 |
New Stoppers
I think it is true to say that a weak point in many small organs, is the
pipe stopper seals. For the pipes to perform properly these have to be 100%
airtight, there also has to be a compromise to allow for adjustment. For
the amateur, some of the professional methods can be very difficult to repair,
or reproduce. Many scorned the draught strip stopper seals as used
in my Busker organ, but it was a practical answer to a tricky problem, however
the manufacture of the foam strip has now changed making it unsuitable.
My latest way of making stoppers might be of more general interest as it
is suitable for new pipes or repairs. The wooden part of the stopper is made
roughly 2 mm smaller than the pipe bore, the lower corners are chamfered
off and a piece of new chamois leather glued onto just its face. The
leather should overlap the wood by about the same amount as the depth of
the stopper. When the glue is dry just push it into the pipe, the soft
leather will form itself around the wood and even seal those awkward corners.
If adjustment to the fit is needed then card shims can be fitted around
the wood. A little tip: Before fitting stoppers to suspect, or new
pipes, test them using a ball of Plasticene as a temporary stopper, this
will show up any leaks in the pipe itself.
Tracker Bar Modifications
As most of you will know, my DIY organ is direct action, the air simply goes
through the holes in the paper roll directly to the pipes. To get enough
volume with this system I had to use larger than standard holes, 4mm instead
of 3mm, and for the bass notes even larger 6mm ones. Originally I
recommended two sizes of hole in the paper rolls, but it was not long before
my good friend Edward Murray-Harvey pointed out a better way. Apparently
some of the old instruments got their extra wind for the bass notes
by extending the length of the holes. So I carried out some tests
and issued this modification: The lowest note hole is now lengthened
to 9mm and this process continues gradually diminishing over the next 6 note
holes. The main result of this means that it is no longer necessary to cut
larger holes in the rolls for the bass notes. If you have already made
your Busker organ using the early plans, never mind, as the holes can
be extended in situ. (Carefully stop any sawdust passing to the pipes) I
did mine by pushing a strip of soft cloth into the reader holes and then
enlarging them, removing the cloth while vacuuming the hole.
Improving your Music Rolls
It may now seem unnecessary to keep the 6mm holes but it is still an advantage
as it allows for use to be made of a unique quality of the direct action.
By varying the size of the holes in the roll the volume of particular notes
can be changed, for the bass this means they can be made even louder, very
effective to give a particular note some extra punch. There is a good deal
of scope to personalise your rolls, a true vibrato can be obtained by punching
individual holes, rather than continuous slots. Also try cutting wavy
slots for an amazing bagpipe effect.
Back to the Articles Index
This web site is copyright (C) Melvyn
Wright and individual contributors |
