Re: I am looking for the procedure for producing a brass-coated penny.

Hi there,

This is a simple but fun laboratory experiment.  I have copied a procedure 
form a site on the Internet.  

It's called the "Gold Penny Lab".  Forming Brass from Zinc and Copper 

Objective: The objective of this lab is to use a post-1983 penny to produce 
a thin layer brass alloy and a pre-1983 penny to make a bronze alloy. 

Scientific Principles: 

In order to save expensive copper, penny coins, starting in 1983, were made 
of zinc with a thin layer of copper plated on the surface. If these coins 
are heated, the zinc will diffuse into the copper layer, producing a 
surface alloy of zinc and copper. These alloys are brasses. Not only does 
the zinc change the properties of copper, but also the color of the brasses 
changes with zinc content - reaching a golden yellow color at around 20% 
zinc and golden at 35-40% zinc. Copper also oxidizes when heated in air, 
producing a black layer of copper oxide (CuO). Thus when heated, there is a 
competition between the rate of oxidation (making the surface black) and 
the rate of diffusion (making the surface a golden-yellow color). Bronzes 
are alloys containing tin and copper. 

Applications: 

Brasses are used in many industries because they are fairly corrosion 
resistant but harder and cheaper than pure copper. Bronzes are sometimes 
used for the same purposes and are also used to make bearings. Bronzes are 
generally harder and more corrosion resistant than brasses. 

Time: 40 minutes 

Materials and Supplies: 3, pre-1982 pennies, 5, post-1983 pennies, steel 
wool, hot plate or Bunsen burner, wire gauze, forceps or tongs. 

General Safety Guidelines: Hot metals can cause severe burns. 

Procedure I: 

   1.Obtain five post-1983 pennies. Thoroughly clean them using the steel 
wool. 

2.Pre-heat the hot plate using the setting, which is 75% of the maximum 
value. For Bunsen and wire gauze, place the Bunsen to produce maximum 
heating and pre-heat. 

   3.Start the time and place four of the post-1983 pennies on the hot 
surface in a ring around the center. 

   4.FOR HOT PLATE: Using forceps, remove one of the pennies at each of the 
following time intervals: 
          1 minute 
          5 minutes 
          10 minutes 
          20 minutes 

     FOR BUNSEN AND WIRE GAUZE: Use the following time intervals: 
          15 seconds 
          25 seconds 
          35 seconds 
          45 seconds 


Good Luck and Have Fun!

Jared

Reference: http://matse1.mse.uiuc.
edu/~tw/metals/g.html