Green goo on pan in electro tank

[Tommy Harris]

I pulled my breakfast griddle out of the tank yesterday and saw these blobs of goo on it.   I rinsed it off and scrubbed with the ss chore boy.   What is it from?  It did sit in the tank while I was at work and it wasn't running.   I believe this may be what caused the dark spots on my #3 Griswold I asked about before.   Any ideas?   

[Cheryl Watson]

Ruh Roh....

The dreaded Green Slim...

Which BTW, can damage the iron.

We have not quite figured this out completely, which is why I have a few cardinal rules that I follow:

1.  NO EXPOSED COPPER in the solution.
2.  Never leave a piece hanging in the solution without active current flowing.
3.  Always run at 20 AMPS, not below. 

I will have to search for some other posts on this.

Just reminds me of Galvanic Corrosion... JMO

[Cheryl Watson]

http://www.wagnerandgriswold.org/Attachments/CR1340024758.pdf

[Jeff Friend]

That skimpy copper wire . . . is that how you connect the pan to the negative charger lead?

[Tommy Harris]

That wire is tied to the pan.  The hooks.are hooked to that wire.   That wire is welding wire, not copper wire.   Now I did just look it up.online and it has manganese and silicon in it.  I wonder if that is causing issues.   I have some stainless braided cable scraps that I am going to try to use for the hanging and see if that changes things up a bit.    For the time being, I took the piece out of the tank.   

[Jeff Friend]

My point is this: the connection between the welding rod and breakfast skillet is not adequate to carry the current.  The other hooks are really not needed and may be causing other issues.  You need to get some sort of clamp to that can make a good mechanical connection to support the weight of the piece you are cleaning and at the same time make a good electrical connection to carry more than 20 amps.

Keep in mind that stainless steel is a lousy conductor.  Its electrical resistivity is about 40 times higher than that of copper.  You will need a really large conductor to avoid an excessive voltage drop and heating.

One last thing - some welding rods are coated with copper to prevent them from rusting.  Manganese can form some green compounds, but I cannot say how likely this is in an electrolysis system.

[C. B. Williams]

I have always used a multi-strand copper wire, the size you might find on a jumper cable, never had that problem.

[Duke Gilleland]

Probably bad connection from welding wire & hooks. Wire could be flux core. Get you some good small "C" clamps and insulated # 8-10 copper wire. I like the solid wire. C clamp the wire to your iron.
Bad/loose connections will cause everything to "run hot" as will light wire. Just my findings after cleaning a few pieces ;)

[Tommy Harris]

OK.  I will get some clamps of some sort and heavier wires to connect.   Thanks for the recommendations, guys and gals.  :)

[Cheryl Watson]

Tommy, I have stripped out lengths of Insulated Copper Wire from Romex (I have quite a few coils since having all the Electrical Work done in the past 5 years).  Solid copper, and designed to carry household current.  I have used that to make all of my Jumper cables when needed. 

[Jeff Friend]

Get a Pony 2-inch clamp.  Take a piece of 12 AWG solid copper wire 3 ft long and remove the insulation from a couple of inches in the middle.  Use a machine screw, a nut, and a washer to attach the wire to the clamp.  Solder a big chunk of copper to the other ends of the of wire.  That gives a good place to attach the charger clamp and the doubled wire will carry a lot of current.

The clamp is also strong enough to hang a No. 12 skillet by the handle.

[Lewis Downey]

I have had a couple of instances of the green "slime";  in my case the stuff was not slimy at all.  It came of in flakes, ran down the sink to clog the strainer, and made metallic sounds as it hit the plastic sink while the strainer was being cleaned. I almost saved a flake of it for posterity.

In both cases a piece of iron was inadvertently left hanging in a weak electrolyte with leads connected and power supply turned off, for at least two days.  The connecting rod that carried the current and held the piece was 3/16 in stainless threaded rod - copper was a non-issue.

The second time it happened I decided to photograph it. The substance eventually came off but left a permanent mark on the iron (shown in third pic). I think that the green substance was a result of the weak electrolytic solution and time with a slight current (a tiny fraction of an amp at almost 2 volts) traveling in the wrong direction. That is just a guess of course.

At some point maybe I'll use a piece of junk iron and see if I can do it on purpose. I hate to do that because it would tie up the electro for days.

I wonder if the stuff is/was green magnetite.

[Mark R. Smith]

I remember being told or reading somewhere not to leave the cast iron in the electro tank after it is cleaned. If you can't finish the cleaning and seasoning to place it back into the lye bath, where it can sit forever without problems.

[Lewis Downey]

Mark,

I am sure that is right. It happened by accident. I was not storing the pan in the fully-connected but powered-off electro. I was showing the electro to a middle-schooler and his dad; we started talking about something, and it slipped my mind to turn it back on. Two+ days later, viola...

The same thing happened the first time - except no middle-schooler or dad :-)

[Mark R. Smith]

Did you try turning it back on and see what happens? Maybe it would clean the green off.

[Lewis Downey]

Good idea and worth a try!  Instead of that, the pan in the pictures made its way to a sink, and I went after the stuff with a brush.

[Tommy Harris]

Thanks everybody for all the info.   I definitely have a few things to change up.  First, a deeper tank.   That will make the hanging situation easier.   

My slime developed while.hanging in the tank, charger off, and jumper cables not attached.   So it had nothing to do with the current flowing backwards.   Unless of course there was somehow electricity stored in the plates and tank.   I'm pretty sure that's not the case.   The first time it happened,  I tried to just put it back in and have the electro clean it off.    No dice.   It didn't seem to change it.    I hosed it off, scrubbed it with a stainless steel chore boy and put it back in.   It definitely left a dark spot behind.   Once I get the electro tank set up in the new and improved  style, I will put the pieces back in and see if I can get the marks off of there.   I doubt it will happen, but I'm gonna try.   

[Jeff Friend]

I frequently leave a piece of iron hanging in the electrolyte solution, but I always disconnect the charger.  I just don't trust the diodes in the charger to enforce the traffic rules when the juice is off. 

Tommy, in your situation, it is possible that you are only partially correct about the slime having "nothing to do with the current flowing backwards."  Maybe the current wasn't flowing backwards through the charger, but the current (the electrons) could have been flowing from the cast iron to the welding rod.  Galvanic corrosion is a big deal with just about everything made of iron and steel.  So, maybe there is electricity "stored" in the plates of the tank after all.

[Cheryl Watson]

Google GALVANIC CORROSION, and you will understand better that the electron exchange that we use in electrolysis,happens naturally, especially in the marine environment.

After studying and understanding that, I decided to never leave a piece suspended in a known conductive liquid (the solution in the etank), charger clamps or no charger clamps.

As stated in reply #2

[Dwayne Henson]

Learned something today.