Bass Horn Part 8 - AAARRGGGHHH!!!

AAAARRRGGGGGHHHHHH!!!!

I asked Dan about how to fit the two bell parts together, he suggested cutting triangles out of the flare to decrease the throat....

MISTAKE #1

I had flared out the baritone bell stack to nearly match the bell flare taper, but still couldn't get it close enough.

Then, I cut about a quarter inch of the large end of the stack to decrease some of the extreme flaring at the edges. This was to help mate the two sections together. Asking Dan what to do next was not very helpful - he wasn't sure but gave me a suggestion to just start brazing the two section together.

MISTAKE #2

I had to cut more of the bell stack off, about another quarter inch, as it wasn't touching the inside of the bell at all. The overlaps of the brass on the flare - should have cut them off - meant that I was brazing unevenly and effective filling large gaps with brazing wire.

MISTAKE #3

Once I had brazed the first half (in thirds around the bell), I had to hammer the section together more and flatten out the overlap so I could braze some more.

MISTAKE #4

In realizing that I was just screwing up, I figured out that I should have soft soldered the parts together, that way if I had to adjust something I wouldn't have to cut it apart. The triangles I had cut from the bell didn't help, I was left with ugly gaps and three small holes where the bell stack didn't go far enough down (I still need to fill those).

The bell was together, but was EXTREMELY UGLY. I started filing and hammering, and filing, and hammering, on both the outside and inside until I got something sort of smooth. The problem with the triangle cutting was that I had uneven flaring on the bell, meaning that I have I think two flat spots that WILL NOT come out because there is too much brass in that area to move.

I'm probably going to have to apply two ring patches around the inside of the bell and on the outside to cover the massive EYESORE and make something that looks a little better.


On the plus side I tacked it on to the body and now it actually looks like a french horn....

Unfortunately....

I screwed up the leadpipe. I found the right position but kept thinking about having a removable leadpipe like a crook extension on a french horn. I decided to bend it by hand.

MISTAKE #5

Leadpipe is trashed, it might work if I need it to, but for now I'll have to find and pay for another.

During the final hour of the day I decided to begin strapping the slide crooks to smooth out the hammer marks from bending. Well, I must have not hammered enough because I strapped a hole right into the first crook trying to remove the hammer marks - must have been a ridge there.

MISTAKE #6

Tomorrow I'll be bending a new first valve crook.

Bass Horn Part 7

BENDING!

I didn't buy the right wood. I should have spent the money on actual timber, instead of the particle board. But it was cheap and I still have a 6' x 4' piece (cut into 2x2).

Anyway, bending the crooks was interesting.

The first valve crook took me about 4 hours in order to make it look right, it still isn't right and I have no desire to fill it with Cerrobend again, Dan thinks I should be able to slightly bend the tubing with a drumstick or mandrel. It's off by like three millimeters from parallel, it won't run inside the slide as smooth as needed.


The third slide was bit more involved but took less time as I had some practice bending the right curves. plus I had to make another tool and had to screw down more board to support the tube during the bending process.





I didn't think I could bend the tubing in a close enough curve (2.5 inches) without using an entire 30" tube (I have 6 left for the leadpipe/main-slide and the fourth valve), so I only bend the outer portion and used parts from my huge euphonium to complete the inner curve.


Oh, and I had little accident in filling a tube - didn't hold on to the cork...





Friday, I spent the day making ferrules and tacking the body together. I may need to flip the valves after-all...


Here are some pictures:

Bass Horn Part 6

Working on the valve block today didn't go quite as planned. I had hoped that the valve caps could be on top like they are on the French horn, but with the paddles flipped and the relatively short paddles, I couldn't fit the tubing around where needed, but most importantly get the correct height for the linkage to move freely.

I'm sure if I had more time I could machine a solid rise to sit between the two supports and the linkage bar, but trying to shim the two spots and still not achieving the right height was leading to more headaches than necessary. The work-around was to flip the section back over like you would find on a tuba... Sure you can still have access to the rotors for maintenance, but it loses some of it's Professional-Quality-Appeal. This does move the valves down and up a little, and should give me enough clearance to still depress the paddles. It should, if I wanted to and had better skills in the future, allow me to flip the valve section over again and use a new linkage set - maybe even strings!

I also filled the first branch after the valves with Cerrobend and bent the end toward the valve block. In draining the oil from the tube before filling with Cerrobend, I noticed a small crack in the seam. It's a little worrisome as this might lead to more crack, but it's in such a spot that I can cover it with a brace. Found a ferrule to fit the tube that I had torn through (old stupid mistake...) and made a ferrule for the two new inner branches. Then I cut the ends of the new inner branches and fit them together, then cut the first branch connecting to the valve section to the proper length to bring the tubing around as it should.

The current total estimate length, through the valves, leadpipe, two branches, body, throat and part of the bell (maybe) is around 178.5", this leaves me with about 37.5" to add between the leadpipe and the to inner branches. This is where it gets tricky....

I need to add the main tuning slide, but leave enough room to either cut tubing out to adjust the pitch up, or add a longer tuning slide to adjust the pitch down. This of course means I need to figure out the bell situation...

