Looking for some conversation about sound deadening, dampening. I've done my own car with generic asphault sheeting and jute, and enjoyed the results, wondering if I can strike up any opinions...

Here's some info for the generic stuff I used vs. Fatmaat (which is indicitave of any asphault based sheeting)...

Grace Ice and water Guard
108 sq. ft = 66$ (for me a while back w/tax) picked up
Roll Length 11.0 m (36 ft)
Roll Width 914 mm (36 in.)
Roll Size 10.4 m2 (108 ft2)
Roll Weight 15.3 kg (33.6 lbs)
Thickness, Membrane 1.02 mm (40 mil)

Fatmat
100 sq. ft = 100$ plus shipping, with shipping = $129.98
Shipping Weight 31 Pounds
Installation Weight 23 Pounds
Thickness 45 Mil

That's $0.61 a square foot for the 40mil grace ice and water guard
That's $1.29 a square foot for the 45mil Fatmat

Difference? 5mil but that 5mil might be because Fatmat has an aluminum backing... Grace ice and water guard has a plastic one... Which one would you rather have? If somebody wants to do the calculations to compensate for the 5mil difference, be my guest, but 5mil is not 5mm 5 mil is like a piece of paper... and the grace ice and water guard weighs more anyways, and that's what you're trying to achieve, weight on the doors... in addition to also pinning plastic pieces down and joining undamped metal parts.


Data taken from:
http://www.na.graceconstructio...did=8
http://www.na.graceconstructio...J.pdf

and

http://www.fatmat.com/fatpaks/100.htm


I would have loved to find some compressed fiberglass sheeting that I could have used for my interior, but couldn't come up with any good cheap sources... I used to work in a home theater company, and they used compressed fiberglass in the 3-5 lbs/sq foot range and that stuff was fabulous... I have some 1 lb/sq ft 2" duct board around my apartment and that does wonder for high frequency baffling...

 

 

somebody asked where you can get it. You can get it at any roofing supply store. I got mine in Maryland near DC off River road at a place called the roofing center... 66$ was for a 3 feet by 33 feet roll. That is more than enough to do 2 cars, or 1 car double or triple in most places.

The Jute cost like 20-30$ for quite a bit, to cover all my doors and floor and rear seats and trunk and back panels.

over all <100$ and I'd bet it's the quietest EP3 out there... But I dunno, not heard of too many people doing this sort of thing unless they're going 1,000$ all out open cell foam, heavy as concrete type insulation... for half the cost, I personally believe you get better sound deadening/dampening than somebody who spends 1,000$ foolishly on professional acoustical treatments and uses them incorrectly... (which IMO most people do)

 

So I guess DYNAMAT sucks? I need some sound deadining soon and all I am familiar with is Dynamat.

 

Here's the two keys to stopping sound:

Sound Dampening: If you wanna stop the boom boom, add weight.

Sound Deadening: If you wanna stop hearing clinking of the rocks add something "soft"

The way I remember it, you "dampen" a cymbol, like you're "touching it"... but if you were to put your ear up to jute/cloth(soft things) your ear feels dead because you don't hear any sound bouncing off of cloth... hence "deadening" = soft high frequencies. You Dampen "to soften" something metal (cymbol) ...

hard things transmit noise, soft things slow it...

Dynamat, Fatmaat, raamat, etc.... are all just asphault/tar sheeting. Originally it was used as a roofing water sealant, some day mr. Dynamat came along and knew how to sound deaden (add weight), and marketed it and put a ridiculous price tag on something very cheap... The only purpose for asphault is simply adding weight, in home speaker building they use lead sheeting even sometimes, and ever noticed why speakers are so heavy? So part of the way to sound deaden is to weigh down pieces that are isolated vibrationally (read sheet metal)...

So your panels are no longer vibrating/resonating, but most of the noise you're hearing is much higher in pitch, rocks banging off the bottom of the car, tires etc... Anything soft like cloth works well... In some more expensive theatre's I've help build they use fabric covered compressed fiberglass. The idea is that any high frequency sounds don't come from reflecting walls, but from the speakers only once. If you stand with your ear a few inches off one of those fiberglass walls, it sounds as if you're deaf in one ear, the magic properties of fiberglass. Anyways, a cheap solution to adding something flexible and cheap to sound deaden in your car is jute. Jute is just cheap carpet padding, greyish fiberous stuff made out of all kinds of scrap fabric materials.

There is also Dynamat extreme and I think the grace counterpart is butyl something, just sticky vinyl instead of asphault. Now that stuff will not be as effective as the asphault sheeting for dampening, since it doesn't weigh as much, but it will have a slight deadening effect, since adding anything between you and a noise will deaden it some, but in this case not much. Cascade has a number of products which include open cell foam which works similarly to fiberglass/cloth, in there are alot of air spaces (like heating insulation, air is a good isolator). Look at the price tag of any of these cascade products and you'll flip... Not saying their stuff isn't good, but if you are spending that kind of money on sound deadening, better make sure you know what you're doing with it... from all I know cascade provides good instructions, i.e. Cascade IV on floor, Cascade 3 on doors... where as dynamat seems to imply that you can use asphault or vinyl sheeting any where and get the same effects... the effect is you feel good about it...

 

you know, I think at home depot they have a small roll of asphault sheeting now, it's not called grace company ice and water guard, but same material. it's with the roofing stuff, and I believe it is yellow and black or yellow and green roll, like 12" wide by 3-4" diameter??? it should look like a giant black tar fruit roll up... you can try that and see how it works, like it don't like it, you're only out like 5$. If you want ALOT, you can get the grace ice and water guard cheap... but that's just a test, might be enough for a trunk. Looked at the home depot website, but it didn't have any real roofing products, just smelly candles and chandeliers...

You can get like 10 square feet rolls at home depot... it may be 5-10$ if you want to just try it. If you want the dynamat original type stuff it's like 60-70$ for 108 square feet... I once heard there was only one factory where this asphault sheeting stuff is made, just different people put their names on it and call it theirs.

shyboy817 (7:29 AM 10/19/2004): oh, i can get 10 square ft rolls of 'grace ice and water guard' at home depot for 5-10 dollars? very nice..and it's in roofing section? i'll give it a shot...
Ocelaris (7:30 AM 10/19/2004): it's not called grace company, ice and water guard at home depot, it's called something else... but I don't know what, tell them you want asphault roofing sealant... or a black tar fruit roll up and see what they give you :-)

 

Where did you get the JUTE? Did you put extra into your si?

 

you can get jute at home depot, it's cheap. i put alot in everywhere and it helped a great deal..