Working with Sound Deadeners....

[FoxPro5 5,000+ posts]

Moral of the story: If you are working with this stuff in the heat, put it in the frig first to cool it off ! //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

You laugh, but it's actually a wise thing to do. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

So, RAAMmat is sort of gooey at room temp (70*) but then gets increasingly more gooey (more viscous) as the ambient temperature increases. Car doors can get up to like 125*F, and depending on where you live, can obviously dip well below zero. Keep in mind that damping performance (viscoelasticity) from a constrained layer damping mat like RAAM is dependent on temperature.

A great analogy would be chewing gum: at room temp, it's sort of stiff but still maliable, when you put it in your mouth and heat it up, it becomes soft and more elastic. Take warm gum out of your mouth and put it in the freezer and it's hard as rock. It's form and function changes with temperature and mechanical action.

Like chewing gum, deadening products must be able to be liquid-like and return to shape as whatever they are stuck to vibrates. If they fail to do this, they fail to deaden. If you take a bunch of sand which is exactly equivalent to the weight of the deadener you're working with and tape it down in a way so that none spills off, do you really think it will kill the vibrations???? This is the fallacy that gets spread around; sound deadening is nothing more than mass loading.

If you look at the testing done on these products, you'll always see an inverted parabolic curve. Damping performance is on the vertical axis, temperature is on the horizontal. Typically, the peak damping you see is right around 70*F. Higher quality deadeners maintain higher damping figures over a broader temperature range. Lower quality suffer in the cold as well as the very hot. Unless you live in San Diego, then chances are you need to spend some money on some deadener that works fairly well aways.

Here's the damping specs for Dynamat Extreme. If you plot the numbers as I've desribed you can see it's damp-ablity vs temperature much better, but still you get a good idea looking at the data - the damping is just as bad at 14* F as it is at 140* F:

Acoustic Loss Factor @ Temperature (Using ASTM method E756@ 200 Hz):

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0.081 @ +14F (-10C)

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0.240 @ +32F (+0C)

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0.257 @ +50F (+10C)

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0.417 @ +68F (+20C)

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0.259 @ +86F (+30C)

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0.194 @ +104F (+40C)

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0.140 @ +122F (+50C)

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0.094 @ +140F (+60C)

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Temperature Range (Optimal performance):

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14°F to+140°F (-10°C to +60°C)

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The point is if you have a gooey product to begin with, how well do you think it's going to do it's job when it gets hot? And how many times can it get hot before the viscoelastic nature (deadening) gets so broken down that it's just foil and goo stuck to your car? Ever had a piece of gum loose all it's elasticity and just sort of turn to paste in your mouth? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Does anyone here like the idea of going back and replacing your deadening products?

 

[mannyahles 10+ year member]

Dynamat is the most convenient deadening product out there due to the fact that most Best Buys and Circuit citys and a lot of local shops carry it..... FOR A PRICE>>>A BIG PRICE!

 

[mannyahles 10+ year member]

Raamat never got so gooey that it was losing form or anything. Its just that when you cut it to size/shape when it was hot outside is really messed up and clogged the industrial scissors I was using. I had to clean them off alot. However, when it was 60 outside, my scissors did not clog very much in comparison.

 

[FoxPro5 5,000+ posts]

Raamat never got so gooey that it was losing form or anything. Its just that when you cut it to size/shape when it was hot outside is really messed up and clogged the industrial scissors I was using. I had to clean them off alot. However, when it was 60 outside, my scissors did not clog very much in comparison.

Butyl is a form of rubber. It's the same thing that they use on some speaker surrounds. The black stuff that's stuck to that foil is a synthetic bultylene composite.

Which forms of rubber have you come across in your life that are gooey? (unless you heated it to very high temperatures never seen in a car.)

 

[mannyahles 10+ year member]

Butyl is a form of rubber. It's the same thing that they use on some speaker surrounds. The black stuff that's stuck to that foil is a synthetic bultylene composite.
Which forms of rubber have you come across in your life that are gooey? (unless you heated it to very high temperatures never seen in a car.)

Tire rubber on a race track's asphalt.

Gooey was not a very good adjective to use. I should of phrased it differently.

Cutting the Raamat in cooler weather I had less butylene composite sticking to the scissors.

 

[FoxPro5 5,000+ posts]

Tire rubber on a race track's asphalt.

//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif