peripatetic

I finally got access to the super's workshop/bench vise and tools, and I finally have the day free. Of course, after staring at this handicapped frame for over a year hanging on my wall forlornly, I got overzealous in my attempts to extract the seatpost, and I resorted to the power saw sitting there.

Here is the result.


I must say, I am schocked at the thickness of this post. Aren't they normally no more than a mm or two thick? So now I'm kind of "stuck" myself. I don't think I'll be able to fit a hacksaw blade down into the post to cut it from the inside out. Where do I go from here?! I'm helpless right now!

(Should I post this to Mechanics, instead? People here are just a tad more tolerant of this kind of tomfoolery.)

ENGLISH 10SPEED

How far is the post into the tube?

USAZorro

Have you tried Coca Cola (presuming the post is aluminum alloy)? I'd pour a little in, let it sit a day, then turn the bike upside down, clamp the seat post in a vise nice and secure, and then twist the frame.

Grand Bois

Won't that just soak the BB in coke? I'd skip that first step.

new_dharma

doesn't ammonia work for aluminum (assuming it's stuck because of corrosion and wasn't hammered in)

spider-man

I would also try applying heat to the post. The two different types of metal (steel and aluminum) will expand at different rates. (Plus since you're applying the heat to just the post, it will expand the most.)

Obviously you don't want to heat the frame too much.

peripatetic

Can't tell at all. But it seems deep.

I soaked this overnight on several occasions in ammonia, including last night. I also poured more down there just before I put it in the vise. I think I needed another person or two to work with the vise. I almost gave myself a hernia trying to twist the frame around the seatpost. But the problem now is that I've cut off the leverage point (the seat attachment piece--the part that's SQUARE). I can't really stick it into the vise and get a good grip on it...can I?

Stacey

A pipe wrench or some big arsed vise grips?

well biked

If the hole isn't big enough to fit a hacksaw blade, drill it out larger (measure how large you need the hole to be and buy a large drill bit at the hardware store if necessary, assuming you have access to a drill). Since it's obviously stuck very badly, and as you say you've cut the top of the post off so you can't very well get a good hold on it, I think the hacksaw method is going to be your best bet. FWIW, the method I've always found affective on a stuck post is to attach a junker saddle and pound on the nose of the saddle with a hammer, first one side and then the other. The leverage is excellent and the force from the hammer is substantial. Worst case, you break the junker saddle and/or seatpost clamp before the seatpost comes loose from the seat tube, but this method's never failed me. Too late to try it on that one, though-

ENGLISH 10SPEED

Maybe a normal hacksaw blade won't fit-what about a junior hacksaw blade or a copping saw blade.
Also poke a wire down the center applying pressure to one side when you feel the end of the seatpost-
remove wire and measure-this will tell you how far it is in.

McDave

This is the correct answer. Then clamp what's left of the seatpost into a bench vice and twist the whole bike to break the post free. (I can't take credit, believe I read it on Sheldon's website)

TimJ

I just got done removing a stuck stem from a frame. I used lye to dissolve the aluminum and it worked beautifully. I don't think you're going to get that out through any amount of force. Before I cut the stem off I had the forks in a brace made of 2x4s secured to a metal fence. I put a pipe through the stem (old, thick road stem) and pulled. I had a lot of leverage, so much leverage I bent the clamp of the stem without ever moving it in the fork. I also tried ammonia for days- never worked. I also drilled out large chunks of the stem, figuring if I got enough of it out then the rest could be freed... Nope. The aluminum had bonded to the steel, basically.

The tricky thing is to keep the lye off the paint and get a good seal so it doesn't leak out of where you're putting it. You'd need to cut the seatpost down as close to the seattube as possible. I think what I'd do then is coat the top of the seattube with some sort of silicone or epoxy or something- maybe that plastic stuff you dip tool handles into, shoe goo maybe, something that will protect the paint but will come off easily enough. Then figure out a way to plug up the seattube so the lye can do its work but won't run all over the seattube. Take out the BB and with a flexible spout pour some lye into the seattube.

