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FYI, Another tool I made last year was a magnetic dent remover. Works great on the bow and bell areas. The handle is 3D printed; I designed it in Sketchup (just guessed a comfortable shape; got lucky; first print worked well). To work more smoothly on concave areas and reduce the force (bell areas), I place over the magnet a 2" PVC cap with smoothed over surface (squeeze fit with cork strip). Here are the items I used for my kit (no recommendations; just the least expensive I found at the time):

Description - - - - - - - - - - - - - - - - - - - - - - - -|Price| Seller
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2” x 2” cylindrical N42 neodymium magnet - - - -| $45 | CMS Magnetics
Set of 14 non-magnetic steel balls (15/32” – 2”) | $27 | BC Precision; Amazon.com
Note: Only steel balls 5/8” or bigger generate enough magnetic attraction to
be useful, but still cheapest solution I found.
Handle for magnet (3D printed) - - - - - - - - - - -| $0 | me
2" PVC cap - - - - - - - - - - - - - - - - - - - - - - - -| $2 | hardware store
Total - - - - - - - - - - - - - - - - - - - - - - - - - - - - $74

Beware: These magnets are powerful and dangerous. Read up before you buy, and learn the technique to remove a ferrous object stuck to a powerful magnet. Seriously, read up.
 

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Nice tool. Yes the magnet demands a degree of safety. Good note
 

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That is an ingenious way to make a handle. When I made a set of magnetic dent tools I used various sizes of pvc pipe, I used a grinder "side handle". I glued both flat and curved steel plates to the faces of the magnets to protect the working surface. magnetic dent mushrooms
 

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Discussion Starter #6
That is an ingenious way to make a handle. When I made a set of magnetic dent tools I used various sizes of pvc pipe, I used a grinder "side handle". I glued both flat and curved steel plates to the faces of the magnets to protect the working surface. magnetic dent mushrooms
Thanks, very generous of you. Yes, protection of the magnet surface is paramount. When I'm not using the cap, I cover the surface with a traditional dust cloth (still requires care). One should also use a sheet of plastic (mylar(?)) to cover the area of the dent. It should stay put, not move around with the magnet, otherwise it won't protect the instrument from getting scratched.


do you have the stl posted on thingiverse?
I don't have thinguniverse account, but see attached .zip file
 

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I have been using my homemade magnetic dent removal tools exclusively for saxophone work since 2013. For this application I would strongly suggest not using a larger or stronger magnet than 2" x 1" N52 270 lbs. pull. That strength used with the appropriate size dent balls for saxophone bows is more than sufficient pull. I started out with this size and a couple of 1 1/2" and 1" diameter magnets for smaller work, but eventually made one using a 2" x 2" N52 with 450 lbs pull. That is far too much power for saxophone dent repair and the danger factor increased exponentially. I think I have used it only once. I have friends in the trade who use that size for extreme tuba dent repair when that much force is needed, but for sax work it is overkill.

For the protective shield I found that running a laminator sheet through the machine without paper in between makes a perfect shield. I glued a thick sheet of .010" thick teflon to the tops of the magnets to eliminate friction and the chance of scratching the finish
 

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Discussion Starter #9
As I recall, the n42 was much cheaper, and I determined it was close in strength and in any case strong enough. It is strong enough, and it often benefits to weaken it by using a spacer. I also determined that for the greatest bang-for-the-buck shape, the height should be equal to the diameter (or width). So, if you were to get a second one, say a 1.5" diameter, to reach somewhat tighter spaces, the height should also be 1.5". Note: anything smaller, say 1" x 1", probably generally won't work---too small/weak.
 

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For the protective shield I found that running a laminator sheet through the machine without paper in between makes a perfect shield. I glued a thick sheet of .010" thick teflon to the tops of the magnets to eliminate friction and the chance of scratching the finish
Nice ideas. Is the teflon durable, or do you have to replace it once in a while?
 

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@saxoclese, what is interesting though is you need the bigger magnets for the smaller balls to generate enough force to get the smaller dents. Not going to argue with your experience, but it definitely seems a little counter intuitive.

