State of the Union on Soundproofing

[cicada]

I've been researching soundproofing in between wiping off old layers of melted bitumen from the floor pan of my SL. I'll be happy to be rid of all the stuff. Still one section left, barely visible, on the top right where the glove box is supposed to be. That one will be a tough removal! A technique I figured out is to use a very stiff brush head on a vacuum, spray down the melted foam or whatever with your choice of solvent, and scrub it off. That kept the paint looking nice. And yet, it's tiring working under a dash.

Anyway, since Sound Deadener Showdown isn't around anymore, I found some discussions about this company called ResoNix which actually backs up its product with testing. It seems to be moderately more effective than DynaMat, and it is certainly cheaper. It seems to be highly regarded by the audiophiles on Reddit, for what it's worth. Testing done here: https://resonixsoundsolutions.com/independent-testing-data/ Their product seems to work identically to SDS's material, which always was top-notch.

Some old discussions I've found speak highly of materials that use a lead layer. That must have been nice to use since it seems one could put that on a transmission column without adhesives, its weight would keep it down. However, this seems pretty tough to find nowadays, and most threads referencing it on assorted car forums are from 10+ years ago.

I'll likely proceed with this ResoNix stuff. Their reference information section has also been extremely useful and forthcoming. Will report on results whenever I get it done.

 

[bmw2800cs]

I've been researching soundproofing in between wiping off old layers of melted bitumen from the floor pan of my SL. I'll be happy to be rid of all the stuff. Still one section left, barely visible, on the top right where the glove box is supposed to be. That one will be a tough removal! A technique I figured out is to use a very stiff brush head on a vacuum, spray down the melted foam or whatever with your choice of solvent, and scrub it off. That kept the paint looking nice. And yet, it's tiring working under a dash.

Anyway, since Sound Deadener Showdown isn't around anymore, I found some discussions about this company called ResoNix which actually backs up its product with testing. It seems to be moderately more effective than DynaMat, and it is certainly cheaper. It seems to be highly regarded by the audiophiles on Reddit, for what it's worth. Testing done here: https://resonixsoundsolutions.com/independent-testing-data/ Their product seems to work identically to SDS's material, which always was top-notch.

Some old discussions I've found speak highly of materials that use a lead layer. That must have been nice to use since it seems one could put that on a transmission column without adhesives, its weight would keep it down. However, this seems pretty tough to find nowadays, and most threads referencing it on assorted car forums are from 10+ years ago.

I'll likely proceed with this ResoNix stuff. Their reference information section has also been extremely useful and forthcoming. Will report on results whenever I get it done.

There has been some success on our forum using Dry Ice to remove all that stuff:

Dry ice works

One hour. All sound deadening material gets hard and brittle and cracks right off.

e9coupe.com

 

[cicada]

There has been some success on our forum using Dry Ice to remove all that stuff:

Dry ice works

One hour. All sound deadening material gets hard and brittle and cracks right off.

e9coupe.com

Oh yes! I used dry ice to get the bulk of it off. Sadly, everything that was left required lots of solvents, scrubbing, and chiselling.

 

[jefflit]

Interesting. I'd like to know what resonix weighs (i.e. per SF or whatever). Dampening is often a function of thickness/weight. I'm assuming these are all just butyl rubber mats? Then there's the heat barrier aspect as well. Most people who install Dynamat or the like are doing so for both sound and heat barrier effects. What are the thermal properties on resonix?

 

[stphers]

Look at Lizard skin as well It is a spray which I find much easier to apply and able to get into places that it is so hard to put something in like dyna mat They make both a sound deadener and a heat barrier material as well. I used it on a 2002ti that I have done, works quite well

Thanks, Rick

 

[cicada]

Interesting. I'd like to know what resonix weighs (i.e. per SF or whatever). Dampening is often a function of thickness/weight. I'm assuming these are all just butyl rubber mats? Then there's the heat barrier aspect as well. Most people who install Dynamat or the like are doing so for both sound and heat barrier effects. What are the thermal properties on resonix?

The CLD squares (butyl rubber) weigh 1lb per sq ft. Dynamat Xtreme weighs 0.45lbs per foot. The weight from the ResoNix material is clearly from it being almost twice as thick -- Dynamat Xtreme is 67 mils vs ResoNix at 106 mils. The sound stuff doesn't really have any true heat reducing properties. An r-value isn't even listed on the spec sheet, and some YouTube torch/heat gun tests indicate it doesn't reduce heat transfer whatsoever. Dynaliner, however, is claimed to be their best heat insulator, and also "the best single-layer heat insulator". It is available in three thicknesses -- 0.125", 0.25", 0.5". They give the following for each thickness:

0.125: 0.42ºF * ft²* hr/Btu (0.07K * m² * hr/W)
0.25: 0.83ºF * ft² * hr/Btu (0.15K * m² * hr/W)
0.5: 1.7ºF * ft² * hr/Btu (0.3K * m² * hr/W)

Lizardskin has an r-value closer to 3, according to people's best guesses on the internet. Lizardskin themselves refuses to give an r-value in their FAQ. I looked into that product since I did think it was promising. I know plenty of hot rodders use it. I think it is less effective than Dynamat for noise and next to useless for heat, unless one was to paint the exterior of their vehicle with it. The EPA does not recommend it.

I think there are lots of scams in this world. Lots of hand-waving and woo-woo.

Edit: After some more research, it seems the foam layers in Dynapad are a flexible closed-cell polyurethane foam, which has an r-value of around 6.5 per cubic inch. The thermal conductivity of such a foam is 0.042 W/m*K. That gives me the thermal resistance outputs claimed in the r-value formula above. I was only able to arrive at their numbers by using a low density foam vs a high density foam. I suppose the low density allows for flexibility.

The ResoNix Fiber Mat, which they advertise as having good thermal resistance, has a total r-value given as 7.15. I'd hope so, since it is 45mm thick, or about 1.77". It's r-value per inch should be about 4. An equivalent 45mm layer of the polyurethane foam in Dynapad would be around 6, whereas the r-value of an inch would be about 3.4. Unlike Dynapad, a fibrous material like the ResoNix mat can be compressed. However, I have no doubt that would have an effect on the r-value, as air is an insulation itself.

Another idea is melamine foam. However, the stuff isn't so flexible. Some places carry that, including ResoNix. It has an r-value of 4.16 per inch. Their "Guardian" material is 1.375" thick. 0.125" is MLV and the remaining 1.25" is melamine. So that's 5.2 + 0.55 for a total of about 5.75. If reduced down to an inch, the r-value would be 4.18. Probably a superior material for noise, but it seems the fiber mats are better for heat. What would be critical is understanding how compression (like inside of a door) might effect the r-value of the fiber. However, that isn't so important for many vehicles, since there is a cavity in there that won't compress material.