so this is happening:

[bloke]

And I have found that on my new-to-me CC the first valve slide will not stay put where I want it. Clearly has been massaged so as to be easily movable for the slide-pulling crowd. I have some custom sticky-goo that the local tuba repair guy gave me, that I put on the necessary parts of it so it doesn't slide down and make all first valve notes sharp. And if that doesn't work I'll put a rubber band around the tube in the appropriate place.
I think you're just blowing too hard, bloke. Scaring the hell out of the tuba so it drops its pants.

It probably is always looking askance at me, much like a dog towards its mean owner...
...and - after all - anyone who unapologetically champions individual liberty and widespread prosperity is automatically deemed to be mean, yes?

[humBell]

Has the room temperature been factored for? is it just warmer where the slides live up to their name?

And have you tried long tone chrimatic scales to see if there are notes more likely to cause it to slide?

How about playing while sucking in? If that successfully causes the slide to come in, perhaps it is the air pressure differential.

Or should i relegate these experimental procedures to the bad ideas thread?

[bloke]

Mostly, I think it's probably just a "bad idea" to let it fall out.

good idea:
(for the third or fourth time, and coined by someone else...) a "slide brake" - whereby the release lever will be located right where I would normally grasp the slide to move-or-remove it.

slide expanders:
"work" (as a last resort) but also ruin nice/straight/smooth/nicely-machined tubing

[P@rick]

...I don't see how I could possibly "blowing it out". Without my body absorbing vibration (using the stand) with the riser not absorbing nearly as much vibration as the floor in my house, I suspect it's being vibrated out.

Not really interested in screwing up the alignment of this slide...

I had the same with my Besson 2nd valve slide. I blow it out. It does not come out any other way besides blowing on the Tuba. It does not pop out at once, but with lots of air and especially with "air attacks" it moves out further and further. I tried thicker slide grease, which helped a little, but did not solve it completely. I finally "screwed up" the alignment, but only by a fraction. In theory I basically changed the valve slide shape from U to V shape.

The adjustment was however so small that it's barely measurable. This fraction of a difference was enough to solve the problem. The slide still inserts perfectly (no noticeable misalignment). I only notice a little more resistance while sliding it in or out, but that was the goal. Sliding the slide in and out does not leave any visible “tracks” in the grease on the slide and there is defiantly no “metal grinding”. For me this was and is the perfect solution
…but I basically “screwed up the alignment...

[bloke]

Thanks for your post, P. I've done the same thing at others' request. I spent a little too much time and care on this slide - when I raised the pitch of the instrument - to screw it up on purpose - even when doing so on purpose has a purpose - so I'm going to stay with the strategy of adding a spring-pressure friction pad on the outside.

This being such a large instrument, I do have to move this slide out as it slowly warms up, in order to respect 440 tuning.

Knowing that brass instruments don't involve moving very much air at all - and mostly have to do with vibrating air, I was slow to consider this possibility, but I guess it's possible - along the capillary portion of a huge tuba - for air to actually have an effect on something like this...
...OK, and - when it's called for - I'm not exactly known as a timid sort of player...so OK...maybe (??) it is air-driven.

[P@rick]

It was not trying to contradict the vibration theory. I should have written “play it out” instead of “blow out”. The vibration theory makes sense. The air flow is indeed very limited, but not completely excluded I think.
In my case it was clear that “legato/ppp” pieces did not move the slide (or almost not), but “fff/sfz/>” pieces did move the slide.

[bloke]

It was not trying to contradict the vibration theory. I should have written “play it out” instead of “blow out”. The vibration theory makes sense. The air flow is indeed very limited, but not completely excluded I think.
In my case it was clear that “legato/ppp” pieces did not move the slide (or almost not), but “fff/sfz/>” pieces did move the slide.

perhaps a combination...??
It's happening with extremely loud playing during very exuberant sounding or "Rock and Soul" types of Christmas tunes being played, where - unlike classical music - I'm playing loud loud loud (relentlessly).

...The same thing would surely happen during a performance or rehearsal of 1812, etc.

