Author Topic: Has anyone tried to remove a stuck seat post with dry ice/freeze spray  (Read 821 times)

Gattopardo

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Ok have two on one inbred frames with stuck seat posts.  So steel frame and aluminium seat posts, so was thinking how to un stick them so thought dry ice/ freeze spray as aluminium shrinks more than steel in the cold.

Any one tried it?

PaulF

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Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #1 on: September 11, 2019, 05:27:56 pm »
Yes, once with success. Wrapped the “jacket” round the frame, froze it put the seatpost in a vice and twisted the frame. It loosened with a creak and then was persuaded out.

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #2 on: September 11, 2019, 05:49:31 pm »
I went one further and put the seatpost into liquid nitrogen whilst the frame was wrapped in hot tea towels - it didn't work. It was incredibly spectacular though, huge clouds of boiling nitrogen!
Local frame builder removed it for a fiver with fire!
Bike needed a respray anyway!

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #3 on: September 11, 2019, 11:09:01 pm »
that's the problem with seatposts; they either come out or they don't, using any given technique, and (like jam jars...) one effort may have 'loosened it'.   So its impossible to know just how seized the seat pin is/was, and therefore be absolutely certain which removal technique works best.

cheers

robgul

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Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #4 on: September 12, 2019, 07:18:34 am »
I've had success with a spray freeze can - used loads of it for 3 applications but eventually it worked with some help from a water pump wrench turning the post.

What you might try, I have seen it work, is:  take the BB out, bike upside down clamped at a slight angle from the vertical and (assuming you can see the open end of the tube in the BB) pour Coca Cola down the seat tube ..... it's very corrosive/penetrative and after quite a lot of applications might release the seat post.

The moral of the story is of course anti-seize/copper grease before insertion and repeated applications now and again.

Rob

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #5 on: September 12, 2019, 08:31:17 am »
If all else fails, and your frame is worth it, this guy:
http://theseatpostman.com/ :thumbsup:

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #6 on: September 12, 2019, 11:27:06 am »
Freezing and heating and stuff didn't work for me. I ended up dissolving the seatpost with caustic soda. There's thread on here somewhere!

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #7 on: September 12, 2019, 11:45:17 am »
Yes. It didn't work for my Hewitt Cheviot, nor did any of my other attempts to remove the seatpost (e.g. using PlusGas)

When I can find the time, I think I need to package my bike up and send it to The Seatpost Man to remove it with his special tools.

Old enough to know better, but young enough to do it anyway

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #8 on: September 12, 2019, 12:22:06 pm »
Not the freeze method, but I got away with the following withdrawal:  https://yacf.co.uk/forum/index.php?topic=107323.msg2285893#msg2285893

SheldonB says never install* a seatpost with a hammer, so technically removing a stuck seatpost by hammering it in to break the 'bonds', then twisting with a wrench to remove, is different, but I guess may not work for everyone.

*Probably installing with a hammer, indicates that the seatpost is in fact likely the wrong diameter in the first place, as opposed to a seatpost of the correct diameter that has become stuck.
Destroying rainforest for economic gain is like burning a Renaissance painting to cook a meal.  EOW.

Gattopardo

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Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #9 on: September 12, 2019, 01:03:31 pm »
I went one further and put the seatpost into liquid nitrogen whilst the frame was wrapped in hot tea towels - it didn't work. It was incredibly spectacular though, huge clouds of boiling nitrogen!
Local frame builder removed it for a fiver with fire!
Bike needed a respray anyway!

Quick stupid question, why wrap the frame in hot towels.  I understand that you want to maximise the temperature difference but wouldn't the liquid nitrogen just freeze the towels too?


 That's the problem with seatposts; they either come out or they don't, using any given technique, and (like jam jars...) one effort may have 'loosened it'.   So its impossible to know just how seized the seat pin is/was, and therefore be absolutely certain which removal technique works best.

cheers

At the moment I just want the seat posts out, one I'd like to keep but the other I don't care about.  Suspect both frames will be repainted/powdercoated depending on what I want.

I've had success with a spray freeze can - used loads of it for 3 applications but eventually it worked with some help from a water pump wrench turning the post.

What you might try, I have seen it work, is:  take the BB out, bike upside down clamped at a slight angle from the vertical and (assuming you can see the open end of the tube in the BB) pour Coca Cola down the seat tube ..... it's very corrosive/penetrative and after quite a lot of applications might release the seat post.

The moral of the story is of course anti-seize/copper grease before insertion and repeated applications now and again.

Rob

Dry ice will be colder than freeze spray, I think.  Hence the greater contraction, I hope.

About the coca cola thing, the bit is phosphoric acid, so could I just use vinegar or citric acid?  Or any limescale remover type stuff.

I did not fit the seat post, the issue is buying frames second hand that need work.

If all else fails, and your frame is worth it, this guy:
http://theseatpostman.com/ :thumbsup:


Yeah saw him from torslandia, and am wondering how he does it.  At the moment the seatposts are removed by magic ;)

Freezing and heating and stuff didn't work for me. I ended up dissolving the seatpost with caustic soda. There's thread on here somewhere!

