Re: What is the outside of soft drink cans made of?

Soft drink cans can be made out of aluminum or steel, but we only use aluminum 
now in the US.  The aluminum goes through long rolling, cupping and 
coating processes in order to become a can.  If you would like to see the 
process, visit 
Ball Corp.'s life of a can".  
They describe each of the steps in detail - with pictures.  

The colorful graphics you see on the outside of the can bodies are made from 
layers of various laquers and varnishes.  The exact composition of each coloring 
is generally a trade secret and often will vary depending on what conditions 
the soda will be exposed to later in its life.  For example, if the cans are 
to be stored outside, the varnish should have better UV protection so the colors 
don't fade in the sunlight.  I suggest you try the FAQs section of Ball Corp's 
web-site to see if they have any more details about varnishes.

I hope this information has helped a little.

Kieran