I learned pipe building at the Kilgren Organ Works in St. Louis in the
mid-1950's.  We sawed wood, and poured metal on sheepskin and doctor
bladed it to a thickness spec.  We hammered and soldered and glued and
all kinds of things to build the pipes used in St. Patrick's Cathedral
in New York City.

The guy I learned this ancient art from had learned it from his father
and so on for four generations.  His family had come from Germany and he
knew the history and secrets handed down from the past.  He had strong
opinions backed up by experience.  He said that as far as he knew the
idea of placing wood or metal at the speaking flue of a wood or metal
pipe to modify the tone was invented by Arp Schnitger in the 1600's.
Gavioli patented the idea specifically as the Gavioli Frein 200 years
later.  In reference works Gavioli is sometimes recognized and sometimes
ignored.

I personally believe that, long before Gavioli, the French organ builders
of the late 1700's perfected the use of the "Frein" on stopped wooden
pipes to achieve string sounds.  The Germans used the "frein" before that
to diminish the chiff on rohr flutes and the like.  Gavioli did, however,
patent the idea, but I doubt that he collected a penny from other organ
builders.  I doubt that most of them even knew Gavioli existed.  I also
suspect that they looked down on the Fairground organ contingent.

Bill Finch