adding sound deadener

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Apr 8, 2015
Messages
521
Reaction score
66
Location
Upstate NY
My Car
71 Mach 1, 351c 4v, C6 trans, grabber blue with white interior
Since the seats and quarter panels are out of the car I wanted to add in some sound deadener padding to the floors and sides. In the body cavity between the side of the car and the quarter panels the PO has stuffed in some foam rubber type stuff. I'm assuming for some sort of sound deadener.

I see in the assembly manual the addition of sound absorber to the floors, doors, roof etc.. but I didnt see any thing to indicate putting something in that body cavity so what, if anything, typically goes in there?

 
Are you trying to stay stock, or don't care and just want it to make it quiet ?
Not necessarily trying to stay original especially since I'm sure that the foam in there is just something stuffed in.

Just wanting to add sound absorber since the interior is all taken apart and now would be a good time. I'm thinking of a product would be a sheet that is stuck down as opposed to spraying a coating. Just not familiar with whats available and works the best.

thanks!

 
Last edited by a moderator:
Are you trying to stay stock, or don't care and just want it to make it quiet ?
Not necessarily trying to stay original especially since I'm sure that the foam in there is just something stuffed in.

Just wanting to add sound absorber since the interior is all taken apart and now would be a good time. I'm thinking of a product would be a sheet that is stuck down as opposed to spraying a coating. Just not familiar with whats available and works the best.

thanks!
https://www.homedepot.com/p/E-O-12-in-x-15-ft-Self-Stick-Foam-Foil-Duct-Insulation-FV516/100028603

 
Are you trying to stay stock, or don't care and just want it to make it quiet ?
Not necessarily trying to stay original especially since I'm sure that the foam in there is just something stuffed in.

Just wanting to add sound absorber since the interior is all taken apart and now would be a good time. I'm thinking of a product would be a sheet that is stuck down as opposed to spraying a coating. Just not familiar with whats available and works the best.

thanks!
From my research (not an expert, but read alot) things like foam do nothing really to deaden sound because it does not absorb the vibrations. and it  passes right thru it. The metal in cars vibrates with the sound and can actually increase it. What you need to do is stop this from happening. That is why Dynamat is used. It adds mass to the metal so that it cannot vibrate as freely. Same with the lizard skin, which you spread on like thick paint.

I spread 5 gallons of lizardskin in my trunk and back seat area. Then added a 3 part foam plastic sheet. This stuff comes with an adhesive backing that works best if adhered to the metal, but I didn't do that because nothing was flat enough. See my trunk thread.

https://www.7173mustangs.com/thread-the-trunk

In the passenger area I used poor mans Dynamat. It is roofing material from Lowes, easy to work with and cheap. I found it while researching and stumbled into a Corvette forum. It is also aluminum backed and helps with heat transfer from the exhaust. BUT, it is never coming off, so if that is important to you forget it.

https://www.lowes.com/pd/Peel-Seal-Instant-Waterproof-Repairs-6-in-x-25-ft-Aluminum-Roll-Flashing/1018733

I put it everywhere, I don't have pics of the doors for some reason, but I reached thru the holes in the door to apply it to the entire inside outer panel. I then entirely covered the interior panels. it is amazing as to how much better the doors sound when closing them. No ringing, it is like a dull thud like a new car.

Almost all of the road noise is gone.  If I  could get rid of the roof and window noise I'd be in heaven. It is not bad until about 50 MPH and grows after that.  

P6090018.jpg


P6090017.jpg


P6090016.jpg


P6060013.jpg


 
Last edited by a moderator:
I am wondering if Dynamat can be applied to the area under the seat platforms since mine are out of the car because of floor replacements! I also think I saw a Custom Kit from Dynamat for 71-71 Convertibles, the kit is not cheap...300 bucks! :chin:

 
I would avoid or be careful with isolation/sound stuffs, especially foam in the "in between" body regions. There is already lack of ventilation and plenty surface for water to condense. Water would then stay longer trapped in there...

 
I am wondering if Dynamat can be applied to the area under the seat platforms since mine are out of the car because of floor replacements! I also think I saw a Custom Kit from Dynamat for 71-71 Convertibles, the kit is not cheap...300 bucks! :chin:
Thats true, Dynamat isnt cheap but it does get good reviews. Peel and Seal is an alternative thats mentioned here and other places but the trouble with that is that it is asphalt based. Supposedly this can get sticky and give off an asphalt smell. Since its meant for roof repairs, you would think it would be able to stand up to heat without lifting off.

Dynamat is butyl rubber based which doesnt do this.

Now, how much external temp is required to cause that, I dont know. Maybe someone in Arizona or Florida would have issues but not Northern states?? Maybe all negative posts related to Peel and Seal are Dynamat sales people that want car owners to buy their more expensive product??

 
Well my guess is you will have LOTS of options (as shown by those that go this way)

Here is what I found in my boss and tried not to change

from how Ford did it in 1971.

Mark

PS I don't drive, listen to music or "plan Bluetooth" either (just historical restoration for the next guy)





 
The duct tape on the watershield is factory? I thought they used the strip calk stuff.
Black caulk is on the back.

Mark

P.S.  I choose to reuse the 45 year old black tape.   The width is the same under the "rocker cardboard" for the sill plates (covering the wire)

 
I used some stuff called Raamat - much cheaper than Dynomat (because it doesn't have logos printed everywhere that you'll never see again ;) ) - which is still not as inexpensive as the Home Depot stuff.  http://www.rammat.com

In addition to the covering the inside panel, cut some strips (about 2"x6") and stick to the inside of the quarter panels to dispel the tinny vibrations from the panels themselves.

As for the seat platforms, just install them as normal, then cover with the mat material as if they were part of the floor pan itself.  The small area underneath the seat platforms isn't large enough to be concerned with much (if any) vibration at all (since the platform welds isolate those small areas from any larger area vibrations).

Just remember to locate and poke holes through the mat material for anything that needs to be mounted before putting carpet, pads, etc., back in, otherwise you'll have a lot more fun trying to figure out where the holes are supposed to be through the carpet AND sound deadening material.  (ask me how I figured that one out ;) )

And for the record: 7000th post!  Woo-hoo!  :whistling:

 
Back
Top