Expanding Foam Sound Deadener (will it stick on my trunk lid?)

[nobb 10+ year member]

My main priority is to reduce road noise, so for that purpose, it seems foam is a good choice to use. I've deadened most parts of my car which I can get my hands on, and it seems now alot of road noise is coming in from the trunk (I drive a sedan). The floor of the trunk is already covered in two layers of carpet underlay, so my main priority is the kill the noise coming from the side panels and the top lid of the trunk.

So I am just wondering on your experiences with expanding foam. Is there a specific type that will work better for sound absorption? Will the stuff stick to bare metal such as on my trunk lid (and resist all the cycles of the trunk lid opening and closing)?

Other than the door panels, what other places could I use the expanding foam on for reducing road noise? Perhaps the dash maybe? My doors are already deadened, and there are two layers of heavy carpet underlay underneath my carpet.

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[DBDRAGGUY 10+ year member]

Carpet padding is not an effective automtive sound deadener.

 

[morgans432 10+ year member]

you didnt deaden anything so go back and deaden the right way

 

[SethPhillips 5,000+ posts]

My main priority is to reduce road noise, so for that purpose, it seems foam is a good choice to use. I've deadened most parts of my car which I can get my hands on, and it seems now alot of road noise is coming in from the trunk (I drive a sedan). The floor of the trunk is already covered in two layers of carpet underlay, so my main priority is the kill the noise coming from the side panels and the top lid of the trunk.
So I am just wondering on your experiences with expanding foam. Is there a specific type that will work better for sound absorption? Will the stuff stick to bare metal such as on my trunk lid (and resist all the cycles of the trunk lid opening and closing)?

Other than the door panels, what other places could I use the expanding foam on for reducing road noise?

ive used great stuff expanding foam..

cover anything and everything you dont want this shit to stick to.. yes it will stick to anything!!!! makes sure you cover every hole on ur trunk lid cause it will find a way to seeep out.. once you have squirted the foam into the trunk lid... let it dry.. it took my trunk lid over 2 month's to dry completely.. ( in the middle of winter)...

this stuff is very very sticky!!!!

 

[Savstyle 10+ year member]

I used some cheap stuff from home depot, it worked really good and expanded a sh!tload more than i expected. but it worked really well. Its messy as all hell but it was fun to watch the stuff expand. Also this stuff dryed in about 20 or so mins. Good stuff in my book just very very messy.

 

[bigbangtheory 5,000+ posts]

ive used great stuff expanding foam..cover anything and everything you dont want this shit to stick to.. yes it will stick to anything!!!! makes sure you cover every hole on ur trunk lid cause it will find a way to seeep out.. once you have squirted the foam into the trunk lid... let it dry.. it took my trunk lid over 2 month's to dry completely.. ( in the middle of winter)...

this stuff is very very sticky!!!!

Huh, it took 2 months to totally dry? I used it before and seemed to dry right away. Strange.

Also I would use a type of deadener to quit down the road noise.

 

[rumple4skin 10+ year member]

great stuff is what you want man, there is cheap knock offs but there all 1 buck cheaper a can...spend the exstra buck. and yes nothing is soundproof, the quality of the soundproofing materal is what matters, there is a reson some things are cheap as hell. i recomend takeing all the carpet padding out and replacing it with fatmat, raamat, dynamat if you want to go all out but i think fatmat is a varry resonable choice and stand up product. eather way man cartpet padding is not soundproofing. make sure not to use to much great stuff is exspands like crazy and on door and dash work will push the panaling out. have fun

 

[MikeyB 5,000+ posts]

Be careful with expanding foam in the trunk lid.....I had an experience once that caused the metal to bow all over the place once the shit expanded. It settled back down after a couple months though, but at first it looked horrendous, just an fyi

 

[nobb 10+ year member]

Thanks for the advice, I'll stop by Rona and see if they have Great Stuff. I also forgot to ask, how would I go about smoothing this stuff once sprayed around the trunk lid? I dont want it to look like some big expanding mess. Is it pliable so that I can just smooth it out with a piece of cardboard or something?

The existing carpet underlay was free and it seems to do a really good job at killing most of the road noise, so I dont see a need to go with some expensive aftermarket stuff. I'm only trying to kill the last bit of road noise, which is from my trunk and firewall area.

 

[Dingleberry 10+ year member]

Use that shyt sparingly, we overkilled my cousins altima with expanding foam. Not a pretty sight, bulging panels etc .. Use gloves if you're going to manipulate it.

 

[SPL Blazer 10+ year member]

The only way I can think of shaping it is with a thin saw blade, you can trim off the dry pieces you can get to. Make sure you don't go nuts with it either, cause like everyone said, it will expand a great deal and you could damage the trunk lid. And make sure you don't cover any holes that you'll need to get into later on, like holes for replacing lights and such.

Once you've applied some of this stuff you should try sound deadening the rest of the vehicle the right way, with real sound deadener. I picked up 100 sq feet of FatMat for around $100 and it works great. They have an Ebay store called "Noise-killers" that you can buy it from.

 

[SethPhillips 5,000+ posts]

Huh, it took 2 months to totally dry? I used it before and seemed to dry right away. Strange.
Also I would use a type of deadener to quit down the road noise.

i'm scratching my head too. it honestly took that long to dry... but that was like the inside of my trunk so im sure there was no air circulattion... but yea other car's i have done it dried within a few hours..

 

[mdillon 10+ year member]

be careful. over the years from heat and cold with the added vibration, it will break down and end up rattling inside the crossmembers