F***** Seat Post

[Amanda P]

Ivan agrees with Sheldon:

"Aluminum seatposts frequently become stuck by corrosion also, and penetrating oil is almost useless against aluminum oxide. Fortunately, aluminum oxide can be dissolved like magic by using ammonia."

The question is, where can one get ammonia? Will peeing on the seat post help at all?

(I ask because I have a bike whose alloy seat post has been stuck for years).

 

[skwerl]

30 mm drill does indeed cost about £30, it has a narrower section to allow it to fit in a normal chuck, however, unless you've got a drill that has a chuck that uses a key - forget it, the torque it produces when it sticks just spins it in the chuck.

also a major issue being that those drill bits are for masonry. the reason they slip is because you end up breaking your wrists when they jam, hence the reason a decent SDS drill has a clutch.

anyway - have you tried whacking it with a hammer? It will go further in if successful but the fact that it's moved means it will have loosened off and will then come out

 

[Ivan Ardon]

Ammonia - I've got it on trips to France before. It's not something you see in supermarkets in the UK. Would a chemist sell you a little?

Peeing on the seat post? Give it a go. Post pictures.

 

[simon_adams_uk]

The other option (which I don't think has been mentioned) is clamp the seat post in a vice and use the frame as a lever. This is only if you have enough seat post still visible and used in conjunction with all the other plusgas / ammonia suggestions...

S

 

[Amanda P]

Peeing on the seat post? Give it a go.

If nothing else it might be an appropriate expression of contempt for the thing.

 

[Piemaster]

Don't some household cleaners contain small quantities of ammonia? Oven cleaner maybe?
Worth a readof the labels in the supermarket if you are desperate.

 

[dubhghall]

Ammona based cleaners are often used for cookers and gravestones.

Looks to be available on fleabay . . . . . . .

http://shop.ebay.co.uk/items/__ammo...word=ammonia+cleaner&MT_ID=11&agid=1382011179

Good Luck

 

[Black Sheep]

also a major issue being that those drill bits are for masonry. the reason they slip is because you end up breaking your wrists when they jam, hence the reason a decent SDS drill has a clutch.

they slip due to no grip in the chuck and the ones i have are for steel.

 

[Brahan]

I drilled a hole in the seatpost and put a big heavy duty screwdriver through it. Then I hooked my car jack to it with the top tube taking all the strain. After 3 full revolutions (enough to lift my golf estate off the ground) it still didnt move so I took it to a mate with a vice and it took 45 minutes to work the dam thing out. I know someone else who took almost a whole day to cut the tube out with an open ended hacksaw....

 

[threebikesmcginty]

How about kicking the shite out of it and shouting 'you bastard' now because that's probably what you'll end up doing!

 

[J4CKO]

I think its going to the engineering shop to be drilled out, will try the ammonia thing, did try Soda Crystals which come with promising sounding dire warnings about putting it on ally but it didnt seem to do anything at all.

 

[Amanda P]

A random thought: I've got some stuff for cleaning alloy car wheels. Does that have ammonia in, and would it help shift the seat post?

I'll try it and let you know.

 

[02GF74]

I think its going to the engineering shop to be drilled out, will try the ammonia thing, did try Soda Crystals which come with promising sounding dire warnings about putting it on ally but it didnt seem to do anything at all.

washing soda, contains ammonia of some sort - aluminium does not like it.

it would take a faair bit of time to dissolve a seat post, weeks if not longer is my guess; you would need to replace the solution.

 

[Bodhbh]

http://www2.uni-siegen.de/~pci/versuche/english/v44-10.html

I'm not sure how it would really work in practice, I suppose it would be fun to see! Drain cleaner is pretty much pure sodium hydroxide afaik. I once split some sodium hydroxide solution on a aluminium computer stand and it left a white scorch on it, despite been wiped off almost immediately. Hrmm some drain cleaner downstairs, wonder what happens if I throw an old chainring in some.

/edit - not been entirely serious, probably make a godawful mess, and it's not stuff you really want to be getting in your eyes, on your skin or splashing about .

 

[nickb]

A random thought: I've got some stuff for cleaning alloy car wheels. Does that have ammonia in, and would it help shift the seat post?

Hydrochloric acid usually.