Magnetic Dent Removal

[Mojo workin']

Did that dent affect intonation, Wade?

Dave Fedderly had a similar one in nearly the same place in his Yorkbrunner years back. Said it knocked a couple of notes out.

[Tubaman2365]

Nice work! How much does one of those go for out of curiosity?

[The Big Ben]

Those videos were fun! Especially the second one.

A person would need a lot of skill to get a good dent removal. Probably as much skill as
using a dent machine or traditional dent ball but without needing to take the horn apart.
I'm guessing that using the buffing wheel would be next if you were doing the "full monty" on that dent?

I found this video of a 'factory' dent ball system being used in a repair shop:

http://www.youtube.com/watch?v=4vAM8_BE ... re=related" target="_blank

[PMeuph]

Great job!

....(much better than any of my work)

I purchased some magnets and steel balls off of ebay a few months back. (I read about it in another thread). I would like to share two pieces of advice that I learned the hard way. 1. If you don't have a handle, it might be best to use construction gloves to handle the magnets. That way there are less chances you will pinch your finger. 2. Never used on a bell. Luckily the horn I bought to "tinker" with (an indian mini sousaphone) didn't lose much of it's value by me putting a funny crease in it's bell.

[bigtubby]

For around $50.00 I built one of these. Personally the handle is a must for me and has removed some damage that was beyond what I thought would be possible.

The parts were an ebay magnet (1-1/2X1-1/2) and some PVC plumbing bits:


Left to right, top to bottom:
Magnet, 1-1/2" coupling, 1-1/2" to 1-1/4" reducer
1-1/4" cap, 5" length of 1-1/4" pipe, fender washer
Adhesive backed 3/32" dense foam

The fender washer has an OD close to 2" - fits inside the coupling but is trapped bu the welt in the middle. Holds the magnet in place. A series of photos showing the sequence of assembly:






The washer and foam hold the magnet pretty well in place. When I first used this rig I decided that I needed to remove the foam and epoxy the magnet in place. Glad that I didn't - the foam acts as a bit of a shock absorber and also allows the magnet to be removed. The latter is great because for $15.00 I purchased a radiused slug (not shown) and now can simply reverse the magnet for flat or radiused use.

I've been very well pleased with this setup. As many have mentioned it has its limitations but has far more than paid for iteslf in just a couple of months.

[Dan Schultz]

I've used layers of silver polishing cloth over the magnet (monitoring its condition as I use it) on silver-plated surfaces. I've found that I can also micro-control the amount of "pull" of the magnet(s) by adding layers of cloth.

The more 'cushion' you layer over the face of the magnet.... the better the chances of putting 'reverse ball tracks' in the brass or transferring imperfections from the inside of the tube to the outside.

[Dan Schultz]

I've used layers of silver polishing cloth over the magnet (monitoring its condition as I use it) on silver-plated surfaces. I've found that I can also micro-control the amount of "pull" of the magnet(s) by adding layers of cloth.

The more 'cushion' you layer over the face of the magnet.... the better the chances of putting 'reverse ball tracks' in the brass or transferring imperfections from the inside of the tube to the outside.

If you're ever fixing any of my stuff, please remind me not to ask you to use my methods.

Joe, I knew you knew that. I just didn't want any of the 'wannabees' out in 'tubaland' thinking that they could avoid scratching their lacquer or silver by padding the face of the magnets. The first commercial 'Dent Erasers' that UMI sold came with replaceable pads for the magnet faces that could be replaced. I deemed them totally worthless.

[bigtubby]

This thread is great. I'm a major do it yourself guy, and this thread has convinced me that unless I have a junk horn to practice on, do not try this at home.

Yes, I'm glad that I didn't lay into my Besson 3v compensating or York monsters before trying on more expendable horns.

This has all been proof of concept stuff for me, to see how much I can pull out without taking the instrument apart. For once I remembered to take a "before" photo. The top bow was smashed almost flat, perhaps 2/3 of the original volume, and with some serious creases. Please excuse the cell phone photos (yeah, and I'm a photographer even).



It took a lot of patience (and muscle) and I had to patch part of the crease with silver solder but got it close enough for this horn. I think I'm going to buy a stronger magnet ...

[bigtubby]

Okay, so in going back to the top of this thread I realized that the photos I originally posted were moved by me recently, so the links are dead.

Here they are again, in case magnetic dent removal interests anyone in the future. This new album is probably where these photos will live for all eternity, so the links will not break again.

Before, with patina...


After, with necessary cleanup and polishing...

Looks great! Are you using the gold tinted lacquer to match? If so how does it age - does it get darker then doesn't match?

[tbn.al]

Looks like you have earned some well deserved brownie points. Could I borrow a few? I really need them today.

[MartyNeilan]

Maybe the cat doesn't like the horn...??

Whenever any of us get out the bagpipes and start messing around with them, one of our cats will r-u-n towards us (from as far away as seventy-or-more feet) and bite our ankles!

Whenever my wife practices singing at home, the cats paw at her.

Strangely enough, one of them is not even remotely bothered by the tuba and will just sit in the same room and look at me. The other one stays far away.

[bigtubby]

Thee is no lacquer on my horns. I hate most lacquer unless it is one of the new formulations. They are all raw brass or silver plated. (Or silver plated with big patches of raw brass, heh, heh, heh...)

For customers I use the normal rattle can Nikolas stuff sold by Allied. I have both the clear and the tinted that sort of goes with the current Holton student line tint. (Holton stuff is a bit more pinkish, though, than the Nikolas gold tinted stuff.) I do not like how the spray can stuff holds up over time. And if you do dent work to an area with that formula on it and it is more than a few years old, it comes off really easily in flakes as the dent comes up.

The new stuff at the factories is great. Someday when I grow up I might have to set up a lacquering booth with a real gun and the ability to mix my own stuff.

Thanks for reading this thread, though!

Wade

Thanks Wade, on this topic do you know of a way to remove the new (epoxy???) finishes? A friend wants to get his Yamaha naked and asked about this. You are right, those finishes are great when you don't want them to come off, even with the soldering torch. The horn in question has quite a bit of wear and he'd like to just strip it bare and polish it.

[Ken Herrick]

40years ago I took a job teaching "brass" in a school where instrumental music was compulsory for grade 6. There had been nobody to teach brass and I had a class of over 50. There was not a single playable instrument as with no teacher the hoons had totally destroyed everything.

I made my classes elective by quickly sending most to the headmasters office for special physical education. Every week I took boxes of pieces home and made a few more playable horns. I set some very rigid standards. By end of year we had a decent little brass band and I could even trust the kids enough to let one use my King to learn tuba.

IF you can set and enforce discipline, work your guts out and develope two way respect and trust, success sometimes comes.

[Ken Herrick]

IF you can set and enforce discipline, work your guts out and develope two way respect and trust, success sometimes comes.

Ken, that "enforce" bit is where things seem to terribly wrong most of the time.

VERY TRUE!! In this case I had support of administration to give students the option of proper participation or leaving so that those who DID want to learn some music could without disruption. Those who left were likely to spend the class period cleaning the school grounds. A few of the real wreckers received harsher sanctions.

Not meaning to hijack this interesting thread.

[Ken Herrick]

Nah, Ian,
Leave it as is and when you have your own repair shop, it can be a "before" item hanging over the counter. Its got soul.

As a very good banjo player I used to work with inChicago would say, "If you don't like this mouldy oldy, you got a hole in your soul".