Liquid/spray noise insulation -?-

[Lubb]

I need some noise insulation for the case I am doing. Because of the spaces I have to work with, the typical foam kits won't work, they're too thick. I only have room for maybe 1/16" to 1/8" for the noise insulation. Anybody tried using auto underbody coating or clear silicone sealant? I'm considering any rubberized substance I know of that will adhere to metal well, and that's about all I can think of (well there's other types of caulks, but none of the common types that I have yet seen were specifically for noise-absorbtion....). The fans and HD"s in the box will have sorbothane mount pads, but I don't got enough sorbothane to cover the whole box....
-?-

[BrianE]

Something that thin would be something self-adhesive and bitumen-based like Dynamat/Brown Bread or the often suggested cheaper roof patching/flashing tape. These and undercoating might smell for a while though...

The only thing is, these are really only good at mass damping things by making them heavier and aren't really known for actually absorbing sound the way foams can. That's why stuff like Dynamat is described as a sound deadener/damper rather than absorber.

I guess you can always experiment with thin sheets of craft foam. You can find the stuff in dollar stores for cheap, although I don't know how well it'd work.

[mathias]

Mutemat is very compressible, check the thread on that.

[Lubb]

The Mutemat is 19mm thick, about 16mm too much. I need something that thin when applied.
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Also I tend to agree with some points in this thread:
http://forums.silentpcreview.com/viewto ... ht=mutemat
....that the sound-deadener is really controlling most of the noise heard outside of the case. If all sound-absorption is basically mass dampening, then it makes sense to skip bothering with the low-mass foams and lay on a thicker layer of higher-mass rubber material. What I'm thinking is spray underbody inside, and use thicker silicone on the outside. My case is a case inside a case! So I can apply different materials to inside+outside of inner case, and not worry about second layer damaging the first.
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What I looked around for was a local source of neoprene rubber sheet, but I could not find one other than the local scuba shops, and I can't afford to cut up a wetsuit. What I'd think would be best would be a spray-on rubber flexible coating that sprays or applies solid or nearly-solid (80-90%), and then on top of that a layer of the same rubber but foamed maybe 40-50% with gas, say each layer maybe 1/16" or 1/8" thick....
~

[Sooty]

Performix PlastiDip - spray on rubber coating "insulates vibration, heat, and deadens sound":
http://forums.silentpcreview.com/viewtopic.php?t=9680
http://forums.silentpcreview.com/viewtopic.php?t=10084

There's also been talk on SPCR of people using 'roofing felt', a relatively thin ashfelty type material.

[Lubb]

-I went and just tried doing the inside with undercoating.
----Good news is the undercoating is holding onto the aluiminum very well....

----Bad news is that it doesn't seem to spray real thick, which is kinda good news because it smells really badly. It's not totally dry yet, but still. It's supposed to cure in an hour and two hours later it's still not done in some of the spots where 1/8" collected. I'll give it a day, try hitting it with a heat gun tomorrow if it's still smelling bad. And then burn it out if so I guess, with a propane or welding torch. Shoulda gone with the silicone inside/out, it cures totally clean....

[Tom Brown]

You might consider going to a shop that applies spray on truck bed liner. They can apply that stuff as thin or thick as you wish and it's rubbery, textured, and known to deaden sound.

[matthewla]

I am new to this forum, but have to deal with sound issues in my home as I am a singer/songwriter. Aualex makes some very good products to handle sound absorption/deadening. I was wondering if anyone in the forum has had experience with their SonoFiber Panels or Mineral Fiber Insulation?

http://www.auralex.com/sound_absorption ... ofiber.asp

http://www.auralex.com/sound_isolation_ ... on_mfi.asp

Regards,
Matthew

[WayneSherman]

The Mutemat is 19mm thick, about 16mm too much. I need something that thin when applied.

Another idea here:
http://www.7volts.com/quieter.htm

This site recommends the following:

"Where thick carpet padding isn't used because it is too thick, you can use thin rubber (very cheap rubber "welcome" mat). I found some mats for $1 each at the "Dollar Tree"."

[BrianE]

-I went and just tried doing the inside with undercoating.
----Good news is the undercoating is holding onto the aluiminum very well....

----Bad news is that it doesn't seem to spray real thick, which is kinda good news because it smells really badly. It's not totally dry yet, but still. It's supposed to cure in an hour and two hours later it's still not done in some of the spots where 1/8" collected. I'll give it a day, try hitting it with a heat gun tomorrow if it's still smelling bad. And then burn it out if so I guess, with a propane or welding torch. Shoulda gone with the silicone inside/out, it cures totally clean....

Shoot, I forgot to tell you about that... For the spray can undercoating stuff, it's always thin and it takes a lot of coats to build up. I don't know if the smell is going to go away any time soon but if you really want to give it shot I'd suggest leaving it in the sun for several days. Low odor probably isn't a high priority with this stuff. I wouldn't try to force dry it with a heat gun because that stuff is basically tar/bitumen and/or rubber (if rubberized) and you might just end up melting or burning it.

