I found this link and found it fascinating.  It shows the way all
metal organ pipes are made, but these happen to be an octave of
32-foot Diapasons for a church in Los Angeles.

http://www.giesecke.de/prospektpfeifen_e.htm

Go to the link and click on picture number one, hitting "next" on
each page thereafter.  It goes from metal ingots all the way to
installing into the church in an earthquake resistant racking system.
Oh, yeah, the copper inserts are not used in smaller pipes, but that
is the only difference in making this rank.

D.L. Bullock    St. Louis
www.thepianoworld.com

 [ The caption at the English page simply says,
 [   "The Way of building big Facade Pipes."
 [ At the corresponding German page :
 [   http://www.giesecke.de/prospektpfeifen_d.htm :
 [  "Here you see a picture gallery of our sequence of production
 [   events connected with some short information about the example
 [   of a particular production [process]."
 [ But I couldn't find the "short information" anywhere at the web site.
 [ -- Robbie