Electrolysis question

[julianf]

Imagine a tube, with a base welded on.
There's rust on the inner face of the base.

Will electrolysis ever remove this rust, as there would always be a shorter path for the current?

(unless the electrode is placed down the tube to its base, but assuming this is not possible)

 

[AndersK]

If the diameter is very large in relation to length it will. Otherwise you will only get effect close to the opening.

 

[The_Yellow_Ardvark]

It will, my bucket has 1" wire mesh arranged in 2 layers.
It works, slightly longer than surrounding the part with sacrificial bars on the side of the bucket.
Plus is "Pulls" down the removed rust to the bottom.

 

[julianf]

This is the actual job -

Its a fuel tank. It will, im sure, leak from the seam.

My plan is to use electrolysis to clean up the seam, and then run a fresh bead of weld arround it.


There was further damage to the sides, but thats a much easier fix.

Its fizzing away, but i know the single anode will limit things - im in no rush though.

 

[julianf]

ps -

i know the outside of the anode is painted. im using naoh, so that wont be the case for long.

 

[Swift&Bold]

It will.....eventually!

 

[500e]

Why not insulate the electrode with only an end showing then you could position it to give max cleaning where you required

 

[Swift&Bold]

The thing with electrolysis is that when the process is complete then it stops, so if the rust has gone from the point nearest the Anode then it will move up the workpiece until there is no more to work on.
It may not leave you a bright surface but it will 'detach' the rust from the metal to make it easier to remove and what can't be removed has been converted and the clean surface covered in that black, messy stuff which acts as an inhibitor itself.

 

[julianf]

In answer to the last two comments -

500e:

Its getting down into the base of the seam that im on about. Ill never be able to make the bottom of the seam the closest place to the electrode.

Sip:

That's what i was wondering - i mean, if you put a clean bit of metal in the bath, with some rust at the furthest point, maybe not even line of sight, would the current still flow to that point, or would it 'short' out on the closer, clean metal?

 

[Swift&Bold]

Yep, it would work it's way around to the rust, it'll just take longer than, 'Line of sight'.
Just remember than electricity is lazy but tenacious, it will always take the easiest route, if that route is blocked then it will find the next easiest route.