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Dynamat ?---or what interior insulation??

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Allen,

Sound deadening comes from two distinctly different arenas. One is the prevention of transmission, the other is the absorption of transmission.

Generically, asphalt sheetings work on the prevention theory. They dampen the motion of the sheet metal they are attached to, preventing it from acting as a drum head. This is why oem applications of the asphalt sheets seems so sloppy and haphazard. It doesn't need to be very precise, or cover the whole panel. A blob sitting in center area works just fine.

Absorption of sound is what the jute padding under the carpet does. Ever notice how it looks rather similar to the accoustical tiles you remember in the band room of high school? Anything with convoluted passages will effectively capture sound waves. This is very different than asphalt patches! Open cell foams do a very good job of absorbing sound waves.

Thermal insulation is different from accoustical insulation and absorption. Though some overlap does exist. Foam makes a decent thermal insulator because of the multiple cells of air. It's hard for the heat to travel from one cell to the other, so it doesn't. Closed cells work much better thermally than open cells do. But, make the material thicker, and open cells work pretty well also. Aluminum and other shiny panels work by reflecting the heat, but beware of the drum head like properties you can encounter from this.

So in a nutshell, the asphalt patches work to prevent large panels from acting like drum heads and booming. Large pieces of soft faced materials absorb the soundwaves already traveling in the air. And multiple layers of small air pockets provides good thermal insulation.
 
Ed - what got you to decide to use that particular product?

Tom
 
Good question. Price, feedback from others that had purchased the product (all were very positive, and somewhat from the sales pitch. I figured with that many sales and positive feedback that it was worth the shot. The material seems tough and will hold up well in my opinion. The foil is well reinforced and reasonably heavy duty. I think it will prove to be a huge help with heat.
 

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On my Spit the previous owner had applied Dynamat liberally. In hindsight I wish it wasn't installed, it can hide any interior rust that might be starting.

Its almost impossible to remove once installed. I called the tech support line, they didnt have any good ideas for removal. They only said if its that hard to remove, its unlikely water would traped and rust would start.

I think its good for the tunnel, but personally would not install it on a metal floor surface.
 
Joe - I've never used Dynamat. Is there a reason to "glue" it in place? Wouldn't just cutting it to fit under the carpeting accomplish the same thing?

I used that Home Depot Reflectix. Cut it to fit under the carpet. Stays in place, easy to remove, no water accumulations worries.

Only place I glued it was onto the bottom surface of the bonnet.

Tom
 
you don't glue it, it comes pre sticky so it mates to the surface for sound dampening, not absorption like what your reflectix does, if i'm thinking of the right product.

dynamat and most products like it are a layer of thick, rubbery, heavy material with a sticky side and a foil side. you peal the paper and stick it to the panel and the weight and squish damp the noise while the foil does a little heat reflection.

foam/insulation/etc on the otherhand usually isn't glued and just absorbs the noise created.

it was explained better above, but dynamat, fatmat, peel-and-stick, raamat, etc. are all dampeners and all stick to your surface. think of tightly squeezing a tuning fork to quiet it and barely touching it witha finger, that is the difference in adhesion. with the same tuning fork, placing a pillow over it just absorbs the noise already created by the vibrating panel, like foam products.
 
I use R-BLOX extreme sound deadener and Quality Heat Insulation p/n 25070. The R-BLOX is in a 18 inch x 33 foot roll = to 50 sq ft. Last price for a roll was 189.00 US.
R-blox is just like Dynamat.


Conan
 
NutmegCT said:
Joe - I've never used Dynamat. Is there a reason to "glue" it in place? Wouldn't just cutting it to fit under the carpeting accomplish the same thing?

I used that Home Depot Reflectix. Cut it to fit under the carpet. Stays in place, easy to remove, no water accumulations worries.

Only place I glued it was onto the bottom surface of the bonnet.

Tom
Click to expand...
as said above it comes peal and stick. Im sure its a great product, but for how I use the Spit, I would have never bought and installed it. What wrong with a little noise. ?
 
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