Reverse electrolysis

[joevann]

Everyone has their own thoughts and methods on this subject, so I'm just going to throw in my two cents.  I have always preferred backing soda as an electrolyte.  It is mild, works well, no chance of chemical burns, and no environmental hazards with disposal.  I use plastic containers, usually 5-gallon buckets, but for larger items like 12-inch Coast Artillery mortar rounds, or those from Naval main batteries, I've used 55-gallon drums and even a coffin vault liner.   For my waste electrode I've found nothing beats CRES (stainless steel).  I get the pieces I need from scrap yards.  You can often find a piece of discarded pipe that is just the right size to line your container.  I find with the combination of stainless steel electrode and baking soda electrolyte, it is possible to do items of disimilar metals al at once without damaging lead, zinc, or copper parts.   The stainless electrodes last an extemely long time, are very inexpensive if purchased at scrap weight compared to copper, and you don't run the risk of copper-plating your iron parts.  Post processing is extremely important, too.  Your shell has absorbed salts from the ground and backing soda is also a salt.  These have to be removed, and boiling in distilled water will do the trick.  Keep changing the water until it is clear after boiling.  To make sure all the salts are gone, add a few drops of silver chloride.  If it turns milky, you need to change the water and boil again.  When all the salts are gone, then you need to drive out all the moisture.  After the piece is cool to the touch and OUTSIDE,  immerse in acetone and leave it for several hours.  Then, remove it and allow any residual acetone to evaporate from the piece.  You can now brush your piece clean.  All the salts and moisture have been removed, and the molecular structure has been stabilyzed.  You are now ready to fill in the pores so no moisture is absorbed from the atmosphere.  There are a number of thoughts on this subject, but in my experience the best all involve gentle heat and thick petroleum distilates.   

[CarlS]

Joe,

Thanks for sharing your process.  Very good info.  I agree with the baking soda.  I use pool PH adjuster (sodium carbonate I think) and it works great.  Disolves easily and, as you mention, is much easier on me and the environment.  Ialso agree that stainless is the only way to go.  I have a couple stainless tanks I have had for years that I have cleaned many dozen shells and other items in.  They are holding up pretty well. 

[misipirelichtr]

Carl, what are the dimensions of your stainless steel tanks?  That's a great idea.  Thanks

[CarlS]

I have a variety of sizes but most are about 11 to 12 inches in diameter about 18 inches or so tall.  These suffice to run up to 24 lber size stuff fine and even does a 32-lber ball ok.   They should be deep enough that there is at least 3 or 4 inches of water over the object to allow some running of the relic's topside even though you should also rotate the relic for good coverage.

Some of the tanks have welded bottoms that are water tight and can freestand.  A couple have bottoms that are just spot welded and I have sitting down in a 5-gallon paint bucket.  even the water tight ones will probably eventually get a pin hole leak in them after enough use so they'll probably end up in buckets at some point.  The way Joe descibes is a great inexpensive way to effectively do it.  Just make sure you have the item adequately surrounded on the sides and I recommend something on the bottom as well.  You can tack weld them together or join them with stainless screws/nut-n-bolts to get electrical contact to all the pieces.

[misipirelichtr]

thanks!

[joevann]

You can also pick up stainless steel pots cheap at personal property auctions.  They will eventually get pin holes, but you can always put then in a second non-metallic container.  The important thing is to get those dug pieces in the tank as soon as possible to stabilyze the ions and to get rid of as much salt and moisture as possible before sealing.

[CarlS]

Joe,

Good point on the steel pots.  One I use that I like a lot because the released crud falls below the bottom is a deep fryer basket the RelicRunner found for me.  It's a big deep pot with 3/4 inch holds all over it.  I put it on small blocks in a bucket so the crud could fall though.  It works really well and the price was right!

[emike123]

Lots of good info here.  I have not always boiled my projectiles, but when  I thought they needed it, I was amazed how many impurities boiled out of them.

I have a very good friend who owns a steel business and he keeps me well supplied with thin steel shims that I use for the sacrificial metal.  The surface rust needs to be ground off quite often if I don't swap them back to him for new ones.  If anyone wants some of these squares of steel, let me know and I'll pass along some.

[joevann]

Carl,

Great idea with idea with the deep fryer basket.  That gives me another idea.  I'm going to see if I can form a completely surround closure of expanded mesh CRES with plastic rods to hold my piece equadistant all around.

