Rubber selection input

[MuEagle05]

I'm making an external box (pics to come when it's done) and I want to put a sheet of rubber between the box on the top of my case to prevent vibration. I also need to something to line the inside of the box with for noise isolation/vibration damping.

I've browsed McMaster, and I've found a number of products that would work. I need 3/8" thick whatever. I'm not sure what hardness to get though. Extra soft(chewing gum), soft (rubber band), med. soft (pencil eraser), med. hard (car tire). The material I'm not sure about. There's a TON, thanks McMaster. I think Neoprene foam rubber is the best bet. Any input on the hardness though? The box it'll be under won't weigh more than liek 5 lbs.

[A-Speck]

I'd go with this: Part Number 8647K45. It's soft, but durable, won't absorb moisture from leaks, and won't break the bank. You might want to check your local Home Depot or Lowe's before you order, though. Sometimes they have similar stuff for much better prices.

[Korndog]

packaging rubber foam or the stuff u find in seat padding is simliar and sometimes free, i would rather go with that.

[Sean Lindstrom]

Four rubber pads will work too.

The best dampening (assuming you're securing this to the case) would be with springs - the bolts pass through the springs and be sure to use nylon lock nuts.

EDIT: Some gyms use flooring made of large interlocking rubber sheets. They're recycled from car tire, I suspect, and exactly 3/8" thick. I've got one flopping around in my workshop and haven't a clue what to use it for. So if you're ever in Vancouver...

Similar flooring products are available at Home Depot, and of course you're not only paying prices you can walk on but also you can see it up close before purchase. "Anti-fatigue flooring" or "play mats" it's sometimes called.