HOWTO make a magnetic "reverse hammer" to remove dents from brass instruments


15 Responses to “HOWTO make a magnetic "reverse hammer" to remove dents from brass instruments”

  1. Cowicide says:

    I wonder if this type of thing could be used to get dings out of car doors, etc.?

  2. EH says:

    Hair dryer + canned air =

  3. Alvis says:

    Motorcycle gas tanks FTW.

  4. spacemanmatt says:

    Without this I wouldn’t have guessed it’s so easy. Now I can fix my fugly old saxophone to look as good as it sounds!

    • Sam Jelfs says:

      Just watch out, repair the dents and you change the internal volume of the instrument and the air flow through it… With some instruments the quality of the sound comes from the fact that it is dented.

  5. Tom says:

    I don’t get it. Can someone post a vid of this in action?

  6. This very well may be the most personally relevant post I have ever seen on boingboing.  I have (literally) dozens of dented brass instruments that could use this kind of fixing.  You guys have no idea how amazing you are!  Thanks!

    (And to all the people who want to apply this to steel parts, keep in mind that a lot of the reason WHY this technique will work so well on brass instruments is that the magnet isn’t going to stick to the brass.  So it may not work as well on steel body panels.  I’m still going to try it, though)

  7. cstatman says:

    i wonder if this could be used on dirtbike exhaust pipes.  this is a great idea!

  8. John Gratton says:

    spot weld a washer edge on to the dint. Hook the slide hammer through the washer. Tap it out. Give the washer a twist to get it off. File it smooth.  It worked on my expansion chamber.

  9. Luke Snyder says:

    I’m a band director. This is relevant to my interests.  :D 

  10. The first method is similar to mandrel bending.

  11. Just a heads up on this. The magnets we use for this kind of work are incredibly strong. Getting your fingers caught between them and the steel ball, or even worse, another magnet can result in pinch skin and bruises at the least and broken bones at the worst. Anything in your workspace that can be pulled to the magnet is also a hazard. We won’t let anyone near our set in the shop that isn’t one of the repair techs. They are just too dangerous. Conn made a set of tools like this marketed towards band directors. I can’t imagine the potential liability of something like this in a school environment.

    Anyway, we’ve been using something like this in our repair shop for about 8 years now. While it can be a great tool, you can also do far more damage than good with them. I’d never use it on a trumpet, trombone, or horn as they are so soft you’re almost guaranteed to make things worse.  Some of those fancy euphoniums and tubas are really soft as well and you can easily pull a large crease into them or put more dents in trying to get the ball into place. This isn’t to say I have seen great results with this method of dent removal, but, it’s no magic cure all. It’s just another tool available for a repair tech when the situation is appropriate.

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