I saw the making of a aluminum cylinder when I took the VIP course and found it quite interesting. Of course I'm that type of a person. So I was snooping around You Tube and ran across the videos that I was shown. So if you're like me you just may enjoy seeing how your life support equipment is created. They're only about 5 minutes each.
Enjoy
Catalina Aluminum Cylinders
Worthington Steel Cylinders