At the moment, the bell is in two parts. I have a throat from a euphonium/baritone bell, it fits the body collar perfectly and is just about the right length to fit with the design. The bell is the flare from the mini sousaphone - 19", again a near perfect fit for the design. The only problem is that the tapers of the two are different, meaning that I either have to make a new throat and mate it to the bell, or add a right of brass around the section where the two ends meet. The former would involve serious brazing and cutting tabs to join the main throat and then more tabs to join the ends with the bell - possibly more trimming of the bell inner throat. The latter would probably involve less work, but would look much worse (in my head). Of course if I could find a small 5.25" sousaphone collar, I could have a removable bell.

This is the next goal, although I could always start on bending the first and third crooks.

Of the parts I still need:
Braces (I should have the right ones)
Possible second valve crook from a King tuba/sousaphone
Possible trigger mechanism for the main slide and a thumb lever
Some other things I might think up...

Finish-wise, I buffed the leadpipe, though it has been drained of pitch as I still might need to bend it more or bend it back. When I'm done with it, I'd like to get it bead-blasted with bright trim and then a coat of lacquer, but that's just wishful thinking at the moment.

Updates all around!

BASS HORN 

Lots of progress made on the Bass Horn. My tubing showed up sometime in March and I purchased some Cerrobend - then found the paint can full of pitch.... Bought a pitcher, thermometer, pan, and electric hot plate to melt the Cerrobend. Also bought some wood and made the big jig and some drawings of the approximate sizes for the valve crooks.

In bending the tubing, I had to first fill each pipe with vegetable oil, drain it and then fill it with Cerrobend. Then let it sit in a cold bath for 30 minutes, before bending it into the curves I needed.

The first part didn't go to well, I over-annealed on 30+" tube and burnt two holes in it.... ugh.... Second and third try were much better, the the second tube suffered a kink during the bending process. So I had to hammer out the marks and then will have to sand the hammer marks off before buffing and assembly.

The next issue I ran into, was that I couldn't get the ends to be as curved as I wanted. I have a 17" circle by which I'm bending the tubing, but because I have about a 1/2 inch or so where I plugged the ends, I couldn't get the extra bit to be as curved. The solution was to take a smaller diameter circle and bend the ends around that. This helped especially for the tube leading into the valve section and will help when I bend the branch after the valve section (so that it meets up with the fourth valve).

I also bent the leadpipe and cut the end to match the receiver. Just need to buff it and burn out the pitch, then buff again...

On Friday, I got two of the inner bows in relative positions, although I may need to refill them in order to get the exact position... Not much time left. Still need to address the bell and the paddles for the valves.... OH and bend ALL THAT OTHER TUBING, though I might not have enough for the fourth valve if I screw up another 30+" tube. AND I need to find braces!

Finally, I'm almost done with my King Jumbo econo-overhaul. Just need to solder on the last two guard wires and do a final buff/polish/cleanup. I've buffed the bell with rouge two weeks ago, even got inside the back of the bell! I think there's some gold plating left back there. The body should look just as nice once I get around to polishing.

Before and After (almost)

Bass Horn Part 4

Took off all the tubing from the valve section, unscrewed the linkage finally, and ordered about 35 feet of tubing.

A little riser between the linkage and the posts will be enough to level out the arms and provide a smoother valve function.

Bought a leadpipe and found someone to make me a bass trombone sized french horn mouthpiece for a reasonable cost.

Bass Horn Part 3

Did some more work, well not much...

The rotor block and linkage has been giving me a lot of trouble. I had to use corrosion cracker three times under heat twice and about 5 days to free up the screws that held the linkage on the valve block. Once this was free, I unsoldered the braces, removed the tubing, and ultrasonically cleaned the valves and casings. No need for the tubing anymore!

Trying to figure out a way not to machine a whole bunch of new parts or trying to find parts to work, I looked at the linkage braces - these would work if I mounted them back on the valve block. I tried this, but soon discovered that, although the linkage hooked up with the stop arm on the rotor, it wouldn't fully depress. So now I either have to file off a millimeter or two from the braces or add a washer to each side to bring the linkage up. It should work since the distance between the "S" links and the stop arms doesn't change, just the height.

I had wanted to know where the valves needed to be and some length of the overall bugle, so I grabbed a F horn off the wall and started sizing things up to get the correct valve/left-hand placement. After that I started planning how I would add the extra tubing needed to drop the pitch to BBb. Unfortunately, this quick measurement gave me about 222" or 18.5 feet! And this was without a tuning slide! Now I'm going to have to readjust the open wrap in order to place a main tuning slide and still looks like a french horn.

Still need to find a leadpipe - it was recommended that I locate an Allied universal euphonium leadpipe, but I might have to have a custom leadpipe made to expand to the .687" bore needed for the main slide and the valve block. Also a mouthpiece that resembles a french horn mouthpiece but fits the bass trombone/tenor tuba shank receiver. Lastly a whole bunch of tubing to bend into shapes and most importantly ---- a collar and tenon for a removable bell!

Lots of work ahead....

Bass Horn Part 2

Worked on the bell today. Took a scrapped euphonium bell, cut the rim off and part of the throat to the approximate sizes needed.

Unfortunately the rate of expansion of the euphonium bell is slight more that the taper on the sousaphone bell. I'm going to try and see if I can mount a male/female collar/tenon for a removable bell right where those parts are so that the difference in the tapers won't be as obvious.

Otherwise.... It looks good!