The following article originally appeared on the trumpet discussion list and I got it in 1996 on another list I was then part of.
Presumably even though this article is oriented toward piston valve
performance, this information about the properties of valve oils is of
some interest to rotary valve players also. (As used in my Hagmann valved Bb/F trom I use in a dance band, for example)
-----------------------------------------------------------------
VALVE OILS vs PERFORMANCE
Over the last few weeks since I discovered this forum, I have been quite
impressed with the depth of the interest in the technical aspects of
trumpets. I have also noticed that the subject of valve lubrication and
corrosion, was approached with trepidation. Since there is no literature
on the subject, I would like to offer our help in answering some questions,
as well as dispelling those prevailing myths about trumpet lubrication which
only serve to keep a horn from delivering its best performance. There is
much to say, and it might actually be easier if interested parties would
post their questions to the list so that all members can read the answers.
In the meantime, I'll break the subject of valve oil into several sections.
Our company was founded by a musician and a chemist, hence the name
MusiChem, Inc. The information we offer is from our in-house laboratories
and field tests, and is the result of a company we started in 1972.
Although we generally don't advertise, our oils are used by some of the best
players in the world. However, please understand that although we
manufacture valve oil, this is not an advertisement to buy our products;
the information is applicable to any piston valve oil.
The most common question is "Are all valve oils the same ?" Store owners
that do not play trumpet will tell you that all valve oils are basically the
same. However, the differences between valve oils are serious, verifiable,
and have a dramatic effect on how your horn will perform. Valve oils for
trumpets fall into 3 groups: Type 1 are the low technology formulations
based on a modern day version of kerosene (the odor is quite obvious); Type
2 are high viscosity oils; and Type 3 are light weight oils with little or
no petroleum odor. By the way, the word "premium" is not a technical term.
There are so many trumpet oils available because there are so many
businessmen who combine a little kitchen chemistry with a lot of advertising
dollars to create a product. However, developing a functionally correct
lubricant requires a thorough understanding of Material Science and Fluid
Dynamics. Ignoring these principles has resulted in the proliferation of
fundamentally poor valve oils. For example, one trumpet oil company that
uses silicone oils is ignoring the hysterisis and buildup problems that
plague silicones when used on sliding metal surfaces. In fact, a primary
manufacturer of silicone - Dow Corning- specifically recommends against
using silicone for sliding metal/metal lubrication.
"Some oils gunk up valves." We have all heard this misleading statement,
but when we complete this presentation, you will have enough understanding
to never again suffer from a "gunked up valve". The statement, however,
leads us into the main part of the subject: Speed and Endurance.
The primary purpose of valve oil is to provide a thin film of slippery fluid
which clings to the valve and casing, thereby acting as a barrier to prevent
direct metal to metal contact between these critical surfaces. A thick oil
(Type 2) may be slippery and provide an excellent barrier, but it would
cause the valves to be very slow. A thinner fluid (such as kerosene in Type
1 ) would be fast initially but its rapid evaporation would cause the valves
to slow down quickly, and eventually stop moving altogether. Consequently,
long ago we recognized that there are two major performance considerations
in researching a new oil for piston valves: Speed and Endurance. To ignore
either in favor of economy or naivet, is to guarantee disappointment for the
musician.
SPEED
The most important quality in a valve oil is its ability to promote speed by
reducing friction. But, the oil also causes some resistance of its own.
This measured resistance is called viscosity, and the unit of measurement is
centi-Stokes (cSt.). Musicians seeking a "thin" oil are simply looking for
a low viscosity oil. Although you can get a rough idea about how viscous an
oil is by applying some to an inclined surface and watching it run, the
accurate way to measure viscosity is with capillary viscometers. Since
actual viscosities of different oils have not heretofore been published, we
have presented some in table below. These oils were purchased from
different stores.
