This seatpost has won many battles, but it will not win the war. (I am putting a stupid amount of effort into an already f’d frame)

Coca-cola? Bag it up with 2L bottle of Coke for a week.

Blind bearing puller

Never give up!

Never surrender!

Tbh I just recip saw those suckers out. Done enough that I usually end up only touching the inside of seattube a hair or more then when I’m ready to build up I use my finger to throw lil metal epoxy in the saw cut smooth it out , hone it. Throw my seat post in n set n forget it 🤫

Is this the same stuck seatpost I just saw on r/framebuilding?

Lye worked great for me in this situation. Make sure you cover the paint if you want to keep it

Pb blaster; or pour auto-trans fluid on it

sodium hydroxide (lye). It works. I’ve done it with two frames now.

Plug the tube under the post from the bottom bracket as well you can, cut as much of the seat post off as you can… and then just start funelling lye/water solution over it a little bit at a time adding more when it spills out until the post is melted. Should take a couple hours.

Wear rubber gloves and goggles and don’t get it on you or in you at all, extremely caustic.

whatever method you use and works, nothing feels better when it releases.

Take it to a good machine shop! This happened to me, and the bike shop owner who was also a machinist bore it out, fraction of a millimeter at a time.

Have you tried paraffin and heat?

I had a seized post like this. I ended up having to use the softest sawzall blade I could find (one that was not for steel) and carefully cut a slit down the inside of the post. It worked for me.

Only works with aluminum post and steel frame.