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This is my first foray into casting. Forgive the question if its basic.

I would like to cast an object to act as a vibration damper. The initial positive would be 3d printed using something like Polymaker Polycast. It looks like the silicon rubber that is normally used to make molds would be a good option as the casting material.

Is there a particular material that is a better acoustic/vibration insulator?

Thanks!

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Dampening is actually more complicated than what you're asking. It isn't simply a matter of using a material that dampens vibration. It's a function of the frequency you want to dampen. You will dampen some frequencies, but amplify others, and can get resonance that's more problematic than having no damper at all. If the dampers will be supporting weight, you also need to consider things like how the compression will affect it.

There's actually some physics involved in designing dampening to do what you want. If you don't have access to a physicist or engineer who deals with this stuff, your best approach would be to play with different materials, sizes, etc., to see what works best for your application. Another option would be to use commercially available dampers that have been designed for your application and that users have said works well.

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  • That is a valid point. When working with something like mass loaded vinyl you can get access to the manufacturers rated response curves. However is there a resource for material frequency response curves for pourable rubber and silicone? There are acoustic rated rubbers and foams ready made for these purposes, however this does not fit the use case. In my cursory searching, Acoustic materials are not advertised. I am specifically looking to dampen multiple 21.6 Htz sources. Sep 5, 2019 at 20:55
  • @Simianspaceman, probably? I'm not familiar with what manufacturer data is out there.
    – fixer1234
    Sep 5, 2019 at 21:29
  • High frequencies are easy to dampen. 21.6 Hz will be a challenge. You might need mechanical isolation rather than dampening.
    – fixer1234
    Sep 5, 2019 at 22:25
  • Yes, that's a low enough frequency to be tricky. A lightly inflated bike inner tube with a heavy plate (e.g. stone) on top is an old trick that might work. Mass is important at low frequency; you may get away with mass on one side of the cast rubber, but then the rubber shouldn't be too stiff
    – Chris H
    Sep 6, 2019 at 7:52

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