foam for controlling airflow?

kentc · Post by **kentc** » Thu Mar 09, 2006 12:06 pm

ok, still about the case i'm planning:
i'm thinking of using damping foam for controlling the airflow inside the case. figured it'll have double uses then. plastic/paper/metallic devices would just steer the airflow, not help out.
question is though, is it really a good idea or will the foam hamper airflow too much?

reagrds, kent.

Trunks · Post by **Trunks** » Thu Mar 09, 2006 12:16 pm

The prefab kits use foam to direct airflow.

It makes sense to use foam to reduce cavity noise, and baffle direct noise transmission.
It is worth a shot. I guess it really depends on specifically what you are doing.
But high end foam is way more expensive than say, metal or plastic.

teejay · Post by **teejay** » Thu Mar 09, 2006 12:24 pm

My theoretical 2 cents: foam has more friction at its surface than smooth cardboard, plastic etc. For low-airflow situations and/or narrow ducts this might become an issue, where the foam restricts air flowing through more than a smooth surface would. Therefore I tend to use a combination: a smooth surface that the airflow "hits" first, backed up with foam to dampen the noise. OTOH, my first PSU duct was made out of very rigid plastic (from air conduit parts that are used in ventilation systems) and it made one hell of a natural amplifier... so too rigid is not good either.

But then again, I might simply be totally off...

Oh, and I've never spent a lot on dampening stuff: I have a left-over roll of floor vinyl (~3x3 meters) + roofers tape for mass dampening and lots of eggcrate foam from server packaging at work for the higher frequencies.

Post by **MikeC** » Thu Mar 09, 2006 1:33 pm

Use closed-cell foam; it will work fine. I've done it lotsa times.

kentc · Post by **kentc** » Thu Mar 09, 2006 2:25 pm

teejay wrote:My theoretical 2 cents: foam has more friction at its surface than smooth cardboard, plastic etc. For low-airflow situations and/or narrow ducts this might become an issue, where the foam restricts air flowing through more than a smooth surface would. Therefore I tend to use a combination: a smooth surface that the airflow "hits" first, backed up with foam to

my fears exctly... but your ideas on a two-compound combined with mikec's, a thin-ish layer of closed cell foam to direct the air (will still "scatter" it a bit though) and then the good stuff behind that.

teejay wrote: dampen the noise. OTOH, my first PSU duct was made out of very rigid plastic (from air conduit parts that are used in ventilation systems) and it made one hell of a natural amplifier... so too rigid is not good either.

good point! i hadn't even thought of that. so i guess if i should use for example plastic i should cover the back of it in some sort of vinyl or foam to kill off vibration then?

thanks you guys, if my case is a success i owe it to spcr bigtime!