This was much easier with a fork because there's no paint on the steerer tube. I used a plastic plug that went around the steerer tube and sealed it with- well first it was hot glue but the reaction gets hot so it melted that. Next was shoe goo and it got hot enough to melt a little gap at one point but after that it was great and only took a couple days to melt the stem away. I had a hard time finding lye. I eventually found it at a place that carried industrial cleaning supplies. Some drain openers are basically lye and they'll plainly state if they are.

USAZorro

Yeah - I got 'em mixed up. Ammonia for Aluminum, coke for steel.

I had a stuck stem in a fork that was a real bear. I hand-sawed the inside of the stem at 120 degree increments (roughly) until I was feeling worried that I was getting close to going through. I then crimped the protruding section of the stem, which reduced the area that was in contact between stem and tube. I put in a bit more loosening fluid in and let it soak for a day, and then used vice grips and vice (with padding). With a little bit of muscle, it came free with no damage to the fork.

I think the technique is transferrable to a seat post, but you obviously are dealing with one honkin' thick seat post there.

peripatetic

Right?! I had no idea that it was this thick! Who the heck made seatposts this thick?! SR Laprade. Why?! Strength, sure; so then why the heck would you bother with fluting? Obviously, not to save weight. So someone with more experience tell me I'm not crazy--this is an abnormally thick seatpost, right?

Hmmm. Okay. This is really tough. And to be honest, I don't really have the space or the resources to be dealing with this. Jeez. Zorro, your description was what I was hoping to do when I decided to cut off the top of the 'post, but the small size of the internal hole (maybe 4/5 mm, +/-) seems like it'll be impossible to get a blade in there. I guess the quickest next step is to try and get that junior blade or other small blade as suggested. But as point of reference, I cut off the top of this thing with a Dremel electric hacksaw, 18v. And while it cut easily, it was sort of slow going (imagine that moment after a long while of sawing when I actually cut through, and it began to dawn on me just how thick this post was. Ug.) So even if I can get a small blade down in there, the cutting time is going to be extraordinary. I mean, this thing looks like 6x thicker than any post I've ever seen! Will I even be able to crimp and bend it, provided I get it cut?

The other important point which someone alluded to, is I think that this is not so much a matter of being seized as perhaps being in too far. That also adds to the quandary. I don't know if the crimp and bend method will actually work very well, because there isn't enough to bend the post inwards. I guess I can drill it out. I do have a drill, but it's 12volts, not super powerful; don't know if that'll cut through. What kind of bit would I need?

This leaves me with lye, I guess. Ooooh, man. I don't have a bb remover/wrench whatever, so first I'm going to have to get one of those (which I need to do anyway: I realized when I removed the cranks that the bb needed replacing/rehauling.) Then I'll have to swing a system with a plug and paint protector, etc. TimJ, d'you think I could just use tape of some sort? Maybe electrical tape, carefully placed? All that plastic, gummy, pour-masking technique just sounds like yet another step I don't really want to try if I can avoid it. I don't have to worry about the lye on the inside of the frame? Will it at least clean out the inside?

Thanks a lot for all your suggestions, everyone. This has become very demoralizing .

Sammyboy

Lye you say? I've got a stuck seatpost that might just cost me $800 if I can't shift it. Been trying ammonia for weeks. Surely the smart thing is to remove the BB and pour it in from the bottom though? I'm totally gonna get some lye, the very moment I figure out what the hell that is........

peripatetic

Lye = NaOH, sodium hydroxide. The basic base. Base equivalent of HCl. It's used in lots of industrial settings, especially to make soap. Sammyboy, note TimJ's description above--it's not good for paint.

cuda2k

lye is nasty stuff, read lots of procautionary information FIRST.

