Experiment 10: Silver Pennies by Electrochemistry

So I saw some little kid on YouTube trying to explain how to electroplate pennies with zinc, but he was probably six years old and really didn't go into detail about what to do.  I had seen the silver & gold pennies experiment with zinc sulfate, but since I didn't have zinc sulfate or the stuff to make it, I decided to wing it.  I first placed some zinc metal I smelted out of pennies into a jar of vinegar and left it overnight to dissolve into zinc acetate.  It was probably about a 1/2 cup of vinegar.  On looking back, overnight was too long and made the solution too concentrated, so maybe leave yours dissolving for 4 hours.  When doing the electrochemistry, you do not want a very concentrated solution, or else crystals will grow instead of a nice atom-thin coating.  Anyhow, after I had the zinc acetate solution, I buffed a penny with a wire buffing wheel and a Dremel tool.  This cleans off the gunk.  After that, I cleaned it with alcohol to take off grease and other minor impurities that might interfere with the electroplating process.  Next, I used the 3.3V line on my lab power supply and hooked up the penny to the negative lead and a piece of zinc metal on the positive lead.  I placed them both in the zinc acetate solution, making sure that the negative lead was submerged and the positive lead was not.  If the positive lead is in the solution (instead of just the zinc metal) it can corrode.  After rotating the penny a few times, I had a very good plating of zinc.
I noticed that the plating was not very shiny, so I buffed it with the metal brush Dremel buffing wheel.  It turned out absolutely amazing!  Here are pictures of the finished penny (the images do little justice to how nice the penny really looks).