[bigironman]

If electrolysis is applied properly you will not need to boil the artifact to remove soda ash (sodium carbonate) or baking soda. Heating an artifact to 220 degrees can expand the iron core in a salt water artifact and damage the graphite layer on the outside. After electrolysis I leave the projectile outside in the raw weather for months with no coating. Humidity is no longer a threat. The soda ash excretes out over time and I wash it with water to clean it off.
 Coatings are cosmetic! Wax coatings stop future electrolysis! If you need to run it again the wax is too difficult to remove. When I do apply a coating I use a tannic acid base. That takes care of the remaining soda ash in the artifact.
I have been doing this for 25 years. Herb Bumb was my instructor. He was the top gun of electrolysis.
Glad to see a strong interest in the preservation of artifacts that come out of salty environments - marsh, ocean -
Hope this sheds some light on this important work.

[joevann]

As I said in the beginning of this post, everyone has their own thoughts on this subject, and I’m just sharing mine.  If you are happy with your current methods, please carry on.  It’s your collection.  I am more than happy to explain the reasoning behind my methods.  I’ve been experimenting and refining my techniques since 1965 when I bought my first metal detector with the proceeds of my paper route.  Baking soda, which I prefer as an electrolyte is sodium hydrogen carbonate.  Sodium carbonate is washing soda.  Rust is an electrolytic decomposition of iron.  The ions of iron are bonded with oxygen, carbon, and other substances surrounding the item.  In either the ground, air, or water, it is caused by the presence of a conductor (electrolyte), moisture, and a flow of current.  Most environments have a flow of current; it is just so small it’s difficult to measure.  Left to nature long enough, there will be nothing left of your iron artifact but a stain in the ground.  A good example of this was an English cuirass excavated at Martin’s Hundred.  Baking soda is a salt.  I remove the salt and the moisture and then prevent the moisture from reentering the porous cast iron.  No moisture and no electrolyte mean no flow of current and no more rusting.  Cast iron has a coefficient of linear expansion of zero.  That means it doesn’t expand or contract with changes in temperature.  That is why it was used for tie rods in masonry structures.  At about 80 degrees Celsius (less than boiling) Baking soda is also reduced to calcium carbonate.  The ‘graphite’ or ‘black rust’ as it is sometimes referred to, actually has the same chemical structure as magnetite.  Graphite is in reality the most stable form of carbon and is not actually present in this equation.  After going to all the trouble of reverse electrolysis, which stabilizes the magnetite and causes it to adhere tightly to the surface beneath it, why would anyone ever have to do it again?  (Unless, of course, it rusts)

[Dave the plumber]

    big iron man,             welcome to our forums !!    It's about time you showed up here..  We look forward to your input, as we all throw out ideas and see what sticks.  There are some very, very knowledgeable people on here you will meet, a fine group of guys.......
            Saw the article in guns and garden magazine and may I say;  yourself, Jack and Harry all came out sounding as sane people with an interest and passion that didn't get the typical screwed up editing job by an ignorant reporter.             Anyway,  welcome !!

[pipedreamer65]

Concur, that was a great article and some excellent PR towards educating people.

Little late to the game here on this topic, but I've used baking soda and pool ph adjuster.  Both are very mild of course and for the last year or so I have been using just the ph adjuster for the most part.

I also use stainless steel.  It is a cleaner process and it lasts a long time before it even starts to deteriorate.  My DC power source is set for sub amp.

The handfull of salt shells I have ran, I have boiled.  Most of the stuff I do comes from the ground.

I finish up using a tannic acid mixture and a flat or matte finish.

So far, so good.

[bigironman]

Hello Dave, glad to hear from you. Hope you are doing well. I am.
My take on the boiling is that it is an unnecessary step. If it works for you OK.
I took my Hamilton Guide and gave it away long ago.
Sodium Hydroxide is used by the conservators of the Monitor and at the Hunley lab. Not as user friendly as baking soda or soda ash but it is slightly more effective. But I would never use it as it can cause problems on brass.
The article In Garden and Gun was a long time coming. I did not want to do it unless I was sure that it would be useful for the general public to know the  world we inhabit. And, of course, I did not want to be identified. I was pleased with the result except the author of the article has been getting calls from Hollywood. They want to do a reality show and I will not talk to them. I gave them your phone number Dave

[joevann]

Here is a very nice free manual from my Alma Mater:  http://nautarch.tamu.edu/CRL/conservationmanual/