I've recently found a nice bike with a steel frame. Well I noticed the aluminium seatpost was stuck but had no idea how heavily. To be honest I never had a similar problem and underestimated that beast...
So here's my question. I'm pretty sure the problem comes from the galvanic corrosion between the two materials, I understand that the post gets thicker due to this and therefore is stuck. Now I made some measurements of the seatpost diameter which gave me 27 mm which is correct. Then I moved on to the frame, measuring the diameter just at the top and on a few positions further down. The result is, there's quite some variation: 29.7mm at top, 28.7mm further down. I've attached some photos: https://photos.app.goo.gl/Yt3s3ycS74GfBagA6
to me this sounds quite heavy and I would like to have your opinion what to try next: a) try some chemicals b) cut out the seatpost c) sell the bike again (I wouldn't like to because I really like the frame, it's a Fuji Feather)
concerning a) I already tried WD40 without luck. I've got the hint to try ammonia: Remove bottom bracket, having the bike hanging upside down fill the tube with ammonia and leave it for at least 2 weeks. Then there's hope to get it out.
concerning b) what tools would you suggest for such an act? How can I prevent to ruin the frame?
thanks in advance!