Products Viscosity (cSt)
WATER 1.00
MINERAL SPIRITS 1.34
CLARK TERRY 1.83
BENGE 1.99
BLUE JUICE 1.99
PLAYERS 2.15
JUPITER 2.20
ROCHE-THOMAS 2.31
HOLTON 2.38
HYBRID 141-A7 3.02
PRO-OIL RED 3.61
SPACE FILLER II 3.72
AL CASS 3.73
PRO-OIL BLUE 3.80
SPACE FILLER I 5.10
SLIDE (for trombones) 5.12
ALISYN 7.59
As you can see, several valve oils are so "thin" that they approach the
viscosity of water, while others are very viscous.Water has by far the
lowest viscosity, but if low viscosity was the only criterion for speed,
then the spit in your horn would be enough to keep your valves fast. The
fingers of an experienced trumpet player can sense even the slightest valve
hesitation, and this experience has shown that the optimum viscosity for
speed lies somewhere in the 1.1 - 5.0 cSt range.In developing HYBRID (our
experimental reference standard for piston valves) we have discovered that
the optimum viscosity for valves in good condition is in the 2.0 - 4.0 cSt.
range. However, badly worn valves can tolerate or even benefit from somewhat
higher viscosity oils. Nonetheless, viscosity isn't the entire answer;
speed means nothing if the action is not smooth, or if the valves become
slow in the middle of a performance. A working musician cannot afford to
even think about his valves during a performance. In other words, what
about endurance ?
ENDURANCE
Endurance is the oil's ability to maintain the original fast and smooth
valve action over many hours despite playing conditions. This
characteristic is very difficult to develop in an oil without compromising
speed because endurance is the end result of a complex series of
interrelated properties and conditions: evaporation rate, film strength,
surface tension, water solubility, and valve cleanliness.
The first property is evaporation rate. In most student and mid-line horns,
when a valve oil evaporates so that less than 40% of the original oil
remains on the valves, they will begin to hesitate in an unpredictable
fashion. In more expensive horns with clean and very tight valves, the
slowdown is much sooner and sudden seizing of a valve is common. In the
relative evaporation rate table below, we have listed the percent of oil
remaining on a surface as a function of time at room temperature. The data
does not suggest that a given valve oil will last the number of days shown,
but rather the percentage of oil remaining after a given period of time.
Compare the evaporation rates of the oils with their viscosities, and
remember that Endurance is enjoying fast consistently smooth action for a
long time - not slow action for a long time. Some trumpet oil manufacturers
include a heavy oil in their formulation to slow down the apparent
evaporation rate, and (hopefully) to make the oil last longer.
Unfortunately, as evaporation occurs, the lighter oil content diminishes
until only the slow heavy oil remains on the valves. Our experiments back
in 1976 proved this.
EVAPORATION RATE TABLE ( PERCENT REMAINING VERSUS TIME )
Products Vis.(cSt) 19 hrs 48 hrs 72 hrs 96 hrs 120 hrs
WATER 1.00 0%
MINERAL SPIRITS 1.34 0%
CLARK TERRY 1.83 16% 7% 6% 0%
BENGE 1.99 35% 13% 8% 5% 4%
BLUE JUICE 1.99 44% 23% 17% 12% 8%
PLAYERS 2.15 44% 20% 13% 8% 4%
JUPITER 2.20 33% 17% 15% 13% 10%
ROCHE-THOMAS 2.31 16% 13% 13% 12% 11%
HOLTON 2.38 25% 7% 4% 0%
HYBRID 141-A7 3.02 92% 75% 64% 55% 46%
PRO-OIL RED 3.61 74% 44% 33% 21% 11%
AL CASS 3.73 75% 48% 37% 26% 16%
PRO-OIL BLUE 3.80 77% 50% 37% 25% 13%
SPACE FILLER I 5.10 100% 100% 100% 100% 100%
SLIDE (t-bones) 5.12 100% 100% 100% 100% 100%
ALISYN 7.59 100% 100% 100% 100% 100%
Endurance is very sensitive to the integrity of the oil film on the valve
surfaces. As the piston slides down the valve casing it rubs against the
oil film. This movement tends to rupture the film and allow direct
metal/metal contact. In hyper-tight valve assemblies (i.e., Monette and
Schilke) oil film rupture is potentially more frequent and disastrous. This
is a purely mechanical phenomenon which can only be prevented with an oil
having a high film strength.
Achieving a high film strength oil within the optimum viscosity range (2.5
- 4.0 cSt) is quite difficult. Although it is not easy to measure this film
strength directly, it is best understood through demonstration. Firstly, a
high film strength will give a smooth, slippery feel when the oil is rubbed
rapidly between the fingers. When shaken, an oil with a high film strength
will yield bubbles that collapse within 1- 3 seconds. Whereas an oil with
poor film strength will tend to entrap air for a much longer time.
