Following the thread on silicone sealants, I remember having a problem
with a split pipe several years ago.  The pipe in question was a very
inaccessible bottom 'D' of a 16-foot Bourdon in a church organ.

The split ran down one seam at the top, for about 12 inches, caused by
dry central heating shrinking the timber.  The stopper, made from two
pieces with the grain running in opposite directions, had not shrunk,
and so the glued joint had parted, with a gap of at least one-quarter
of an inch.

The stopper was hell to remove as it was so tight.  But that done,
I tried clamping the pipe to bring the boards together, but could not
get them to meet.  After some thought I resorted to injecting the split
with silicone sealer and tidying the inside corner by running my finger
up the seam.  The stopper was trimmed and re-fitted, and the pipe spoke
perfectly.  This was done without removing the pipe from the organ.

John Page, UK