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Thread: Magnetic dent removal

  1. #21
    Sara, you can see videos on YouTube. It’s pretty neat.
    Clayton M.
    Musician for Fun
    Euphonium Newbie - XO 1270S
    Trumpet Novice - XO 1602RS

  2. #22
    Well I was able to remove quite a few dents with the 220lb magnet. I have contacted the magnet supplier and they are sending me a 330 as well as a 500lb. After some research I found the N52 magnet used by many pro sets has a pull of 600lbs. Me being conservative in my expenditures will go the cheaper route. I have had an issue removing the old lacquer off a baritone I have been working on. I finally ordered some aviation paint remover from Amaz. as where we are living, it is not just a drive to a supply store that carries the stuff. I tried several less caustic methods but they didn't even budge the old finish. I must caution anyone reading this, always wear gloves. It isn't to protect you, It is the keep the integrity of your magnet and the dent balls from rusting from your body oils. This is very important. My next trial will be making a set of dent rods, I have access to a welder so getting a strong enough steel shaft that wont flex will be my next hunt. I had to send back one "550lb" magnet as it seems the trick to these things is singular pull vs a combined pull. Nevertheless, our daughter and her section in the band (6 other baritones) are excited at what her loaner is starting to look like without the massive dents it had. I still need to roll out several more, then try and re lacquer at the least the bell inner and outer that would really make it pop. keep you posted...........yours red

  3. Thanks to Gary for starting this thread, and others for chiming in. I finally got the nerve to give this a try. Gary, I believe your assessment of older brass being harder is true, at least with my two horns. My 1971 Besson is made of alloy which does not seem to be substantially thicker than my Adams (.060"), but it is much harder. I think I could dent my Adams with my finger tip, but not so with the Besson. I found that I could get what I needed in terms of magnets and balls from Amazon, economically. I had a few small dings in the bottom bow of my Adams that were bothering me, so my plan was to practice on my Besson and move on to the Adams (CAREFULLY) if all went well. This technique works very well! I got all the little dings out of my Adams very easily, with NO unintended consequences. My Besson still has a dent in the 4th valve tuning slide loop that didn't want to come out. For one thing I think there is something about the physics involved with a smaller diameter tubing versus large--also the ball I was using (1/2") isn't quite large enough, and of course the alloy is very hard.

  4. #24
    Sears (Craftsman) make polishing sticks in 6 different grits. I used these with a 4" cloth wheel on a desktop drill press to polish stainless steel parts from a 50 year old car. It takes time. A lot has to do with the amount of scratching on your horn. If the scratches are deep, like 200 grit sand paper, you will never get it polished. If the finish has been sanded with a scotchbrite pad, the scratches are too deep to remove with polish. You would need to sand up to 1000 grit or finer before you being polishing. Since brass horns are shiny due to the clear lacquer finish, I don't know what results you would get if the lacquer is gone.

  5. #25
    Join Date
    Dec 2011
    Location
    Central North Carolina
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    Quote Originally Posted by red423 View Post
    I must caution anyone reading this, always wear gloves. It isn't to protect you, It is the keep the integrity of your magnet and the dent balls from rusting from your body oils.
    Well, the first time you get your ungloved hand pinched by one of those magnets, you may reconsider this view. Or maybe you're just a lot more skilled or careful than I am.
    Gary Merrill
    Wessex EEb Bass tuba (Denis Wick 3XL)
    Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
    Amati Oval Euph (DE N106, Euph J, J6 euph)
    1924 Buescher 3-valve Eb tuba, modified Kelly 25
    Schiller American Heritage 7B clone bass trombone (DE LB K/K9/112 Lexan, Brass Ark MV50R)
    1947 Olds "Standard" trombone (Olds #3)

  6. #26
    Join Date
    Dec 2011
    Location
    Central North Carolina
    Posts
    2,039
    Quote Originally Posted by daniel76309 View Post
    My Besson still has a dent in the 4th valve tuning slide loop that didn't want to come out. For one thing I think there is something about the physics involved with a smaller diameter tubing versus large--also the ball I was using (1/2") isn't quite large enough, and of course the alloy is very hard.
    It involves geometry as well. I was loathe to try to remove dents in the small diameter tubing, partly because I was concerned about getting a ball stuck in it or -- the other alternative -- using a small enough ball to avoid getting stuck, but then having it distort the circular cross section of the tubing. If the curvature of the ball gets to be too far away from the curvature of the tubing, you'll be noticeably flattening the tubing. This is why the approach won't work (or is very tricky) on bell sections where you'll start to get flat spots and some "edging" because your ball curvature is so much tighter than the bell section curvature.

    But I'm glad that this has worked out so well for you guys -- though we may not have heard from others because they're still pinned by their magnets against vises, anvils, or other steel items, and can't reach their phones or computers.
    Gary Merrill
    Wessex EEb Bass tuba (Denis Wick 3XL)
    Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
    Amati Oval Euph (DE N106, Euph J, J6 euph)
    1924 Buescher 3-valve Eb tuba, modified Kelly 25
    Schiller American Heritage 7B clone bass trombone (DE LB K/K9/112 Lexan, Brass Ark MV50R)
    1947 Olds "Standard" trombone (Olds #3)

  7. Quote Originally Posted by ghmerrill View Post
    -- though we may not have heard from others because they're still pinned by their magnets against vises, anvils, or other steel items, and can't reach their phones or computers.

    HA HA!


    Yes, I said physics, but you are correct-- "geometry" is more like it. I can't explain exactly why, but intuitively I know that something about popping a dent out of small diameter tubing is going to be more difficult than larger tubing with "flatter" contour.

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