cocacola v stuck seatpost

[foz]

I have a steel frame with an alloy seatpost stuck in it. Both frame and post are in decent condition, so I don't want to damage either of them if I can avoid it.

On sunday afternoon I turned the frame upside down and filled the seatpost with cocacola (full fat proper cocacola, not light, zero, tesco's own, or any other rubbish ). I guess there's not a lot to lose, it's a lot cheaper than plusgas or anything else, and at worst I think it will make the inside of the seattube a sticky mess.

I haven't tried to move the seatpost yet, but it's been in for just over 48 hours.

should I:

- give up now, it won't work?
- try and move the post now?
- wait a few more days? (and if so, how many more?)
- tip the coke out and replace it with fresh coke?
- none of the above?

 

[kingbling]

try and move it if no success replace with fresh coke and and wait a few more days

 

[dyna-ti]

Ive always found an engineers vice well bolted down is the thing for stuck bits. Using the frame to put the pressure on exerts a heck of a lot of torque, but too much and the seatpost could shear :shock:

Clamp it up or use some locking moles and apply some pressure. Avoid sudden snaps, as you can get just that.
If your fix has done anything it will become obvious and likewise should you judge it too tight, and think more pressure could shear it then move to stage 2 of replacing the cola with some caustic soda mix.
A strong as possible mix using COLD water. Apparently hot causes an increase of fumes to a dangerous level. In fact Rampage on here is the best one to ask on using chemicals to dissolve or strip things with.
Probably best outside and down wind
Hang it up , pour in mixture and leave to do its work.
Not having removed a stuck post this way i wouldnt know for sure, but i'd think that pouring out the mix and replacing it with fresh, would at least be better than not refreshing it. Well one would think so.

Ive used various strengths of caustic solution to strip ano and a strong mix on bare is quite a violent reaction.




TIP: Don't use an alloy container to make up the solution in

 

[foz]

I've tried clamping the head of the seatpost in a bench vise - no luck there.

I'm not keen on caustic soda as it will eat the aluminium if left for too long - I'm not sure it would eat away any corrosion between post and frame before it would destroy the post too much.

I think if the coke doesn't work, ammonia will be the next step.

 

[Robbied196]

Re:

If its definitely stuck you may well have to sacrifice the post. I've always found the quickest, cleanest way is to cut it out, that way theres no paint and no frame damage. Excuse the CTC link

http://forum.ctc.org.uk/viewtopic.php?f ... al#p539519

I know caustic will work but its pretty volatile stuff and it will wreck the paint. There is also 'The Seatpost Man', he reckons he can get them out and save the post.

http://www.theseatpostman.com/

 

[kingbling]

Just been having a look at the seat post man's site and I'm impressed so if you have no luck I'd save that bottle of coke and talk to him (now to work out how he did it )

 

[The History Man]

Best I've seen is weeman's slide hammer set up. It's on here somewhere. If I find it will link

That was quick! viewtopic.php?f=1&t=329177

 

[kingbling]

good technique with the slide hammer which gives me an idea how the seat postman does it with out destroying the post :idea:

 

[foz]

well beyond my expectations, it appears that the coke is working! the post is now moving, although I need to put a saddle, fork and wheels back in the frame to be able to get a good go at it. Have left it soaking with fresh coke until I can find time to do that.

 

[Nob]

If you don't have a vice bolted to a concrete floor coupled with a 16t overhead crane. Then try replacing coke with White Vinegar leave for 7 days then give it a go