Oil film rupture can also occur for a different reason: moisture. Water
trapped in the valve chamber experiences the shear force of the piston
moving rapidly past the walls of the valve casing. This action tends to
emulsify the trapped moisture into the oil. This micro emulsion not only
has an elevated viscosity, but also displaces the oil from the valve
surface. With the oil film thus compromised, the valve and casing easily rub
against each other to produce friction, slowed action and wear. Therefore,
in addition to the properties discussed above, for an oil to be truly
effective it must also resist emulsion formation.
STICKING VALVES
How many times have you heard, "My valves were slowing down, so I reoiled
with a different oil and suddenly the valves stuck." The tendency is to
blame the oil, and although the oil played a part, other causes are more
likely for this 'Gunking Up' phenomenon.
Every note pushed through the horn is borne in the musician's moist breath
with the valve chamber acting as a trap for not only this moisture but the
aerosols suspended in it. These aerosols contain enzymes, proteins, and
salts. As long as the valve oil rejects this mixture, it will simply pass
through the valve chamber. But, as the oil boundary film becomes depleted
or compromised, the moisture and its aerosols become attached to the metal.
When the musician reapplies oil to the moisture impacted valves (or to
valves that had enough time for the spit to dry onto the metal) the oil
will actually deposit on top of this layer. As this process is repeated a
series of sticky layers and high spots build up until the valves become
sluggish or stick completely. There is no oil that can permanently protect
against this "spit sandwich" but you can prevent it through effective
cleaning and proper oiling.
CORROSION
A lesser know consideration in selecting a valve oil is corrosion. It is
absolutely necessary to liberally coat the valve and casing surfaces so that
excess oil will transfer to the internal solder joints. In doing so it will
protect them against dezincification (red discoloration) and corrosion
(blue-green discoloration) which are caused by exposing the naked metal to
moisture. Monel valves will similarly be protected against spotting. An
oil with low surface tension and a low viscosity will spread quickly and
evenly, thereby coating these surfaces without fear of over oiling. It is
very difficult to properly coat a valve, the casing and the solder joints
with a high viscosity oil. The topic of corrosion will be covered in depth
at a later time. Players of rotary valved instruments will want to pay
close attention to this article.
HOW TO SELECT YOUR NEXT BOTTLE OF PISTON VALVE OIL:
1. A high speed oil is a thinner oil. If you don't recall which oils are
heavy, a quick test in a store is to apply a drop or two of each valve oil
onto smooth surface (ie. a clean mirror, a sheet of glass or a sheet of
metal). Tilt the surface and see how fast the oils run down the sheet; heavy
oils move slower and can be eliminated from the selection.
2. The oil should have a slow evaporation rate and be remain slippery. A
good evaporation test is to place some of the oil in the palm of your hand
and feel how long it feels slippery relative to a different oil. Kerosene
based oils are not desirable because they evaporate quickly. The presence
of kerosene is apparent from its characteristic odor which will become
evident in this test.
3. The film strength is crucial. Hold a group of well capped bottles of
high speed oils in your hand, turn them upside down and shake them as a
group for 5 seconds. Note how fast the foam breaks; the faster the better.
Weed out the ones that have a slow foam break.
4. Water rejection is important. This is a test of how fast the water and
oil separate but since it requires sacrificing some oil, a store owner might
not want to do it. The test is to add equal amounts of water and the valve
oil to a small container (a test tube or even an old bottle), and shake
vigorously for 10 seconds. Observe how long it takes for the oil and water
to separate almost completely.
CONCLUSIONS OF PARTS I & II
Speed and Endurance in an oil are two different properties; experience will
show that the best oil will not sacrifice one for the other. To quote a long
time friend of ours (Art Farmer), "I play very fast, and I have to
concentrate on the music. I can't afford to even think about my valves
during a performance."
To develop an oil for horns built on better technology, one must employ
better lubrication technology. Until now, no one has tried to enlighten
either the musicians or store owners that there is a science to improving
valve oil, and only a few valve oils take advantage of the science.
Hopefully the results of our research brought out in this article will
dispel the mystique of valve oils, and make oil selection almost bulletproof.
ps its a Courtois 167 R II BTW (I had a I before, it was crap) (I also had a sovereign before it so was that) (Imperial before that was great!)
