Freeing up slides and stoppers is a problem sometimes when the organ
has not been tuned for decades.  The sliders on the outside of metal
pipes will often knock loose or since they are often spring rolled tin,
they can be pulled at the seam up the side.

For outside wooden sliders you must often take screws out of the side
brackets to remove them and sand the shellac with fine paper, 320 or
400, with a very flat wooden block.  The shellac just sticks when two
shellacked surfaces touch each other for long periods of time.  It also
often migrates or pulls off when you remove them. Hence the need to
sand and sometimes to use Johnson's baby powder on the surfaces.

For freeing stoppers, I find a heavy weight or weights that will fit
into the mouth of the pipe. Then turn the pipe with stopper end down
and shake up and down only enough to make the weights jump up and down
on the inside surface of the stopper.  The jumping weight will usually
knock the stopper out of the end of the pipe.  Sometimes you must push
the stopper a little farther in first to break it loose from the sides.
Don't let the weights fall to the languid end of the pipe as that can
revoice the pipe not in a good way, especially metal ones.

Never, please, _never_ use the old pipe organ man's goop to lubricate
a wooden stopper.  Some of them mixed paraffin, petroleum jelly, beef
tallow to make a glop that was once promoted to make stoppers seal and
slide.  All that does is soak into the wood and grease up the pipe.
After a couple of years, it sticks the stopper even worse than having
nothing as lubricant.  It takes hours to remove this stuff.

When releathering wood pipes make sure that the felt and leather for
stoppers is tight enough to need some muscle but not tight enough to
split out the pipe.  If there is a crack in the pipe it will not speak
the correct pitch or at all.  The corners of the releathered stoppers
must be square to fit the corners of the pipe or they will leak just
like a crack.

You may need to sand the inside surfaces of the pipe to make it slick.
Use Johnson's baby powder to lubricate the new leather and the inside
of the pipe.  Only Johnson's seems to be slick enough.

Remember!  These stoppers have only one way of going in.  You will
notice there is a mark of some kind on the front side of the stopper
handle.  Keep this or put one there before you remove the stopper.
These stoppers are made as part of the pipe or rather the pipe is
made around the stoppers so they fit the shape of the pipe perfectly.
A 180-degree turn of the stopper will usually not work.

D.L. Bullock    St. Louis
http://www.thepianoworld.com/