3M rubberized undercoating/sound deadener

[Klutch9]

Has anyone used it on their car? 3M makes three very similar aerosol cans of this stuff, the only difference being size of the can, surface smoothness of the final product, and drying time. It's a rubberized spray that is meant to prevent rust, but also supposedly (says on the can) that it deadens sound as well. Has anyone used this stuff? My car doesn't have any sound deadening on the bottom of the hood, or trunk, or anywhere really

and I'm thinking that maybe this stuff could work well to absorb a little bit of the sound. One of the cans actually says "for use underneath hoods" on it, but I was wondering exactly how effective it was. Anyone used it?

Here's a link of the biggest can they have of this stuff http://solutions.3m.com/wps/portal/3M/en...TglM992B0Z9G7bl

 

[urrlord]

I used it as a rust proofing and sound deadener in my 4wd sidekick.I sprayed inside door shells and body panels.It cut the road noise down a good bit.

 

[Klutch9]

Thanks for the input. I was thinking of putting it under the hood, in the trunk, and on the front wheel-well panels. How many coats did you apply, and how many cans did it take to get decent coverage?

 

[mechtech2]

The more you use, the more sound deadening there will be.
A couple of light coats is sufficient for rust concerns.

If you use it under the hood, keep an eye on it because of engine/exhaust heat. It may melt or crack.

 

[urrlord]

I did the door shells ,sprayed some into the fender openings in the door jambs.Sprayed into the body tub thru speaker openings ,tail light openings and tail gate.I'd spray a coating into one side then the other.Wait a while for it to dry and then spray another coating.I also cleaned the wheel wells and put a good coating on each one.
I did not get 100% coverage but I did get a good bit and I got a quieter ride for a few bucks and some time.Well worth it IMO.
Its been a few years but I think I used 4-6 cans.

 

[Vikas]

Does it harden up and eventually allows water to sip in underneath? If so, then it is worse than not doing it because water gets trapped which otherwise would not have trapped.

 

[Klutch9]

So I ended up buying some of this stuff last night. Not the 3M brand, but the Duplicolor brand, which was about $3 cheaper per can. It contains 28% asphalt by volume, so it does stink, but a half day later I can already tell a big difference in smell. I figure that within a week the smell should be gone.

Anyway, I stripped out all of the panels and sound proofing in my trunk, coated everywhere (used 2 cans, and barely had enough for 1 coat). I let it dry, then put everything back in. I'm not sure I notice a difference while driving, but giving the panels a little knock does reveal a difference in sound. I'll report back after I drive the car some more.

 

[GMBoy]

Originally Posted By: Vikas
Does it harden up and eventually allows water to sip in underneath? If so, then it is worse than not doing it because water gets trapped which otherwise would not have trapped.


Yep. I had completeley sprayed my Jeep CJ7 body floor with the stuff only to have rusted floor boards years later.

 

[rslifkin]

From using some of the stuff on the door panel of the Jeep tailgate (1 can of 3M, and I added a can of the Duplicolor stuff recently), it's a bit stinky at first. However, even in hot weather, once it's fully cured, there's no odor from it.

 

[Vikas]

Originally Posted By: GMBoy
Originally Posted By: Vikas
Does it harden up and eventually allows water to sip in underneath? If so, then it is worse than not doing it because water gets trapped which otherwise would not have trapped.


Yep. I had completeley sprayed my Jeep CJ7 body floor with the stuff only to have rusted floor boards years later.


Scientifically, only real galvanic protection (e.g. Audi) or oil based one (e.g. Canadian companies) would work.