How to bend a mouthpiece? (solution applied - new image)

[GC]

Another way to bend a mouthpiece is to ship it through the post office in a bubble mailer.

<img src="http://i81.photobucket.com/albums/j221/ ... MG0072.jpg" border="0" alt="Photobucket - Video and Image Hosting">

[Dan Schultz]

This might make the Darwin Awards!

[yohan]

... the cross-section will go from round to oval at the bend. That's why tuba builders fill tubes to be bent with lead, bending alloy, pitch or Slurpee juice. And you still have to run the bent tube though a draw ring to restore the round cross section....

I understand why this happens. Could you also explain what an oval vs. a round cross section would do to the properties of the instrument, both if the oval section is located in the mouthpiece and if it is later in the tubing, say in the leadpipe or after the valves.

[Chuck(G)]

[I understand why this happens. Could you also explain what an oval vs. a round cross section would do to the properties of the instrument, both if the oval section is located in the mouthpiece and if it is later in the tubing, say in the leadpipe or after the valves.

No, I really can't qualitatively say, never having squashed a mouthpiece shank. However, I think it's worth observing that the Conn short-stroke valves on the 20J are viewed as being acoustically inferior for their oval ports.

And I've never run across someone who asked me to squeeze the leadpipe on their instrument to an oval in the name of improving it.

So, I'm going to go out on a limb and say that the effect of taking a round mouthpiece shank and making it oval isn't going to be an improvement.

[Art Hovey]

I believe that it could be done, but you would want to practice on a few junk mouthpieces first. Heating the metal to anneal it before bending is a good idea. You also might want to put it onto a lathe and remove some metal from the outside where you want it to bend. I would make a wooden jig to hold the cup firmly in a large vise, and rig up a steel pipe about 2 feet long to slip over the shank. It will need a tapered opening like a mouthpiece receiver. When that fits right, start pulling. It may or may not be necessary to fill the shank with molten lead (or solder) depending on how much you want to bend it. Go for it. Take some pictures and post them here.

[Chuck(G)]

I don't know if mouthpieces are made of ordinary yellow brass, say C260. It would make sense to make them of 353 or 360 free-machining brass--but maybe not.

If you've ever tried to bend that stuff, you already know tht it's very brittle--machines like a dream but will crack if bent.

Just a thought.

[yohan]

I don't know if mouthpieces are made of ordinary yellow brass, say C260. It would make sense to make them of 353 or 360 free-machining brass--but maybe not.

If you've ever tried to bend that stuff, you already know tht it's very brittle--machines like a dream but will crack if bent.
.

You're probably right, since I could bend the mouthpiece to say a little more than 10 degrees, before it snapped right off when I got eager to bend it just a wee bit more...

The material visible in the crack is fairly bright, almost white.

[Daniel C. Oberloh]

Chuck is on the right track.

Okay, this is how you do it. first the angle of the bend needs to be determined, divide the angle in half, make the cut through the waist or narrowest section of the mouthpiece with a fine blade jewelers saw, rotate the cup 180o and silver braze back together. I have performed this trick for a couple customers in the past and it works quite nicely. of course, the plating need to be removed before silver brazing is to be done and the piece will need to be re-plated afterward. Oh yeah, for best results with the cleaning up of the finish, it is a good idea to make a brass "C" collet that can hold the mouthpiece by the rim of the cup without damaging it while turning it in the lathe chuck. This technique, when performed correctly also helps avoid damage and distortion of the back-bore. it works very spiffy but you do need a few tools and some skills if you want a nice final product.


Daniel C. Oberloh
Oberloh Woodwind and Brass Works
Seattle,Wa
www.oberloh.com

[yohan]

Thanks for all suggestions everybody.

I like the beauty of the miter cut/silver braze method, especially the "half angle cut" 180 degree turn. However, I guess my local jeweller is better qualified to perform this kind of surgery than my local brass repairguy.

Regarding the opinion about marching - I don't do much of it, but when I do, I want to save my back.

/Johan

[twoconnguy]

Curiosity got the better of me, so I bent a Kelly 24AW 20 degrees by carefully applying heat using a propane torch, after I realized the hair dryer wouldn't generate quite enough heat in one spot to get it to bend. I applied heat where I wanted it to bend and placed the tapered part in a piece of plumbing pipe, that was a good fit, clamped in a vise. The bore stayed round, and the only real flaw was a few bubbles that developed in the plastic. The plastic only stretched, so I didn't get any wrinkles on the inside of the bend. It's quite comfortable when standing with one of my Mirafone's, so I can see why Yohan wants one!

[Chuck(G)]

Well, it must be a good thing. Dave Monette's selling bent mouthpieces. See his Winter 2005 Flash slide show--unless you want to watch Dave mugging with a bunch of trumpet bums I mean that in the best possible way, skip to about the last 1/4 of the presentation, where a tray of mouthpeices is being shown. Note the bent ones.

http://www.monette.net/newsite/online/2 ... /index.htm

[iiipopes]

Since the lexan had to thin out to make the bend, if you start cracking on louder dynamics, wrap the thin spot with golfer's lead tape, and it will settle back down.

[yohan]

Inspired by twoconnguy I bought a Kellyberg and used an electric heat gun to heat it and bend to about 20 degree angle.

Here is the result:




As you can see, I did avoid bubbles, but the MP did wrinkle a little on the inside bend. Plays just fine however.