Seatpost Stuck in Frame - with a difference

I had a good experience with Argos Cycles in Bristol a few years back. Aluminium frame (early Heckler) with alloy seat post. We tried all sorts before we sent a real mess for them to look at and they were done in a couple of days.

https://theseatpostman.com/ but depending on where you are there might be somewhere local that can do it

I put in a substantial amount of effort to remove an alloy seat post from an alloy Trek Domane for a mate. Lots of soaking in PlusGas, leverage, etc. In the end it was heating with repeated kettles of hot water poured over slowly that got it going.
I'm not sure that will work as well with a steel frame :/

That's a good one John, well done 😀

Not much left there to work with!

Iain at The Bike Works in Stirling has a marvellous contraption for getting stuck posts out, but given there's not much to go on there I'm unsure it'd work.

View this post on Instagram

I was trying to remember where that went after the Bike Doctor closed his doors

EDIT: Ooft, hadn’t sent the photo before!

Ha ha Scruff.

It's messy and gross but Caustic Soda might well be the best option at this point! As I'm assuming you can't get a saw blade down there. I might be stating the obvious but if you go down this route I'd strip the whole bike down first! A mate once took his bike to Halfords with a stuck seat post. They didn't strip the bike down and the CS got into the other frame tubes and wrecked other components such as the headset and fork. I'd rinse the frame out after and let it dry. Yum yum!

Anyone ever tried using gallium for this?

Caustic soda isn't that bad an option, as long as you're not in a hurry. I did an alloy post in a steel frame a few years ago and managed to keep paint work intact.
Definitely don't do it in the house and wear gloves and glasses and don't rush it. Can fizz up when pouring into the seat tube, so take it very easy.
The BB was sealed so I just filled up, left a couple of days, emptied and then filled up again.
Assume it would eat through what's left of the post, which could be an issue if the seat tube has holes that run through into the BB, be worth checking that first.
From memory had to order caustic soda crystals online and then dissolve them first.

Jeez, that's proper ****ed, isn't it!

Erm... Good luck!

Can you get a reciprocating saw blade in there?

+1 for caustic soda (and goggles + gloves).

The tricky part is sealing up the BB.

Given the alloy for the post seems particularly soft, can you not now hammer a small screwdriver in between the frame and what's left of the post to begin to separate it?

I'm not too keen on messing with the caustic soda but I will if I have to. Because the remains of the steel inner are still there a hacksaw blade won't touch it and I'm reluctant to use a jigsaw or reciprocating saw.
I've filled in a message box on the Seatpostman's website and I'll wait for his reply before taking drastic action.

Thanks for the advice - what you can see in the picture is what was left after sticking it in the vice, tightening it up enough to stop it spinning and turning the frame as hard as I turned it half an hour earlier to undo a seized square taper bottom bracket.

Moral of the story - don't let your son have your bike for 2 years.

I was dreading the caustic but having done it once it would be my first go to now.
It's so easy. It didn't even mark the paint on a frame I did.

Seal the frame with corks & plasticine. Just leave it outside the shed and tip a bit in every evening, by the end of the week the post will be liquid.

It's zero effort.

Seatpost aside, is that a ghost in the background? And where do you get Adidas branded curtains from?

OK then the caustic soda advocates: what concentration do I need?

I've got some old plastic bottles in the garage that say caustic soda, but may have a mix of sodium hydroxide and sodium carbonate. Should I use that or try to find a shop with pure caustic soda?

I'd go from above with a thin chisel.

Well, that's well and truly fubarred.

is that a ghost in the background?

That's Mrs John saying "Oh FFS, you've borked that"

I just bought the off the shelf stuff in Robert Dyas mixed it up strong in a pyrex jug. It gets HOT, don't use plastic.

Is there any way you can cut it flush? You could then seal the seat tube with tape and pour it from the bottom bracket using a funnel.

Only pour a bit at a time, when it starts working it will bubble up.

Leave that bit overnight, tip it into a bucket and repeat for a few nights. Post will be liquid by the weekend.

I've done a couple with expanding reamers but it is exhausting, takes hours and won't work with the steel dropper guts in the way.

If it were mine I'd be very carefully doing it using caustic.

Melting it out with a brazing blowtorch is also a fast and surprisingly effective option but obviously trashes the paint....

In my head the process that may work:
Frame in a jig
Drill centrally down the existing post to remove the steel parts of the dropper
Mill out the rest of the seatpost

Zero damage

I've got the same jig from Stirling if you are near Sheffield and anything left to grip onto

NaOH, why are you thinking anything else?

Have you tried freezing the inner post alu

Thanks for reminding me I need to loosen my collar and give my post a bit of a wiggle and regrease it.

Thanks

Wasn’t there an article or post on here recently about a chap that specialises in removing seized posts?

Wasn’t there an article or post on here recently about a chap that specialises in removing seized posts?

There was an article in Cranked a few issues back, if that's what you're thinking of.

I'd probably go caustic soda, but I've removed one with a similar amount left outside the frame recently, using a hacksaw. You might be able to do the same if you can get the steel out with the right size holesaw, though you'll need some sort of extension.

Had a discussion with a bike mechanic at the weekend. He said the worst he ever had he managed to drill out then pick out the remains. Finding the 30/31mm diameter drill bit may be awkward though.

Already posted above is a link to The Seatpost Man and he has featured in this Mag. He is in Chorley, which is then other side of the Pennines to me. I had occasion to use his service last year and you really can't go wrong if you want to save the bike. Less of my seatpost tube remained visible than on yours. I sent the guy a thanks which sums up my experience and this is what I said:-

Thanks again for extracting the remains of my broken seatpost from my Charge Duster Ti framed bike last week. It was such a relief not to have to write off a good bike. All done without any damage or marks to the bike frame. Much appreciate the excellent customer service that you give. It is such a refreshing change to be able to make an appointment at short notice, bring the bike along and have the job done in a few hours. Not only that but for you to meet me at the railway station, collect the bike and return, is so much more than you expect these days and it was nice to chat with you too.
And whilst I waited the large park near to the town centre was great for a walk and the café at Astley Hall in the park does excellent food at lunchtime.
Thanks again for your excellent service.

Seat post man retrieved a very stuck reverb from my cotic Solaris.

I'd not quite got as far as the original picture in my attempts, but had used oil, coke (the drink!) vice, drills and made a hole perpendicular to the post axis to stick a rod through to try and rotate it.

I left it for an hour or so and came back to find the frame in great condition.

Well worth the cost.