Ayup. Sometime in the 80's, as I recall. There is a *legal*requirement*
that the face value of any U.S. coin, when produced, be higher than the value
of the metal(s) used to make it. The price of copper had risen to the
point where there was 'nearly' one cents worth of copper in a penny, and
the price of copper was still climbing. Thus, something *had* to be done.
Zinc is cheaper than copper. Considerably so.
Modern pennies have a fairly thin layer of copper/tin cladding over a zinc
On Tue, 02 Dec 2003 21:19:54 -0800, "Dr. Rev. Chuck, M.D. P.A."
most chrome plating on steel is put on over a layer of pure copper,
mostly because chrome doesn't like to stick to steel, but it will
stick to copper, which will stick to steel. if you cut into that, the
exposed steel *will* rust.
copper alloy parsts- brass and bronze- and for that matter monel-
don't rust because they are non ferrous, not because they contain
Forget the pennies. You may try a charcoal briquette or two in each drawer.
Charcoal will absorb the moisture.
Or you can get some packets of silica, just like you see in packing
material. Usually packed with metal objects, and shipped from overseas. I
think you can get them at hardware or packaging/shipping stores, like UPS.
"...I am truly skeptical of all that I have said..."
It is true. Something to do with static electricity and cathodic
protection. Similar to those solar panels near bridges on the
freeway keep the steel from rusting... I have had a short length
of copper pipe in each drawer of my Snapon box since it was
new.... NO rust on the tools at all.
I can imagine that it works for bridges because the solar panels are
electrically connected to the bridge. I might also imagine that there is a
sacraficial anode somewhere. This would be similar to the way underground
storage tanks are protected. I wouldn't rule out the penny trick out of
hand, but if it does work, it would have to be under some special
conditions. To have a chance of working, there would have to be an
electrical connection between the penny, drawer, and tool. Copper might be
electrically dissimilar enough to induce a voltage when in contact with
steel, but I'd have to check that out.
| It is true. Something to do with static electricity and cathodic
I doubt it. You need some kind of electrical connection in any type of
cathodic protection scheme. Just placing metals in close proximity won't
Since there's no DC power source, this would have to be a sacrificial anode
system. And in order for that to work, the anode has to be more
electrochemically active than the cathode. Copper is not a good choice for
a sacrificial anode because it has less affinity to oxygen than many other
metals, including iron. Zinc is a popular choice for a sacrificial anode.
Do you remember the Statue of Liberty restoration several years back? The
copper skin was fine, but the original iron framework had corroded in many
places. The iron was actually the "sacrificial" anode for the copper in
| I have had a short length of copper pipe in each drawer of my
| Snapon box since it was new.... NO rust on the tools at all.
Is there an electrical connection between your pipe and any of the tools?
If not, then you are probably not employing cathodic corrosion protection.
Is there any visible oxidation on your copper? If not, then the lack of
oxidation of your steel tools is more likely due to the relative absence of
moisture and/or oxygen in your tool chest, not the presence of the copper.
A few have danced close but I don't think anyone has nailed it yet.
So here's my two cents...
I suspect that the tool corrosion could be due to the dissimilar
metals in the tool box reacting with moisture and salt to produce a
mild acid, enough to get a small current flowing and over time cause
corrosion. IF the pennies work to reduce rust it is probably because
of the zinc content, not the thin copper plating. IIRC it is the
metal with the most available electron slots in its outer shell in the
atom. Zinc has more than most metals so it is the preferred choice
for a sacrificial metal.
You might consider stopping by your local marine supply store and
picking up a zinc block if corrosion is a problem for you. Cost about
a buck or two - more than a few pennies but it should work better (if
this theory is correct) because they are not wearing a copper coat
like the pennies.
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