In a moment of haste (not to say greed) I bought a bike cheaply at the end of a recent swap, thinking it would be a quick clean and flip. And as usual when you make a snap decision, I was careless and did not check the seatpost, which is frozen. In the last few years I've bought and worked on 25-30 bikes, all with steel frames, and I have not been burned by this common malady, so maybe that lulled me into complacency.

Anyway, it's a 1989 Fuji Roubaix, a very nice frame for the time, with an SR seatpost. Naturally I consulted the archives here, at Sheldon's site, and everywhere else I could find.

I have a jumbo crescent wrench, so after applying quite a bit of PB blaster inside and out, my first step was to get that on the 'flats' at the top of the seatpost, and try turning it. No dice. Then I added a 'cheater,' a 4' long pipe that fits over the wrench handle. Also no go.

I took a 5 lb sledge and gave the post some good raps on the top and a few on the sides, hoping that might 'vibrate' something loose, but again to no avail.

I tried ammonia down the seat tube (household strength) for a week while I was out of town, but that did nothing I could detect. I have blueprint strength ammonia too but am reluctant to get into that as it's quite dangerous.

The problem as you know is not caused by rust, but by a chemical reaction from the aluminum post, causing aluminum oxide to bond to the steel seat tube. A lot of references talk of using heat on the post, but aluminum reacts faster and more to heat than steel, so that would seem to be the opposite thing to do.

However I had a heat gun handy and tried various things with it; the main one being heating up the seattube and then quickly squirting an inverted dust-off can into two holes I'd drilled in the post, to get it very cold while the tube was still hot. I did this several times, sometimes just with heat on the post. Nada.

The latest thing I've been doing is also not yielding any progress, though maybe the post is magically just about to fall out.

I have the frame inverted over a bucket outside, with the 'drain holes' in the post taped up, and tape over the chainstay and downtubes, off the BB shell. I've been putting crystal Drano (actually Zep, a copy) in there and leaving it for a while, as it heats up, bubbles, hisses, and spits out gas (smells strongly of ammonia, but it's apparently hydrogen) and have already been through one entire container of the stuff. The active ingredient in the 'drano' is lye, which should be dissolving the aluminum, and sometimes when I open up the drain holes, a black or grey sludge comes out. This is similar to what formed when I tested this method with a ball of aluminum foil and the drano.

However it's not actually loosened the post yet. There is a tiny bit of gap at one point as stuff has bubbled out between post and tube, but not enough to make it loose. I can't find the small dentist's mirror I used to own so haven't been able to look into the tube through the BB shell. I can't tell whether 99% or 1% of the post inside has been eaten away!

I'm reluctant to cut the top of the post off as that is a way to get leverage on it, but maybe I should do so anyway. And after all this I really don't want to go the sawblade route either. But I have got hours in the dang project already with nothing to show for it but a bucket full of sludge.

Any further advice welcome, esp from anyone who has done the Drano method successfully.