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MMD > Archives > March 2002 > 2002.03.07 > 05Prev  Next

Tubing and Hose Sizes for Player Pianos
By Craig Brougher

D.L. Bullock mentioned in his letter that he didn't like that light
gray hose PPCo sells.  I suspect he is referring to the 1-1/8th inch
gray hose that is flattened from being wound up in rolls.  (Durrell
sells 1 inch, 1-1/8 inch and 1-1/4 inch hose in the light grey, to my
knowledge.  He doesn't have any 1-1/16 inch in anything right now.)

If anybody has the problem of pre-flattened heavy-wall hose, there is
a way to fix it.  You use a large heat gun and evenly heat up a 6 ft.
length.  Heat it good and hot! Use gloves because you won't be able to
hold it after awhile.  heat from both ends.  Once it is hot, lay it on
a table between two 2x4s spaced so that when you straighten the hose
out the gap forces the hose to be round again.  Let it cool.  You have
round hose!  You can't use the thin wall for anything, by the way.

On Duo-Arts, the 1" light gray hose is pretty good stuff.  If you don't
like gray, you can dye stain it black.  But on some Duo-Arts, there is
so little clearance between the treble end of the piano action brackets
and the case that twill covered 1-1/16" hose fits too tightly and then
the piano action will not pedal as una-corda without having to use too
much pressure.  Also, the heavy wall 1" light grey hose will not
collapse under high vacuum.

Now what I am looking for, and hope others will encourage it as well,
is some true 7/32" tubing.  Whatever you do, don't use that light gray
7/32" from PPCo!  Most rebuilding efforts today opts out for 3/16"
tubing as a substitute.  This is a bad idea in many cases.  There is
about a 30% difference in air handling capacity between 3/16ths and
7/32nds.  In the case of Ampico B's for instance, that is too much of a
difference and the drawer becomes very under-powered.  Reroll and
repeat suffer the most, but so does tracking.  In all cases, stretching
3/16ths tubing over a 7/32" nipple will ruin the tubing in a decade.
It cannot stretch such a difference in diameter without shortening its
life.  Unfortunately right now, there isn't much you can do about that!

There are very few players that used 3/16ths tubing.  Coinola did,
of course, and there's a few that do, but the vast majority all used
7/32".  So our suppliers need to recognize this and understand that
while PPCo has it, it either kinks right off (the grey stuff), or slides
off (the oily black stuff).  Somebody needs to encourage Schaff (Don
Johnson) to sell 7/32nds tubing in the same quality as their 5/32nds.
That is undoubtedly the best tubing I have ever seen.  Every piano that
has 3/16" then should be changed out to the new 7/32nds.

Craig Brougher

(Message sent Thu 7 Mar 2002, 16:09:46 GMT, from time zone GMT-0800.)

Key Words in Subject:  Hose, Pianos, Player, Sizes, Tubing

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