Got Chrome?

By Staff
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Bumper guards fresh out of the chrome tank at Industrial Chrome Inc
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The nickel tank. Note copper bar where parts are hung.
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An example of hard-chroming, in this case a steel driveshaft yoke from the author’s parts collection.

For those of you thinking about nickel or
chrome plating your engines now, there’s a thing or two you may
want to know first. To find out how the process works, I went to
Industrial Chrome Inc. in Topeka, Kan. Gary Sack, the shipping and
receiving manager, walked me through the whole nickeling/chroming
process.

Nickel plating is more or less just chrome without the chrome,
so to speak, so the two go hand-in-hand. First of all, the metal to
be plated needs to be stripped down to bare metal. Parts that have
previously had nickel plating (such as if they were chrome to begin
with) are probably better left to the professionals, as merely
sanding the chrome off does not rid the metal of its nickel
properties – it needs to be stripped in a special acid bath.

Once the part is down to bare metal, it is dipped in a special
cleaning solution before being acid-dipped and rinsed. It is then
dipped in copper (Gary says this isn’t always necessary) and rinsed
again. From the copper tank, the part goes to the nickel bath and
is rinsed once again. Finally, the part is dipped in the chrome
solution to bring a mirror-smooth shine. Then, once again, the part
is rinsed. It is important that the part be rinsed between each
layer of plating or the chemicals will not adhere and the plater
will have to start all over again.

For the process to work, the part is hung on a cathode bar
running the length of the tank. The nickel comes in small (about 2
ounces), odd-shaped pieces, hung in bags on the side of the tank.
The nickel is the anode. A DC current runs through the tank and
solution, and the combination of these three elements is what makes
the process work. The plating tanks run about 140 degrees
Fahrenheit, whereas the cleaning tanks are kept at 180 degrees or
more.

Another option other than nickel or chrome plating is hard
chroming. Hard chrome is decorative chrome without all the polish
and prep work, leaving a more industrial finish. The piston on a
hydraulic ram, for instance, is hard-chromed.

The level of thickness to be expected on any of these types of
plating are as follows: Nickel plating will add roughly 0.005″,
decorative chrome will add another 0.0001″ on top of that, and hard
chroming is in an entirely different ballpark. The thickness of
hard chrome depends on the customer’s requirements. The thicker it
is, the more durable (i.e., hard) it is. This will typically range
anywhere from 0.001″ to 0.006″ or more. The more time the part
spends in the tank, the thicker the plating.

If the process scares you, it shouldn’t. There is virtually no
heat, and no harsh chemicals are involved in the nickel/chrome
process that could harm your engine’s parts. It’s merely different
elements mixed together to bring us a fairly maintenance-free,
show-stopping finish to last for many years to come.

Industrial Chrome Inc. can be reached at: 834 N.E. Madison,
Topeka, KS 66608; (785) 235-3463.

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