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Old 06-11-2014, 08:17 PM
DSpangenberg DSpangenberg is offline
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Default Re: Electrolysis: Distance btw anode/cathode, current, and more

Quote:
Originally Posted by TFlood View Post
Hi DSpang... thx for you input. Here's some interesting info I found about current/voltage from http://myweb.tiscali.co.uk/andyspatch/rust.htm

The writer states, I think, you should aim for 1mA per square centimeter of the cathode exposed, but it's a little unclear in his writing. I dont know if this means all sides of your cathode or only that which faces the anode, or maybe he's talking area of both cathode and anode. One can play with voltage settings and resistance variables such as distance or series loads to try to achieve this.

One notable thing he points out is that too much current can result in "split up into its component parts resulting in large amounts of explosive hydrogen being evolved at the cathode".. I think what this guy is getting at is too much current is not ideal.
That is a very interesting article! My interpretation of what he said is 1 mill-amp per sq cm of the entire cathode (the piece being de-rusted). This equates to 6ma per 1 sq inch or 1 amp of current for every 166 square inches or 1.15 sq feet.

I did a rough calculation on a 12" diameter skillet and came up with approx 308 sq inches (assuming 2" high sides and a 5" long x 3/4 wide handle)
Applying his 1ma per sq cm I get 1.98 amps for a 12" skillet. So clearly I am using too many amps when I put a single pan in and apply 4 amps.

This statement interested me
"Put simply, if too high a current is allowed to flow from the start, the deposited iron will be very porous and possibly become detached from the surface and the rapid hydrogen bubble production can blast off rust which could possibly have been recovered using gentler methods."


I guess I didn't realize that part of the anode is being deposited on the pan, but it does make sense. I did some searching and found a great article that talks about this issue and why a carbon anode is preferred. http://www.fordgarage.com/pages/elec...cderusting.htm
He states
"One major advantage of using carbon (graphite) material for the anode is that no iron is deposited on the part. Instead, the part gets a loose 'plating' of carbon, which is pretty easily washed and brushed off, and does not promote subsequent re-rusting."
Hmmm...this makes me really wonder if we are compromising the surface of our pans when we somewhat haphazardly apply amps via a battery charger. I saw plenty of bubbles and figured it was working great! Add some more anode and got even more bubbles...even better no? Maybe not!

Has anyone experienced this or notice any degradation of the part due to how the iron is deposited? You may not notice it on a pan that is already pitted and has a less than perfect surface, but I have a couple that still have very clear factory milling marks and I'm not interested in changing that surface, even slightly.

I guess I'm going to hunt for some carbon anodes before I do any more pans and try doing it at a lower amp setting!

Thanks for the reference!
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