On Fri, 21 Jan 2005 16:07:06 -0800, Frank J Warner
wrote:

I see that most fire pistons are made from wood, horn, bone or plastic.
I did not, in my travels on the web, see any made of metal. Is there a
reason for that?

I'm guessing it's because the metal would chill the air heated by
compression. If it were big enough and compressed fast enough it'd
probably work OK. Diesel engines are fire pistons!