Caustic soda time

[dan28]

use expoxy putty from pound shop to make the bung if you put a flame to the expoxy it comes off
does the caustic soda cause bare steel to rust
i cleaned some fork sliders with wheel acid which is caustic a week later they rusted like hell

 

[konacarl]

Caustic soda shouldn’t touch steel. Maybe the sliders were aluminium.
On the stuck seatpost, could you cut it flush with the frame and leave it inverted it in a container of soda and hot water? That way it should get to where you need it.

 

[MR OX]

Caustic soda shouldn’t touch steel. Maybe the sliders were aluminium.
On the stuck seatpost, could you cut it flush with the frame and leave it inverted it in a container of soda and hot water? That way it should get to where you need it.

I'm more about finding the best way to use the caustic soda through a bit of trial & error rather then getting the post out if that makes sense?
Looking for the perfect recipe

 

[konacarl]

Using Boiling water makes it react better.

 

[kingoffootball]

Using Boiling water makes it react better.

I'd recommend not doing this. Sodium hydroxide and water is an exothermic reaction, so it gets pretty hot when you mix the solution anyway. Also, shaking it might not be clever ....

 

[Rampage]

Using boiling water can cause it to explode.
The fumes at any temperature can burn your lungs. The fumes at higher temperatures are far worse.

 

[integerspin]

I have posted this before.
The best solution strength is not a lot, strong enough to raise the temperature of cold water to warm.
But If you mix it strong enougth for the water to be hot, the solution will boil when it finds
some aluminium to react with; it usualy blows it self out of the tubes at this strengh.

I did post some pics of taking a marin seat post out, I measured the temp of the water and even mixed a
bit to strong to see how hot was to hot.

If the seat post has been chopped off I block the open end. Then I hold the frame upside down and
pour the caustic through a bottle hole. You have to empty it out and flusgh it clean when the casutic
reaction slows down[when the frame cools down]. Then you fill with fresh caustic mix.

Does the caustic get hot and eat aluminium?
Pound shop caustic has other stuff in it and it doesn't do the job.

I sawed a post out of an aluminiun frame, pretty quick and easy.

 

[MR OX]

I have posted this before.
The best solution strength is not a lot, strong enough to raise the temperature of cold water to warm.
But If you mix it strong enougth for the water to be hot, the solution will boil when it finds
some aluminium to react with; it usualy blows it self out of the tubes at this strengh.

I did post some pics of taking a marin seat post out, I measured the temp of the water and even mixed a
bit to strong to see how hot was to hot.

If the seat post has been chopped off I block the open end. Then I hold the frame upside down and
pour the caustic through a bottle hole. You have to empty it out and flusgh it clean when the casutic
reaction slows down[when the frame cools down]. Then you fill with fresh caustic mix.

Does the caustic get hot and eat aluminium?
Pound shop caustic has other stuff in it and it doesn't do the job.

I sawed a post out of an aluminiun frame, pretty quick and easy.

I gets hot when I mix the solution up & has slowly been eating away at the post, I must admit I've been erring on the side of caution.
I've not re-filled it this week as I've n0t had the time to devote to it.
I'll track down your post & have a read

 

[MR OX]

It's finally out, what a blooming work up! Very messy No paint damage Would I got to all that effort again?

 

[Bawgixer]

I used cut up inner tubes to block off the seat tube at the top and cage holes the in the bb with funnel and hose
Took about 30/40mins