Great news!!! I’d love to try out your d flutes, still did not have a chance. How about you coming to Bramsche tomorrow night? There is a flute class there with some potential buyers maybe…
Beste Grüße!
Claus
One of my flutes, an eBay acquisition, had a very stuck tuning slide. Unfortunately I don’t have it anymore but the slide wasn’t copper and I don’t recall that it was steel. After the slide was forcefully released, there were indications of corrosion and not just gummed up oils as I recall. It polished up nicely though and worked just fine afterward.
If I understand correctly, the more the metals are galvanically dissimilar, the greater likelihood of corrosion. Aluminum and brass might be another bad combo but it’s used for some whistle tuning slides.
So, you’ve got me curious…what is your background in flute construction?
Rob
Well, almost every maker does it that way, so it can’t be too wrong. Making the entire tuning slide from sterling silver just generates cost (about 150-200 euro more per flute), but doesn’t make the flute a better one. Nickel silver actually is just brass with some nickel added (which, by the way, is known for providing protection against corrosion), so a slide made from brass and nickel silver or nickel silver throughout shouldn’t make a big difference. I can imagine that a tuning slide can stick together if not moved for a long time (talking about a few decades), and that seems to happens sometimes with antique flutes, but I am pretty sure that this won’t happen if the flute is played regularly and the slide lubricated. I use “La Tromba” slide grease for that which works nicely, gives a smooth action and smells good. 
For the record, Gabriel, I think you’re fine there; the world is full of antique flutes with fully functional, dissimilar-metal tuning slides. Your flutes look great. I’m looking forward to a visit with the ambassador flute when it makes the rounds.
Meanwhile, I would still like to know where the advice on the other side is coming from.
Rob
Meanwhile, I would still like to know where the advice on the other side is coming from
Rob,
While it is certainly eminently reasonable to speak from years of experience in performance of a trade, at times the blind adherence to tradition can get us to miss the potential for improvement. In the flute field the relatively rapid evolution of design of the simple system conical flute in the 18th to 19th century is good evidence of this. After all we wouldn’t have tuning slides at all if the early classic Baroque style flute had been termed “good enough” because that was the way it had always been done (not to say that Baroque flute don’t have their place).
If you are actually interested in knowing where m31 is coming from, instead of just dinging him for not being an instrument maker, he, who I’m sure can speak for himself, is referencing a well know phenomenon called electrochemical corrosion. This will take place, to a certain degree whenever there is a significant flow of water containing gaseous oxygen, which all water does, in or around a pipe line where two dissimilar metals are in direct contact. You may have seen it yourself at the connection to a domestic water heater where the copper house distribution lines are improperly tied directly into the steel water heater (now dielectric fittings, which have a plastic barrier to direct metal contact, are used to prevent this and save our heaters, but that is another story).
His recommendation was for a new flute maker, not one with hundreds of flutes under his belt. It was well meaning, even if a bit misguided. Where he went wrong was in discounting the relatively minimal quantity of fluid flow inside a flute, the proximity of brass (basically an alloy of copper and zinc) and nickel silver (an alloy of copper and nickel, often with an addition of zinc as well) on the electromotive-force series of metals, the action of the slide lubricant, the corrosion proofing characteristics of zinc and similar alloy additions, and the polish of the metal tubing used for the slides. Even with all of these, if a slide made of two dissimilar materials were to remain in direct contact over a very long period of time, in a particularly humid environment, there is a chance for corrosion to freeze the slide. As stated above, and by others, it is more likely with metals that are further apart on the electromotive-force series (like silver and chrome steel for example).
I am certain that Gabriel’s slides, as described, will function as needed for the lifetime of the flutes, and am in no way questioning their design. The flutes are lovely and from his clip they sound as good as they look. It is great to see another craftsman making instruments. I’m quite jealous as I’ve enjoyed doing some restorations, but not taken the plunge to manufacture.
Now how come you’re not asking me if I’m a metallurgist or corrosion engineer? Strictly speaking, competence can only be reliably assessed by the competent (y’know, it takes one to know one?). And since competence can never be fully established or even authenticated in a forum such as this, I guess no one has a right to speak?
the world is full of antique flutes with fully functional, dissimilar-metal tuning slides.
And there are gobs of antique flutes with locked slides (granted for any number of reasons). I even (had) own some of them, including the aforementioned flute which was only 1980’s vintage.
Can we split this discussion into a seperate thread please?
m31, you can be assured that if I’ll ever encounter one of my slides being stuck due to electrolytic locking, I’ll be more than happy to reconsider it’s construction and solve the problem for the flute’s owner free of charge. Until now it served me well, and on all the flutes I ever encountered that were not made by myself, it did serve me well, too.
Agreed, sorry (ad hominemers irk me). I’d love to play one of your flutes.
Here are the videos:
http://www.youtube.com/watch?v=GEboYquYiwY
http://www.youtube.com/watch?v=LtWKdFSqJ7s
I used a Sennheiser MD441 microphone for audio recording.
good god i think you just put half the keyless flutemakers out of business, that’s brilliant!
Ditto That 
would love to get on your flute tour list.
Lovely Rudally sound.
Good job!!
Mea culpa, mea culpa, mea maxima culpa, Jon!
Still have it in my cupboard and totally forgot about it. Please PM or email me your current address soo it can find it’s way back.
Sorry, Moritz
So this is the second time my thread has been hijacked. I might take it personal next time.
Back on topic; Great playing Gabriel!
You can’t go wrong with this design. Are you planning offer keyed flutes soon? I can imagine thatthere may be some reluctance there, those pesky keys… How about Prattens? 
I currently have three blackwood flutes in the pipeline that I plan to decorate with silver spoons, block-mounted. Still undecided if I should forge three sets of keys or one and have the rest cast or forged by someone (which doesn’t seem too unusual, speaking of “A·L”…). Silver forging is fun but also takes a LOT of time.
Prattens - maybe…I’ve got the plans and just have to make the reamers. But not in the nearer future…fall, winter or so. Winter is a great time for making reamers, especially if you don’t have a cooling device for machining steel. Just open the windows and go for it.
I’d love to make an Eb flute, though. Mainly for myself (I just want to own one!), but if there’s interest…ah, and the Bb flute…so much to do, so little time!
Yes you will be a busy flute builder, just wait until you have a 10 year waiting list and buyers are hounding you for there flutes… ;o)
Ohhhh… I consider myself very lucky to have tried out these flutes last Saturday. Spot on tuning, excellent workmanship and a embouchure cut which gives just the right blend of attack and smoothness. And Steffen is just starting! Scary…
Go on The Gabe!