has anyone tried just putting home fiberglass insulation inside the rear panels of their 1st gen 4runners? I was at the junkyard and saw a 4runner with insulation behind the panels and was thinking of trying it. Its fire resistant and somewhat water resistant i would think. And there is no moving parts in there like a door that requires the expensive stick on rubber sound proofing stuff so its out of the way of the window regulator. It should do a much better job too. Right now unless you yell you cant talk to the passengers in the rear without turning around when you are at highway speeds.

Any thoughts on this?

 

In a vehicle you really need to tame the resonances down in the steel itself which is why sound deadoning materials such as Dynomat work so well. Allmost anything rigid glued to the steel would work better than house insulation "floating" behind a carboard 1/4 panel. Don't use the expandable foam in the can stuff that can be bought at Home Depot. Sooner or later the foam will lose its adherity and it will become a permanent squicky toy stuck inside your vehicle.

 

My 86 had pillow stuffing used for sound deadner. I was afriad it was just a water trap and would cause rust. I used Peel and Seal. Works great for me.

 

Buy some peel-n-stick/peel-n-seal roofing material if dynomat is out of your price range. Fiberglass is a moisture trap.

 

^This. Check my build thread. Peel and seal plus anti fatigue mat.

 

Also, works great in stereo subs too, especially if they are metal

 

Fiberglass, foam, cotton or anything similar will catch condensation and rot your truck from the inside out. I used peel 'n seal for sound deading. To fill the some of the cavity behind speakers I used plastic drop cloth all bunched up, as well as some creatively chopped up pool noodles from the dollar store strategically wedged in place.

 

a buddy of mine used that underbody rubber paint, then sealed the little gaps and hollow parts with the expanding foam and the peal and seal on top of the underbody and just for overkilling it he used some grey foam for every panel before installing the interior back again

his truck is now quieter than my mom's new CRV honda.

 

^ I agree with everyone above, except for using the expanding foam. P&S is effective in minimizing vibration of the body panel sheet metal. I'm around 90% done with my sound-damping project (got doors and tailgate left to treat). Sorry too swamped to post pics. Cabin's pretty quiet, no rattling and bumps sound like a thud, not clanging, and I can really hear the "purr of the 22R-E" (spoken in the the tone of the Dos Equis Man) - LOL!

 

why don't you like the expanding stuff?? is it something like Green 88 said??
I'm just curious cuse this proyect has been hovering in my head for a while
and it seemed like a good idea for all the thight spots where the underbody could be dificult to aply.

(I wasn't a fan of the sponge, cloth, fiber, etc. the humidity is really not a problem in my area but dust gets absolutly everywhere!)

 

:jessica: I have used the expanding foam the stuff for big gaps and cracks it has to be close to 5 years now .

I used this to fill completely the parts of the body below floor level hence no place for it to go.

I could see where if you just sprayed it on the upper parts with the interior pieces off over time it would start to fall off.

Fiberglass insulation would just soak up the moisture even in dry climates just from condensation over night.

 

Is that expanding foam flame-retardant? If not, I'd avoid it like the plague.