Repair of Bottom Bow Caps

[Tundratubast]

A curious question? It seems to me that I keep hearing that the repair and re-use of a damaged bottom bow cap is impossible, due to several reasons. 1) the cap is damaged (FUBAR) during the removal. 2) If removal has been successful, that the subsequent attempt at repair of dents, creases,etc. will in effect stretch the brass and cap beyond reasonable use. Therefore, without the proper mandrels and tools to re-manufacture a replacement, (i.e. Dan's Shop) what is the option available, other than the typical, repair the bow, skip the cap, and put on a new bow wire guard instead. Any ideas', It just seems the "It can't be done", is an easy way out. Are their available caps that can be slightly modified to match the instruments' cap style, and to fit the range in sizes necessary, 3/4 - 6/4.

[Michael Bush]

http://thevillagetinker.com/miraphone_1 ... repair.htm" target="_blank

[Dan Schultz]

It's quite difficult to get the bow caps back on right. It's a matter of getting the bow straightened out near-perfectly... then getting the cap straightened near-perfectly. Especially on the older European tubas that had an exposed seam on the bottom bow.

Most band directors don't have budgets that will stand for that kind of labor. It's much cheaper to hammer the bow out as good as possible and stick a piece of sousa bow guard over the seam.

[arminhachmer]

well, that answers a question i have not asked, Dan.
The 'comb' on the bottom bow guard on my St.Petes
is puttying a dent in my right leg. I have a wad of
bubblewrap taped to my leg....no, no the horn for now.

Guess thats all i can do and keep saving for a Miraphone,
a helicon or a sousa ??

Armin

[Dan Schultz]

well, that answers a question i have not asked, Dan.
The 'comb' on the bottom bow guard on my St.Petes
is puttying a dent in my right leg. I have a wad of
bubblewrap taped to my leg....no, no the horn for now.

Guess thats all i can do and keep saving for a Miraphone,
a helicon or a sousa ??

Armin

Armin... get yourself a rest to put the horn on while you while you are playing.

[Dan Schultz]

I thought I would jump back in here with some more thoughts on bottom bow repairs. I think there are two primary reason why those caps are put on in the first place:

1) To cover up the ugly unfinished seams on the bottom bows of some tubas.
2) To provide an extra thickness of metal to make up for all the brass that is stretched out of the bows when they are made.

How those bow caps are applied is not very consistent. Part of the repair difficulty lies in how much 'air' there is under the cap. Most of them are only soldered to the bottom bow all the way through. There is only perhaps a thin line of solder around the perimeter of the cap. I've seen these caps that have been left standing 1/16" off the rest of the bow.

Ideally, the cap should be fit line-to-line between the outside of the bottom bow and the inside of the cap. But.... that very rarely happens even from the factory.

Those caps are mainly to make things pretty and have very little to do with function.

I have a Mirafone 180 5V F here now that I'm trying to purchase a new cap for. I could leave the cap off and it wouldn't have any impact on how the horn plays. But... it IS a Mirafone and potential buyers would expect the horn to be 'right'.

[arminhachmer]

Hey Dan: I tried a stand, two different ones actually, BUT,
dont like it. Neither would adjust quite low enough for me AND
i felt more like a appliance/machine operator rather than
a 'musician' (no modesty here for a moment)
playing an instrument as if it were an extension of myself.

Wow. Did i say that? Please no comments on why there is
no need for extending my chubby body...

So, i shall keep looking for the right big fat tuba while i save
up. Call me when you get your hands on a good candidate.

Armin

[MartyNeilan]

The 'comb' on the bottom bow guard on my St.Petes
is puttying a dent in my right leg.
Armin

The "comb" is a separate piece from the flat bottom bow cap. Have a repairman carefully heat and remove the comb from the bottom while leaving the protective bottom bow cap in place. I was able to torch off the "castrator" from my tuba in minutes, and kept cold wet cloths on the bottom bow cap to keep that solder from coming loose.

