Good way to dampen tonearm?


I am in the process of replacing the stock Klotz wiring harness in my Rega RB-900 with the single-piece "Incognito" wiring harness. I have been thinking about adding some damping material inside the tonearm tube, and considered trying a couple of shots of expanding insulation foam.

I'd appreciate comments about the wisdom (or lack thereof) of the foam treatment idea. I am concerned that the chemicals in the expanding foam might be bad for the dielectric on the very thin Litz wire inside the tonearm tube.

If anyone has any ideas, or personal experience, with ways to dampen arm tubes, I'd appreciate getting your commentary.
sdcampbell
Why not dampen it with something from the outside instead of the inside? I remember a local audio dealer that did this with a Well Tempered table (not sure of the arm). He had it wrapped just as you would re-wrap a tennis grip. It was a rubbery material maybe 3 millimeters wide. I'm not sure what it was exactly, but this is certainly an idea to explore. Good luck!
I successfully dampened (wrapped)a tonearm using tiny foam wrap tape that was either from the dental or medical industry. Internally, the foam earplugs seem to be a good shot.
Oh yeah, I forgot to mention I experimented with various shrinkwrapping on the arm also. It is good as it is easily removed.
Some shrink tubing has glue on the inside that is activated by the heat. If you try that make sure you get the kind without glue. It would also be hard to cut off without scratching the arm.
So anyone hears improvement after damping the arms with Teflon tapes or shrink tubing? I know it varies with arm/cartridge, but want to get some statistic from experienced listeners.

It's common for speaker manufactures to damp their drivers, same goes for circuit designers in amplification. Why don't we see more arm tubes with damping materials coming from factories? I have owned SME, Graham, and VPI, none of them have damping on the arm tube. Is it because it's not critical and job of arm tube is to hang the cartridge in place while it reads off the LP? Otherwise, I will expect someone to build an arm from wood or some carbon matrix.

Someone please enlightens me.