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Sticking, noisy piston valve
Posted: Fri Dec 25, 2009 8:03 pm
by sloan
Conn 36J, 1st valve.
A bit "clanky". Occasionally sticks all the way down. *very slightly* unscrewing the stem (making it epsilon longer) seems to help. Cleaning the thick, sticky, black "gunk" in the bottom cap also helped.
Pending a full CL&A (Hi, Joe) - any suggestions on First-Aid that might help and will not hurt?
On a related note, the top cap shows a tendency to cross-thread. Other than "don't mess with it" - same question.
Re: Sticking, noisy piston valve
Posted: Fri Dec 25, 2009 9:43 pm
by imperialbari
A friend came by with an old Forza (I. K. Gottfried’s stencil for B&S/Weltklang) 4 top piston Eb for us to discuss whether he should buy it. With original small mouthpiece too small a sound. With my blokepiece it worked well, if the 5th partial series was played from the 6th partial. Only the valves were terribly slow.
I gave them Blue Juice, which didn’t work immediately. Suddenly my friend exclaimed, that they worked. The Blue Juice had thinned the thick storage oil amazingly well. I use Blue Juice for all valves. My only complaint is, that it evaporates so fast, so I have a second bottle with 25% sewing machine oil and 75% Blue Juice.
Make sure never to let the pistons be turned upside down, as potential dirt may move into the friction area again.
For loose threads thin plumber’s tape (silicone) hardly will hurt.
Klaus
Re: Sticking, noisy piston valve
Posted: Fri Dec 25, 2009 10:08 pm
by Dan Schultz
sloan wrote:Conn 36J, 1st valve.
A bit "clanky". Occasionally sticks all the way down. *very slightly* unscrewing the stem (making it epsilon longer) seems to help. ...
You might have a bent valve stem... among other things.... like dirt and such.
Re: Sticking, noisy piston valve
Posted: Fri Dec 25, 2009 10:42 pm
by sloan
bloke wrote:- Find someone with skinny long fingers and a strong stomach to pick nasty stuff out of the ports leading into that valve casing.
- Clean out the bottom valve cap.
- Run the piston in-and-out of the casing (well-oiled) fairly vigorously from the BOTTOM.
-----------------------------------------
For the valve cap problem, the FIRST (often the last) thing to try is to switch the valve caps around.
Good luck with it!

Thanks. I'll try not to screw it up too badly before you get to play with it.
Access to the BOTTOM of the casing might be a problem, though - there's a rather large piece of brass tubing a mere 1.000001" from the bottom of the #1 casing.
Re: Sticking, noisy piston valve
Posted: Sat Dec 26, 2009 2:19 pm
by Ken Herrick
Don't despair, Joe!!!!!!!!
It could be that his calipers aren't quite as accurate as yours and there might be room yet.
OR
Maybe you could polish off a bit of plating or lacquer to get that bit of clearance.
Re: Sticking, noisy piston valve
Posted: Sat Dec 26, 2009 3:23 pm
by sloan
Ken Herrick wrote:Don't despair, Joe!!!!!!!!
It could be that his calipers aren't quite as accurate as yours and there might be room yet.
OR
Maybe you could polish off a bit of plating or lacquer to get that bit of clearance.
It took all morning, but I finally re-routed all of the large tubing to avoid the underside of the valve casings. I can now run a 10' length of solid Monel tubing (encrusted with diamond flecks and StayBrite (TM) toothpaste) completely through the valve casing - extending for 5' in either direction.
But, the horn now plays 1.367 semitones flat (for me - bloke can lip it up to pitch as long as he's not accompanying an organ).
Is there a mouthpiece I can use to brighten up the sound?
Should I use heavyweight felts (dipped in mercury), or lightweight Campagnolo felts (with holes punched in a tasteful pattern)? I know that the Campy felts will fail catastrophically in the middle of a concert - but they feel SO GOOD when they are working properly.
DAMN! All I had to do to get my calipers to match bloke's was to drop them on the concrete shop floor.
nevermind.
Re: Sticking, noisy piston valve
Posted: Sat Dec 26, 2009 3:51 pm
by Ken Herrick
sloan wrote:Ken Herrick wrote:Don't despair, Joe!!!!!!!!
But, the horn now plays 1.367 semitones flat (for me - bloke can lip it up to pitch as long as he's not accompanying an organ).
nevermind.
Hey, Slaon, He'll prolly wanna keep it now speshly for those organ accompanin gigs.
You've been snoopin aroun too many repair shops - now you know how we adjust measurements - yule no all the trade secrets if ya keep goin.