Polymers in Brass

Polymers in Brass Instruments

Trumpet | Horn | Trombone |
Tuba and Sousaphone | Taking Care of Brass

Brass instruments have a distinctive sound. They are known for clarity and volume and were originally used for war and hunting. Polymers have little to do with how they sound, since their tone is derived from the hard smooth surface of brass, while the player's lips act sort of like a double reed generating the necessary vibration. But polymers do help the instruments sound better, look better, and work more smoothly.

Trumpet

Trumpets and the trumpet family come in a variety of sizes and keys and are perhaps the most visible and obvious of the brass family. They are certainly the instruments you hear the most from in a marching band. There are also little piccolo trumpets like Bach and Handel liked to compose for. Not to mention rotary trumpets and the cornet.

Most of what makes a trumpet work is a set of metal valves which change the length of the tubing to render different notes. ( A long time ago trumpets didn't have valves and the player had to change the notes with his own breath pressure and lips.) But in order to move and work smoothly, the valves must be oiled. Oils in general are formed from polymers. Many of them come from nature, but synthetic oils like silicone are specially made for lubrication and can actually work better than petroleum products like mineral oils, which are more apt to evaporate or become sticky. Trumpet valves also have felt pads made from wool, to keep them from clicking and making noise when they are pressed.

Another important role polymers play is in the rubber seal on the trumpet's spit valve. Since a brass player is essentially forcing air between his lips and into the mouthpiece in order to make the sound, naturally a lot of... well... spit gets through as well. This valve is made to release the moisture which collects inside the trumpet during playing. The rubber or cork gasket on the valve seals it tightly until it is time for the spit to be carefully and discretely disposed of. Some members of the trumpet family even have two or more spit valves!

Horn

The Horn is a beautiful instrument both in tone and looks. It is less piercing than the trumpet or trombone and is actually more akin to the tuba and euphonium in its construction and sound.

One thing that makes a horn or any brass look so beautiful is a coat of clear cellulose acetate lacquer. This resilient outer layer of polymers makes the horn look nice and also protects the metal from scratches and tarnishing. Some silver or silver-plated brass instruments are even coated with a layer of gold-tone lacquer to give them the traditional "golden" appearance of a brass instrument.

Yet another aesthetic use of polymers is on the keys of a brass instrument. The nicer ones have keys decorated with mother-of-pearl, but it is often substituted with plastic which looks like the real thing.

Trombone

The trombone is actually closely related to the trumpet in sound, though it does not change pitches with a system of valves, but rather with a movable slide which is used to change its length. This is where polymers come in. Slide cream is used to help the slide move smoothly, quickly, and quietly from note to note.

Here you see a container of
slide cream for a trombone.

Another type of slide which all brass instruments have is the tuning slide. This is a section of pipe which can be adjusted to tune the horn to other instruments by slightly changing the length of the entire horn. This slide of course also needs lubrication but with slide GREASE. These oils, greases, and creams can be made of a natural oil product like petrolatum or they may be made of synthetics like silicone, which is longer lasting and less sticky.

The trombone also has a spit valve sealed with a rubber or cork gasket to regulate excess moisture.

Tuba and Sousaphone

These three big guys are all essentially the same instrument. The tuba is the lowest of the brass and usually takes the bass line in a marching band. But since a traditional tuba is pretty bulky and heavy, the Sousaphone was invented by John Philip Sousa - the March King. This "wearable" tuba is carried on the shoulders and makes marching a bit easier, but the brass model is still pretty heavy. So the Souasphone has been recreated in light durable ABS resin - a very popular polymer for construction of musical instruments. The ABS model doesn't have quite the same penetrating "brass" sound as the original, but it works well and is very popular with marching tuba players.

Taking Care of Brass

The main polymers used to care for brass are those in the oils which keep valves and slides working smoothly. Silicone is a great polymer for use in oils, greases, and creams. It doesn't get sticky or gunky and it evaporates slowly. It is also thinner and easier to spread than petroleum oils and it is less affected by temperature as well. (Note: Non-synthetic oils, like cooking oil, are made of large molecules, but are not polymers.)

Another thing which brass instruments need is internal cleaning of the bore and tubing. This can be tricky with all those twists and turns. One thing which helps is a rubber snake brush, a long bendy rubber tube with nylon brush bristles on the end. Brass players literally use these things to scrub out the insides of the instrument tubing. different types of swabs and mops as well as soft cotton cloths come in handy for daily removal of moisture and for polishing.

Despite that it is metal, brass is pretty soft, and one of the best ways of caring for it is to keep it in a nice hard case with a soft velvety interior. The hard part and the soft part of the case are both polymers. Polypropylene makes a great hard exterior and the velvety interior is likely some kind of polyester or other synthetic fiber.

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