Author Topic: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame  (Read 5087 times)

cas_uk

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 Well it definitely worked gentlemen
here is what happens to aluminum when submerged into water and caustic soda:-

http://www.youtube.com/watch?v=Y7FmrOatEEA

What i did was :-

1. Purchase caustic soda (1kg container) from local B&Q for 4.49

2.Purchase two Corks (I bought two bottles of cheap y wine as the missus is going Friday and she don't need no corks!!)

3.Prep the bike for removal of post by completely stripping all other  (Aluminium) parts which left me with only the frame.

4.Sort a form of workbench/ area where it doesn't matter if i get it dirty, mine was an old table in the back garden(Caustic soda, water and Aluminum give off Nitrogen fumes,is very toxic,flammable and also makes everything smell like WEE WEE!!).

5.Arrange a drainage system, some kind of bucket underneath to catch the mess and waste product that your removing.

6.Start mixing the caustic soda with the water in a small pourable jug (I was mixing mine in a approx mix of 1.5pints of water to 150grams of caustic soda, this was quite concentrated though and i was experiencing quite a lot of temperature in the frame,not enough to burn my hand,but hot enough to make me careful how much i was mixing).

7.Cut the corks to bung up any holes in the frame where water might drain so the entire seat tube can be filled with solution.

8.Now start to put your gloves on (You forget this step and you will mega regret it, I was quite careful but accidentally spilled a tiny bit on my fingers and it started to eat my skin under my nails, which hurts like chili in the eye!! (Ive also had chili in the eye so it makes a good comparison!)

9. Pour your pre mixed solution into the seat tube and leave for 20-30mins, I was keeping an eye on it from the kitchen window and emptying and refilling every half hour,with a rinse between too to remove the alu which had been oxidized away.

10. After around 4-5hours you should be seeing the end of the tunnel, my process ended with a small, thin piece of alu left,which i managed to pull out with a thin nosed mole grips

Voila one frame with paint intact (hopefully) and no more seized in seat post!!!
hope this helps anyone who comes across this forum and gets stuck in the same predicament as me!

Cheers for reading.
Chris

Tristan

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Re: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame
« Reply #1 on: September 30, 2010, 06:16:10 PM »
Now you tell me!!!!
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markieboy

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Re: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame
« Reply #2 on: September 30, 2010, 07:50:57 PM »
In my bmx days, we used to use lots of WD40 and a stillsons wrench.
A Gentleman in the mountains, no matter what his means of access, should be appropriately attired at all times, specifically in a manner which befits his modesty and public decency.

cas_uk

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Re: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame
« Reply #3 on: September 30, 2010, 09:35:20 PM »
Now you tell me!!!!
whats wrong fella?

Pilau

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Re: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame
« Reply #4 on: September 30, 2010, 10:52:22 PM »
Tristan got his out via the MAN method!!!  ;)
In my bmx days, we used to use lots of WD40 and a stillsons wrench.

What you really need is Chuck Norris. If it were Chuck Norris's seat post the the bike would hand the seat post to you in gift wrap! ;D

cas_uk

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Re: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame
« Reply #5 on: September 30, 2010, 11:37:24 PM »
Tristan got his out via the MAN method!!!  ;)
In my bmx days, we used to use lots of WD40 and a stillsons wrench.

What you really need is Chuck Norris. If it were Chuck Norris's seat post the the bike would hand the seat post to you in gift wrap! ;D

thats funny!!!

stillsons wrench doesnt grip hold of it tight enough.not even with my vice like grip (i actually bent the handles of a mole grips once,think it was when i worked in action bikes!!!) must have had a red bull for breakfast!! ha

Pilau

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Re: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame
« Reply #6 on: September 30, 2010, 11:40:10 PM »
Tristan got his out via the MAN method!!!  ;)
In my bmx days, we used to use lots of WD40 and a stillsons wrench.

What you really need is Chuck Norris. If it were Chuck Norris's seat post the the bike would hand the seat post to you in gift wrap! ;D

thats funny!!!

stillsons wrench doesnt grip hold of it tight enough.not even with my vice like grip (i actually bent the handles of a mole grips once,think it was when i worked in action bikes!!!) must have had a red bull for breakfast!! ha

Perhaps you had been watching Chuck Norris films. Even watching Chuck in an admiring (but by no means gay) way can make you significantly stronger!  :D

cas_uk

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Re: Caustic soda for removing an aluminium seatpost from a steel/cromoly frame
« Reply #7 on: September 30, 2010, 11:45:49 PM »
Tristan got his out via the MAN method!!!  ;)
In my bmx days, we used to use lots of WD40 and a stillsons wrench.

What you really need is Chuck Norris. If it were Chuck Norris's seat post the the bike would hand the seat post to you in gift wrap! ;D

thats funny!!!

stillsons wrench doesnt grip hold of it tight enough.not even with my vice like grip (i actually bent the handles of a mole grips once,think it was when i worked in action bikes!!!) must have had a red bull for breakfast!! ha

Perhaps you had been watching Chuck Norris films. Even watching Chuck in an admiring (but by no means gay) way can make you significantly stronger!  :D

I havent of late,which prob explains why i feel like a girly 2nite!!! haha got another nine hours left of this shift 2nite!! erggghhh,NEED SOME STRNGTH AND ENEERGY!! will find some chuck norris on youtube now me thinks hahahahahaha