Bending a trombone

In making a trombone, what is the soft flexible metal poured into the brass tubing when bending?

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snipped-for-privacy@gmail.com wrote:

Probably Cerro-bend alloy. Melts at about 75C (167F).
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They use soapy water. It gets frozen. The soap keeps it in a slightly mushy condition and prevents splitting of the tube from expansion of the frozen water. Cleanup is real easy.
Paul K. Dickman
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Bingo. Exactly right according to the instrument maker located just 50' from my shop...
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Regards,
Joe Agro, Jr.
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More importantly, that's how they did it on 'how its made'...
Dave
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snipped-for-privacy@yahoo.com wrote:

    --Saw that. Knew it was water but the 'soapy' part is new; glad to know that. Gotta give it a try now! :-)
--
"Steamboat Ed" Haas : Whatever happened
Hacking the Trailing Edge! : to Andy Philbrick?
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Joe AutoDrill wrote:

Cannot recall if it was an episode of "How It Is Made" or Mr Rodgers, that I stumbled across one day, but they were in an instrument shop, and followed through the whole process, bending, spinning and soldering together the parts of a trombone or trumpet. I think it may have been a trumpet, as I recall valves being there.
The freezer scene featured large, showing a person lifting out a batch of frozen parts and bending them.
Cheers Trevor Jones
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snipped-for-privacy@gmail.com wrote:

In the video I saw they used pitch, in the next thread over they used soapy water.
I suspect that anything that is normally used to bend tubing will work, and will have advantages and disadvantages. Can't one pack a tube with sand for this operation as well, or am I hallucinating?
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Tim Wescott
Wescott Design Services
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Tim Wescott wrote:

I suspect sand would cause internal abrasion marks that would be undesirable.
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Sand is indeed used to bend large pipes. After packing with sand the pipe wall is heated with torches, and then bent into shape.
Wolfgang
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snipped-for-privacy@hotmail.com wrote:

Oh, I'm well familiar with that use for things like header pipes and roll cages. I just wouldn't want to use that method on the internals of a musical instrument. the clarity of tone might be affected by the internal finish.
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wrote:

Pitch would work too, but it is hard to cleanup and getting a reliable fill might be tough. However, for something like a french horn, where the bend is in the bell taper, pitch would be required. The slushy water would just squirt out the wide end. Pitch is sticky and glues itself to the walls forming a plug that keeps the backpressure in.
Paul K. Dickman
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On Tue, 13 Nov 2007 06:25:42 -0800, snipped-for-privacy@gmail.com

Saw this on "How it's made" the other day. They use this compound called "Dihydrogen Monoxide" heated beyond its melting point, and then they allow it to cool to below the melting point so it becomes a solid that is soft enough to allow bending but strong enough to prevent kinking. Be careful of the stuff (if it's not banned where you are), see http://www.dhmo.org/ for details on its hazards. Inhalation hazards and all that...
Dave
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Dave Hinz writes:

I hear there's a chronic shortage of it in several parts of the country. Very impractical of you to suggest using something that exotic and hard-to- find. Sand, on the other hand, is in everyone's shoes.
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We're in clay country here, you insensitive bastard.
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Dave Hinz writes:

So you can have no proper agriculture, the basis of all virture and economic prosperity, and in turn the leisure to develop the liberal arts, of which music is prime, so you clearly have NO NEED OF TROMBONES.
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Ah, that's where you're wrong. Clay is just fine for my tree farm. (oak/maple/ash/pine/spruce/fir/walnut). Makes 'em grow nice and slllllow, which makes for nice lumber given proper trimming (which I do). So, it's, er, a _feature_, not a bug, you see. So let's see the lumber then, provides for WOODwinds, rather than brASS.
Point remains that DHMO is used in torture, found in tumors, and will kill you if you get a lungful of the stuff. But nice try at diversion there. Lets keep our eye on what matters, mmm-kay?
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Not to mention ruining the sound of the trombone, so it's provided with a purge portal.
"Never look at the trombones, it only encourages them." - Richard Wagner
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On Tue, 13 Nov 2007 22:32:45 -0600, with neither quill nor qualm,

I feel that clay is of extreme importance in the use of trombones in that it works so well as a mute!
-- Real freedom lies in wildness, not in civilization. -- Charles Lindbergh
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Actually, what I really intend to bend is steel tubing for a tubular chassis.
A mandrel bender would be nice if I could afford it but it's just too expensive for me.
I do have here a simple hydraulic bender (ram style bending... see http://www.oceanmachinery.com/how-to-bend-pipe-and-tube.htm ) which I think wouldn't make good, smooth bends and so I'm thinking of putting in something to support the inside of the tube while bending.
I was thinking of some metal with a low melting point. but you guys mentioned sand? Can sand help me get bends similar to those of a mandrel bender?
wrote:

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