Sciencemadness Discussion Board

cover for cathode back suggestions ?

avi66 - 13-1-2011 at 18:20

I am looking for a chlorate cell/chlorine(inert material) which is non-conductive , which practical to use for covering the back of my cathodes to avoid corrosion(from low density) and large surface area(chlorate reduction undesirable), i already try to press molten\sticky pvc part against my 316 steel cathode after sandblast/drill, its wasn't stick at all, somebody have batter suggestions ?

hkparker - 13-1-2011 at 18:27

Maybe this wont work at all and isk if its worth the risk to try but mighty putty or some sort of epoxy? Ive used that in joining glass parts together for distillation and it withholds concentrated nitric acid.

avi66 - 14-1-2011 at 05:53

organic epoxy's usually degrade by the chlorine and temperature, pvc, ptfe, and pet plastics are resist to the chlorine corrosion in the cell, somebody know how to apply a layer of plastic or some sort of material strongly to the back of the cathode ?
usually when you melt plastic on the cathode, its wont stick, so somebody know how this procedure is usually done ?

[Edited on 14-1-2011 by avi66]

watson.fawkes - 14-1-2011 at 07:13

Quote: Originally posted by avi66  
I am looking for a chlorate cell/chlorine(inert material) which is non-conductive , which practical to use for covering the back of my cathodes to avoid corrosion(from low density) and large surface area(chlorate reduction undesirable), i already try to press molten\sticky pvc part against my 316 steel cathode after sandblast/drill, its wasn't stick at all, somebody have batter suggestions ?
Use a mesh material, rather than a plate material, which will greatly reduce the difference in electrolyte-path resistance between front and back surfaces.

avi66 - 14-1-2011 at 07:34

i know .... but i don't have a mesh material !
there most be a material which block the electricity behind the cathode ....
ill keep searching !

dann2 - 15-1-2011 at 14:01

Hello,


If you have a drill you have mesh material. Just drill lots of holes in your flat plate material.

I have used plexiglass (perspex) bolted to flat plate.
PVC would also be OK or any resistant plastic.
I would think you could simply tie on a flat pieces of plastic to the Cathodes using cable ties.
Glass or ceramic would do to,

Dann2

avi66 - 16-1-2011 at 02:03

Thanks dann2, i think i will adopt the holes method, i don't want ugly strings and unreliable plastic coat to take place in my professional cell.

garage chemist - 16-1-2011 at 03:58

Just use a titanium cathode, it doesn't corrode on the backside since it is resistant to the conditions in the cell even when no current is flowing.

avi66 - 16-1-2011 at 10:30

dear garage chemist, you want me to ruin my second precious titanium coated anode.. just to make cathode ? i will get steel 316 drill holes, and enjoy big cell will 2 anodes runing at crazy 35 a/h ! :D

[Edited on 16-1-2011 by avi66]

mnick12 - 16-1-2011 at 12:34

I have had some luck protecting my iron cathodes using 200-500mg of chromic acid or some dichromate salt. This doesnt stop all oxidation but it certainly does help. Also why not just add more electrolyte and cover the part of the cathode that is getting damaged, as long as current is flowing the reducing conditions should protect it. Also using Ti as a cathode certainly won't ruin the Ti.

garage chemist - 16-1-2011 at 12:58

avi66, please tell me why you think that using titanium as a cathode would ruin it.
Perhaps you misunderstood me and thought of coated titanium (a.k.a. MMO) as a cathode, which would indeed be a waste.
I was suggesting a cathode made of plain titanium, which I know to be working excellently.

avi66 - 16-1-2011 at 15:26

:D garage chemist you didn't understand what that i meant, i mean that i will not waist my titanium anode as a anode, or remove the anode coating from titanium to use it as cathode, because i don't have a spare cathode, i know that titanium is function perfectly as a cathode, i don't have choice, so i am forced to use 316 ss, i will drill holes in order to make a sensible current density in back of the cathode, to avoid corrosion&chlorate reduction, as much as possible.
Thanks for help guys !

[Edited on 16-1-2011 by avi66]