Official Luthiers Forum!

Howdy all.
Just recieved three truss rods today, and observed that they have a heavy shrink wrap on them covering the full length. Should I not remove it and just use a couple dabs of RTV to keep them from rattling? Seems to me that the wrap would really "put the damper" on the neck.
On the other hand, the wrap looks like it`s meant to be there.
Coe

_________________
Give me 50 cents worth of regular.
Check my oil too, if you don`t mind,,,

Leave it on, works fine. Prevents any glue from ever getting between the rods. It's not like the truss rod is a magical tone machine or anything...

[QUOTE=Cocephus] Howdy all.
Just recieved three truss rods today, and observed that they have a heavy shrink wrap on them covering the full length. Should I not remove it and just use a couple dabs of RTV to keep them from rattling? Seems to me that the wrap would really "put the damper" on the neck.
On the other hand, the wrap looks like it`s meant to be there.
Coe[/QUOTE]
I don't think you have to worry about the shrink wrap damping the guitar.

There are three things you need (you need ALL of them) to add significant damping to a structure. I used to teach a short course in structural damping ( how to ADD damping to structures) , and this is how I usually started:

1. The damping material has to deform a lot when the structure vibrates in the mode you want to damp.

2. The damping material has to be stiff enough so that it takes a lot of energy to deform it.

3. The material has to be "lossy" so that when you put energy into ( see #2 above) it doesn't give all of the energy back - it turns it into heat.   Most materials are not very lossy. Think bubble gum.


The shrink wrap on the truss rod doesn't meet ANY of the above criteria.

1. It doesn't deform a lot when the neck bends, since it's close to the center of the neck. Also, the neck is pretty stiff to begin with, so it doesn't deform much, anyway - especially compared to the top, where most of the vibrational motion and energy is.

2. The shrink wrap is not very stiff. Even if you did somehow deform it a lot, it wouldn't take much force or energy to do it.

3. It isn't a particularly lossy material.


So, I wouldn't worry about it. You may be more likely to end up with a "buzzy" rod if you take it off.


On the other hand, if you cut off the shrink wrap, flattened it out, and glued it to the top (which deforms a lot) , you might be able to notice a change to the sound of the guitar caused by increased damping. But, my guess is that, even then, it would be hard to hear the differenc.

Phil

Good points, guys. I was taken back a little when I took a look at them for the first time.
Thanks, Coe

_________________
Give me 50 cents worth of regular.
Check my oil too, if you don`t mind,,,