It's all lies!

[dfthe1]

Just do 2 or 3 cuts with a hack saw blade, they said. Use mole grips to collapse it and peel it out, they said. Never fails, they said.

Yes -- I'm struggling with an aluminium seat post in a steel frame. Did the usual tricks but nothing worked so went for hacksawing it out. The actual sawing wasn't as bad as I expected, but it had no effect. I just had 4 pieces of seat post still bonded to the steel tube. Was up until 3am working on it.

So tonight I'm laboriously chiselling pieces out. Here's 1.5 hours' progress.

And here's how much post is still in there:

I'm using loads of penetrating oil. For nostalgic reasons I want to keep the paintwork as is, so caustic soda is out.

Anyone have any tips?

 

[S-Express]

Anyone have any tips?

View: https://www.youtube.com/watch?v=aCbfMkh940Q

 

[Gravity Aided]

Lye? Caustics are dangerous, and hard on the paint, and slow, and smell bad (hydrogen) but they dissolve aluminum, but not steel.

 

[Cycleops]

View: https://youtu.be/-dYnSVVDxrE

Bit messy but as @Gravity Aided says it does work.

 

[dfthe1]

I've ruled out caustic soda as I want to keep the paintwork as it is.

 

[Bazzer]

There is something in the back of my mind about coca cola dissolving aluminium. Takes 3 - 4 days IIRC.Might be worth some research.
If you can fashion a bung, or test the effect of coke on the paint and invert the frame into a solution.

 

[Bazzer]

[QUOTE 4782172, member: 9609"]are you sure you hacksawed through 100% of the ally post ? just a little bit still connecting them will keep them well and truly jammed in.



does coke not come in an ally can ?[/QUOTE]
Yes. I wasn't sure if the inside of the can was coated. I had added an edit about research whilst you were posting.
The only reason it came to mind was I happened to see a video a while back about someone removing a stuck bolt from an engine block, something I am struggling with at the moment.
Actually thinking a little more about it, it may have been a steel bolt in an aluminium engine block, which is the reverse of the OP's current predicament. My bad. Apologies

 

[Cycleops]

The problem you've got as I see it is that you've removed all of the post above frame level. If you still had something to work with you at least can attach a slide hammer and pull it out or a long handled plumbers wrench to twist it free.

The only option you have left now is the soda.

 

[Smokin Joe]

Sheldon Brown reckoned ammonia did the trick.

 

[Drago]

Was that just before Sheldon died a mysterious ammonia related death?

I think I'd take that and have it machined out if I wanted to preserve the paint.

 

[Yellow Saddle]

You made 2 mistakes:

1) You did not leave enough seatpost above the seat collar to work with.
2) You did not saw all the way through all the way down. Just the length of the wire you showed kinda proved that. Admittedly it would have been very difficult to get all the way down and that's why one should not insert long seatposts all the way down like that in the first place. Cut them down if necessary.

The only thing that keeps that post in there is swelling pressure, not a chemical bond. If it is sawn through, just the thickness of space created by the saw blade is enough to undo the swelling.

Anyway, stay away from the caustic stuff.

 

[lpretro1]

Should have taken it to The Seatpopst Man - http://www.theseatpostman.com/ - would have saved a world of pain

 

[Heltor Chasca]

Maybe give Argos Bikes in Bristol a bell if you are in the South West? I think they used to charge about £40 to remove a seatpost. But you might find that is with a workable amount of SP exposed. I believe they wang it about, which is a technical way of saying they put one end in a vice and wiggle and waggle the other end. This can bend frames. I've heard and tried the Coke trick too. Meant to break down oxidised metals. Didn't work on the bike I tried to rescue. But it was nice to have fizzy drinks in the house.

Not very positive, sorry, but I hope it works out ok for you.

 

[Dirtyhanz]

Oh dear that's not good you could try and put some heat to it might bundg it might not its fused together very very difficult to remove best of look sorry could not be more helpful

 

[Gravity Aided]

I've also heard household cleaning strength vinegar may help. I'm in rather the same predicament, only steel on steel, and I haven't sawn the seatpost.