
Straightening out brass instruments (2013) - wallflower
https://www.supermagnete.de/eng/Magnet-applications/Straightening-out-brass-instruments
======
camtarn
There's a great video on repairing a severely damaged tuba, which includes the
use of the magnet-ball for straightening the walls of the tubes, as well as
disassembling parts of the tuba to gain access to individual parts:

[https://www.youtube.com/watch?v=wflildRmcJw](https://www.youtube.com/watch?v=wflildRmcJw)

------
theoh
The business of forming pipes with curves typically involves mandrels. A
mandrel, in this case, is a solid body that prevents the pipe from deforming
in undesirable ways.

[https://en.wikipedia.org/wiki/Mandrel](https://en.wikipedia.org/wiki/Mandrel)

Musical instrument _repair_ is clearly more complex than this—it's a skilled,
improvisational profession that would probably welcome this kind of trick. I
feel that, outside of Mega City One, those specialists just would not exist,
their skills wouldn't be sustainable as a source of employment. That's the
economic side of this—it's cool to come up with new techniques for instrument
repair, but try being an instrument repairer in a city on the periphery. It's
scary that this kind of (fairly mild) specialization is so precarious.

------
kazinator
Speaking of hammering from the inside: that's how you make "jumping beans"
using a steel ball wrapped in foil:

[https://www.youtube.com/watch?v=Y9sl1jLlekk](https://www.youtube.com/watch?v=Y9sl1jLlekk)

Made lots of these as a kid.

[https://www.youtube.com/watch?v=3BwIOSpD6ro](https://www.youtube.com/watch?v=3BwIOSpD6ro)

------
skaomatic
I am so very disappointed that this article was not about uncoiling the
instruments.

~~~
SimplePeople
This is something that I too want to see.

In my search I found this[0] fascinating page on the physics of brass
instruments. But this [1] is the best image I could find.

0:
[http://newt.phys.unsw.edu.au/jw/brassacoustics.html](http://newt.phys.unsw.edu.au/jw/brassacoustics.html)
1:
[http://newt.phys.unsw.edu.au/jw/brass/graphics/lipreedbores....](http://newt.phys.unsw.edu.au/jw/brass/graphics/lipreedbores.gif)

------
beering
This seems very similar to a lot of "paintless" dent repair for automobiles -
basically figuring out a way to apply force from the inside to gently smooth
out small dents (often with the help of looking at gridlines in the
reflection).

------
londons_explore
I am unconvinced by the 'reverse hammer's method.

Does it rely on eddy currents in the steel ball? Wouldn't copper work much
better in that case? Will the ball be large enough for eddy currents to be big
enough to have much effect?

~~~
jpitz
To me it seems to be operating like a slide hammer that connects via magnetic
force instead of mechanically.

[https://en.wikipedia.org/wiki/Slide_hammer](https://en.wikipedia.org/wiki/Slide_hammer)