Tried caustic soda in the past, on a stuck stem on a moulton fork and a stuck seat post and ended up cutting the post and took ages as the post needed four cuts to get the post out.


Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #11 on: September 12, 2019, 05:24:14 pm »
Quote
Quote from: eckagain on Today at 08:31:17 am
If all else fails, and your frame is worth it, this guy:
http://theseatpostman.com/ :thumbsup:


Yeah saw him from torslandia, and am wondering how he does it.  At the moment the seatposts are removed by magic ;)

I had a long chat with him when I was thinking of sending my (carbon) frame with stuck (carbon) seatpost. I asked him how he did it. Tapping the side of his nose, he basically said..... It's a secret!  :-X
Nice guy though.
He had to trash my seatpost (which he warned me was likely to happen) but the frame came back immaculate.  :thumbsup:

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #12 on: September 12, 2019, 05:27:39 pm »
Quote
Quote from: eckagain on Today at 08:31:17 am
If all else fails, and your frame is worth it, this guy:
http://theseatpostman.com/ :thumbsup:


Yeah saw him from torslandia, and am wondering how he does it.  At the moment the seatposts are removed by magic ;)

I had a long chat with him when I was thinking of sending my (carbon) frame with stuck (carbon) seatpost. I asked him how he did it. Tapping the side of his nose, he basically said..... It's a secret!  :-X

I think he has a number of custom-made tools for the job
Old enough to know better, but young enough to do it anyway

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #13 on: September 12, 2019, 05:33:39 pm »
Quote
I think he has a number of custom-made tools for the job

Indeed, he did give that much away. The only thing I could add is what a friend in the trade told me: that the seatpost is drawn straight out of the seat tube, with no twisting involved. Whether he uses chemicals, heat / cold or magick, I've no idea.

Gattopardo

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Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #14 on: September 14, 2019, 11:55:38 am »
Quote
I think he has a number of custom-made tools for the job

Indeed, he did give that much away. The only thing I could add is what a friend in the trade told me: that the seatpost is drawn straight out of the seat tube, with no twisting involved. Whether he uses chemicals, heat / cold or magick, I've no idea.

As I have said before, magic. 

So do we have to burn him as a witch? ;)

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #15 on: September 14, 2019, 02:54:36 pm »
I went one further and put the seatpost into liquid nitrogen whilst the frame was wrapped in hot tea towels - it didn't work. It was incredibly spectacular though, huge clouds of boiling nitrogen!
Local frame builder removed it for a fiver with fire!
Bike needed a respray anyway!
Liquid Nitrogen!
I've got a small jar of that somewhere  ;)

P.P.

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Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #16 on: September 14, 2019, 03:19:25 pm »
Quote
I think he has a number of custom-made tools for the job

Indeed, he did give that much away. The only thing I could add is what a friend in the trade told me: that the seatpost is drawn straight out of the seat tube, with no twisting involved. Whether he uses chemicals, heat / cold or magick, I've no idea.

I’d guess that he uses some sort of hydraulic puller with a combination of heat/cold to help it on its way if needed. Gripping the seat post and pulling against the top of the frame where the seat post goes in will likely get most things out and a hydraulic puller can easily generate many tons of force in the correct direction. The biggest problem would be making the adaptors to avoid damaging the frame and grip the post.

We used a similar method for getting interference fit bolts out in the aircraft industry and I believe they do similar for getting out siezed in fuel injectors from dirty diesels.

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #17 on: September 14, 2019, 03:26:50 pm »
There's no secret, no magic.

Search on Youtube with "seatpost removal puller tool". They're basically a screw operated puller which attaches at the bottom bracket.

Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #18 on: September 14, 2019, 07:58:43 pm »
The freeze spray can worked for me. Took two cans to do it and two of us, one straddling the frame and the other utising a a steel bar as a lever inserted through a hole drilled in the seatpost. Destroyed the post but worth it.
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Torslanda

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Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #19 on: September 15, 2019, 04:09:43 pm »
I've been in his workshop.

He still wouldn't tell me how but he does have a horizontal borer...
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

robgul

  • HoECC & Cycle:End-to-End webmaster, S Warwickshire Bike Shop in Wellesbourne
  • . . cyclist, Cytech accredited, manages an LBS
    • Cycle:End-to-End
Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #20 on: September 15, 2019, 04:49:42 pm »
There's no secret, no magic.

Search on Youtube with "seatpost removal puller tool". They're basically a screw operated puller which attaches at the bottom bracket.

The RJ the bike man films are interesting - the one with the "slide hammer" uses a thing I have which is a gear-puller - same concept of a heavy weight that slides and the shock should do the business.   The giant puller off the BB was something else!

Rob

Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Has anyone tried to remove a stuck seat post with dry ice/freeze spray
« Reply #21 on: September 15, 2019, 05:44:04 pm »
I've been in his workshop.

He still wouldn't tell me how but he does have a horizontal borer...

So that can draw the seat post out