Dynamat / sound deadener, or Line-X? - pros and cons?

Interior

  1. Triplegreen500

    Triplegreen500 Well-Known Member

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    I have the interior out of my new-to-me 70 Charger and will be getting one spot in the floor replaced due to rust (driver side, rear seat footwell). The rest of the floors are rock-solid with good factory paint on them. I see a lot of folks with the silver dynamat/noise mat on their floors and I'm considering it, but I'm curious - do they hold any condensation/moisture against the floorboards at all? Or do things stay dry and solid?

    I had an old '92 Jeep YJ Wrangler soft top years ago, and had the local shop Line-X the interior of that (it made a YUGE difference in noise, and that tub NEVER rusted!), and am actually considering having it done to the Charger (under the carpet, of course)...but if people are having good luck with the dynamat it would likely cost a lot less than the Line-X...

    The car is going to be garage kept (of course), but as we all know temperature changes make metal sweat and I don't want to cause a problem by adding the mat, if it traps moisture against the metal.

    Thoughts or experience?
     
  2. funknut

    funknut Well-Known Member

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    Dynamat is butyl rubber and non-porous, so it will not hold moisture, so you should be good there. If you're interested in heat barrier I would look at a closed-cell foam, they should not hold any moisture. I would avoid the 'bubble-wrap' type, they create lots of voids that can hold water. There are some products made from recycled blue jeans and stuff like that that are bad news for moisture.

    But, if the metal is painted and there is no water collecting in the car (leaks, etc.) I think you should be more than fine.
     
  3. Triplegreen500

    Triplegreen500 Well-Known Member

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    Yeah, I'd do the thick-textured gray stuff that you have to roll on, with the foil side that faces the carpet. Not concerned about heat, but the car has 2-chamber flowmasters on it (for now) and I'd like to quiet things down a bit in the cabin (good news is, I don't have to worry about any radio repairs!). I figure while the interior is out anyway...
     
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    • VitaMeVas

      VitaMeVas Well-Known Member

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      I bought this to do the interior of my Jeep JKU. I had a lot left over and now I’m doing my 68 Satellite. I have some surface rust under the carpet, so I’m degreasing, then cleaning with mineral spirits, then painting 2 coats of rust converter and finally the mat. I’ll let you know if it works. Yes....spray liner would be easier but this costs me nothing but time. I had all the stuff already. Also if I get rust from the underneath, I can pull it up to do welding/repairs.

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      • Triplegreen500

        Triplegreen500 Well-Known Member

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        I'd suggest a finish coat of some sort over the rust converter - like primer, you don't want to leave it bare because it can/will hold moisture. It can't tell the difference between moisture and paint...all it knows is, it's designed to hold on to it.
         
      • VitaMeVas

        VitaMeVas Well-Known Member

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        Good point. I’ll do that on the front part as I already did the rear. The front has some deep rust and areas to repair too.
         
      • ChargerST

        ChargerST Well-Known Member

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      • slepr1

        slepr1 Well-Known Member

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        I do the foil sound deadener to all my cars when I'm done with the interior. If the floor is in good solid shape and you cover it with this product it'll outlast your grand-kids children's kids.

        I don't limit myself to Dynamat...there are plenty of other similar cheaper brands out there. As long as its butyl rubber. I get mine on Amazon.
         
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        • Nevada dan

          Nevada dan Well-Known Member

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          I would shy away from any rubberized liner inside the vehicle if your trying to cover or lock in a rust issue your only making it worse in the long run because if you missed even one pinhole that rust will grow and travel under the coating because it cant dry out and you wont notice it until its really bad
           
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          • OH71RRunner

            OH71RRunner FBBO Gold Member FBBO Gold Member

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            When I was doing car audio installs, we would use Peel & Seal for sound deadening. It is like Dynomat but a lot cheaper.
             
          • Master Gunner

            Master Gunner FBBO Gold Member FBBO Gold Member

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            Lizard skin works well if you've got the interior out.
             
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            • Kern Dog

              Kern Dog FBBO Gold Member FBBO Gold Member

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              FBBO member Darius used Lizzard Skin...I think they spell it with two Zs anyway.
              Drawbacks? Removal may not be so easy if you ever need to do so. I used "Fat Mat-Rattle Trap" for my '70 Charger. I had to peel some up recently to do some floor modifications for the 5 speed swap I'm doing and I expected the sheets to be a bear to remove. They were a lot easier to pull up than I thought.
               
              Last edited: Feb 8, 2021
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              • Kern Dog

                Kern Dog FBBO Gold Member FBBO Gold Member

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                • CoronetDarter

                  CoronetDarter Well-Known Member

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                  I used the same Rattle Trap as Greg. Installed it on the floors, C pillars, roof, and inside the doors. It definitely helps muffle some of exhaust noise.
                   
                • moparedtn

                  moparedtn Ed on the Ridge FBBO Gold Member

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                  For the love of all things holy, do not use Line-X inside a Mopar...
                   
                • VitaMeVas

                  VitaMeVas Well-Known Member

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                  Same stuff I’m using!! Thought it would be good to remove later if I need to do any tranny tunnel mods, etc... I’m almost done.... but I’m being pretty meticulous.
                   
                  Last edited: Feb 8, 2021
                • Kern Dog

                  Kern Dog FBBO Gold Member FBBO Gold Member

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                  Yeah?
                  I guess that cold weather made removal easier....like picking up dried dog turds instead of fresh ones.
                  The warmer it gets, the softer and more gooey I expected the sound deadener to be.
                   
                • uk-maxie

                  uk-maxie Well-Known Member

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                  Maybe a bit late to the discussion but I just wanted to add...
                  We (brother and I) considered whether to use Dynamat or similar a few years ago when redoing our Sport Satellite's interior. We decided against it solely because we had noticed that in our 63 Polara, which has a transparent rubber mat that goes across the trans tunnel into both front footwells, after parking up, the heat that comes up thru the floor and carpet, leads to condensation under the rubber mat (visible cos it's transparent).
                  We were just a bit worried that if the dynamat wasnt completely sealed against the floor, there would be a gap for condensation to form and therefore, as has already been said, could lead to rust that wouldnt be found until it's too late...

                  just my 2c :thumbsup:
                   
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