White "haze" on CI piece after electrolysis

[Andy Robillard]

Hi everyone,

I was unable to find anything about this particular problem when I did a search.  Please forgive me if this has been covered before.

I use electrolysis to clean my pieces and occasionally notice a white haze on the pieces afterwards.  My typical approach for cleaning the pieces is to use electrolysis, then hand-scrub with steel wool to scrub of residual carbon and gunk.  I will then scrub the pieces using a plastic dish brush (it's dedicated to CI and used for nothing else) with mild dish soap in cold water.  I am cautious about thoroughly rinsing off any soap, etc.  I will towel dry and then place in the oven for 30 minutes at 250 degrees to thoroughly dry the piece.

Attached is an example of piece with the haze on the handle.  FYI - this piece was fully submerged in the electro.

Any help or guidance is sincerely appreciated!

[Roger Barfield]

How are you attaching the cast iron to your negative lead?

[Cheryl Watson]

Andy, can you post a pic  of the entire piece, top and bottom?

Looking at the picture above, my first impression is that this may have been an originally plated piece, with only remnants of plating remaining.  Additional pictures of the piece may confirm or deny this.

[Cheryl Watson]

Other information that would be helpful:

1.  Pic of electro
2.  Describe what material you are using for anode
3.  What Roger asked above, regarding connection(s)
4.   Ratio you are mixing for electrolyte (how much washing soda/gallon)
5.   Pic of battery charger used and amps used to clean
6.   Are you allowing the piece to hang/sit in the electro without the current running?

[Andy Robillard]

Thanks everyone for all the responses so far!

The picture that I posted is a standard WagnerWare cast iron piece, no plating.  The latest one that had this issue is a Martin Stove #8 skillet lid.  The haze covered a good portion of the piece.  I can't get a picture of it because I experimented with seasoning it to see if the haze affected the seasoning.  It did so before attempting to re-electro it I wanted to ask if anyone else has experienced this.

I've attached a picture of the electro tank set up.  I use stainless steel sheets as the anode and connect the positive to it via a stainless steel bolt through the SS that acts as a post.

For the negative I have created a copper "hook" of heavy gauge stranded copper wire that's used both to suspend the piece in the solution and as the post for the negative clamp.  The stranded copper is threaded through a 2X4 that bridges across the top of the tank.

For the solution I use the standard Arm & Hammer Super Washing Soda laundry soap at a ratio of 1/3 cup soap to 5 gallons of water.

I've posted a picure of the battery charger.  Typically I'm able to get the amps between 10 and 20 (on a good day).  Seems like it's mostly in the 10 - 15 amp range, though.

I never allow the piece to remain in the solution without actively cleaning it.

[Andy Robillard]

Here's the charger:

[Cheryl Watson]

Critical question:  Are you letting the piece hang in the solution when the charger is turned off?  This would allow particulate to settle and/or migrate back onto the iron.

I'd also get rid of the bare copper stranded wire that is submerged in the electrolyte, as the copper can and will dissolve into it.

[Andy Robillard]

Critical question:  Are you letting the piece hang in the solution when the charger is turned off?  This would allow particulate to settle and/or migrate back onto the iron.

I'd also get rid of the bare copper stranded wire that is submerged in the electrolyte, as the copper can and will dissolve into it.

I never let the piece sit in the solution if I'm not running the battery charger.

I didn't know that about the copper.  I'll look to replace it with SS.

Thanks!

[Russell Ware]

I'd also get rid of the bare copper stranded wire that is submerged in the electrolyte, as the copper can and will dissolve into it.

I agree with Cheryl. Replace the copper with something iron or stainless.
Have you tried soaking the pan in a 50/50 vinegar bath to see if that removes the haze? You might try wiping the area with a cloth soaked in full-strength vinegar first to see if that gets you anywhere.

[Jeff Friend]

Andy,

I have some questions for you.

Are you certain the haze isn't there under the crud before the pan is cleaned?  You first picture shows what looks like spray paint.  Is that an accurate description of the haze?  Does it appear only after you have taken the pan out of the oven, as you have described in your procedure?

You say it happens occasionally.  What does that mean?  One pan in 20 gets the haze?  Is there any pattern to when you observe it?  For example, maybe it happens on the first few pieces you clean after you have changed the electrolyte.  Or it only happens when the electrolyte solution is really nasty.  (The picture you posted looks like really clean solution to me.)

Is the entire piece covered with the haze on all sides?  Or splotches all over the piece?  Or just the area where the wire is attached?

Does the haze rub off under running water?  Do you need a stiff brush to get it off?  Or a wire brush?  Does undiluted vinegar dissolve it?

Any other observations?

Jeff

[Roger Barfield]

Andy, after seeing that twisted strand of copper wire, I wonder if occasionally a piece is not making good contact and you are getting some arcing.  I would switch to a solid piece of metal to suspend the cast iron.  Always make sure the two pieces are making good contact.  You can take some emery cloth or something similar to remove the seasoning in the area where it makes contact. I bet that fixes the problem. 

[Cheryl Watson]

Looking at the electrolyte in your tank, I am assuming that you are NOT doing a lye bath first? and are placing the piece in the tank to clean the old seasoning off also? 
I would recommend the lye bath first.... it sure extends the life of the anode.

I would say dump the electrolyte, and replace.  Water and washing soda is cheap, for sure.

