Sulfide Contamination. I have a new favorite kind of paper.

My workshop is a glorified toolshed in my backyard.  I love it very much but it is not without its shortcomings.  When I bought the workshop I had to install power, lights, a floor, shelves, storage air conditioner, fume hood, dark “room”,  etc.  One of the worst problems with the workshop is the lack of environmental control due to it being, well, an uninsulated toolshed.

I live in North Carolina and let me tell you that the summers hear are murder.  If it isn’t hot, it’s humid.  Often it’s both.  The current temperature of my workshop as I write this is 84F.  I’m unsure of the humidity but my shirt is decidedly moist.

One of the big problems with humidty other than discomfort is the danger of contamination of my materials.  Did you mom ever make you polish the silver?  Well let me tell you that the black stuff you worked so hard to remove is caused by sulfur contamination… and the air is full of it (among other things).  Silver is not alone in its susceptibility to corrosion… copper, brass, and countless other materials are ill-suited to storage in my workshop.

I made the mistake of storing some freshly (and exhaustingly) polished copper plates in the workshop for a few days.  After polishing I had wrapped the plates in paper towels to keep them safe from scratching.  A day after I took the plates to Surtronics I got a call saying “we can’t run your plates… they’re covered in spots and marks.”

-Cue lump in throat-

So I solemnly picked up the plates and my buddies at Surtronics gave me a few feet of some special paper of which I had not previously heard.  Let me tell you that this stuff is rocking my world.

Armor Protective Packaging makes an exciting paper (in as much as paper can be called “exciting”) called “Silver Shield.”  You need some.  Now.

Silver Shield™ prevents tarnish and maintains the metal’s true finish. This neutral pH paper absorbs hydrogen sulfide vapors, which causes corrosion and tarnishing. When compared to other options on the market, ARMOR’s Silver Shield™ offers a distinct advantage. When fully wrapped in close proximity to metals, Silver Shield™ emits VCI (Volatile/Vapor Corrosion Inhibitor) molecules, which creates an extra layer of superior protection-eliminating the possibility of corrosion and tarnish.

Be still my heart!

This Silver Shield paper is a specialized version of a class of Vapor-phase Corrosion Inhibitors that interrupts the corrosion process.  Corrosion (AKA tarnish, rust, etc.) is simply a chemical reaction wherein an electrolyte on the surface of the metal (eg. humidity from the workshop!) reacts with oxygen (or sulfur, etc.) in the air to form a salt of the base metal by moving electrons fro and twixt.  This is fairly similar to electroplating, really and if you’re ever in need of a nap it can make for some interesting reading.

The plates probably would have fared better had I simply left them uncovered instead of tightly wrapped in paper towel.  The paper towel remained moist and the close proximity to the copper made the reaction all the more swift.

VCI materials lay down a (very very very very) thin molecular barrier that prevents this oxidation from occuring.  In the case of Silver Shield, the paper has been treated in such a way that it more directly prevents sulfide contamination which is really bad news for silver.

Much more can be learned at the frighteninly titled Corrosion Source.

I have not yet located an online retailer of Silver Shield.  If you know of one, please leave a note in the comments.  By the way, the toolshed’s temperature has climbed to 85.5F during the writing of this entry.