natterberry 

I can get dry ice at my local grocery store, and CO2 at a local tank filler, home brew store, or sporting goods store (paintball supplies).

jdawginsc 

And if you keep the saddle, you can sacrifice it again and again!

curbtender

Two man job. Used the old seat method and an extra large crescent wrench. I lifted and twisted the seat post while my buddy held the frame and hit up on the wrench with a mallet. Worked fairly quick.

LBCwanabe 

Draino crystals with just enough water to cover. Let simmer for a couple days outside or in a well ventilated area. Check and repeat as necessary. Of course you’ll need to plug some holes if you go this route. I’ve had good luck with this method. It took about a week to fully dissolve and had to removed in shards. It has to be crystals and not gel. This way you can make it more concentrated.

MiloFrance

Just a thought... if the frame has so little value that you're happy to drill a sizeable hole in the BB shell, is it really worth the effort and time to do this? Or is it sentimental value?

TXsailor

We might have I'm really not sure. There are some wineries not very far away. Do home brewers use dry ice?

Homebrew01

Plenty of frames intentionally drill holes in the BB shell. No big deal. Often done with their logo.

MiloFrance

Not structurally, but would you do it to a nice Pinarello or Masi?

mgopack42 

^^^^^ there is already a "M" shaped hole in the Masi, not sure about the Pinarello.^^^^^

curbtender

I was thinking for CO2.

verktyg 

Back in 2007 I picked up this Ironman dirt cheap sans wheels and saddle:



It came from some Tri rider in SoCal and was rode or at least abused hard and put away wet.

The first thing to go was the radar array bars then I started on the stuck seatpost. After a number of violent mechanical attempts I decided on major surgery.

After amputating the unnecessary top of the post I started cutting a slot in the rear with a jab saw and then a folding buck saw being careful not to cut into the seat tube.





After cutting an 1/8" slot all the way to the bottom of the seatpost I used a 20" pair of Channel Lock pliers to crush the seatpost enough to break it free from the seat tube.




Fortunately the Tange # 1 tubing had a double butted seat tube with a 0.9mm wall thickness at the top. I was able to ream out all of the corrosion in the seat tube and hone it to take a 27.2mm seatpost.

3 hours of work!!!

After a lot of clean up - a nice IM:



I wonder who the idjet at Western States was who came up with the idea to use a deeply fluted Sugino seatpost in a tri bike so water could easily get in???



verktyg

verktyg 

Back in December I spotted this 1986 Reynolds 753 Bernard Hinault Look bike at an LBS.

They were planning on restoring it but I talked them in to selling the bike to me as is. I didn't look the horse in the mouth too carefully until I got home.

These were pretty rare, only 250 or 500 of those frames made.

It was my size, 56cm and had an almost complete Mavic gruppo except for a Shimano FD, an SR MTE-100 adjustable setback seatpost a goofy SR bar and stem.



The first thing to go was that SR seatpost - I knew someone who wanted one of those. Not so fast!!! It's become a permanent fixture in the frame!

That's also when I noticed the rusty spokes and other clues that the bike had been abused by a tri ath idjet !

After several attempts to loosen the post by twisting, expanding the lug ears and so on, I tried 3 weeks of Kroil. No joy.

I'm taking it to a friend's shop who has a large vise on a stand bolted to the floor.

Reynolds 753 is pretty thin stuff. One gentle try in the big vise then it's surgery time - see my Ironman post above.

Idjet, Idjet, idjet !!! Just a little grease !!! May he have sand in his Vaseline !!!

verktyg

joeswamp

That's a gorgeous bike and those fluted seatposts are the worst...

Your best bet is 1) getting everything as cold as possible, and 2) impact, i.e. a slide hammer setup like RJ the bike guy demonstates on youtube.

The corrosion is very strong but also very brittle. It's very hard to break a glass by squeezing it, but easy to break by tapping it on a hard surface. This is why impact wrenches work so well on corroded fasteners -- the impact breaks the corrosion.

Twisting the frame is dangerous as it puts huge twisting forces on the seat tube, forces that thin tube is not designed to take...

If impact/cold doesn't work I'd try dissolving the seatpost.

verktyg 

Fluted seatpost are merely decorative and save the weight of maybe one wet crepitu, pet, scoreggia....

