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It seems to me that instead of buying the "MDRS" from JL Smith or wherever for $550 for the "starter kit," someone could make their own kit by buying a rare earth magnet with a handle and large steel balls from a budget online retailer.

Anybody ever do this?

e.g.:

https://handymagnets.com/metal-test-mag ... ith-handle



plus:

https://www.amazon.com/steel-ball/s?k=steel+ball

Thoughts/opinions?

Or maybe something a bit more heavy duty (rated at 90+lbs): https://handymagnets.com/test-magnet-ir ... ting-metal

90# isn't going to do anything. You'll need 200+

https://a.co/d/2xw7KGJ

The handle is going to f up instruments. You need to just be holding on to the magnets with your fingers and using the strength of your own wrist.

If someone's fingers and wrists aren't strong enough to do that, I guess there are some exercises that will strengthen them eventually, but most mechanics end up with finger and wrist strength simply from using them to do their work.

Just a warning... If you use a 200#+ dent ball combined with a 3 inch steel ball, you better have strong hands and shoulders to pull them apart. It helps to position the ball under a ferrule or dent guard, but it's TOUGH

They can do amazing work though

when you are ready to purchase the dent balls, remember that anything less than one inch doesn't do jack, and you want to match the radius of the dent ball as close as you can to the size of tubing that you are working with.

I have and use 1" 1.25, 1.5, 2, 2 1/2, and 3.

I wrap the magnet in socks to give me a handle and also protect the brass. SOme people use a Drum head, but i've always found that to be awkward

But... I'm an untrained self taught hack, so maybe you shouldn't listen to me

A whole bunch of tubas - percentage wise, compared to other brass instruments - sport finishes which aren't worth saving. When using magnets, annealing is beneficial when the dents are particularly sharp-edged. If a dent is near some solder joints, those solder joints can actually be wired together, and - using that strategy plus controlling where the heat goes - can allow this to occur without taking an instrument apart. Combining magnet techniques with other techniques to remove severe dents often is the most effective way to approach them, particularly if attacking areas that aren't the most magnet technique friendly. I use oblong balls under an inch in diameter to remove some dents with magnets. If not round, it's helpful to coat steel dent balls with something like STP or something with a similar viscosity.

Besides using magnets of different thicknesses/strengths and balls of different sizes - which define how much magnetic attraction they will have, the amount of pull can be fine-tuned by the thickness of a rag wrapped around a magnet. It's important to fine-tune the amount of pull, just as the amount of push or ironing tension is adjusted when using other dent removal techniques.

As stated in a previous post in this same thread, attaching elevated handles to magnets is a very bad idea, in my view.

I bought a 3 cm diameter strong magnet and various steel balls, the larger ones hollow, from Amazone. Some I did fine sand and polish myself, others where perfect. Works just fine. I glued a thin plastic sheet on one of the flat surfaces, to avoid scratching the instrument, otherwise I just use finger force to manipulate. To get it on and off the instrument without making dents, I use a plastic wedge to slide it on and off, works just fine.

Practise on bad instruments first, it is very easy to mess everithing up with a strong magnet. ...

Most people seem to find their own way of using magnetic dent removal tools. Finding ways that end up working for individuals are really best done via trial and error. Just don’t do that on your daily driver…

I have a bunch of the “commercial” stuff here that I bought used from a guy that spent a lot and then never used it because he decided it was too much work fixing the stuff he messed up with it. (I think it was tough on his hands, wrists, and elbows, too.) I also had a “Dent Eraser” set (Conn Selmer marketed them years ago…) I got cheap at a tuba show. I passed it on to a friend who collects that sort of thing.

The tools I probably use a bit more than the commercial stuff I made myself. They’re sort of variations on what can be bought.

I did this last year.... I bought a 250# fishing magnet off amazon for like $25. It has a eye bolt that threads into the back. I work in a machine shop and my boss gave me some old used gauge balls ( I think they can be bought for like $20 to 80 depending on size. McMaster carr) the 2" ball worked fantastic. When removing dents, I used a thin piece of plastic between the magnet and the brass. I posted more in depth about this on the my eb tuba adventure on the repair page. Enjoy.

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Ok. I reviewed that post. I thought I had posted more about the magnet and dent ball. Sorry. I'll get some pictures of them up here when I get a chance. Anyway, my total cost was the purchase of the magnet. You could look for some small machine shops in your area (tool and die, etc) and stop in ask. They likely have old gauge balls they would sell you cheap.... maybe.. if they're nice people.

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Here.

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This magnet off amazon.

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I continue to see pictures of things with handles on them which allow the magnet to easily and accidentally tilt when going over bumps and which digs in nice deeper than original dents.

I used a thin plastic sheet between the magnet and horn.

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Out of curiosity I bought a magnet claiming 310# pull force and a 2" steel ball from Amazon. Tried it out on a small ding on one of the sousas. Ball dropped from magnet as soon as I hit dent. There is no way the magnet is even 100#. Stick it to a piece of 1" carbon steel plate and was able to remove it fairly easily. Buyer beware... Don't get the cheapest one.

Regarding handles and magnets…

A lot of (repair) people see that big old “handle” on the tool they bought and see, well, a handle. What hides inside that “handle” is a hunk of steel. Having a hunk of steel on the back of the magnet does stuff. Using that “handle” as a handle turns it into a lever to tip the magnet face and allows the edge of the magnet to dig into the brass and inflict a “b.a.d.” (Joe’s point about handles, I think.) If they would just grab the magnet and keep that hunk of steel “handle” between their thumb and forefinger it removes/lessens the tipping chance.

Don’t handle the “handle…”

If the handle is actually a help(??), the hand itself needs to be touching it at the bottom of the handle at least within an inch of the surface of the instrument.

Something else, there are a lot of shapes and overlapping appendages on tubas, and there are a lot of places that I can push a magnet that's only one or two inches thick but I could never push a magnet that's one or two inches thick plus a tall handle sticking up from it.

I can offer suggestions and point out reasons for doing or not doing things, but - when it comes right down to it - people are going to do whatever they please and use whatever they are going to use, and I can't really be too concerned about that.

On and off, I've emphasized the importance of those who are involved in a physical craft to develop remarkable strength in their fingers, wrists, and forearms, and here's one of the prime examples of why in the repair industry as it has evolved. I'm tired of going back over the example of these young guys with big chest muscles and big biceps showing up to work at automobile repair shops, and not being able to break bolts loose.
... it really doesn't take that much physical strength to flip a 27 lb tuba upside down, pull up on it a little bit (to control how much downward pressure there is), and run a bell flare across a roller. Those who have encountered trouble in older age doing this could possibly benefit from looking at a whole bunch of those Instagram reels that show how to stretch and straighten out the lower back and get rid of the pain from sitting too much or standing and walking with poor posture for so many years. That stuff - in addition to weight loss (eschewing sugars) and core strengthening - works.

bloke wrote: ↑Sun Aug 11, 2024 4:52 pm
... it really doesn't take that much physical strength to flip a 27 lb tuba upside down, pull up on it a little bit (to control how much downward pressure there is), and run a bell flare across a roller. Those who have encountered trouble in older age doing this could possibly benefit from looking at a whole bunch of those Instagram reels that show how to stretch and straighten out the lower back and get rid of the pain from sitting too much or standing and walking with poor posture for so many years. That stuff - in addition to weight loss (eschewing sugars) and core strengthening - works.

My repairman, up until he recently passed away, was doing this at age 90, and did a damn fine job.