Water Keys 102
So, you decided to install a water key or two or three on your horn.
You just take it to your technician and say, “Put on a water key.” Right? Not so fast, there, horn player! You have to actually make some decisions.
First, talk with your tech about where to place the key or keys. Most players want one on the leadpipe. The water condenses here first and fastest. Another popular place on a double horn is to put the water key on the 3rd Bb slide crook. But don’t forget other trouble areas. Remember that a water key is for convenience, and nothing else.
Second, you have to decide on the style of water key you want installed. Each has its own advantages. There are three major types of water keys commonly found on horns: lever-style, Amado, and the Joy Key. There are other types, but they are rarely used on horns so we’ll skip over them, at least for now.
The lever style
The lever-style key is the oldest and most common type. It consists of a water key nipple soldered on over the hole, and a saddle which holds the lever and the spring which pushes the lever down. The hole is sealed by a cork. Advantages include the positive seal, the slim profile which follows the tube length, and the potential operation by attaching a string to the lever, which can be operated by the thumb. Disadvantages are cost (typically the most expensive key to buy and install) and the occasional need to replace the cork. Installation is a bit more labor-intensive, as well.
The Amado key
The Amado key consists of a brass casing soldered cross-wise to the tubing which houses a stainless steel piston. The piston is sprung so that one merely pushes the end of the piston inward to create an opening to release water. Advantages include lower cost of the part and installation, a seal that is very close to the tubing itself which creates a smoother inner surface. Disadvantages include the need to regularly oil the piston, a tendency to become leaky over time, and a profile that is not good for the 3rd slides because it can interfere with the other slides or the bell.
The Joy Key
The “new kid on the block” is the Joy Key, invented by Andrew Joy. It consists of a water key nipple soldered on to the tubing much like the lever key’s, but which is also used to hold a special insert which both seals the tubing and is also porous and allows the key to drip, and therefore drain, constantly and without any user operation. The insert is made of extremely tiny fused metal balls. Holding it in place is a screw ring with an O-ring. Advantages include never having to operate the key and therefore never having any water accumulation. Disadvantages include the need to replace the insert when it gets clogged. I have a personal concern about making one’s horn permanently leaky, but I have not yet heard that players who use them feel their horns’ performance is adversely affected. You have to decide if you want a horn that drips constantly, which it does.
There is one advantage to installing a water key: you can un-install it. Every style of key can be replaced by another style more suited to your needs. And, if want to remove it completely, the hole can easily be patched with no adverse affects.