B&S Piston Valves

[apsapienza]

Hey TubeNetters,

I'm currently playing a PT-6P with a set of MAW valves and the Alan Baer washers. Since I purchased this horn, I've had a rough time with my piston valves intermittently sticking, both with my factory valves, and now with these MAW valves. I've heard (frequently) that I'm not the only PT-6P owner who struggles with this problem. I've tried switching oils, replacing valve alignment guides, I've cleaned and scrubbed the horn myself, and I've had it professionally cleaned. The MAW valves have been block lapped, which at first worked great, but then the exact problem I had on my factory valves started happening to these MAW valves.

I'm sorry if there's already a discussion thread on this exact topic, I did try searching the forums but I did not find anything. I live in Colorado, but I'm at the point now where I'm trying to find anyone in the country, really, who might know what's causing this, and has a way to permanently rectify the problem. Any pointers are greatly appreciated. I love the horn, but it's frustrating when I can't focus on making music because I'm too worried about whether or not the valve is going to stick.

Thanks for any help you can offer.

[eupher61]

Have you contacted MAW? Not truly his problem, since it happened with the originals, but he may be your best reference right now.

[Dan Schultz]

Many of the valve problems on these horns stem from burrs in the valve guide slots but this problem sounds different since you are not complaining about rapid guide wear.

How long does it take for the problem to come back? Minutes? Hours? Does ambient temperature seem to be a factor? Which valves cause the problems?

[apsapienza]

Thanks for all the suggestions. Please keep them coming. Going to try and answer everyone's questions and responses:

Actually, Martin reached out and sent me a private message. I will try his advice.

The only other person who had a PT-6P and I know had the same problem, was my current professor, and eventually gave up, sold his horn and bought a rotor model. But he said he was suffering from the exact same problem. Everyone else cited off hand that it was a problem with these horns in general, and that they'd heard of the problem before.

After the MAW valves had been lapped, it took about 3-4 weeks before I started noticing signs again. I haven't noticed a relationship to temperature, and what's odd is that it almost seems worse when I oil them. First valve is always the worst offender, but I've noticed Second Valve is also having less-frequent trouble. I've also heard of the valve guides being the culprit, so I'll reevaluate that as well.

Bloke, What brands of oil do you suggest? And is there anything I can do about hard lime deposits? I'll try to clean the casing more regularly and leadpipe. Is there anything else I should be considering?

[MartyNeilan]

I would suggest lapping as a last resort, and only by a very qualified repairman. "Casual lapping" can remove needed valve material that cannot be put back, and pistons require a much higher tolerance than rotors.

Also, when you pull your pistons, do you see any green gunk in the ports?

Marty "whose 1st piston expertly lapped by da bloke is now much smoother and less likely to stick than the other three"

[Sambrose8vb]

Hey there,

I've had the same problem: PT-6P with MAW valves that were sticking-up. I had the valves slightly lapped and I use Hetman oil. Problem solved. Take it to a shop, and clean your horn/valves regularly.

[jtuba]

Running a brush through a valve casing does little-to-nothing. The piston itself performs that same operation hundreds or thousands of times every time a player plays his instrument. Loose filth lurks in the ports IN-BETWEEN the casings, and requires particular effort to locate and remove. It's also (typically) formed in a ring around the bottom valve caps.

Anything those of us at home with no decent repair person nearby can do to clean between the casings or the lime in the casings? CLR? Blue toilet bowl cleaner? Thanks.

[Will Hammer]

This is interesting. I've been playing my PT-6P for a little over a year, and the only time I've ever had problems with valves sticking was for a couple weeks after I got my horn chem cleaned (and going weeks without oiling my valves). I pretty much had to make sure my springs were actually pointing straight up, and I didn't push the valve down at a weird angle. Outside of the short period after a chem clean, I've never had a problem outside of user error of not oiling it for a long time. I use Hetman oil by the way. I'm not sure if this is the case because I'm pretty sure I have the 'older' model valve section or not.

[Three Valves]

It's for you...

http://i1.ytimg.com/vi/SqvvfeSIxZQ/maxresdefault.jpg" target="_blank

[Levaix]

Not the same model, but my B&S euphonium has VERY tight tolerances. I find I have to use fairly light valve oil or my first valve gunks up like nobodies business. The two best that I've tried so far were Roche Thomas and La Tromba T2.

[bort]

Might not be related... but are you sure that you're pressing the valve straight up and down? Some piston valve tubas seem to have problems if you get lazy with that. It doesn't sound like the problem though.

I'm not sure who is the best tech in your area, but if no one else can identify or fix the issue, you may need to send if off to one of the "experts."

Long ago, when I had a Miraphone 1291, I had trouble with sticky valves. I solved it by cleaning the valve casings with a bit of mild dish soap and a valve casing brush. Took one or two rounds, but after it was fixed, it never came back (and I never mixed and matched oils after that too).

Hope you find a solution soon. FWIW, I have never, ever, not even once had a rotor stick. Rotary tubas have their own disadvantages, but sticking valves is not one of them.

[jtuba]

Anything those of us at home with no decent repair person nearby can do to clean between the casings or the lime in the casings? CLR? Blue toilet bowl cleaner? Thanks.

Have fun. I would not put those things in my own tubas.
http://i.ytimg.com/vi/95XyqJXPdS4/hqdefault.jpg

OK neither will I. Am I out of luck then?

[jtuba]

Understand. Thank you.

[ArnoldGottlieb]

Hey Bloke,
What do you use to clean your own tuba valves, and other parts for that matter?
Thanks
ASG

[MartyNeilan]

Bloke, What brands of oil do you suggest? And is there anything I can do about hard lime deposits? I'll try to clean the casing more regularly and leadpipe. Is there anything else I should be considering?

The "oils" remark was meant to be sarcastic (as "certain oils" - rather than cleaning - seems to be the TubeNet solution for "sticking valves"...much as those who go to "additives" rather than "repair" for automotive problems...).

The product is composed of 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard.[1]

[Dan Schultz]

Having read all of the previous posts... once you establish that your valves have the proper clearances and are working freely... pitch all the 'designer' lubricants and go buy a quart of Ultra-Pure Lamp Oil and apply it liberaly. NOT just two or three drops at a time.

[swillafew]

In Des Plaines Illinois, Dana Hofer is a good repair person. I play rotor instruments, but he told me he frequently fixes new models of piston horns delivered with piston trouble. Dana does great work.

[MikeW]

If you have checked the springs, guides, guide-slots, valve-stems, etc. it may be worth looking for "crush syndrome": the horn gets slightly crushed or knocked in transit, so the tubing gets slightly bent. This applies torque to the valve casings, and the first valve gets a bit sticky (and less often the second). Often the problem only shows up when you have been playing for a while, so the instrument is thoroughly warmed up. The fix is (very carefully) to pull the valve tubing outward a very small ammount (if you overdo it, you will make the problem a lot worse), in the away-from-the-bell direction. Sometimes a brace or two may have to be unsoldered, to let the torque relax, and then soldered back on. A visit to the repair shop may be in order.

[Untersatz]

going weeks without oiling my valves

huh? wtf?

[ArnoldGottlieb]

Thanks for the reply!
Peace
ASG