Either way, I just got a 2x2 n52 and we'll see what happens. Have some cheap throwaway horns from one of our local schools they'll let me take a crack at *marching baritones and sousaphones* that they have deemed too far gone. Will see how it works next week when everything gets here
 

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@saxoclese, what is interesting though is you need the bigger magnets for the smaller balls to generate enough force to get the smaller dents. Not going to argue with your experience, but it definitely seems a little counter intuitive.

Either way, I just got a 2x2 n52 and we'll see what happens. Have some cheap throwaway horns from one of our local schools they'll let me take a crack at *marching baritones and sousaphones* that they have deemed too far gone. Will see how it works next week when everything gets here
There is very little difference between the contact area of a large ball and a smaller ball so using a small ball for small dents doesn't make much sense to me. Besides, the dent is removed by "rolling" the ball back and forth over it. I typically use the largest ball that fits inside the tube with the strength of magnet that is proportional to the depth of the dent. I have found one must be especially careful choosing the strength of the magnet when removing dents in the bell section so as not to "deform" the surface by expanding the brass with too much directed force. Remember I am speaking only of dent work on saxophones, brass work is a different matter. One must be extremely careful not to have any metal object of any kind anywhere near when using a magnet with 450 pounds of pull. Good luck with that and please be careful.
 

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Discussion Starter #14
@saxoclese, what is interesting though is you need the bigger magnets for the smaller balls to generate enough force to get the smaller dents. Not going to argue with your experience, but it definitely seems a little counter intuitive.
There is very little difference between the contact area of a large ball and a smaller ball so using a small ball for small dents doesn't make much sense to me.
To follow up a bit, as I understand it, the "pull force" measurement is based on the pull against a large thick flat steel plate (at least as wide (wider) and thick as the magnet---but I don't think there is a defined universal standard). A round object will generate much less pull force due to most of the mass being at some distance from the magnet---in keeping with Saxoclese's comment. But a small object relative to the size of the magnet will also generate far less pull force. So, big magnet + small ball = no good (weak force). The small ball (small amount of ferrous metal) is the limiting factor.
 

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I have 3 sizes. I always use the D2x2".
It was an early acquisition, before N52 was marketed. That makes it perhaps 11% weaker than N52.
I don't think a smaller one would touch a student Yamaha.
I have over the end a thin sheetmetal disc with one side of velcro stuck on it, so that offers perhaps a mm of spacing between the magnet's now-steel surface and the brass.

It is good to do the work with the largest diameter ball that fits easily inside the bore. If there is too much pull, reduce it by using the hollow balls. (or increasing the distance between the ball and the magnet's surface.)
 

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I have 3 sizes. I always use the D2x2".
It was an early acquisition, before N52 was marketed. That makes it perhaps 11% weaker than N52.
I don't think a smaller one would touch a student Yamaha.
I have over the end a thin sheetmetal disc with one side of velcro stuck on it, so that offers perhaps a mm of spacing between the magnet's now-steel surface and the brass.

It is good to do the work with the largest diameter ball that fits easily inside the bore. If there is too much pull, reduce it by using the hollow balls. (or increasing the distance between the ball and the magnet's surface.)
What if any are the other advantages of "hollow balls"? [low hanging fruit for someone to make a joke I know]
 

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Is there anything strong enough to work on a Leblanc Paperclip Contrabass Clarinet? These are made of nickel and are only about 30 mm in diameter.
 

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Is there anything strong enough to work on a Leblanc Paperclip Contrabass Clarinet? These are made of nickel and are only about 30 mm in diameter.
Keith, when I have mine done in a week or two, I'll send it and a few balls up for you to try it out
 

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Is there anything strong enough to work on a Leblanc Paperclip Contrabass Clarinet? These are made of nickel and are only about 30 mm in diameter.
I don't think so. Not enough pull for a ball that small, especially when the metal is so typically strong.
 

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What if any are the other advantages of "hollow balls"? [low hanging fruit for someone to make a joke I know]
I don't think so, but that is a biggie when working on larger diameter tubing.
 
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