Almost free acoustic foam.

bigdaddyd · Post by **bigdaddyd** » Tue Sep 14, 2004 10:47 pm

Guess what I came acrosssed? I was at one of my wholesalers and I spied a stack of charcoal colored foam sheets, about 2" thick in the main body, about 3 1/2" thick in the peak of the little egg carton looking pointy dealeys. (i forgot the technical description) This stuff looks just like the typical acoustic foam sheets that you can buy for $45 for like one or two, and they throw it away by the boxfulls. I told them Ill buy it for $1 a sheet for beer or pizza money and the agreed. Its packing material, they unpack and throw it away.

Does any one have any input on whether or not a packing foam that resembles acoustic foam is structurly adequate to control noise, or is acoustic foam made different so that collecting and installing the packing foam will be a waste of my time?

thanx

d

bigdaddyd · Post by **bigdaddyd** » Tue Sep 14, 2004 10:53 pm

looks just like this-

http://www.uline.com/Browse_Listing_863.asp

Consul · Post by **Consul** » Wed Sep 15, 2004 12:27 am

Acoustic foam is open-cell polyurethane foam, if I recall correctly. If this packing foam is the same stuff, then it may be usable. Note the emphasis on "may"...

Foam By Mail carries open-cell foam for a reasonable price:

http://www.foambymail.com/soundproofing.html

rawtunes · Post by **rawtunes** » Wed Sep 15, 2004 5:03 am

....in searching out suppliers for a purchase of acoustic foam last year I learned that it has a density rating....usually "2 pound Ester"...if that's the case with this packing foam I'd say you've probably got a pretty good deal there...I came across a similar situation at an electronics store but they were unwilling to part with it as they used it for returns...

knightfly · Post by **knightfly** » Wed Sep 15, 2004 4:36 pm

Packing foam is unlikely to be fire retardant in any way - if you value your safety, you would need to spray it with a fire retardant spray, which would put its cost probably equal to the foam by mail stuff, which IS claimed to be fire retardant -

Also, foam doesn't work as well as rigid fiberglass or rockwool for most things - less lower mid absorption for same thickness. If you use this, besides finding a fireproof spray

http://www.natfire.com/

you should mount it with the "pyramid" side toward the wall - it will work slightly better due to increased average depth of material... Steve

bigdaddyd · Post by **bigdaddyd** » Wed Sep 15, 2004 9:51 pm

Good to know, good to know...

That stuff made specifically for acoustics is just so dang expensive. And I have a lot of area to cover. Considering that fire that great white had, and if I remember correctly there was a foam insulation of some type on the ceiling that ignited. I am very safety minded.... I'd hade to cheap out and create a fire hazard.

thanx for the input

I may just bite the bullet and order up a few boxes of the gold....... CHIKCHING!

D

Shaz · Post by **Shaz** » Thu Sep 16, 2004 2:24 am

Hmmm .... I wonder if the foam available at foambymail.com really works ... They call it sound proofing foam

I have problems with dealers that mislead people into buying stuff

knightfly · Post by **knightfly** » Thu Sep 16, 2004 3:45 am

I know what you mean - that comment makes me cringe too.

Short of "free", (which usually ISN'T) one of the lighter density rockwool products is probably your best bang for buck - works better than foam, is intrinsically fire proof, doesn't rot, only needs a cloth cover unless you WANT to build frames, can be hung by using "impaling clips" and construction adhesive, works better than foam, works better than foam, works better than foam...

Did I mention that it works better than foam??!?

Steve

AVare · Post by **AVare** » Thu Sep 16, 2004 4:47 am

Short of "free", (which usually ISN'T) one of the lighter density rockwool products is probably your best bang for buck

Total agreement. I would write more, but there is nothin more to say. Steve said it all.

Andre

bigdaddyd · Post by **bigdaddyd** » Thu Sep 16, 2004 10:37 pm

Every once in a while someone asks about something like rockwool and next pops up a link with the product. Beuller,... Beuller,... Beuller..

I'll buzz around the net a bit to see what rock wool is and looks like. My framing is up and I will wire it soon, so sheet rock paint and finishing arent to far away. If I plan on using rock wool, Id like a mental picture to think about.

g

lovecow · Post by **lovecow** » Thu Sep 16, 2004 11:57 pm

Foam, "Rockwool," whatever...

Seriously, just thought I'd let folks know that you can order Mineral Fiber (same stuff as "Rockwool") in 2" or 4" thick 2'x4' sheets from any Auralex dealer. Ours is 8 lb/ft³ density. Absorption coefficients are on our Master Table (PDF download). Price is probably not "almost free," but we try and keep it competitive.

knightfly · Post by **knightfly** » Fri Sep 17, 2004 6:13 am

Sorry Jeff, that foam comment wasn't aimed at you

8 PCF - have you done any comparisons on ACTUAL room effects vs lighter weights to see what effect the higher weight/density has on grazing incidence at mid/high frequencies? Or are you using a specific cloth covering that helps that some? Curious minds (read T-W-I-S-T-E-D) want to know, an' all that -

BTW, I can top your avatar for "ugly" without even resorting to a passport photo, but John would get pissed if I scared off ALL our members

Ethan Winer · Post by **Ethan Winer** » Fri Sep 17, 2004 6:35 am

Steve,

> I can top your avatar for "ugly" <

Hey, that's "Milton" (Stephen Root) from Office Space - one of my all-time favorite movies!

--Ethan

lovecow · Post by **lovecow** » Fri Sep 17, 2004 6:38 am

Steve,

No worries: Didn't take any offense.

Reason why Auralex carries 8 lb/ft³ Mineral Fiber: Because it's the best for improving isolation. This increase versus standard "pink" batt insulation is marginal, but oftentimes situations requiring maximum isolation need all the help they can get!

As for its absorptive properties, I have no more information than what you can readily find in our Master Table (above) and through other manufacturers' data sheets.

I have tested fabric-wrapped 705 for grazing incidence absorption and it does go down. (By how much varies with frequency. E.g., at 2 kHz, it drops 40% or so.)

I have not tested Mineral Fiber in the same configuration, with or without fabric. I have a hunch that, either way, it would measure about the same as the fabric-wrapped 705.

Finally, no particular fabric in mind. We are a GoM distributor, so we tend to stick to their more common styles.

Does that help?

knightfly · Post by **knightfly** » Fri Sep 17, 2004 6:52 am

Yeah, thanks - I'm a bit curious on the "improves isolation" comment though - is this for in-wall use, or as a gobo? And at what frequencies? Steve