I'm trying to do a little research before buying sound deadening products.
Second Skin does not tell exactly what its Overkill product is, but I'm assuming it's some type of closed-cell foam, as described here.
But Don has not replied to my email(s), and i'm not sure I want to commit $35+ yet just for "foam"
So I did some research, and price hunting, and found a site with good prices and wide variety: Closed Cell Foam, Padding, Minicel, Polystyrene Foam, Styrofoam Sheet
So now I'm wondering which of those products would work best for killing rattles/squeaks while also being durable and impervious to moisture/mildew.
From looks/description, I'd probably go with the neoprene. However, the technical name of the "gymnastic rubber" is Polyvinyl Chloride Nitrile Butadiene Rubber, which sounds like it could be what Don from SoundDeadenerShowdown (link above) uses for his CCF. Also, the site claims that the Volara is "good for sound deadening" but i've felt it before (I work in a poker room) and I'm not sure if it would be good for the application or not.
Second Skin Overkill Pro (3/8" thick): $29.99 for 9 square feet
SoundDeadenederShowdown CCF (2/8" thick): $27.65 for 13.5 square feet
Parts Express Foam (2/8" thick): $21.20 for 9 square feet
FoamFactory Gym Rubber (3/8" thick): $14.99 for 16 square feet (details here)
FoamFactory Neoprene (3/8" thick): $22.99 for 13.3 square feet (details here)
FoamFactory Volara (3/8" thick): $20.98 for 10 square feet (details here)