Sound proofing / deadening

[Thor]

Yes, mass also helps, but the concept of two relatively stiff sheets sandwiching a softer layer does create good damping, so do try it because it is a really easy thing to do. You have to use a product with a good tough outer foil layer, not some cheapo stuff. The materials used by builders should be tough, being left outside for years in use, but the stiffness of that layer is what makes the product work in sound deadening situations.

I know the tank of my 409 is steel.

Thor.