One of the most rewarding and immediately gratifying processes in
metalsmithing has got to be forging. It's certainly one of the
things that hooked me. Actually seeing the material grow in direct
response to the hammer--an extension of the hand--is magic.
One thing that I do to show students how metal reacts to the hammer
is to give them each a strip of, say, 18ga copper. With a cross peen
hammer have them hit the strip squarely and with the axis of the peen
perpendicular to the strip's length. A few whacks and the strip grows
in a more or less straight direction.
Now have them move to one side of the strip and forge one half for
about an inch. The strip will, of course, bend away from the blows as
one side stretches. Then have them repeat this on the other side,
further up the strip.
This gives students an immediate idea of how the metal responds and
what is happening. It also clues them in to the reality of deep or
misplaced cross peen blows. I also have them "planish" out some of
the blows with a ball peen or dome peened hammer.
From there they can forge square stock draw tapers, etc.