Patching a Bell Crack: Restoring an Antique French Horn #4

This is the 4th video in the "Restoring Loose Rotors" series. In this video, I take a break from the rotors and I patch a crack in the bell rim.
Here is the link to the playlist "Restoring a Wunderlich French Horn with VERY LOOSE Rotors"
• Restoring a Wunderlich...
Here is the link to the playlist "How To Solder: Repairing Broken Joints"
• How To Solder: Repairi...
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[@user-ti7hx5kr6s]

I never knew patching the bell took so much effort ! Thanks for sharing !

[@davemiller7633]

Art, that patch looks remarkable!

[@youtuuba]

Another thought....ammonia leaches zinc from brass, so I am wondering about mitigation for THAT after the ammonia is used to neutralize the flux......? A quick exposure of ammonia should not be a problem, and the ammonia evaporates quickly in free air, but I have read on brass instrument forums about ammonia that wicks into tight seams, and potentially remains un-evaporated long enough to do some damage to the brass. I don't have any real data or personal experience with this, however.

[@MarkGeelen78]

Correct. Ammonia + brass = Nono.

[@youtuuba]

When I still worked in brass restoration, my flux bottle had a needle to better direct the flux to where it needed to be; in this video, it looks like a lot of flux is going anywhere but where it needs to go. My shop also had a steel roller on a wooden handle (I forget the tool's name) that was ideal for rolling brass around the bell wire, would have made quick and accurate work of what is being done in this video. I also had a wet sponge, along with another flux bottle with needle containing water, to quickly cool an area that had just been tack soldered.

[@davemiller7633]

RIP to the brave trombone who donated their life to music 🎶

[@Jared_De_Leon]

Have you tried using liquid polishes? They tend to work much better when hand buffing and remove even less material that rouge.

[@selmer1971]

Why didn’t you just hard soldered it and then file it down? I’ve had these situations before and it came out almost unnoticeable

[@1090yoyo]

My concerns about silver soldering it would be: - The instrument is super old, so is the brass, so overheating it does not seem a great idea - Heating enough for a hard solder would anneal part of the brass of the bell, so you'll have a super soft part of the bell while the rest of the bell is work hardened => the mechanical stress will not be handled super good - This would overheat the soft solder that holds the bell ring wire, and in case you never experienced it, trust me: you do not want to deal with overheated, crystalized soft solder

[@javierquesada798]

Master is using gas in the torch?

[@amsmithonline]

Art, if you think you can fix the lathe with just a left hand acme nut, look here. www.mcmaster.com/brass-acme-nuts/acme-lead-screws-and-nuts/

[@cpmusicservices8185]

to make an acme screw, look up "This Old Tony" his you tube channel has a lot of great machining videos

[@LaurasLastDitch]

You know when there are houses with arched windows or porches and they get sided, they always seem to have an edge around the curvature that is not smooth, instead, it is cut into notches and just kind of shoved on so that it looks a mess and is no longer a curve. When I see you affixing this curved piece of metal, I can't help but that people who want their houses with arches sided, they'd be better off hiring a skilled band instrument repair person than someone who sides houses. Certainly you could figure out how to make a nice curve around an arched window.

[@javierquesada798]

teacher I think there is a pliers for that. or a round-headed pliers

[@alanlangway7607]

I’m sure Keith Rucker of Vintage Machinery can help you with your lathe he is also on KZbin

[@richardwilliams9471]

I had a thought about your "loose" valves. The analogy in my mind is that of piston rings that seal the cylindrical piston within the engine block. The piston is not flush to the edge but the piston ring seals it. Could you solder thin rings to the valve assembly that could seal tighter and not try and increase the diameter of the whole valve ?

[@1090yoyo]

The issue with valves is not so much the air leaking to the outside of the instrument, but the leaks between piping parts of the instruments (between the main tube and the valve slides, for example) which would not be fixed by a piston ring... instrument valves really need a flat surface. They are pneumatic distributors more than engine pistons

[@mal2ksc]

Unlike engine pistons, valve pistons aren't built to contain pressure like that. Everything is done with an interference fit and oil. And rotary valves, like this horn has, resemble engine pistons even less. However, "bore and sleeve" is still a viable option.

[@mal2ksc]

Since this instrument already had one patch, but the crack had exceeded that boundary, does it ever make sense to first remove the old patch and replace it with a larger one?

[@davemiller7633]

I suppose...but possibly due to the age of the horn, Art is being as ginger as possible. Could possibly end up with some unknowns under the old patch...but I see your point

[@mal2ksc]

@@davemiller7633 I just thought the point where the two patches meet is now under more stress than the rest of the bell rim, and if the metal is already that weak, maybe that's not such a great thing. If there was only one long patch, this problem wouldn't exist. Honestly, with almost half the rim being patched now, I think it would be more visually appealing if it was reinforced all the way around in one continuous ring. Then it may well look like it was intended to be that way from the start.

[@davemiller7633]

@@mal2ksc maybe so! No argument here but I just don't know!

[@LaurasLastDitch]

He mentioned in an earlier video that the owner of the horn is trying to keep the repair costs low, so that may also be affecting how he's handling this.

[@johns3106]

@Mal-2 KSC I couldn't quite see just how Art did it, but generally in cases like this, the two patches wouldn't be butted up against each other, resulting in the weak point you mentioned...rather, there would be a slight overlap between the two patches resulting in a much stronger joint. And, as another comment pointed out, cost may be a big factor in determining just how this repair is approached.

[@SMcCaskill]

😳😳😳