[arminhachmer]

[quote="bloke"]I've always referred to those chunks of metal as "keels"...

...so "combs" are they?

ah.. You swhould know best Sir Bloke...
Keel, comb, a keelcomb would be a wire brush?

When my horn sits on the bell...it's a comb, like a rooster.
When it sits upright...it's a keel, like a boat.

Would be nice to have it gone.
Armin

[arminhachmer]

The "comb" is a separate piece from the flat bottom bow cap. Have a repairman carefully heat and remove the comb from the bottom while leaving the protective bottom bow cap in place. I was able to torch off the "castrator" from my tuba in minutes, and kept cold wet cloths on the bottom bow cap to keep that solder from coming loose.[/quote]

Thank You for that Marty. I shall ask Mr. Dan when i pass through his
shop in April, if he does not take the shingle off the wall and lock the doors.

Armin

[Dan Schultz]

..... When my horn sits on the bell...it's a comb, like a rooster.....

Never thought of it like that. Pretty good analogy, though.

Pretty easy to take off. Your local plumber could probably handle it! If it's still on your horn next Spring... swing by here and I'll knock it off for you.

[Tundratubast]

Thanks to all for your input, I'm surprised that here at a repair school the perspective is that it cannot be done, or is ineffective to even attempt it, even on likes of a 345 bottom bow.

[Tundratubast]

Actually, Bloke, I've already removed the bow from the body and the bottom wire, it seems that the time to actually discuss, or demonstrate the process isn't part of the curriculum at this point. But, the answer I was given when I was removing the bow, was that the cap is not repairable. But, it seems that I had seen examples of it being possible, as shown here, that it is indeed possible and should be something I need to learn for my potential market area.

And, yes I have have thought about sending it out to have it done, because I want the bottom bow to look and be right on the finished project. Getting it done or doing it myself while here in school, seems to be the limiting element to the project. Any suggestions to time, place and of course cost? Thanks.

[Dan Schultz]

..... I've already removed the bow from the body and the bottom wire, it seems that the time to actually discuss, or demonstrate the process isn't part of the curriculum at this point. But, the answer I was given when I was removing the bow, was that the cap is not repairable. .....

Probably a way to look at it is that in a great many cases, it's not cost effective to repair the cap. There are a lot of variables in messing with a bottom bow. I would guess that most of the training you're getting is how to repair school rental instruments... because that's where the money is made at local music stores. Most shops would simply quote a price to replace the bow assembly and be done with it. My local music store will look at you like you have one big eye in the middle of your forehead if you walk in with a smashed-up tuba!

[Daniel C. Oberloh]

The cost of some manufacturers replacement caps often make it very worth while to repair. Very strange how some say it can't be done or it's not cost effective. I have lost count of the number of top and bottom bow-caps I have restored or made from scratch over the past twenty-five years. Yeah, it's a bit of work but what are you to do if one is not available to purchase? Its also nice and handy to have the skills when a custom one-off pattern is needed for a given project. Pics should tell some that if I can beat one out in a day, straightening one out and properly refitting it should be very doable and it is.

Daniel C. Oberloh
Oberloh Woodwind and Brass Works
http://www.oberloh.com" target="_blank

[SousaSaver]

@Dan Oberloh -

Your work never ceases to amaze me. You make it seem so quick and easy (and it may very well be for you). You are no schlepp (no offense to the user of this board who uses that handle of course).

I apologize for gushing, I am a fan of your work.

[JohnMCooper]

"I am a fan of your work"

Aren't we all?

[Dan Schultz]

Here's a set of guards I took off a King 2341 today. Both of these guards were fit to the horn very poorly FROM THE FACTORY! There was as much as 1/8" of air under the center of both the bottom bow and the top bow. This had to have been either a 'Monday' or a 'Friday' horn! I'll try to do a better job of assembly when I put them back together.