Hey guys,

I have a stuck seatpost that for the life of me, I can't get it out. Seems to have chemically welded itself to the frame. It's an aluminium seatpost in a steel frame. I've tried the following methods

Hammer and twist with old saddle
Soak in WD-40, twist frame in bench vise
Soak in windex (ammonia), twist frame in bench vise
Cut a slit along the seatpost, roll it up (seatpost cracks apart when I try to roll it up...it's glued)
Soak in lye, attempt to dissolve seatpost overnight, just won't dissolve completely, too much bulk

So now I have a seatpost that welded itself to the frame with the ID too small to put a smaller seatpost inside. Any other suggestions or cheap hole reaming tools?

How far in is the seatpost?

You can try an auto dent puller threaded through the mounting bracket if you can get a good enough purchase on the seatpost.

Try using a penetrating lubricant like Break Away.
you can also try some heat so long as you dont go hot enough to melt any of the brazing material.
Conversly, try cooling the aluminum seatpost with some dry ice to get it to shrink, or use a combination of cooling the aluminum and heating the steel.

My LBS soaked in Tri-Flow and twisted on mine for two months without success. Finally came loose after a bath in Corrosion-X. Look for it in gun shops. PB Blaster has a loyal following. I would expect the WD-40 to be about useless. YMMV

Jon Z.

@peugeophile

I'll try PB blaster. I've never seen a gun shop in my life, haha.

@sooprvylyn
It's pretty much flush with the end of the seat tube. My attempts at prying it out broke out what was left.

Get a star fangled nut for inside steertubes and cram it down in the seatpost, you may have to shave it down a little so it will fit, but it should be very very snug . That can at least give you something firm to grab onto as you try your other methods.

Time to cut it out with a hacksaw, very carefully!!!

I had a suspension seatpost that took at least 10 hours to remove(in many pieces).I didn't care much about the frame-hence the heavy handed methods.
Pipe wrench and hammer to finally get it to twist-lots of various penetrating oil-aluminum post-steel frame.
I then twisted it maybe 300-400 full turns-figuring it would loosen up- it didn't!!
3 lb Maul and large cold chisel hitting the top of the seatpost upward-maybe 200 hits-no outward movement.

Soaked several times in full strength HCL-great rust remover.
Rinsed-tried all above-no upward movement.

Pulled guts out of seatpost.
Took hacksaw with just a handle-made two cuts all the way down the seat post- cuts were 100% thru on 4" of the 8" post, and 80% thru the last 4".
Finally twisted it with channel locks after it was weakened by the hacksaw-out it came.

Really a miserable experience. I did have to slightly "adjust" the rear triangle after all this. I bought mainly for the parts-frame was just a bonus I'll sell for $10 or so(Chrome Moly Specialized-probably Katrined judging from the rust/silt)
Luck
Charlie
HCL is a good rust remover-. I suspect the chromo frame is a little more resistant to it than high carbon steel.I wouldn't use it on a frame I actually wanted.Much quicker than Citric or Oxalic acid( dangerous to work with-blind you-hard on lungs , burn skin etc). I had it around to etch concrete before painting.

I tried all of your listed methods to no avail. I finally just took the bike to my local shop and they drilled it out for about $35. Well worth the hassle it saved me, and my wife will tell you that I will go to great lengths to save a buck.

Thanks for all of the advice! Tried a ton of methods and so far still SOL. I'm going to my university's machine shop. Hopefully they have the right sized drill press or something.