What is the purpose of the bag?

The purpose of the bag is two-fold.

  1. It must contain air in the short term (i.e., for several minutes), and
  2. It must pass moisture in the long term (i.e., several hours).

This combination will allow the pipes to be playable, but to "relieve themselves" of excess moisture by transport through the walls.

Copyright S.K. MacLeod 1996-2016