PU Resin for Layer Damping?

[Tenson]

It's that XenCast stuff I was planning to use. PX90.

I might just wrap a layer of butyl rubber around the inner core (I know that damps well) and then fill the gap with polyester resin like car fiberglass repair stuff to constrain it.

[Kchink]

Not trying to put you off, I'm intrigued to see the final test results.

Just warning you, that standard polyester resin may attack the butyl. I may be wrong about that but the styrene (solvent) in polyester can be pretty aggressive. Epoxy or polyester infusion resin (less styrene content) I know are safe. I use butyl rubber to seal a vacuum bag prior to infusion, to make composite part's.

In fact I could test friendliness of butyl - polyester next time I'm in the workshop if your interested?