budget soundproofing

One of my clients works for NASA designing the heat shield material, like on the former shuttles. After the explosion on re-entry several years ago, we talked about the heat shield. I asked what it is held in place with, and she said silicone adhesive, nothing too fancy or exotic. Is seems to me that a silicone adhesive would probably work to hold sound deadening material in place on the inner skin of a vehicle if it works on a space vehicle like the X-37b. Of course, the adhesive on the space vehicles is on the COOL side, not the hot side...but what would the max temp be on a van? 300 degrees Fahrenheit?

hulagun said:

Maybe I am using the term MLV incorrectly. Isn't it describing the dense vinyl or butyl rubber sheet product that is sold under names like Dynamat?

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Mass Loaded Vinyl is much different from Dynamat and its competitors. MLV is more like those vinyl tile squares you see on commercial floors. That stuff is actually called "Vinyl Composition Tile" It's loaded with silica for wear reasons and weighs about the same as MLV per square foot.

MLV is very similar to VCT, except the MLV material is far more flexible, more like linoleum flooring.

Dynamat has virtually no mass compared to MLV. Its stated job is to damp vibration, not block it. My tests with Dynamat showed it to be largely ineffective compared to what I wound up with. It also cost several times as much per square foot.

We sell Thinsulate but I am not an expert on noise barriers. I need to do more reading so please excuse my limited understanding.

I am under the impression that Thinsulate can take the place of both MLV and panel damping (Dynamat). It's much thicker (~2") so rather than absorb sound energy directly, the sound gets lost in the unique layered structure of the material. I have read that the frequency range of a sound absorber is directly related to its thickness. The barrier becomes less effective if the wave length is longer than the thickness of the material. Thinsulate is not a cheap material. But if it can eliminate the need for MLV and reduce the amount of Dynamat needed (20% panel coverage is actually quite effective) then the overall cost is reduced.

hulagun said:

Maybe I am using the term MLV incorrectly. Isn't it describing the dense vinyl or butyl rubber sheet product that is sold under names like Dynamat? These are made to be used in motor vehicle builds and some versions are designed for high heat overhead applications. If you can't imagine why someone might modify a van or vehicle firewall or roof for improved acoustics or quiet then you don't get out much.

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Seriously - what benefit would you get blocking noise from the roof?? I've never heard enormous amount of extra noise when driving in a convertible? If there was a great need to block sound from above, surely driving with no roof would highlight that? And aren't vehicle firewalls somewhere between horizontal to vertical? That's a lot different to an inverted, upside-down application.

And what glasseye said about MLV. To make sure everyone is on the same page, here is sound deadening 101. In the order that you would install in the vehicle:

CLD: Constrained Layer Damper. Self adhesive material that is installed directly on vehicle panels. This is all your products like Dynamat, Second Skin, etc. These are relatively lightweight (~.35lb/sq ft) aluminum foil backed product. The purpose of CLD is to reduce vibration of the vehicle panels, ~25% coverage is effective.

CCF: Closed Cell Foam. The foam is used as a decoupling layer to stop objects from conducting vibration, that's all. No good at blocking or absorbing sound.

MLV: Mass Loaded Vinyl. This is the material that actually blocks sound, which is simply a function of the mass of the product (1lb/sq ft). Lead sheet is also very effective. This is where you want 100% coverage to effectively block the most sound. Generally anything below the glassline is going to be sealed in MLV, any gaps in the MLV should be sealed by overlapping a strip of MLV and fixing with contact cement. Anything from the windows up isn't really worth it since glass is always going to be the weak link, and there's not much noise coming from above anyway.

Absorbing material: This could be Thinsulate or similar (Thinsulate seems to be pretty darn good tho). This can be used to fill any voids, under the headliner etc. Since it's lightweight it's a good to use on the roof. Thinsulate is an excellent decoupler as well as thermal insulator. It will help with external noise as well as absorb reflected sound from inside.

I don't know about Thinsulate replacing MLV and CLD materials, would be good though as it would save a lot of time on the install.

What I hate is you can sound insulate your van 3" thick (joking) and when you pop your roof vent open it catches the sound waves like a big ear and sends them down into the van. Im such a light sleeper I need to run a fan or something or I wake up to anything out there.

mugget said:

Seriously - what benefit would you get blocking noise from the roof?? I've never heard enormous amount of extra noise when driving in a convertible? If there was a great need to block sound from above, surely driving with no roof would highlight that?

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Your point is well taken for normal driving conditions.

However, many of us here use our vehicles for camping and, much though we try to avoid them, we do occasionally find ourselves in crowded campgrounds with inconsiderate neighbors. We are more concerned about shutting out the noise of televisions, those damned generators (yes even the supposedly "quiet" ones which are only quiet because their owners can't hear them over the sound from their televisions), drunken campfire revelers, and Diesel pickup trucks that always seem to pull into camp at 1am with their 4-inch diameter "free-flow" mufflers. Hence the concern for blocking sound from the roof and upper walls.
Brent

I just ordered this stuff: ESP Low-E SSR Reflective Foam Core Insulation on Ebay
Its the same exact stuff as EZ-cool, made by the same mfg, except it costs less.

glasseye said:

Mass Loaded Vinyl is much different from Dynamat and its competitors. MLV is more like those vinyl tile squares you see on commercial floors. That stuff is actually called "Vinyl Composition Tile" It's loaded with silica for wear reasons and weighs about the same as MLV per square foot.

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All right. I've got a couple cases of that Vinyl Composition Tile that I bought but never ended up using for a playroom floor. Is this something I can glue to the floor of my Sprinter as a sound barrier? It's not flexible at all but the floor is flat and I would put the plastic/vinyl passenger floor covering back over it.

Type2Teach said:

All right. I've got a couple cases of that Vinyl Composition Tile that I bought but never ended up using for a playroom floor. Is this something I can glue to the floor of my Sprinter as a sound barrier? It's not flexible at all but the floor is flat and I would put the plastic/vinyl passenger floor covering back over it.

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Almost. It will have to be decoupled on both sides in order to work.
I made a sandwich from the foil faced 1/2 denim, 075lb MLV , and another layer of denim in the cab and firewall only.

For the first few miles i felt deaf. Then I noticed how weird is to hear the engine from the back.
Then I got used to it and it is back to what it was before.

mojogoat said:

I just ordered this stuff: ESP Low-E SSR Reflective Foam Core Insulation on Ebay
Its the same exact stuff as EZ-cool, made by the same mfg, except it costs less.

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Mojo how did this product work for you, and how much did you need?