Help dynamat didn’t work

I have a chrysler 300c with 2 JL 10w6v2's in a sealed enlosure firing towards rear w/ 1 zapco 500/1 going to each.  Applied dynamat  extreme to entire trunk and it still rattles bad.  Should I apply another layer? 

I'll tell you what I was told by a car audio shop owner. He orders dynamat for people who want their whole car done in it. He reccomended not to buy it because it's costly and doesn't look great. He told me to go to lowe's/home depot and get a can of "great stuff"..I believe it was called. It will run you about $5 and its basically a foam insulation that plumbers often use. You spray it into all of the wholes and spaces in your trunk and in 24 hours it hardens and supposedly takes all of the rattel out. I would assume most of it anyway. It will get rock hard and any excess you can scrape off with a razor blade and spray paint over it if you feel necessary.

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Dave

Pioneer Premier DEH-P660
15" Kicker CVR
Profile AP1000M
It's Loud

Find out where the rattle is coming from and then apply accordingly.

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~The Rookie~
Rookie of the year that is...
Don't let the smoke out of your equiptment..it doesn't go back in.

don't do this! Please.Great stuff gets rock hard. Then you will play it and it will begin to break apart.Now you have a mess of powder in your trunk as well as a surface that has to be recleaned. Does the trunk rattle or is it the lights. If you applied enough mat to the trunk area then the next step is to get some rubber "O" rings and some foam rubber with self adhesive on it.Remove the tail lights.Put some mat(Hushmat is great) to these exposed areas. Then put some foam over that. This will stop the plastic and metal from vibrating against each other.Now where these screw in, place an O ring on both sides and tighten it up. You may never get all the vibration noise but this should eliminate a lot.

biker8018 wrote:

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don't do this! Please.Great stuff gets rock hard. Then you will play it and it will begin to break apart.Now you have a mess of powder in your trunk as well as a surface that has to be recleaned. Does the trunk rattle or is it the lights. If you applied enough mat to the trunk area then the next step is to get some rubber "O" rings and some foam rubber with self adhesive on it.Remove the tail lights.Put some mat(Hushmat is great) to these exposed areas. Then put some foam over that. This will stop the plastic and metal from vibrating against each other.Now where these screw in, place an O ring on both sides and tighten it up. You may never get all the vibration noise but this should eliminate a lot.

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I'm out of town right now but from what I remember it was mainly the trunk because I could put all my weight on it and get it to stop.  Good idea with the tail lights.  I'll have to listen to those.

From what i've heard great stuff works good. Never heard of it breaking off before. Id say its worth a try. Might save you $100.

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Dave

Pioneer Premier DEH-P660
15" Kicker CVR
Profile AP1000M
It's Loud

Is there anyway to adjust the hood latch? If you can adjust the latch to make a tighter close that could solve your problem.

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2004 Mazda 3s Hatchback
2- MTX 4500 8" subs powered by MTX 251D

maaudio1 wrote:

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Is there anyway to adjust the hood latch? If you can adjust the latch to make a tighter close that could solve your problem.

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i'll look into that.

foam rubber,o rings and a little hushmat $25-$30 1 hour time. It can't hurt to try this for that much

"don't do this! Please.Great stuff gets rock hard. Then you will play it and it will begin to break apart.Now you have a mess of powder in your trunk as well as a surface that has to be recleaned."

Wrong! Great Stuff a.k.a. Expanding Foam, does not break down as you suggest. It does not become "rock hard" either. It does work kind of good at stopping the metal/Plastic from resonating because it actually adhears to the surface and does not easily transmit vibrations.

Now, it is not a really good sound absorber either. The foam in "Great Stuff" is a closed cell material. For a material to be a good sound absorber it must have "open" cells it it. This allows places for the sound waves to cavitate and eventually "die-out"

Anyway, when using Great Stuff, only fill the area approximately 1/3 full because that stuff expands alot.

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Be careful with ANY spray on foam product.....THEY EXPAND. It would be ashamed to "create" a dent or bulge in your trunk lid or side panals......Ive seen it!!!

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What i do a lot of times when a truck rattles really bad. Move the trunk latck down 1/8th, to 1/4 inch. Just loosen the bolts and slide it down some and tighten it back, you will have to press down on your truck a little bit harder, but it will stop some of the rattling. Great Stuff works pretty good for some things too..but like the other guys previously said, use it sparingly....because it will expand and possibly mess something up.

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