Buzzing bottom bow guard

[MartyNeilan]

I finally traced a buzz in my tuba that has been there since I got it. The bottom bow guard (nickle silver plate soldered around outside radius) is loose in one area, where the horn had long ago been dented on the bottom (possibly dropped too hard on a chair). The dent is not deep, but enough to have loosend the plate. I figured I would heat it up, get some flux in the crack, and melt a little solder in there to fill the crack and quiet things down. EXCEPT each time I heat the bottom the guard separates a little more from the bow.
Any ideas (besides take it to Joe)?

[tubamirum]

Two things: get a thin knife blade between and scrape back and forth so the surfaces are clean, keep the guard against the bow with as small as you have when soldering and hold it down until the solder cools. Patience.

[Dan Schultz]

... each time I heat the bottom the guard separates a little more from the bow. Any ideas (besides take it to Joe)?

As someone already suggested... you're going to have to get some flux under the guard. Also, the nickel guard is going to raise when you heat it. Try wiring the guard down in several places and don't use any more heat than necessary.

[Dan Schultz]

Heat the BOW next to the cap - NOT the cap itself.

Yeah... I was going to say that!

[MartyNeilan]

I'm guessing you scorched it and cannot now go to the seller/dealer/manufacturer for correction (more likely though, additional frustration.)
Mind my asking what kind of horn yours is?

20 yr old MW2155R prototype that has seen some rough times with previous owners, but Lee Stofer rescued it. Got passed around a few times and I decided the sound was worth the third partial, so I scooped it up about a year and a half ago for a very reasonable price. The horn isn't in too bad condition cosmeticly, but there is some lacquer wear, a few inconsequential dings in the larger pipes (one or two courtesy of me), scarring from bell repair, and a collection of dings in the bottom bow with a slightly flat area (problem spot). Since this horn was a prototype, the overall quality of original manufacture is outstanding. I am reasonably certain the guard issue is caused by previous mistreatment.
Frankly I could care less about how it looks. I like my unlacquered F and don't mind if the CC goes that way eventually. If I had the time and $$$ I would take a road trip to Joe or Lee's new Midwestern digs and humbly beg for mercy, but currently have neither at my disposal. My F also has an automotive hose clamp securing a popped solder joint, so it would be worth the trip.

[Chuck(G)]

What Joe and Dan said, and don't use too much heat--just enough to melt the solder and have it wick between the guard and the bow.

However, since it separated when you heated it, I suspect you now have some solder built up that may prevent you from wiring the guard down tight when things are cold.

Here's something to try that might get you out of this mess. At least it won't hurt things any more than they are already.

Where the guard is making good contact with the bow (i.e. is already attached) on either side of the gap, wire it down firmly--you don't want the gap to widen more than it has.

Next, after fluxing the separated area, heat it up and feed a bit of solder into the gap. Then, while things are still hot, take a sturdy flat stick of wood and press the guard into contact with the bow and hold it there until the solder solidifies. That should do it for you.

Wash the soldered area with water--flux is corrosive if left around. If yo know how, clean up any solder that squeezed out, otherwise, leave it alone.

[Lee Stofer]

Marty,
What Bloke said! At my shop, the eventual repair bill will be less if you DON"T take the torch to it again, or wire it, etc. Also, do not put any epoxy in there, as that would be hell to get out in the future, short of removing the entire bottom bow cap (read, $$$). That is one massive horn, and you don't want to go there. Insert some thin cardboard, cut off the excess, and use some wide, clear packaging tape on it, and no one will notice.

FWIW, during the internship I did at Rudolf Meinl's, I did a restoration of a 1901-vintage Conn tuba, and the single largest task of the whole restoration was making and installing a new bottom bow cap and guard wire. The amount of work to correctly fit those three parts in such a way as to look like they belong together was more than I could have imagined. I spent a 10-hour day just getting that one part, the bottom bow, right.