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Many scientifically-minded
pipers like to use a manometer to control how regularly they blow,
since uneven pressure in the bag often leads to uneven pitch when
playing; I found several how-tos on making a water manometer with
coloured water in a tall transparent U-shaped tube, but this is
very bulky, awkward to set up and carry around, and you are stuck
in one place while using one. So I looked into making one that
would
pack
in my pipe-case, and
let me walk around
while practising,
This meant using an aneroid manometer, but an aneroid-type piping
manometer retails at a minimum of $50 + P&P from piping
supplies shops, which offended the frugal inclination of my Scots
forebears.
So I went into Al Gore's wonderful Information Superhighway to gather some ideas, look
around for cheap (or free) sources for the materials, and here it
is, a portable piping manometer for around $15 to $20, or less !
To this end you will need the following:
- One aneroid manometer, as used on blood-pressure testing
apparatus (sphygmomanometer).
A cheap (read:free)
source of usable manometers is from a friendly doctor or health
professional who may have some lying around from old
sphygmomanometers whose cuffs have perished; if not, search Amazon
for "aneroid manometer" in Health and Personal Care, and you
should find several offerings around $10 + P&P each.
- One #0 or #00 rubber stopper, or a
cork, to fit the top opening of a drone.
Rubber stoppers can be
found at your neighbourhood scientific supplies shop, or through
mail order: Once again try Amazon, where at the date of writing
(2013) you can get a pack of "Rubber Stopper, Solid 5Pk #0" for $4.75
including P&P, which turns out cheaper than ordering a single
one directly from a scientific supplies web-site. - A 1
meter length of 5 mm inside diameter plastic tubing (40"' of 3/16" ID
tubing for the Un-Metrical Heathens).
Here again, you friendly
doctor could be of help with tubing from an I.V. drip kit; if not,
the tubing sold in automotive stores for motorcycle fuel lines
should be available in the size you need.
- A 50 cm length of 5mm (20" of 20 AWG) steel wire.
Now, getting all
together. You will find the following step easier if you have
access to a pillar drill; if not, use a hand drill with
due care. Remember
you need all your fingers for piping.
- Drill an axial hole through the cork, of the diameter as
the OD of your tubing.
- Push one end of the tubing in the hole,.
- Install
the manometer at the other end of the tubing, and you are done.
The
support, which holds the manometer where you can easily watch it
while playing, is made from steel wire shaped as shown in the picture on the
left, and fits as shown on the picture on the right: the round loop
in the middle fits around the blowpipe stock, the wide hook at one
end around the bass drone stock, and the U-bend is where you clip
the manometer on. Shape to fit your pipes, bend so that the
manometer face points towards you. I have slipped some plastic
tubing over all three curves, to protect the stocks from being
damaged by the metal, and to give the manometer clip something to
grip on.
To use, remove the blowpipe and put the support in place over the
stocks, clip the manometer in position, wind the tubing a few
turns along the length of the middle drone and stick the stopper
into the top of the drone.
Random musings and
after-thoughts:
- I found no need
to put in an elbow to avoid a kink blocking the tubing; that which I got at the
automotive store is stiff enough that it curves with no kinking.
But watch this if your tubing is thin-walled.
- Rubber stoppers are easier to drill if you keep them for
an hour or so in the freezer beforehand.
- There is
no need to remove the drone reed, enough air leaks by to give you
the pressure reading.
- Drilling through a spare #3 stopper will allow use of the
manometer on the bag without drones, when used a a goose for
instance.
- If you want to compare your readings with those obtained
from a water-tube manometer, a reading of 10 millimetres of
mercury on the manometer equals 13.6 centimetres (5 3/16" or 5.3") of water
pressure.
- Remember that unless you use the pressure reading to order
reeds of a given stiffness, the precision of the instrument is not
very important, what really matters is that the pressure should
remain constant (=manometer needle not moving) while you are
playing.
- A simpler support can be made on the lines of the tuner support described here.