Stupid question- “dent pullers”

[DonO.]

I’m just curious about these. Conventional wisdom says to take a dent out, you bang it back into shape from the other side- either with a hammer, dent ball, or magnet/ball setup. I have seen these things advertised to take small dents out of auto bodies. With the kit you get several different shaped tools that you glue to the dent with a hot glue gun. You connect the tool to another tool that has handles that you squeeze, and supposedly the mechanical advantage enables you to pull out the dent. Then you disconnect the handle tool, and re-melt the hot melt glue to remove the other tool, then clean up the glue residue, and voila! No more dent.

I suppose if these worked on brass instruments, someone would be using them. But again, just curious. Do any of you think that a brass instrument dent could be taken out this way? Why or why not?

[the elephant]

This will not work on brass instruments. First, they are TUBES, meaning that every square centimeter has more curvature than ANY part of a car's body that you could possibly use this method on, using his collection of plastic pins, which you have to purchase as a part of his kit, which is aimed at business owners looking to pull many thousands of dents — this kit is not inexpensive.

Also, I suspect that the glue used will not work with lacquer. Two-stage automotive paint is nothing at all like lacquer (or you would see more home repair guys clear-coating their tubas). It bonds to steel differently than super-super-thin lacquer bonds to copper alloys. First, an etching primer is laid down, which bonds to the steel very well, and the base coat of paint (the color) bonds to it just about as well. On top of that is a clearcoat that is like Future acrylic floor wax from the 1970s. It is thick and tough.
So I guess that if you used this "hot glue" (definitely NOT the hot glue that you are thinking of, but some sort of modern polymer that is like superglue but that is easy to remove) on lacquer it will just pull it off of the horn.

The old school procedure he is trying to sell you a replacement for is welding the pins to steel or soldering them to brass. This has been done by some in the past, but to be honest, any skilled brass repairman can do a better job, usually faster and for less money, by taking the instrument apart, fixing it with traditional dent balls and a set of hammers, reassembling it and refinishing the torch marks and work area than using this method.

To do this to a car is to be able to hide all your sins under the paint. The paint on tubas is clear, so there can be no flaws or you can clearly see them. So the old soldering method would require a ton of finish hammering and then some sanding, which thins the brass and is not good for the horn.

I do not see his adhesive working on brass instruments in the intended way, I do not see his packet of custom-molded dent pins fitting any part of a tuba in order to get a proper grip on the metal, and the actual method used in automotive body shops for decades will require lots of sanding, bondo, block sanding, and a full respray of the primer, base coat, and clearcoat, if your tuba has two-stage paint. Lacquer? Forget about it.

You could spend the money on the kit and give it a whirl on some very shallow dings on a car (and it might turn out very well, too). Once you get a feel for how it works, try it on a tuba. (The tuba is the only instrument large enough to even hope of having one of the pins glue down to the surface in a meaningful way. Trumpets? Absolutely not.)

If you spend the cash on this kit, learn to use it, and then give it a try on a tuba, please video the process and post here with your results. I am not saying that it won't work. I am saying that my experience in autobody and brass instrument dent work tell me that it won't work well.

BUT I DON'T KNOW THIS TO BE A FACT.

Best of luck if you spend the cash needed for this super-fancy system. I would like to get a field report from actual usage on a brass instrument.

[the elephant]

[MiBrassFS]

.

[bloke]

I may be wrong...as - so often - I am...

...but (yes?) these days, a whole bunch of vehicle panels (even-or-most-often pickup trucks) - with these super-low average gas mileage requirements - are now fabricated from painted aluminum (rather than steel)...

Aluminum is pretty soft, and car dents are often (at least, when I look at them) less angular than dents in brass musical instruments tend to be.

bloke "yeah...Aluminum panels create serious problems when damaged, as do the gimmicked-up engines (tons of early mileage failures - at least, according to the "Car Wizard" guy) which have (apparently?) ALSO been created as attempts to trick out mpg..."

[MiBrassFS]

.

[Tubajug]

Warning: I am not a professional repair person. I am a home hack who has collected some tools over the years to mess with my own instruments. The following is what I have and what I've used in my own home tuba repairs.

I don't have a dent puller like the ones used for cars, but I do have one that I made (I've also heard it called a "slide hammer"). It consists of a solid steel cylinder with a hole drilled through it for a piece of brass rod. The cylinder slides between two brass plates. I use low temp silver solder to solder the brass rod to the dent (usually the deep ones that magnets and balls can't get out). I usually have someone else (my lovely wife or one of my children) hold the puller in place while I do the soldering.

Once soldered, I quickly slide the cylinder up several times, striking the brass plate and slowly pulling the dent up. You have to be careful not to pull it up too far, otherwise you end up with dimples that point up. I used it to pull the dent up to where I can get it with my magnet and ball bearings. I used that procedure to remove this dent in a Martin Mammoth I had. It eventually breaks off as you pull up the dent, or you can unsolder it and reposition it. I did that several times to get the dent out.



This is a picture of it (zoomed in from a different photo):

[the elephant]

Yes, exactly, that is what we are talking about, except that this "system" attaches "pins" to the dent via a heated glue that is then removed with the pin, so that you can do this to a car without removing the paint. The slide hammer he sells is made to only connect to his plastic "pins" and there is a collection of various profiles and sizes of these "pins".

But a slide hammer is the basic tool for dent pulling. Mine is made from a destroyed Bach 24AW, and honestly is the best use for one of those mouthpieces I have ever seen, heh, heh…

Mine is 18" of .25" brass rod, hammered into a hook shape at one end and filed into a flat hook, with threads at the other end. The mouthpiece slips over that end and is "captured" via a large nut. The mouthpiece is "destroyed" from the corners of the nut "flats" mercilessly impacting the throat of the mouthpiece millions of times since I made it in 1995. It works as intended, thank you very much…

[MiBrassFS]

.

[the elephant]

By the way, that was nicely done, Jordan.

[bloke]

By the way, that was nicely done, Jordan.

...and I'm delighted it didn't crack, and that Jordan didn't have to pull out the silver solder.