Posted by John Swensen on February 28, 2002 at 15:49:41:
In Reply to: stuffy mirafone? posted by Graham Smith on February 28, 2002 at 12:14:14:
In order of increasing difficulty to fix, I would:
1: clean out the horn, being sure to snake out the leadpipe and individual slides; removing built-up crud can do wonders for a horn's playing. On an old horn with an unknown history, there may be something in the tubes past the tuning slide; I bought a plastic nozzle to screw onto a garden hose that allows me to flush out a horn on the lawn without fear of damaging the horn with a hose end.
2: as recommended by Archie, check the valve alignment by unscrewing the back covers and checking the alignment marks on the back plates and rotor spindles. Also, make sure all the marks on the back plates are aligned with those on the valve casing. Replacing corks with new cork, neoprene, or nitrile rubber is cheap and easy.
3: you may be using a mouthpiece that is poorly matched to that horn; checking the archives may give you some ideas about mouthpieces that have worked well for the 186.
4: another way to check for leaks is to push a plastic tube or garden hose over the mouthpiece receiver, plug the bell with a beach ball, pressurize the horn by blowing on the tube, and spray soap solution over the horn; leaks will show up as bubbles. Leaks in the joints can be resoldered pretty easily, but leaks in the valves are harder to fix.
5: the horn may have some big dents that could affect the reponse; in general, the closer the dent to the mouthpiece, the bigger the effect, for a given size.
6: I have heard stories about Miraphones from that era that came from the factory with substantial quantities of pitch (like a pound of pitch!) still in the bows. That, as well as large solder blobs, would be difficult to diagnose without a flexible bore scope, and would probably require disassembly to fix (hundreds of dollars). Maybe if you sloshed some kerosene through the large bows for a while (I would remove the tuning slide and plug the tube with a cork, first, to keep pitch out of the valves), a dark brown or black color of the kerosene, once poured out, might indicate residual pitch, but not how much there was.
7: the horn may be like my Alex F, who deeply resents being ignored, and reacts by playing badly until, after many hours of practice, I am gradually forgiven.