Technical Articles

Bulb Horn Performance

The flex tubing of the bulb horn frequently will become so loose and leaky that it will not deliver sufficient air to the horn reed. To correct this, line the inside of the tube with thin wall, extra flexible, clear plastic tubing, available from medical supply houses. Outside diameters are in one-sixteenth inch increments. On your ailing horn, ream out the excess solder at the end ferrule joints, and measure the ID of your horn tube. Purchase the plastic tubing with an OD about one-sixteenth of an inch greater than the ID of your tube, and long enough to cover the soldered end joints.

 Form a U-hook on a piece of wire longer than your tube, and hook it into one end of the plastic tubing, having predrilled a slightly over wire size hole in the plastic tubing. Pass the wire through the horn tube and clamp the wire end in your vise and then pull the brass tube over the plastic. Under tension, the elastic plastic tubing diameter will be reduced by about one-sixteenth of an inch and its length will increase. Before removing the hooked wire, release the tension and flex the horn tube several times so the plastic can seat itself tightly and permanently. Remove the wire and trim the ends of the plastic.

 A little liquid detergent will make the installation smoother. Hidden in the tube, away from UV, the life expectancy of the tube is years.