well biked

Measure the width of the hacksaw blade, then go to the hardware store and get a drill bit that's for drilling through metal, in a size that's slightly larger than the width of the hacksaw blade. The aluminum post is a fairly soft material, you shouldn't have any problem drilling into it (especially since it's already got a huge pilot hole), even with a 12v drill. Once that's done, insert the blade into the hole, and begin the process of cutting the post. Again, aluminum is soft, it can be done. I've seen my grandfather cut galvanized steel using a similar method in tight places (he was a plumber). "It's a slow road," he'd say when he was about half done. Then he'd hand the blade to me.........What you're seeing with the thickness of that SR Laprade post is the difference in the aluminum alloys they used back then vs. the more refined stuff they use today. I've got a newish Thomson post on one of my mtb's, the post is taper walled 7075 alumuminum, and the tapering is to insure that not one ounce of material is used that's not needed. A definite contrast to an SR Laprade, for sure. And I think the flutes are for added stiffness, not weight savings. That, and maybe the cool look they give, I don't know-

Sammyboy

Well, ammonia is nasty too, but I seem to have managed with that. The through-the-bb-shell method keeps it away from the paint nicely. However, I will take a look.

peripatetic

Great. Thanks for the tips. I'll work this way first. Even if the fluting were for stiffness, on this post, it's minimal relative to the thickness of the post. I've read the long debate about fluting, but this is one case where none of the usual justifications make sense.

Sammyboy, not to be patronizing, but simply informative, lye is far nastier than ammonia--to your skin as well as to any paint on a frame. Pure base. It can give a person serious burns from even minimal contact. As I recall the bikes you have, you really don't want to take any unnecessary chances with the stuff. Be careful.

TimJ

I tried taping up the bottom with duct tape at first and it didn't work that great. Shoe goo, for instance, if you don't know what it is it's just a silicone (I believe) based adhesive marketed to glue the sole on your shoe back together. If you had a tube of that, or even aquarium sealant which is just pure silicone, just spread it around the top of the seattube everywhere some errant lye might leak and it should protect the paint. That's seperate from the issue of plugging it up so the lye stays in there.

I mean, disolving the seatpost is like the crappiest way to deal with this, but if you try other stuff and it just won't budge, it's the last resort. I tried cutting my stem out and may have been able to do so, but it would have meant a couple hours sawing each side, at least, and that's a lot of time spent doing something I'd really rather not be doing (I already spent 8 hours at work each day - ba-zing!). I drilled that sucker as much as I could. I actually removed about 60% of the top half of the stem and the thing still wouldn't budge. So I stuck the fork in a bucket, poured in some poison and after a few days there was nothing left.

TimJ

Oh yeah- wear big rubber gloves and eye goggles when messing with lye. Since you're using a small amount in a very small space (the seattube) you don't have to do it outside- a room with a window is fine. That's what I did and, sure, I can't remember what number comes after 8, but everything else is fine.

aussiepug

I used the Lye method on a stuck headstem. It pretty potent and dagerous but works ...


https://www.bikeforums.net/classic-vintage/199130-old-new-me-531-paconi-stuck-stem.html

colnagorider

I would just like to add word of caution in the idea of using the drilling out method. Even though aluminum is soft, my experience with drilling it is that there is the possibility of shattering your drill bit. I know it seems impossible, but I did it once about 20+ years ago with a 1/2 " drill bit. It shattered not in the shank which was 3/8" but in the fluted area. The bit was not new but was sharp and in good condition. I saw it happen at work about 5 years ago. The position you will be in when drilling into the seatpost will put you in a very vulnerable position for injury due to that possibility. Should that not occur, the possibility of your drill jerking is even greater, granted you will be using a cordless drill but I have seen those become much more powerful than in the past. If you choose to use a power drill, use extra caution because, once again the position you will be in is not optimal. I have seen a strong wrist get broken while using a drill. Just be careful and if at all possible use a handle on the drill.

Also remember that if you drill it out and can't remove it that way you will have nothing to wok with because the post will be thinner and break easily with tools. My recommendation in that instance is to fit a tube or pipe in the top of the seatpost, that is snug, to help keep it from collapsing while trying to remove it with tools.

FlatTop

I'm wondering if a slide hammer with a hook might budge that seatpost. Not hard to rig something up from scrapmetal, or borrow the tool from an auto bodyshop.
You'd have to anchor the frame, maybe with one foot on the bb. The pull would be up and out, rather than rotary motion.