Please, Sir, my valves keep sticking!

Discussion in 'Trumpet Repair and Modification' started by trumpetsplus, Jul 1, 2011.

  1. trumpetsplus

    trumpetsplus Fortissimo User

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    Here is my blog post talking about possible reasons for sticking valves.
    ivan?s blog

    And here is the text without the pretty picture:

    “Please, Sir, my Valves Keep Sticking!”

    When your student says this to you, what do you do?

    First – is it the player or the valve? Oil the valves and play the instrument yourself. If the valves do not stick, help your student with finger technique; he could be pushing the valves at an angle. This scrapes off the oil and leads to metal rubbing against metal. This is not good.

    If the valves stick for you it means that the valve has gotten too large for the casing (or the casing too small for the valve).

    Likely causes are the 3 Ds on either the valve or the casing:
    Dirt
    Damage
    Distortion

    If it is just the 3rd valve, remember that this is the first in the airstream and is the most likely valve to get the player’s undigested breakfast! Breakfast, or lunch, or even soda, is not totally conducive to smooth valve action.

    Otherwise, look closely at the casings and the valves.

    Is there discoloration on the valves indicating the need for a chemical/ultrasonic cleaning?

    Is the valve plating starting to bubble and lift?

    Is there an obvious dent in a casing (perhaps from a loose mouthpiece)?

    Is there damage to a piston (the old “screwdriver to push up a stuck valve” trick!)?

    Is the top felt so worn that the valve depresses further than originally intended?

    Has a spring been stretched so that it collapses to the side and rubs in the spring box? By the way, the strength of a spring is determined by the elasticity of the wire and the number of turns. The overall length has little to do with strength. All you achieve by stretching a spring is to guarantee its dispatch to the garbage. Strengthen a spring by removing some turns. We do this on rotary valves, which have similar springs to water keys. I have never successfully done this on piston valves – there is no need, springs are readily available in the Jaeger workshop!

    Are the brass guides or sharp ports causing problems as in one of my earlier blogs?

    Has one of the slide receiver tubes been bent which has reflected a distortion in the casing?

    Has the whole trumpet chassis developed a twist (sight over the tuning slide receiver tubes to make sure they are parallel)?

    If there is nothing obvious, was a valve dropped and bent? Are the valves interchangeable as to sizing (because of CNC machining, virtually 100% of modern trumpets are) and one will not fit anywhere?

    Often, just holding the trumpet in your hands can suggest the likely diagnosis. A trumpet, which has been badly re-soldered, could be out of alignment and distorted, a trumpet with a lot of dents elsewhere may have some on the casings, we know some brands which are prone to prematurely losing their valve plating.

    Once you determine the cause, the remedy will straightforward. You will either have the capacity to carry it out or not, depending on your skills. The art is in the diagnosis.
     
  2. flugelgirl

    flugelgirl Forte User

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    Seattle, WA
    I've also seen some cases of valve oils that react badly to each other that leads to sluggish valves. Amazing how borrowing someone else's oil can cause such problems! Thanks for suggestions of things to look for, Ivan!
     
  3. kingtrumpet

    kingtrumpet Utimate User

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    New York State USA
    +1 -- but at least I have always been the over-prepared guy with 2 bottles of oil - so everyone got the oil I had on hand!!
     
  4. coolerdave

    coolerdave Utimate User

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    San Pedro
    I had that problem on my Bach..the petroleum based valve oil was creating a sludge with my lanolin based slide lube ... after a bunch of cleanings and switching to a synthetic oil and slide lube the problems left .. finally
    Thanks again Ivan!
     

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