A pen friend recently entrusted me with his Sheaffer Balance Jr. The ink sac had hardened and needed replacing. Fortunately, it didn’t take much effort to remove the section from the barrel. A little soaking in water and gentle application of section pliers were all that were needed to remove the barrel and remove the old sac.
Inside the section is a long piece of hard rubber. The flat side of the rubber rod has a channel cut into it to help get the ink to the feed. (Read more about feeds here.) The section is beautifully transparent. After more soaking and flushing to clean out old ink the new sac was installed. With a bit of practice installing a new ink sac is the simplest of pen repairs.
Even though the Balance Jr. measures a little over 4″ from nib tip to barrel the pen holds quite a bit of ink. (The capped pen measures 4 3/4″.)
Richard Binder has written a great profile on the Sheaffer Balance. Read it here.
As always click on photos for the close-ups.