The Kroil has been in there for well over a month. My vise is on a wooden bench that's not very rigid. A few gentle attempts at twisting the frame held by 2 people with the seatpost held in a floor mounted vice may work and even save the seatpost.

Reynolds 753 seat tubes have a wall thickness of 0.5mm at the top. There is no way I'm going to risk dissolving the seatpost with chemicals or using an impact wrench or slide hammer.

If I can't remove the post intact, I'm going to carefully cut it out... A lot of work that I'm not looking forward to.

I don't suffer fools gladly... May the PO suffer many saddle sores if I have to go the surgical route.

verktyg
....

machinist42

I've enjoyed success using an ultrasonic cleaner and ammonia, alternated with penetrating fluids - I spray PB Blaster, wrap it in a plastic grocery store vegetable bag, and stuck it in the device filled with ammonia, then remove the bag, repeat. It may be that ultrasonic vibration and ammonia is sufficient? I don't know.

Haven't lost a frame, seat pillar or stem yet.

Homebrew01

Seatpost is OUT !!
No drastic action required. Frame was upside-down for a few weeks with Kroil sprayed down the seattube.
Today, I put the top of the seatpost in the bench vise, grabbed the head tube and rear dropout & twisted. It took moderate force, but nothing crazy and the bond "cracked".

Then it was just a matter of twisting & pulling for 5 minutes. The deepest part of the seatpost was dry, so not sure the kroil did any good, since it didn't seem to have penetrated the bond.

Homebrew01

What type of slide hammer ?? Why would that be dangerous ?

Are there cutouts in the BB shell ? Maybe my thought of sliding a bar through the BB, up inside the seatpost, then a few whacks with a mallet would break the bond ? It shouldn't stress the seat tube except in tension.

63rickert

The verktyg cut a slot method is very safe. If the corrosion is real bad cut two slots. Cutting aluminum has a completely different feel from cutting steel. When the saw touches frame metal you know it. The frame doesn't even get scratched, more like a polish mark. Need not take more than 15 minutes. Use a thin hacksaw blade, not some fat thing. Hacksaw blade can be held with fingers, no special handle necessary. First time takes longer from excess of caution. Will not work with super long MTB posts deep inside frames.

SJX426 

[/QUOTE} ….Reynolds 753 seat tubes have a wall thickness of 0.5mm at the top. There is no way I'm going to risk dissolving the seatpost with chemicals or using an impact wrench or slide hammer.

If I can't remove the post intact, I'm going to carefully cut it out... A lot of work that I'm not looking forward to.

I don't suffer fools gladly... May the PO suffer many saddle sores if I have to go the surgical route.

verktyg
....[/QUOTE]

I can understand your concern. I used lye on a steel frame with no impact to the steel. The AL all but disappeared in a cloud of H2. The paint is subject to damage, however.
P1030272, on Flickr
P1030290, on Flickr
WP_20160107_001, on Flickr
P1030378, on Flickr

Slightspeed

Nice job. I had the same issue a few years ago with a Raleigh 531 frame and aluminium post. I asked a bike shop friend, and he said, lots of PB Blaster and patience, mostly patience. I removed the BB, inverted the frame and pumped in large quantities of PB Blaster. On the third day, I felt some movement from clamping the post in a bench vice. I was so excited, I broke it loose, forgetting the big slurpee of PB in the seat tube which dumped all over the floor, work bench, etc. But at least it came out. The previous "owner" must have used a pipe wrench on the post, which marked it up, but didn't move it. It also cracked the seat stay braze, so he pitched it all in the scrap pile, where I found it. Turned out to be one of my favorite bikes - a '73 Super Course. I was so desparate (this was my first ever build), that I tried the hot and cold method too. I filled a coffee can with ice cube slurry, and left the frame and ice out in a 100° day, thinking the frame would heat up and expand, while the frozen post shrunk. No joy, till I tried the PB Blaster.

As found in scrap pile.

Built into a nice ride. Never give up!

Johno59

Sometimes the anodised weld between the ally post and the frame is so complete even quarter portions of a fully divided seatpost won't budge.
A blowtorch flame directed straight down a decapitated post melts the post in around 5 minutes and you just shake it out hi.
You have to repaint the frame's seatpost ofcourse.