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Stryk wrote:What is the biggest factor in the decay of a brass instrument? I read in one of the other posts of a study that said brass could literally die from not being played. Will an instrument played regularly last longer than one that is not?

Man... THAT's an excellent question. One that I would like to read definitive answers to.

I've seen several cases where brass was literally falling apart. Then again... I've seen horns nearly 200 years old that were solid as a rock.

I don't think being played or not is as much of a factor that the environment. The Romans used both brass (copper and zinc) and bronze (copper and tin) and many of those items seemed to have survived the ages rather nicely.

I think this is more a question for metallurgists and the scientific community. Anything coming from tuba players and repairmen is going to consist of pure conjecture.

I know very little. I play just play tuba and fix stuff!

molecules in the brass crystalize and become rigid when the horn isn't played for a long time. This results in a loss of resonance and vibration.

All it takes is a good cryo treatment, though, and you're back in business.

Stryk wrote:

TubaTinker wrote: I know very little. I play just play tuba and fix stuff!

I have a feeling you are more knowledgeable about brass instruments than most anyone here. I understand that the sugars, etc, in our saliva can do a lot of damage - just wonder what other factors may be involved. This stuff fascinates me.

I do know lots of 'stuff' that's very difficult for me to quantify in a way that myself and anyone else understands.

By-the-way... Mike lynch mentioned the thingie about brass degrading from not being played. You might look for one his posts in the last two weeks or so.

Red-rot is one thing, but finding hairline cracks in old brass is another I have found quite a few hairline cracks in my B&F Kaiser BBb -- I've "patched" them in various ways (solder, epoxy, copper tape). There is evidence of previous repairs/dent work. I think the brass was not properly annealed when the tuba was made many decades ago, and with dent work (work hardening) has produced some cracks.

Brass does not consist of "molecules". It's an alloy (mixture) and not a compound.
It does not live or die, nor does it decay. If you cut into a hundred-year-old mouthpiece you will find bright, shiny brass under the crud of the ages. But it is subject to corrosion. Acid rain, polluted air, human sweat, and saliva can all be corrosive.

Wiki entry on Brass

If you scroll down to the season cracking, you see mention of ammonia, and an entry about its effects on old brass cartridge ammunition. Art and Tinker are definitely correct that the environment can have a major effect on brass.

I am also very interested and want to see the study Tuben mentioned, Terry. I am not knowledgeable enough about brass crystal form, annealing, and the effect of vibration. If effect, hammering a brass instrument is enough to work harden brass and reverse the annealing process. What does vibration do?

I'll have to say that I can't offer an opinion about brass instruments actually degrading from not being played. I have seen brass instruments get "stiffer" or less resonant after a period of not being played. And then after being played, that metal seems to "loosen up"and gets more resonant. But that is different from the metal actually degrading or deteriorating. Of course, there are occasions where instruments may do both (and noticeably have the metal degrade). Where the metal physically degrades, that is a different situation from that I was discussing earlier in this thread.

Mike

Might find something of interest on this matter on pages 55-57 of Brass Scholarship in Review, Proceeedings of the Historic Brass Society Conference, Cité de la Musique, Paris 1999.

Briefly, I believe they're saying yes, but not such a real issue for modern brass instruments because the brass has fewer impurities.

There is a good chance that the opposite is true, that the instruments that are played decay faster. That's because moisture contributes to corrosion.

There is a theory that historically the best instruments were played a lot, and the clunkers became the equivalent of wall hangers. For brass, that means the good ones were worn out. But for strings, the playing and the maintenance prolongs the life.

So what we see in museums are the worst examples of brass instruments and the best examples of strings.

It makes sense that playing or vibrating improves stringed instruments.

First, the instrument itself makes the sound. The strings vibrate and drive the wood, and there is a degree of coupling to the contained air volume. The vibration modes of the wood are critical to the sound. Not so with brass instruments, where the material primarily serves to contain the air column which does the actual sound production.

Secondly, as the wood flexes the connections of top and bottom plates to sides loosen and become more free. Unplayed wood instruments stiffen up but playing reverses that. Again, not so with brass instruments. Brass does not precipitation harden, it can only work harden. Vibration strong enough to affect that would change the shape of the instrument (as would cryo if it did anything.)

A brass instrument that is played regularly develops an interior layer of slime which tends to seal up any small leaks that may exist. The stuff can create problems if not cleaned out periodically, but it may actually be beneficial in small amounts.

If the instrument is put away for a long time without being cleaned out first, the slime dries out and starts to peel off like old paint. That could lead one to believe (mistakenly) that the instrument has "decayed" in storage.

For empirical evidence, I have a 1919 Holton E-flat. Some dents from being dumped from one closet to the next, but apparently very little playing time. The valves still seal well even though they are unplated. The silver "overspray" on the slides is present. And it has no deterioration of the metal anywhere.

Stryk wrote:wanting to buy a nice old Eb on the cheap.

I really isn't all that nice. I'm not a Holton historian who knows when Holton got their design science worked out, but they did not have it worked out with this model. The craftsmanship is fine, but the design isn't. And it has a mouthpiece shank size unique to this horn. So you use what I assume is the original mouthpiece -- which is unplated brass -- or you get a new leadpipe made.

I consider the horn more of a historical curiosity than something you would want to make your main squeeze and BFF.
However: "Everything is for sale."