I heard Ammonia will do the trick, is that the best way?
How do you get a aluminum post out of a steel frame?
- Thread starter BigMike
- Start date
Which are you more fond of, the frame or the post?sanjuro said:
coca cola, mike.
c'mon you havent heard me rattle on about coca cola and its amazing powers before? seriously. take the bb out and pour coke into the seat tube of the frame from the bottom. let it sit over night and voila. problem solved.
c'mon you havent heard me rattle on about coca cola and its amazing powers before? seriously. take the bb out and pour coke into the seat tube of the frame from the bottom. let it sit over night and voila. problem solved.
If Coke doesn't work, a torch will do the trick. Just heat the seat post a little and it will let loose faster than the steel, you should be able to get it with a smack. If you let the post sit for 24 hours afterward, you can use it again without issue.
The heat trick can work. Not sure about the coke thing. To break it free, it's all about leverage: Flip it upside down, clamp the post in a vise, and turn the frame. (Be prepared to sacrifice the post.) You might try removing the BB, filling the seat tube with liquid wrench, and letting it sit upside down overnight first.
Not so sure on the heat idea in this application. Aluminum more readily conducts heat than steel, and as such will probably expand faster than the seat tube on the frame. Feel free to try it as it won't hurt anything if it doesn't work, just don't heat the suface too much or you'll aneal the frame and soften the steel considerably.
I'd go for the penetrating oil or coke, but not both at the same time down the tube ideas first.
As far as getting more leverage to twist on the seat post, drill a hole throuth the post a little ways down from the seat mount area. Make the hole big enough to get one of those big ass Craftsman flatheads in. Then you can use the screwdriver as a T-handle on the post. And if you need more leverage, slip a pipe over the screwdriver and extend the lever. If it you get totally stuck, take the bike down to a machine shop with a lathe and they'll make quick work of that seat post and shouldn't damage the frame at all.
Good luck with it,
Chris
I'd go for the penetrating oil or coke, but not both at the same time down the tube ideas first.
As far as getting more leverage to twist on the seat post, drill a hole throuth the post a little ways down from the seat mount area. Make the hole big enough to get one of those big ass Craftsman flatheads in. Then you can use the screwdriver as a T-handle on the post. And if you need more leverage, slip a pipe over the screwdriver and extend the lever. If it you get totally stuck, take the bike down to a machine shop with a lathe and they'll make quick work of that seat post and shouldn't damage the frame at all.
Good luck with it,
Chris
chuffer said:
I wonder if it would work for degreasing chains..?
Spray the sh*t out of it with WD40 the use a pipe wrench to remove the post.
Note: The seat post will be way F'ed up afterwards.
Note: The seat post will be way F'ed up afterwards.
Torch is a bad idea. The thermal coefficient of expansion of aluminum is 24, steel is 11 which is to say that the seat post expands about twice as much as the frame as the assembly is heated.
Kroil works wonders if you can find it locally, it will laugh in the general direction of WD40, Liquid Wrench, Coke, etc.
It is made by Kano Labs (kanolabs.com) and by the way, they have a free trial can offer on the site right now.
It is made by Kano Labs (kanolabs.com) and by the way, they have a free trial can offer on the site right now.
Mike B. said:
Best option.
not that i have heard of. the big use of coke that i have found is as the weapon of choice for freeing up old corrosion-siezed IBC motors. i am too drunk, too lazy and hate chemistry too much to bother trying to think about why it really works. First, second and third hand experience tells me it does though...atrokz said:
If it's so far gone there may be significant stresses transfered to the welds that connect the top tube and seat stays. Be wary, and check for crackage.BigMike said:
For the purposes of release, you need something that disolves or prefferentially oxidies aluminium oxide.
ok so first hold out your hand and quickly move it towards you face and follow through after contact.
JK...nah put the post in a vice and twist the frame
JK...nah put the post in a vice and twist the frame
chuffer said:
I knew I liked you for some reason
that kroil looks interesting....... I'll have to check it out!
If you say so, I just know it worked for me in the past. I have gotten a steel post out of an aluminum frame, an aluminum post out of a steel frame, and most importantly, a Chris King Steelset (with those awful deep cups) out of an aluminum frame using light heat from a torch and some leverage. Not too much heat, just enough to make it move. Also this did not damage anything.johnbryanpeters said:
2 of those 3 are the right way round for the torch to help.jimmydean said:
In the steel tube / alu post case a torch can sometimes help because often the Aluminium Oxide is hydrated and the torch can dry it out, which in turn lowers the volume of the oxide. If there isn't too much oxide yet this can allow the post to be forced out a little easier. However because the Alu does expand faster and you've already got compression issues if the oxide is bad you could be doing a world of bad to the frame.
Agreed. The one time i tried this method we had a CO2 fire extinguisher [spare] with the expansion funnel cut off and a short piece of hose clamped on.johnbryanpeters said:
We'd cut off the head of the seat post, leaving an aluminum tube. This was clamped into a bench vise.
After we'd heated the hell out of frame and post, we shot the CO2 into the post. After about 2-3 seconds, we started to twist like mad, one guy still keeping the torch on the frame.
Finally got it apart.
Frame: Fukt Paint.
SeatPost: Totally Fukt.
Fire Extinguisher: Mostly Fukt.
Stories: Priceless.