok for painting practice, as the alloy is pretty corroded and the frame is too small for me anyway.

But the seatpost is stuck. Soddit, thought I could save that. Can I? What can I use for those materials?

Any help appreciated

Muz

P.S. Anyone fancy the 105 triple chainset?

IMG_5919 by Mike Murray, on Flickr

 

[Peachy!]

Hello Mike,
Tricky one this, especially if it’s the post you want to save…. I have had a similar problem and did get a result;
First a couple of don’ts..
Don’t touch the carbon with any petrochemical products or penetrating/lubricating oils, the most likely result will be the resin in the carbon swelling and that won’t help.
Also don’t attempt to pull them apart, this only has the effect of stretching the aluminium tube which then increases its grip on the post.
That leaves you with two options;
1. Cut up the aluminium frame very carefully with a Dremel for example
2. “push” them apart.
To push them apart you will need to make up a jig, utilising some aluminium either side of the seat tube top, and the bolt heads of the seat clamp, these will need replacing with longer bolts with a normal hexagonal head rather than an allen key head, so that you can unwind these against the aluminium spacers/straps which will push down onto the seat tube…

Sounds long winded, but I have done it.

 

[Splatter Paint]

Re:

Hmmm :|

How about a weak acid down the seat tube? I.e. lemon juice or vinegar? That should sort the oxide.

^^ what he said with oils.

 

[Splatter Paint]

Re:

This chap used weights and a flipflop!

https://youtu.be/Kfxl1d4JRmw

 

[Peachy!]

Re: Re:

This chap used weights and a flipflop!

https://youtu.be/Kfxl1d4JRmw

I was waiting to see him drop the weight on his toes :facepalm:

Btw, he was pulling carbon out of carbon.. not aluminium, which does stretch and reduce its internal diameter therefore gripping the seat post even tighter..

 

[tim75]

Re:

I've got a couple of old steel Raleighs in Super Muz size if you want to swap?

 

[Mike Muz]

Re: Re:

I've got a couple of old steel Raleighs in Super Muz size if you want to swap?

Maybe, or you can have it anyway

Mike

 

[tim75]

Re:

Funny you should say that because I was going to try and give you these frames anyway!

I'll send you a couple of pictures later on. Should be going past your way on Sunday if you are interested?

 

[My_Teenage_Self]

https://www.youtube.com/watch?v=7R9agXgRtE4

Mike, if you ever end up anywhere near the new forest, I have a range of slide hammers

 

[tim75]

Dug this project out the back of the shed and managed to unseize the headset and dig out the carbon post with a screwdriver. Fun afternoons work!