I was just starting to think I was going to have to resort to real brute force and ignorance to get the Thomson seat post out of my Gryphon frame.
Deciding to calm down a bit, I did a bit of googling and came up with Finish Line Chill Zone penetrating lubricant. I even found it in a local bike shop open on a Sunday (thanks Rides on Air in Wallingford). I chucked a load around the top of the post and some more by turning the frame over and injecting through a removed bottle holder screw hole. Gave it five minutes and it worked.
To say i’m relieved is an under statement.
Wish I’d known about this stuff last weekend when I was working on the car.

Most people normally try penetrating fluid before resorting to blowtorches and other brutal methods, so what you describe sounds unsurprising.

Had you tried WD40 beforehand (or something similar), and found that this Finish Line stuff is much better ?

Glad you got it sorted anyhow 😉

I’d been using WD40 for about four days, dosing every evening to no avail. heat was a definite no no as I’ve got steel frame and ally post.
I trained as a mechanical instrument make originally, so brute force is definitely the last resort.
I was sceptical of the finish line, but it worked. it seems to be a combination of freezing agent and penetrant.

Good to hear someone had success with a seized seatpost. For a while lots of lower end road bikes would come with a ‘carbon seatpost’ that was really a cheap uncoated alloy job with a thin wrap of carbon material around the outside. Moisture gets into them very quickly and they swell up like Rawl plugs, killing the frame. Thankfully you don’t see those posts much anymore.

People on here resort too quickly to heat and other barbaric methods to remove seized stuff. I’ve been a Retrobike regular for a while and have learnt lots of kind ways to do the same job – essential if you have an old valuable frame with a unique paint finish.