One of the most important components of any brass instrument (apart from trombones) are the valves. They basically alter the overall length of tubing used by diverting the air flow through various additional pipes. A combination of lip pressure and valve configuration allow the player to pitch any note across a range of the chromatic scale.
Cornets, Trumpets, Flugels, Tenor Horns, Baritones, Euphoniums and Tubas all generally use piston style valves to determine the specific note played. This type of valve is generally preferred in the UK to the alternative rotary valves that can be found on some European models. It is vitally important that these valves work freely and without restriction.
When performing work with rapid/hi-tempo passages it is also crucial that valves move quickly. The better the condition of the valve the more reliable it will be and the chance of it 'sticking' will be greatly reduced. There are 3 main materials used in the production of valves which can vary by manufacturer and model. There are various opinions on which one is better and you could present a case for each depending on the criteria you use.
Nickel Plated
Nickel plating, as you would expect, contains 100% nickel with the plating on top of a nickel silver valve. It is a lower cost option so is usually found on student instruments, but not exclusively. The Getzen Company uses nickel plating on all of their valves as they feel the 'slipperiness' of the material means less resistance and a faster action. You could argue though that a more 'slippery' material will be less effective at retaining any valve oil applied.
The quality of plating is also a factor as it can be prone to flaking, particularly if it is a poor/thin application. Think of it similar to painting exterior woodwork, the better you prepare the surface and the thicker coating of paint you apply, the more chance it has of standing up to the elements long term.
Monel
Monel is a primarily a nickel and copper alloy (65% nickel) with several other metals added (including iron, aluminium and cobalt) and was named after its developer Ambrose Monell. It is a very hard material, more resistant to corrosion than nickel plated and will not flake as it is a solid alloy rather than plated. A greenish/brown build up is sometimes found on monel valves due to an electrolytic reaction between the piston and the casing causing the brass to leach onto the piston. Nickel plated and stainless steel valves are less likely to experience this reaction.
It is claimed that monel is perfect for valves due to its hardness as if the valve material is harder than the brass casing it will help to 'lap' the valves in. Often overlooked is the fact that the monel is heated to a red-hot state when the valve itself is assembled meaning the alloy is softened in the process (annealing). For this reason, the majority of companies now opt for stainless steel valves, particularly on their advanced instruments.
Stainless Steel
Stainless steel is now the most popular choice for mid-range and professional instruments and contains 18% chrome and 8% nickel. Like the monel it is a solid material so plating flake is not a concern and makes it preferable for preserving the acoustics of the overall brass tubing. Being a harder alloy it also allows for finer / tighter tolerances within the casing which in turn can improve intonation. It is worth pointing out though that wear on stainless steel (and monel) valves doesn't 'show' in the way it does on nickel plated valves. All valves wear to some degree but there is obviously no plating to wear off on non-plated valves so wear is not always as obvious to the naked eye. I would guess that if you took a poll of brass players and asked them to choose a material they felt would give them a hassle free playing experience the majority would choose stainless steel.
So What's My Opinion?
The intention of this article was to explain the differences between the valve materials used. You see it quoted on instrument specifications so it makes sense that you may want to know. If you ask me which one to choose my honest reply would be 'it doesn't matter'! All materials used by manufacturers are up to the job (or else they wouldn't use them!) and what they are made from in my opinion is very secondary to how you look after/maintain them.
If your valves are cleaned and lubricated regularly then you should have many years of trouble free playing. If, on the other hand, you never clean them, never oil them and eat sugary sweets just before you play then you get what you deserve. An instrument that will give you a whole load of hassle and ultimately become unplayable!
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