sprayable alternatives to CO703, Roxul

[thadman]

Are there alternatives to Corning Owens 703/ Roxul RHT40/ etc that provide comparable absorption coefficients for a given thickness but can be applied through spraying?

I've seen laborers apply fiberglass insulation through a spraying technique to coat walls in homes. I'm interested in using this technique to impregnate an acoustically transparent honey comb structure with the aforementioned fiberglass.

[avare]

There was one spray on insulation I investigated for someone either here or on another forum. The was too light to have any desirable properties. But there may something out there, but I am not aware of it.

Why spray? Would something like USG Acoustic Plaster be appropriate?

Andre

[edit] I found the thread I was refering to. It is here.

[thadman]

The cells of the honeycomb are ~>1/8" across, too little for me to physically insert the material into the structure. However, spraying fibers into the structure shouldn't be too difficult.

[thadman]

Whats the industrial definition for the type of fiberglass provided by Corning Owens and Roxul? I'll take it up with the some of my engineering buddies and find a suitable alternative.

[avare]

Originally Posted by thadman

Whats the industrial definition for the type of fiberglass provided by Corning Owens and Roxul? I'll take it up with the some of my engineering buddies and find a suitable alternative.

they can not be described by company. In general terms OC 703 is 3lb/ft^3 glass fiber insulation and the equivalent Roxul product is 4 lb/ft^3 mineral fiber insulation.

What about the USG acoustic plaster? You ignored that in your last two posts. It seems it is just about perfect for application.

Andre

[thadman]

Regarding the USG Acoustic Plaster, there isn't much information on the web correlating its performance with objective data. I'll have to give them a call.

As for other alternatives, are there open cell foams that possess comparable absorption coefficients for a given depth?

[avare]

Originally Posted by thadman

Regarding the USG Acoustic Plaster, there isn't much information on the web correlating its performance with objective data. I'll have to give them a call.

As for other alternatives, are there open cell foams that possess comparable absorption coefficients for a given depth?

Please post the results of the phone call. I recall seeing absorption data for Acoustic Plaster on the web several years ago, but I can not find it now.

It is difficult to answer your second question because the short answer is yes. However all home/in site spray type open cell foams that I know of are of the self skinning kind, so unless you remove the skin, the sound absorption is negligible.

Are any of the products from International Cellulose Corporation useful?

Andre

[Disjointed]

the spray on fiberglass you are talking about is supposed to attain a higher density then the normal fluffy stuff, but i dont imagine it to be as dense as 703...

spray on cellulose seems to be a great option for sound absorption (though i havent seen any test results, or actually tried it) - it attains a density lighter than the roxul rockboard i have used before, but its uber eco friendly..

the problem is... you say these honeycombs are 1/8" ..... i dont believe either of these products would spray into them... they would both coat the top... fiberglass uses long strands of fiber, and cellulose uses shredded paper (around 1/8" and bigger - you can still read some words every once in awhile)

even a spray on foam would coagulate near the top of the honeycomb and not actually fill it (though it might when it expands)

id say cover it with something (rockwool or 703)

gl

[avare]

I was doing some surfing on the web and found the absorption co-efficients for USG Acousitcal Plaster on page 6 in P 720.

It is reproduced here as well as possible without tabs:

Sound Absorption (ASTM C423 Test Procedure):
Mounting Per
ASTM E795 Nominal
Concrete Thickness 125 250 500 1000 2000 4000 NCR
A 1/4 in. 0.01 0.09 0.15 0.35 0.71 0.85 0.35
A 1/2 in. 0.02 0.16 0.37 0.75 0.85 0.79 0.55
A 1 in. 0.04 0.22 0.60 1.01 1.07 1.00 0.75
Gypsum Panels
D90 1/4 in. 0.35 0.20 0.15 0.40 0.63 0.67 0.35
D90 1/2 in. 0.55 0.20 0.28 0.65 0.88 0.86 0.50

Andre