# Polyfill in the doors?



## Gas Is Expensive (Aug 26, 2008)

I've heard of people stuffing their doors with polyfill. Is this a good idea? If so, what about rain/water? Thanks.


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## 89grand (Nov 23, 2006)

I'd say that is a terrible idea. Polyfill has a purpose, but it's not in a leaky door for obvious reasons, one of which you already mentioned, weather.


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## IBcivic (Jan 6, 2009)

not a good idea, unless you like the smell of cammenbert....


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## ChrisB (Jul 3, 2008)

Oh the smell of mold and mildew while the door prematurely rusts out from the inside.


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## Gas Is Expensive (Aug 26, 2008)

Figured as much. Thanks. I think bikinpunk mentioned it awhile back, which is why I asked. I filled my trunk lid with polyfill, as per his recommendation in the same thread, and it made an enormous difference.


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## Catman (Mar 18, 2008)

Polyfill is a tuning aid ...it is not something that you just automatically throw at a problem that you don't even know you have. Polyfill makes an enclosure seem larger ...if your enclosure is made properly to the specs of the speaker you do not need polyfill. If your enclosure is too large you need to be adding something to make the enclosure smaller. With any speaker ...use a PNG / RTA and see what you have ...make changes ...run PNG/RTA again ....repeat ...

>^..^<


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## Gas Is Expensive (Aug 26, 2008)

Catman said:


> Polyfill is a tuning aid ...it is not something that you just automatically throw at a problem that you don't even know you have. Polyfill makes an enclosure seem larger ...if your enclosure is made properly to the specs of the speaker you do not need polyfill. If your enclosure is too large you need to be adding something to make the enclosure smaller. With any speaker ...use a PNG / RTA and see what you have ...make changes ...run PNG/RTA again ....repeat ...
> 
> >^..^<


Sorry, I was talking about using Polyfill as sound deadening material, not for tuning an enclosure. I should have made that clear, and I wish I could find the old thread that bikinpunk mentioned this in. Like I said, it really did make a huge difference when I stuffed my trunk lid with the stuff. I was very skeptical at first, but amazed with the results.


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## ErinH (Feb 14, 2007)

no, no... I've never used polyfill in the doors. but, everywhere else in the car (that isn't effected by the weather) has some. dash, bpillars, rear deck, console, trunk lid...


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## Gas Is Expensive (Aug 26, 2008)

bikinpunk said:


> no, no... I've never used polyfill in the doors. but, everywhere else in the car (that isn't effected by the weather) has some. dash, bpillars, rear deck, console, trunk lid...


Ah, thanks for clarifying. I have the same car as you, except it's the hybrid. When you say you have polyfill in the dash, do you mean you actually pulled the whole dash from the car, or are you talking about stuffing polyfill in behind the head unit, inside the instrument cluster, underneath the dash and behind the glovebox (areas that can be accessed without removing the entire dash). Also, did you notice a significant improvement from the polyfill in the dash? Thanks.


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## Catman (Mar 18, 2008)

Gas Is Expensive said:


> Sorry, I was talking about using Polyfill as sound deadening material, not for tuning an enclosure....


I still think you have misunderstood BikinPunks intent. Polyfill is not a 'deadening' product. It is not a 'damping' product either. IMO the benefit of stuffing your trunk lid and any other 'chamber' is that you can stuff it into places that you can't get other products. It does help in eliminating rattles. I fear your 'improvement' is mostly psychological. 

It is most useful for 'absorbing' sound and in the manner in which you are using it you will see very little benefits. (but it will help rattles). It is just not thick and heavy enough to absorb the lower frequencies that need to be absorbed in a car. Even Owens Corning 705 (5# per cu.ft.) has its limitations.

Here is some good reading on the topic.


http://www.owenscorningcommercial.com/docs/specification/Fiberglas700Series.pdf

Sound Absorption Coefficients for some common Materials

4.3 What is the difference between insulation & absorption ?

Coefficient Chart

>^..^<


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## Gas Is Expensive (Aug 26, 2008)

Catman said:


> I still think you have misunderstood BikinPunks intent. Polyfill is not a 'deadening' product. It is not a 'damping' product either. IMO the benefit of stuffing your trunk lid and any other 'chamber' is that you can stuff it into places that you can't get other products. It does help in eliminating rattles. I fear your 'improvement' is mostly psychological.
> 
> It is most useful for 'absorbing' sound and in the manner in which you are using it you will see very little benefits. (but it will help rattles). It is just not thick and heavy enough to absorb the lower frequencies that need to be absorbed in a car. Even Owens Corning 705 (5# per cu.ft.) has its limitations.
> 
> ...


Well ****, at this point, all I'm looking to do is kill rattles. I have layer upon layer of luxury liner pro, ensolite, dynamat and the like installed in the floors, panels and doors.


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## Cruzer (Jul 16, 2010)

Gas Is Expensive said:


> Well ****, at this point, all I'm looking to do is kill rattles. I have layer upon layer of luxury liner pro, ensolite, dynamat and the like installed in the floors, panels and doors.


and u still have rattles?

i got some cld tiles from sound deadener showdown, im going to check them.

im going to see just how good they are. i have a crew cab truck and going to try the fewest amount of pieces possible on the back cab wall to see how many it takes to kill the rattles. im hoping just 2 centered, but we will see.


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## Catman (Mar 18, 2008)

Cruzer said:


> i got some cld tiles from sound deadener showdown, im going to check them.
> 
> im going to see just how good they are. i have a crew cab truck and going to try the fewest amount of pieces possible on the back cab wall to see how many it takes to kill the rattles. im hoping just 2 centered, but we will see.


My guess is that they won't stop ANY rattles. They are made to damp a panel and lower its resonance frequency. Rattles are from two or more things in contact with each other. Two different issues that need different solutions.

>^..^<


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## Cruzer (Jul 16, 2010)

well thats what don said to do, when i said it rattles, put them on the back wall =/


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## 89grand (Nov 23, 2006)

Don knows hit ****, so I'd say he recommended the right product for the job, but yeah, rattles are not what the tiles are for. They are for vibration control.


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