Corrosion College

Are Your Metal Parts the Victim of Human Contamination? The Best Solution, Hands Down, is “Hands Off!”

Many of ARMOR’s manufacturing customers experience rust on metal parts that resemble the photo above. X marks the spot, or in this example the fingerprint marks the spot, and what this rusty imprint is really telling you is that your metal part is the “victim” of human contamination.

It is commonly not known that handling metal parts with bare hands can cause rust or corrosion. But in this short exposè, we are going to break this topic wide open and explain why it happens and how to prevent it.

Technically speaking, rust or corrosion is the natural mechanism by which metal returns to its original state. This requires a conductor or conducting solution containing an electrolyte. An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. One large source of these electrolytes being deposited onto the surface of a part is from handling by humans.

“Fingerprints and perspiration are one of the biggest contributors to rust and corrosion in terms of handling metal,” explained Charles Phillips, ARMOR Chemist. “The process is really pretty simple, the minerals found in sweat, such as sodium, potassium, calcium and magnesium, are transferred onto metal by a person’s fingerprints. These minerals along with other acidic chemicals that are found in perspiration combine with atmospheric moisture or simply the water available in the perspiration itself to begin the corrosion process.”

Logically, this form of contamination is more frequently seen in manufacturing plants where conditions are hot and humid, thereby causing employees to sweat more than normal. As reference, a person will typically sweat 6 liters a day, producing 3–5 grams/day of electrolytes. But in a hot environment, a person will sweat more heavily producing on average 15-30 grams of electrolytes. In addition to the increased quantity of sweat, the composition of the sweat also changes to include a weak solution of urea, lactic acid and other electrolytes.

This toxic combination of salt and acidity, transferred via fingerprints, presents itself in the form of rust/corrosion on the surface of metal. The good news is, there is a solution—one that you could say “fits like a glove,” because it is just that—gloves!

To avoid the transfer of salt, oils, acids, and other contaminants that can result in rust and corrosion, any employee coming in contact with metal must wear clean, protective gloves. Be it a shipping/handling packager, inspector, or machine operator, the use of clean cotton gloves (replaced once dirty), is essential to the process of reducing overall rust and corrosion within the manufacturing process. The solution is simple but a simple solution is no less effective.

If you would like to learn more about the prevention of rust and corrosion and how ARMOR’s product line can help in Taking the Work Out of Your Workday™ visit the ARMOR website or contact your ARMOR sales representative.