Wednesday, September 26, 2012

Iron Relic Electrolysis

In my last post, I showed off a couple of cool iron relics that I recovered at the site of Mower's Charge in Bentonville, NC.  Lead and brass relics can be damaged by farm equipment, construction, fertilizer, and moisture in the ground, but are typically fairly stable once removed.  Iron relics, on the other hand, present an interesting challenge.  While they are also damaged by time underground, the rate of corrosion of iron objects rapidly increases once brought out into the atmosphere.  As a result, we have to take steps to remove the oxidation (rust) that is present upon recovery and protect the artifact from further damage.

One of the most effective methods for removing the rust layer is known as electrolysis.  Here's a picture of my electrolysis rig, and although it's a bit crude in aesthetics, the design is essentially the same as those used by universities and professional laboratories to preserve iron artifacts.  NOTE:  Electrolysis can be a very dangerous process, involving electricity with exposed wires and the generation of potentially harmful, flammable, and/or explosive gasses.  Don't try this at home.  Or if you do, be safe, use adequate ventilation, and don't say I didn't warn you.

My rig consists of a plastic container (in my case, a 5 gallon bucket) filled with an electrolyte solution (I used Cascade dish soap, primarily sodium carbonate).  In the solution are two electrodes.  For a positive electrode, I used stainless steel flashing left over from a construction job (EDIT:  I've recently learned that SS results in harmful byproducts, and should be avoided.  Use iron rebar, instead).  As you can see in the picture, I used two pieces on opposite sides of the tub to provide an even current distribution, and connected them together using four lead wires.  The negative electrode will be the iron relic to be cleaned.  In my setup, it is suspended by a crossbar using two connected wire leads.  It is very important that the two electrodes not come into contact with each other!  The positive and negative electrodes are connected to a battery charger (I used either 12V 6A or 12V 2A settings, depending on the object being cleaned).  When the current is supplied by the battery charger, the relic will start to bubble as iron oxide is stripped away, leaving a rust-free artifact.  If you're interested in learning more, I would highly recommend this video from relic hunter Beau Ouimette showing his electrolysis unit in action.

Here is a before and after showing the CS pentagonal cavity shell fragment after the first round of electrolysis.  I will most likely run it through again to remove some of the remaining stubborn rust spots, but you can already see a tremendous improvement.

A more striking example is the lock plate from an Enfield rifle found last weekend.  What was once a glob of rusted iron has been transformed to reveal the mostly-intact mechanism from inside the rifle.  The next step will be to remove excess water from the iron by soaking in acetone, and finally sealing the relic with a hot wax to prevent further rusting.

I do hope this post has been helpful (or at least entertaining).  Thanks for reading, and I look forward to showing you what I dig up next!

Monday, September 24, 2012

Detecting the Battle of Bentonville

The Battle of Bentonville, North Carolina took place on March 19-21st, 1865.  It was the last great offensive for the Confederate Army under General Joseph E. Johnston, commanding about 20,000 men.  The Union, under General William T. Sherman, was comprised of about 60,000 men.  The results of those three days of combat were more than 3,000 men killed or wounded, along with a decisive Union victory that left the Confederate army fleeing and the end of the war in sight.

On the third and final day of the battle, March 21st, General Joseph Mower requested permission to conduct “a little reconnaissance” to his front on the Union right wing.  This quickly escalated, and he lead two brigades on a full scale attack on the Confederate left wing, defending General Johnston’s headquarters as well as the highly important Mill Creek bridge.  This attack, which became known as Mower’s Charge, broke the confederate flank and reached as far as Johnston’s headquarters, forcing a Confederate retreat.  The charge was ended by a counterattack from Confederate General William Hardee (whose only son was mortally wounded during the counterattack), as well as orders from General Sherman to pull back to avoid a larger confrontation.  During the night of March 21st, the Confederates retreated across the Mill Creek bridge, ending the battle.  The drawing above is a depiction of Mower's Charge from the Frank Leslie Illustrated Newspaper.

With field crops now being to be harvested, I was able to get out with my good friend Jim to do some detecting near the site of Mower’s Charge.  I had some very good luck this trip, and broke out of my recent detecting slump in a big way.  Above is a picture of all my finds from the battle.

I recovered three bullets during the day.  The center bullet is an unfired 58 caliber three ring minie ball, the most commonly used ammunition.  To the left is another 58 caliber bullet, heavily deformed from impact after firing.  This is an excellent example of the power of the weapons used, and shows why they were capable of such devastating wounds.   On the right is another type of minie ball, this one a 577 Enfield bullet.  This is a much less common round, and only the third such bullet that I have personally recovered.

After the battle, Union Lt. Matthew Jamison of the 10th Illinois wrote “[We] form line of battle in a heavily wooded country and move forward instantly, scarcely giving time to form the line and to allow the skirmishers to deploy.  Nothing joins our extreme left – skirmishers engaged – as we advance rebel batteries shell us.”  He is describing the advance of Mower’s Charge, and the Confederate batteries (groups of typically four cannons each) firing explosive projectiles (shells) towards their approach.  One of my finds includes this heavy piece of iron, a fragment from a Confederate pentagonal cavity exploding shell.  The pentagonal internal cavity, filled with gunpowder and a particular geometry used exclusively by late-war Confederate artillery, allowed for more consistent fragmentation upon detonation and thus greater damage to enemy troops below.  I have discussed this type of projectile previously, this being the second pentagonal cavity shell fragment I have found near Mower’s charge.

My favorite find the day, though, is this rusted iron piece – a lock plate from a rifle broken or lost during the battle.  It is most likely from an Enfield rifle, although several other less common rifles used similar locks.  The hammer on the outside (which would strike the percussion cap to fire the weapon) is missing, but the internal mechanism seems to be quite intact.  Below are pictures of an original Enfield rifle showing how the lock plate attached to the gun, along with a reproduction lock plate showing the internal mechanism.  I will clean and preserve the iron by electrolysis to prevent further corrosion, and will post new pictures of the results when that is complete.

It is difficult to comprehend the circumstances of that day on March 21st, 1865 when this gun was lost.  We will never know for sure exactly why it was left there, given the incredible amount of musket fire, artillery explosions, fierce fighting, injury and death that was going on around it.  Artifacts like this always provide such a personal connection to the war that was so brutal on both sides.  That is the reason I pursue this great hobby of relic hunting, and share it with you here on Detecting Saxapahaw.

Last but not least, in case you thought it was too easy, here’s an example of some of the many pounds of junk I carted away!  Thanks for reading, and stay tuned for my upcoming electrolysis update!