If you want sheets of rubber, look for "roofing rubber" in hardware or roofing supply stores, or neoprene sheets if you look for shower pan liners (not sure that's what they're called). The former is sold by the foot or roll, and the latter comes in one large sheet (so you can line the bottom of a shower stall).

[Lubb]

.....that stuff is basically tar/bitumen and/or rubber (if rubberized) and you might just end up melting or burning it.....

-Yea, I bought the 3M stuff, it says it's rubberized but it appears to contain a large percentage of tar. This must be the reason they don't use it on the inside of the cars.... I was going to buy some paint solvent (aluminum-safe gel) but may just dab a bit of some old bad gasoline I have on it and see what happens. The undercoating is gonna have to come off, it's crap.
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What's odd to me here is how it applied; on the flat portions I tried to cover, it applied very thin--but on the edges I sprayed, it built up into a thick glob.

[Bluefront]

That stuff is used inside cars for insulation/sound deadening. The reason you don't smell it is because it's coated with another non-smelly coating.

Left outside for a few days, the smell slowly goes away....completely.

It will dissolve using gasoline....outside, be careful.

I have/do use "roofer's tape".......virtually no smell at all. It has an aluminum coating. It's heavy and very easy to work with.

[Lubb]

I managed to strip most of the undercoating off, it was a mess. It still smelled several days later, and I doubt it would have appreciably dampened much of anything--it was simply way too thin.
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I used clear silicone to cover the box again, got most of it done but can't do it all at once. The silicone is much-closer to what I wanted--it spreads easily but comes out of the tube thick enough that you can apply it to vertical surfaces (it doesn't run or slump if you spread it). It has problems curing completely if you use it thicker than maybe a quarter-inch, but that's the only problem. And it doesn't cost much if you get the caulk-tubes, maybe $4 a tube. I used four tubes and will be needing at least one more. As for mass-loading, the box I applied it to weighs about twice what it did before, and the stuff doesn't change in weight that much as it cures.
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Another thing that's nice about the silicone is that it can be peeled off of (flat) metal in one piece, if you have to. The undercoating is like regular thick [smelly] paint, it won't do that. It's gotta be stripped.
~

[halcyon]

I've tried those and they serve one purpose: increase the mass and structural rigidity of the sheets of metal they are applied to, in order to reduce vibration borne noises and their transfer.

They do not absorb noise from air-borne noise sources and as such are a poor fix for noisy components.

They cannot break the basic laws of physics.

One has to have a damping mat thickness of c. 1/4 of the wavelength of the frequency one tries to damp, before it has significant effect.

Thin surfaces will not help for air-borne noise absorption.

[Lubb]

...Thin surfaces will not help for air-borne noise absorption....

-Yes but in this use they don't need to. What I am trying is a case that has one metal box inside of another. The internal box is rubber coated and contains the hard-drives and fans (all mounted on sorbothane), the fans are located near the mid-point of the airflow path through that box and the airflow must make four 90-degree turns to pass through the box. If it's noisy inside that inner box I don't care. It's really noisy inside your car's muffler. Do you care?
...I could use conventional direct-absorbing materials in the case if I need to, but I am expecting that won't be necessary or even of very much benefit. As it happens both exterior side-panels are the same size, so one will have to be loaded with ballast just to make sure it doesn't resonate with the other. I am leaning heavily towards just using silicone to glue channels on the inside of both side panels, use two channels for one side and three for the other.
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[pony-tail]

Automotive sound damping spray decreases the resonance of the panels and does a little to help stop noise escaping , but not a lot ,so depending on the cause of the problem , it may be of benifit or may not . Upside is it will not add to a noise problem . Its irregular surface may help break up sound waves but not to any extent I could notice .
I tried this early in my silencing attempts and it made some overall improvement but it was not great (noticeable none the less) but to do it I stripped the case and drilled out all the pop rivets and painted it inside and out so it was a lot of work for the result gained . Just doing the doors would be futile.

[mutemat]

You could always try our product. More information can be found on out website - http://www.mutemat.co.uk - or see this SPCR thread - http://forums.silentpcreview.com/viewtopic.php?t=21198

The sound absorbing material we use is more effective than acoustic foams and is highly compressible.

The standard MuteMat material is 19mm thick and the kit weighs about 0.3Kg. For the Plus kit we add a 1.5mm High Density barrier layer which is designed to help stop the case from vibrating and also act as an acoustic barrier and the combined thickness is about 21.5mm, this kit weighs about 1.8Kg
The 19mm thick MuteMat layer has a non-woven, micro-fibre structure which makes it VERY compressible. This enables it to be fitted more easily to the case and so it can be applied to narrow areas of the case where 19mm would not fit. The barrier layer in the plus kit is high density, and will not compress.

If you need any more information please contact us.

[~El~Jefe~]

hey thats cool that they just came on hre and gave a link