I have a seatpost (aluminum)t stuck in a titanium tube. I believe some form of oxidation has happened over the years and would appreciate any tips on getting it out. The bike needs to be restored and this the one thing is holding me up.

Thanks folks,

Robert

Since this is aluminum in Titanium you may be SOL because those two materials bond themselves together very well. spray some good penetrating oil in the seat tube from through one of the breath holes in the bb. if you dont care about the seatpost it self after letting the penetrating fluid work for a bit. clamp the seatpost in a vise and while pulling on hte frame twist the frame back and forth.

if you don't care about the seatpost, this may work:

apply some penetrating fluid and let stand overnight (i'm sure you have already)
flip the frame upside down and clamp seatpost firmly in a vise
crank the vise tight
wiggle the frame forward and back, it may break loose
if the post is still stubborn, apply some heat with a propane torch, wiggle some more

i have removed severely frozen posts in this manner. be careful not to tweak your stays when trying to break the post loose. you might put an old hub in the dropouts to hold everything in place. if that doesn't work, i have some tips on how to get seriously medieval on that thing. lmk

use anti-seize compund generously for next build.

Before you try to take the post out let it get REAL cold by placing it outside. Aluminum has a high contraction rate when it is cooled so it may shrink enough to slip out easier. Get an old stem and clamp it to the post then give the post a solid smack downward to loosen it then try twisting the stem. It works for me every time.
NUTZ

Thanks for the advice. Being as it will be below zero tonight I will let her "chill". I have been reluctant to do too much as the seat is still attached to the post but I will try all methods put forth. I was afraid of breaking the seat and being SOL. This particular bike is a 74' or 75' jr, looptail for my son so it has to be perfect in the end.

When I put it back together I will use plenty of anti-seize.

Thanks again

also be sure to hone the seat tube with one of those beaded thingies that go on a drill. you should be able to get one at a hardware store or even a gun shop might have one. don't use anything that will remove any quantity of material though.

Which metal "melts" faster?

Vice idea is good, wiggle, and twist, and then if ya place a floor jack just right, you might be able to use the jack to seperate them. Just make sure you use something to "protect" the frame first. And if it that doesnt work.... Just send me all of your GT stuff Hey, someone has to keep it safe
(did you see that sweet mini f/f Vic has?)

A slide hammer works great for getting those posts out. Better than anything else. If you've ever used an impact gun, you'll know that you can remove rusty bolts/nuts without breaking much easier than by twisting force alone.

Not tryin' to hijack this post,but I've recently had success with the vise trick.I had a real nightmare,a 26mm post hammered into a 25.4 tube!Finally got some time on my hands,which is a good thing,because it took over 2 hours!Found out that you may have to run cold water through the seat post,it heats up alot.Btw,that little trick is what alloyed me to remove almost 3 inches of post!

Least amount of damage is to drill it out with a high speed drill bit.It will eat the aluminum like butter and will not harm the ti frame in any way unless your using a diamond drill bit what is needed to cut grind etc titanium. Using oil twisting etc is a lot more work than is really needed.If it works great.But I can guarantee you my method will work in one shot even if the post is 10 " into the frame. Good Luck and may the best method work for you.