Stuck alu in ti

[hotbuns]

Hi all,

Got a stuck aluminium seatpost shim in my Hei Hei frame. I'm sure it's just due to the passage of time, but any hints on how to remove without resorting to a hacksaw blade? I've heard ammonia may help with alu but any other more friendly options out there?

Al

 

[cyfa2809]

have you tried shocking it?
take a few steps back, cover your face and jump at it saying BOO

 

[cyfa2809]

seriously though, if you can find a way of bashing it to try and dislodge it

or some wd-40/gt85. maybe try and get a screwdriver under it?

 

[hotbuns]

It's a contender, although a bit weary of the screwdriver option after dislodging a stuck seatpost on my Moulton, only to crack the fresh paint job because of the screwdriver digging into the tubing. <has idea > grind a specially radiused non-sharp screwdriver to try again. Currently entertaining the 'immersion in Coca Cola' to free it up idea aswell. Apparently, PlusGas won't do much with alloys

 

[Andy R]

I wouldn't even think of hammering a screwdriver in alongside the shim - that's ging to risk damaging the seat tube.

Presumably the shim is split? Either split the other side using a padsaw or make up a slide hammer using a piece of bar with a with a "hook" that will locate under the shim and drive it out that way.

Soak it in diesel overnight and apply a bit of heat - presumably you have no paint to damage?

 

[hotbuns]

Yeah, after the Moulton I'd rather not touch a screwdriver. The shim has a small slot in it that mimmicks the frame clamp area. No, there's no paint involved which is one good thing! Thanks for the diesel tip, I'll give that a try if the Coke thing fails (I'd be amazed if it works)

 

[Andy R]

Reading your other post on this subject - if it's an original factory fitted shim might it not be bonded?

 

[Huntso]

Plus gas might help and then try knocking it out with blunt screwdriver and mallet

 

[Andy R]

Plus gas might help and then try knocking it out with blunt screwdriver and mallet

But you can't get to the back of it to "knock it out" - except, as I said above, by knocking up (no pun intended) some sort of slide hammer.

 

[Tallpaul]

The OP's statement that the shim is 'stuck' is misleading. It is an alloy sleeve that was fitted to Kona Hei Hei's at manufacture. It won't easily come out as it was never designed to; I'm not sure if they were bonded or press-fit but either way attacking it with tools is most likely going to do more harm than good.

As I said on the other thread, assuming you haven't already damaged the insert, I would have it reamed out to 27.2mm.