It seems that nearly everybody saw a plating demonstration years
ago, and now they are firmly convinced that the instructor showed
them how to electroplate bright, shiny, sparkly, copper onto old
steel with copper sulphate

⇦ on

eBay or
Amazon [affil link] and a battery. But memories are faulty
things. They probably saw a demo of copper spontaneously depositing
onto steel or onto a nickel from that cool blue solution; but over
the years, as they read about electroplating in a science book, their
minds melded what they actually saw with mental pictures of what they
read about, and the shiny products they’ve bought, yielding a faulty
recollection.

Actually, you can’t electroplate copper out of a copper sulphate
solution onto steel (or aluminum or zinc either) really
satisfactorily! Rather, it spontaneously plates out as a thin,
powdery, non-adherent (immersion plating) coating.

The best demo I every saw–by far–was a gold plating demo put on
by Technic of Providence RI.
They took nickel plated bracelets, dipped them in a beaker of
cleaning solution, then activating acid, then into a large beaker of
gold plating solution for 15-20 seconds (rinses in between, of
course). Because both the beaker and plating solution were clear, the
students could watch the piece turn to gold right before their eyes.
Then the instructor took out a pocketful of such bracelets, hooked a
piece of copper wire around each, did the precleaning, and handed one
to each student who wanted to try it. There wasn’t one who didn’t
jump to his/her feet to get on line! My kids still have theirs. And
the kids instantly understood Faraday’s Law and wanted to leave their
bracelet in the solution as long as they could get away with :-) If
you want a plating demo that is really impressive, that’s the one,
but it has to be led by professionals.

For a do-it-yourself project, we recommend the zinc plating of
copper pennies or the copper plating of quarters, which are described
in detail in “Electroplating — How it
Works”. You can also zinc plate or copper plate a brass key, but
a brass key tends to not be very shiny, and the plated item will be
no shinier than the starting point.

A key, copper plated by Ted Mooney in a pyrex desert
bowl from a solution of vinegar

⇦ in bulk on

eBay

or

Amazon [affil link] with a pinch of salt and pinch of
sugar, with copper wire used as the anode material and a 1-1/2 volt
dry cell as the power source. An identical unplated brass key is
shown on the right.

If you would like other opinions and ideas, here are some threads
on the subject of plating demonstrations:

• Help a beginner to copper
  plating

• Science projects in
  electroplating

• Anodizing setup for
  student lab

Good luck! — Ted.