How novice is my perspective?

[olivegreenink]

So I am sure I’m in way over my head on this. But on a scale of 1-10 how ill informed am I? I see lots of old threads discussing accuracies of millimeters when trying to convert a tenor to an alto.....but how about simply replacing a bell flare? If the bell diameter, length, and the “connection” diameter are the same, is that close enough for horseshoes? Or does the precise shape/curve of the bell matter significantly....and how much wiggle room is here on the diameters?

Just towing around with the idea

Thank you

[hyperbolica]

One thing to keep in mind when asking questions here or anywhere on the internet: You have no idea who is answering. They may be an expert or an idiot. It is surprisingly difficult to tell the difference sometimes. This forum has an amazing array of old biddies who constantly wring their hands over possible issues, but will never really know because they don't actually do anything. 9 times out of 10 on this site, they'll try to talk you out of doing something because of some theoretical problem they don't understand.

Naive or not, I say err on the side of doing something. How else are you going to learn? If you're constantly afraid of doing or saying something that other people don't agree with, you'll never do or learn anything. Just do it.

[olivegreenink]

Cool. Let me go pop a BBb tuba bell on my trumpet valve block. Lol.

I’m 100% of the kind for trying things. But one of the things I am trying to do differently this time around, compared to 20 years ago is ask more questions. I was 100% trial and error before and while I did some “caution to the wind” things successfully, like converting a standard trumpet to a herald trumpet...I also now know I got SUPER lucky on a few things. I appreciate your input. I’ll take both your welcomed encouragement and the hand-winging folks into account

Cheers

[Crazy4Tbone86]

If you converted a standard trumpet into a herald trumpet, you probably know what you are getting into. Any time you take a torch to an instrument there are great things that can happen and surprises that can occur. My recommendation is to go for it. No matter what happens along the way, you will learn!

Replacing a bell flare appears to be simple because there are only two soldering points: The bell brace flange and the stem connection to the main tuning slide area. If you have a trombone with an F-attachment, there might be a brace or two for that tubing.....those brace should be removed first and replaced last.

The bell brace flange (either diamond shaped or oval) has a lot of solder on it because of the large surface area. Usually not a problem to remove a bell from the flange, but this flange can be a pain when installing the new bell. Try to shape the flange perfectly before installing the new bell. Use a small delrin or dent hammer to tap the flange gently into form while against the new bell stem. Be patient and take your time to get this right....don't tap too hard or it will dent the bell stem. Use 19 gauge binding wire to hold the flange snug against the bell stem. Make sure the flange is correctly shaped and the binding wire is not forcing the flange into shape. If the binding wire is forcing the flange into shape, you will have a "stressed" solder connection.

I have found bell flanges to be very puzzling. If I were to remove a bell and then place the same bell back on the same flange, the flange probably will still need to be shaped and fitted! Those darn bell flanges always seem to require some work and tender loving care.

The end of the stem connection to the tuning slide area is where you will get your surprises. Some designs are more user friendly in this area than others. If there are multiple solder connections in this area and you use too much heat, you can end up with several components coming apart. One trick is too use "Cold Shield Paste" which absorbs heat so that other solder connections do not melt. Another trick to simply remember that heat rises. If you are trying to avoid melting solder in a particular location on the horn, make sure that spot is BELOW the area you are heating.

Do not listen to the naysayers. Go for it!

[BGuttman]

There's a big difference between changing the pitch of an instrument and simply replacing a bell.

One thing to be concerned about is the length of the bell from the tuning slide flange to the end of the flare. If the new bell is different you may have tuning problems. Otherwise I think Crazy4 nailed it.

Bood luck.

[olivegreenink]

Awesome. Thank y’all so much. Stay tuned

[timothy42b]

Two things to remember:

Measure twice cut once. Not the other way around. (a real carpenter never measures. He puts the wood in place and marks it, eliminating the wrong measurement mistake. I'm replacing studs and sill plate in my shed, and that's what I'm doing even though I'm not a real carpenter.)

Equally important, maybe even more so: hot metal is the same color as cold metal. It's like wet paint, you can't tell by looking.

[Crazy4Tbone86]

The last 4-6 inches of the bell impact the pitch very little. You can hack off the last 3 or 4 inches of a bell and the pitch might only go 20-25 cents sharp. The modern bell flare is designed to kick sound back to the player and aid in articulation. Think about the bell shapes of sackbuts.

When I have replaced bells for customers, I always ask them how they want the bell rim to be placed relative to their 3rd position. Most want it in exactly the same place as before. A couple along the way have requested that the bell be moved out or in a fraction of an inch. Obviously, moving the rim out is much easier if you have a longer bell stem (otherwise you might need to reconstruct many things in the bell). Moving the bell inward might require you to trim the stem a little....be careful.

As timothy42b said......measure carefully. Measuring includes figuring out a way to measure the distance from first position to the bell rim, or the slide receiver to the bell rim. These are the distances that determine how a trombone looks and feels in the hands of a player. Measure MANY THINGS before you disassemble so that everything lines up the way you want it to when you start putting on new parts!