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Thank you for the responses to my dent balls post. I agree with you in that the major work should be left to the pros.

This now gives me an opportunity to ask about the right kind of metal which could used to build sousas and tubas so that dents would be something of the past.

Given that our horns are more prone to denting compared to trumpets and trombones, simply due to our size, I wanted to ask if there is a kind of brass alloy or metal that is being used now which makes dents difficult to have. Or could a tuba be made with a special kind of dentless metal, but still be reasonably affordable to purchase?

Cast iron wouldn't dent too easily, but you'd have to include a truss with every horn purchase

fiberglass.

Unfortunately, neither "metal" nor "cool"

Hank74 wrote:This now gives me an opportunity to ask about the right kind of metal which could used to build sousas and tubas so that dents would be something of the past.

Denting is caused when the stress on the part exceeds its elastic limit, and the material goes plastic and deforms permanently. Stress is the force per unit area of the material cross-section. Just talking about stress first, the trick is to find a material that has a very high elastic limit, which is also known as yield strength. Brass can be cold-worked to fairly high yield strengths. Early spring-driven clocks, for example, were powered buy brass mainsprings. These springs endured considerable deflection without yielding.

Steel is much stronger, and some alloys of steel are much stronger still. Titanium is about the strength of good steel, but not as strong as the best alloys. The advantage of titanium is that it is both highly corrosion resistant and lightweight compared to steel. Stainless steel is pretty weak in comparison to other steels, but much stronger than brass. Aluminum is weaker than brass, generally speaking.

The problem with using a material that is stronger than brass is that the strength makes it very difficult to form the parts. Forget bending high-strength steel tubes into the required shapes without ruining the strength, or without going through a really challenging heat-treating process. Ditto titanium alloys, which are deadly difficult to machine and weld, and require very sophisticated treatment to reach their strength potential. Glasses frames of that material cost about $300 for something that weighs ounces.

So, the property that makes brass easy to make also makes it easy to dent. Sure, we could build stamping machines like the car companies used to make steel fenders, but then we'd have to build the branches in halves and weld them together along the seam. That's quite doable, but the machines would be enormous and vastly expensive considering the size of the market.

The better direction is to find a material that can be made while soft, and then chemically harden it to working strength. That describes both fiberglass and carbon composites, and they do work. You can also use a material that is soft while hot, and can be shaped at high temperatures. Lexan is an example and we already use that for mouthpieces. PVC is another example.

Of course, when we move from a discussion of material properties to material shape, we can make just about anything strong enough to resist dents. The tricky bit is being able to carry it. I assure you that I could design a brass instrument that would be resistant to dents, because it would be so heavy you wouldn't be able to lift it high enough to drop it with enough force to make a dent. I also challenge you to dent a 4" schedule 40 PVC plumbing elbow. You'd have to whack it pretty hard with a big hammer. But what makes that weak plastic strong in the resulting product is its thickness.

Rick "thinking composites, not metals, are the likely choice for an undentable tuba that can still be carried by a single human" Denney

One of these days, when I'm bored with life, I'd like to make a tuba bell out of cedar strips and epoxy resin.

What a beautiful canoe! Is that yours Chuck or did you swipe the pic?

While this might be "neat" to talk about, "dent resistance" is solely in the hands of the operator. It's a tuba, not a dump truck.

If you don't want your tuba dented, avoid situations where it can be dented (like carrying it around in a dent bag or leaving it out of its case where kiddies can play with it).

Try to take the best care of your stuff that you can. You paid for it.

I park my car as far away from the other automobiles (especially sport utility vehicles) because I don't want door dings. Similarly, I proactively keep my tubas out of harm's way whenever possible.

tbn.al wrote:What a beautiful canoe! Is that yours Chuck or did you swipe the pic?

Not mine, but a swiped picture. Around here, plywood drift boats seem to be more in fashion.

cjk wrote:Similarly, I proactively keep my tubas out of harm's way whenever possible.

The best way to avoid dents is to never take the tuba outside the house. In fact, never remove it from the case--my worst dents have happened at home. If it sits in its case and is never used, it will never be dented until a meteorite falls on it.

Okay, I'm being absurd. But we have to balance the desire for dent prevention against the desire to actually use the instrument in the real world. For me, that means no hard case for my big tubas. If I had to use a hard case, I would not play--I just have no way of managing hard cases. They won't fit in my car, they are too heavy to carry up stairs, etc. I already have serious elbow joint problems as a result of schlepping heavy stuff.

So it makes sense to try and identify the requirements for the durability of the instrument in terms of its actual use by most folks. Even if we decide fulfilling those requirements isn't possible for one reason or another, it helps to know what they are. We use brass for tubas because that's what was available and easy to use 175+ years ago.

Those who claim that different materials are different are, of course, correct. That doesn't mean they are 1.) different enough to matter, or 2.) inherently better or worse.

Rick "who really does wish his BAT was lighter" Denney

bloke wrote:

Rick Denney wrote:Rick "who really does wish his BA was lighter" Denney

viewtopic.php?t=19912

That ain't the reason it's big.

Rick "'the smeller's the feller'" Denney

Rick Denney wrote: The best way to avoid dents is to never take the tuba outside the house. In fact, never remove it from the case--my worst dents have happened at home. If it sits in its case and is never used, it will never be dented until a meteorite falls on it.

The first time I picked up my brand new tuba at home to show it to my wife I bumped into the piano and put a nice dent in it. The dent (along with a number of others not quite a bad) are still there after 25 years.

Jim ' Still ticked off at myself over that first dent' Wagner