Originally Posted by max-a-mill
so i got a piece of aluminum seatpost thoroughly stuck in an older steel frame i just got to try and fix up for my ladyfriend. my big wrench wont budge it.... and it needs to come out!
i heard from someone that it might be possible to melt the aluminum post out by using some sort of chemical??? anyone heard of this madness? or anyother good tips for dislodging a stuck piece of a seatpost?
Safety first! I am not a bike mechanic, but I am a metallurgist. The only thing that will melt aluminum is heat. Most aluminum alloys melt at 660 C (1220 F), however aluminum will also readily burn. I would be careful with any chemicals like acids, as aluminum is a fairly reactive metal. It will generate quite a bit of heat and harmful vapors.
If aluminum oxide (corrosion) is the cause of the "stuckness" you can use ammonia to dissolve it. Or you can always cut it out.
See this website for good ideas:
http://www.sheldonbrown.com/stuck-seatposts.html