Repairing a dented tuba with magnets | Hacker News Reader

Repairing a dented tuba with magnets

supermagnete.de

151 pointsmixmax23 comments

I'm sorely tempted to order one of their super-strong magnets, such as http://www.supermagnete.de/eng/K-26-C but I'm almost certain it'd lead to personal misfortune.

I wonder if this one of those "regret the things you do, not the things you don't do" situations, or simply a "don't be an idiot" situation...

EDIT: Just seen this one. Bloody hell. http://www.supermagnete.de/eng/SALE-038

Also interesting, this page http://www.supermagnete.de/eng/faq/price about how the price of neodymium "increased about fivefold between January 2011 and June 2011" due to china reducing export quotas.

Really: be careful. Strong magnets are extremely dangerous. I once managed to get a 1" cube of neodymium stuck on either side of my hand for a few minutes.

Think this is the very first thing anyone does when handed two pieces of neodymium. I know that I did this within a minute of my first experience with two free and loose neodymium magnets. I watched many others do it too. The look on one's face is always of shock and disbelief that this magnets were so strong, mixed in with the pain, even though you warned them before.

To second your warning:

http://www.supermagnete.de/eng/safety.php

for a very graphic demonstration of the dangers of the larger magnets: http://www.geekologie.com/2009/02/guy_loses_finger_to_neodym... (WARNING: gore)

"None of the women I know can separate these two magnetic spheres"

The striking thing about this is not just that it works but that it works so well. That I did not expect.

Wow that beats the heck out of disconnecting the joints, rolling it out by hand, and then soldering everything back together. That would have saved me hours in high school. Plus, magnets.

I guess it's not only a time saver. Unless you actually would unroll/re-solder an instrument worth > 10000 EUR, which would scare the hell out of me.

Funny trivia: The article uses ' as delimiter here, as in 10'000 although Germany (the domain name uses .DE and the company is based there) uses the . here -> 10.000 Seems like the author ('from Italy') of that post is using the swiss notation? Any other (european) country using ' as a thousand separator?

I worked in a music shop during high school and pulled apart a few tubas worth at least that. We had a similar magnet tool, but it didn't always work perfectly, and could leave scars in the metal if you weren't careful. His tool might be better, or he might have gotten lucky.

We certainly didn't try to unroll them, however, and I let my mentor solder them back together.

That's very clever. Their "reverse hammer" is reminiscent of the climbing world's funkness device:

http://books.google.com/books?id=vNyk_tSE2mUC&lpg=PP1...

That reverse hammer is fascinating. I'm a little confused by the diagram, though -- I think the magnet stays on the instrument's surface for the entire motion. It never comes away from the instrument, even after the hammerhead hits the stopper.

It is called a slide hammer. The blow to the end of the shaft is transferred to the magnet on the opposite end and pulls the magnet inside.

Very cool. I talked to a few of brass-playing musician friends and this is the standard process for getting rid of dents in brass instruments.

They use a similar techniques to repair dents on your car.

Too bad they do not ship to USA. Any clue why this could be? Because of magnetic field and air shipping?

Also, any clue where I could find something similar in USA territory?

I just ordered a few magnets from their site, including one that can lift 100 kg. (http://www.supermagnete.de/eng/FTN-63) and worried about the exact same thing.

There's a shipping guide on their site, and apparently it's not as problematic as you would think since you can "shortcircuit" a magnet by wrapping a piece of metal around it. The guide is here: http://www.supermagnete.de/eng/faq/shipping

United Nuclear has super magnets: http://unitednuclear.com/index.php?main_page=index&cPath...

Can this be used to repair bent car body panels?

The magnets would have to be so strong they would be dangerous to work with.

The easier way is just weld rods on to pull a dent out with, and then chop the rod off. There are several dent pulling tools that work this way.

Is your car body magnetic? If you had aluminum body panels, it probably could, though the panel is probably a good deal stiffer than this tuba. If you had steel body panels (which is very likely), it wouldn't.

In England, we don't dent the tuba.

Wow, that is a nice tuba.

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