Also, can you take a picture of the front of the box of the Arm & Hammer you are using?  <I just gotta ask, given what I've seen in the past... it's called quadruple checking...  :D>

[Gary Salsman]

The white happens to me on occasion as well. It is usually the firs few pans I do after cleaning my tank and starting over. Seems to me like it is undesolved washing soda.

[Herman Gagne]

I've been using electro for a couple of years now, with no issues, but last summer, I dumped the old drum, and started fresh; this time I used just about twice the amount of PH+, just for the heck, and I now have this whitish finish on the iron.
Same everything as far as equipment, charger, attach. methods. First the lye bath, then the electro.

I use a 30gal. plastic drum, and 2 cups of PH+ (swimming pool powder).
At this point, I suspect too strong a mix.
This white stuff is a real bear to get off too.

This spring, I'll go back to my original mix, and see what the results are.
Herman

[Tom Neitzel]

I've run into that too.  I learned that if I make sure to wash, scrub the pieces as soon as I take them out of the lye tank, not letting them sit around and dry, that I pretty much eliminate it.

[Jeff Friend]

Well, here it is a year later, and I still have the same questions, plus a few more.

First, the copper wire between the pan and the negative clamp isn't an issue, as long as the connections are good.  Remember, you are pushing 20 amps or more through those connections.  At the high pH and negative electric potential, the copper will not corrode or dissolve - it is in an unreactive state.

The washing soda is very soluble in water and I can assure you that many tablespoons per gallon will completely dissolve.  If the washing soda caused the film, it would rinse off in seconds.

Hard water deposits are another story.  If you have seen the white film, are you using hard water to make up the electrolyte solution?  It could be a calcium deposit that is precipitating on the iron.  If you have access to dilute hydrochloric acid, put a drop on the film and see what happens.  If it bubbles, it is probably a film calcium or magnesium carbonate.  No hydrochloric acid on hand?  Try vinegar with a little scrubbing.  It may not bubble, but it should come off pretty easily with scrubbing.

[Cheryl Watson]

The washing soda is very soluble in water and I can assure you that many tablespoons per gallon will completely dissolve. If the washing soda caused the film, it would rinse off in seconds.

Well, not always.   I have had issues, and I don't know the reason, but tend to blame the Washing Soda, possibly variations in the manufacturing process.

I just dumped the electro yesterday. 

I mixed a fresh batch last October when I built the new electro, did 2 or 3 pieces, and then down for the winter. 

Fired up the electro earlier this week, and stirring the sediment on the bottom, FAILED to disperse the particulate matter on bottom.

Pic #1 is the sediment after running one piece thru.

Pic #2 is how I drain my electro

Pic #3  refill after through rinse out

[Cheryl Watson]

Back in operation. 

Will be monitoring to see if un-dissolvable particulate reappears.

[Cheryl Watson]

The water temperature is still in the 50° range, so I finally used my bucket heater to raise the temperature before adding the pre-dissolved washing soda (HOTTEST water from tap, pre mixed in a bucket)  I am happy to report that the bucket heater did work, but took a while to warm up 35 gallons.

I got the water temp in Electro up to 70° before adding the pre-mix.

[Jeff Friend]

If the sediment stays on the bottom of the tank, it won't interfere with the cleaning process.  Has anyone else had a problem with the mystery substance precipitating on a piece being cleaned like Andy, Herman, and Tom describe?  I will admit that I have not done a complete cleanout of my electro in years, although I do occasionally purge out a few gallons and replace it with new electrolyte solution.  And I have never had any problems.

Regarding the solubility of sodium carbonate, I have created a pdf of some data I extracted from General Chemical's soda ash handbook (soda ash = sodium carbonate).  Here is what it boils down to:

1.  In the range of solutions and temperatures we are concerned with, sodium carbonate is completely soluble. 

2.  1 to 3 percent solutions by weight will not see any precipitation until the liquid is about to freeze.

3.  It is only at low temperatures (43F) and high concentrations (>8 percent or about 20 Tbsp per gallon) does it begin to precipitate.

4.  Commercially available soda ash is more than 99 percent sodium carbonate when shipped.  One specification I looked at indicated that the "typical" material is 99.9 percent sodium carbonate. 

Because of the solubility of soda ash, it is completely dissolving when you make up a batch of electrolyte solution.  Unless the soda ash you are buying is grossly contaminated with something that does not dissolve, that is not what you are seeing.  There just isn't enough of it to create a significant layer on the bottom of the electro tank.

The other item that you put into your tank is water.  A lot of water.  And there can be a lot of solids that are dissolved in your tap water, especially if you have hard water.  Hard water contains calcium, magnesium, or both, and those dissolved solids are going to precipitate when the soda ash is added and the pH increases.  Other ions are dissolved in city water and well water, such as sodium, manganese, iron, sulfate, and chloride. 

Now, if you are experiencing this issue, you might conduct a few experiments. 

Test 1.  Put a tablespoon of soda ash in a gallon of deionized water (something like steam distilled water purchased at the store).  Mix it so it has all dissolved.  Is there any turbidity or visible solids in the solution?  Pour a quart into a clear quart mason jar, cap it tightly, and let it sit undisturbed for a few days.  What happens?  Does anything precipitate and settle on the bottom of the jar?

Test 2.  Put a tablespoon of soda ash in a gallon of your tap water and repeat the procedure in Test 1.  What happens?

Test 3.  If test 2 produces a sediment, drain off the water and add some lemon juice.  Does the juice dissolve the sediment or cause it to bubble?

If anyone gets some results, please post them.