Magnehelic Instructions

Wand Leak Isolator for Magnehelic Leak Tester


Lubricate the O rings with “Magic dust”. Move the tool slowly in the flute bore or sharp/soldered toneholes edges can damage the O rings. Set the Magnehelic so the vertical gauge reads .4 (max) and set the needle so it reads 8 when the tool is not in the flute. If this pressure blows open the closed keys you can reduce the vertical setting. On the other hand, if this pressure blows open the closed keys, then you may want to increase the spring pressure. Using the leak isolator to measure a single pad by using normal finger pressure directly on a cup should give you a reading closer to 0 than 1. Do not exert side (bending) force on the isolator handle or you can get a false reading. It should read near zero when not located on a tonehole or if you kink the hose. If the isolator won’t read near zero then look for a twisted O ring. Measuring the main flute body (without the foot joint) by using rubber plugs (not the leak isolator) you should be able to obtain a reading between 2 and 4. Two being an excellent reading for a well padded flute. Licking your fingers may give you a better reading with open keys. A reading above four is suspect but may pass for a mediocre student flute.