[iiipopes]

Two observations:
1) Expanding the slide a thou so it has more friction, that would still be a "brake" without screwing up the alignment; and
2) My 2nd valve slide (now that the community band season is over until late January) is with my tech having a water key installed, as I also put so much air through the tuba (being the only regular tuba player, including being the only one at the last concert), condensation collects in the 2nd valve slide as well as farther downstream.

[bloke]

Slide expanders are crude tools that ruin tubes.
=========================
I have to work frantically (because I have a customer arriving - now - in about five minutes, and in two hours I need to be clean/dressed/leaving for a gig (because I have two stops on the way to the gig, thanks to Mrs. bloke).

...so here's the slide brake.
The lever is right where I grasp the main slide to remove it.

ALSO...
I plugged up the inconveniently-positioned oem water key drain hole, and moved the water key over so as it drains in PLAYING position.

[Mary Ann]

So did it work?

[bloke]

So did it work?

yes, but how could it not?

...and even though I used this instrument at the rehearsal a few nights ago, I decided to take the compact Holton B-flat to the show tonight, because everyone is so packed in on the stage and also there are a couple of rock and soul numbers where a smaller instrument with a more gritty sound and the ability to cut the sound off quicker works out better.

[bloke]

I suspect that what is not understood is that both of these pairs of tubes already fit just about as nicely as pistons in their casings. If they don't quite fit that well, the fit is close to that. If I expand the inside tubes - wrecking their nice machined condition - they won't slide anymore. The tolerances are already so close on each of these pairs of tubes that - when I first put this back together after constructing this contraption and replacing the water key with the one seen on the picture - the slide wouldn't slide in, and all it was was a tiny little amount of dirt on the small side outside tube. Further, I just didn't want to intentionally wreck the alignment of a slide which I went to a lot of trouble to align perfectly.
@the elephant , I suspect, either gets this, or gets it and ALSO thinks I'm being pretty silly.

[iiipopes]

Slide expanders are crude tools that ruin tubes.

Thanks for your explanation. I understand better now.

[bloke]

crappy picture, but I shined it up and shot clear on it.
(didn't want to take the "slide brake" back off to polish it, because it's awkward and requires Mrs. bloke's help to get it back on - particularly without scratching lacquer, so I had to do some careful 'round-the-edges buffing...)



There's still more stuff to do to this thing, but the list is getting shorter.

[bloke]

OK...So this FINALLY stopped the slide from moving (when blowing the friggin' crap out of this thing)...

...so yes: I guess it IS air that's causing it.

EVEN AFTER installing the "slide brake", the slide brake's rubber pad would just scoot across the nice smooth lacquered surface...

...so I found a new/old REALLY COARSE belt sander belt, cut a rectangle out of it, and contact-cemented it to the outside slide tube.






That FINALLY stopped the sliding-when-I-blow-the-crap-out-of-the-tuba thing.

I was going through ______ Symphony No. _ (which is rumored to be programmed - next year - with one of the freeway philharmonics with which I'm associated). I've played #_ and #_, but never #_ (other than a single movement), and having a crack at #_ is an exciting proposition.

(sorry...but - just like fb - fack chekkuz have censored my post as - since the '23 - '24 schedule hasn't been released - it may only be 97% true.)

Anyway...I was blowing through a loud-as-hell passage in mvt. _, and (sho-nuff) that damn slide was OUT a friggin' INCH and was crackin' the damn pitches in the mid-upper range.
JETSON !!! YOURbbbbbbbbb FIREDbbbbbb !!!!!!!

PLEASE, Mr. Spacely...It's the DAMN SLIDE !!!

[kingrob76]

I'm actually curious - was this latest example at home? It would remove the riser variable, if so.

[arpthark]

Gives me an idea: now you can market these slide brake things as Sellmansberger's Sprockets.

$279.99 + s/h

[Mary Ann]

OK...So this FINALLY stopped the slide from moving (when blowing the friggin' crap out of this thing)...

...so yes: I guess it IS air that's causing it.

Told ya so.

[bloke]

Told ya so.

[cjk]

https://www.thomannmusic.com/yamaha_sli ... rumpet.htm

adaptable?

i envision a rod with a thumbscrew. unscrew the thumbscrew, pull out the slide kinda like how the very bottom of the main tuning slide was on my piggy.