So, this rubbery, gooey, tar like mat underneath my carpet... Is this supposed to be sound deadening material? I am putting dynamat in the 'bird so I want to pull it out to make sure I get maximum dynamat-to-metal contact. Thoughts?
enjoy! its messy and a PITA.
i hear the dry ice helps. i only pulled the loose stuff outta mine so far. ill worry about the rest later
A putty knife and about 2-3 hrs.
Had to use a hammer to chisel some of it in places.
You'll also have a sore hand when your done.
I've also thought about putting radiant foil on, before reinstalling the carpet. also under the headliner.
Radiant foil is a heat barrier? I actually bought fat-mat from eBay (reviews say it's slightly better for sound than dynamat). Dynamat and Fat-Mat both say it also blocks heat... does anyone know how well? My 'bird gets pretty hot; so hot you can barely touch the metal ashtray door! I really want to block a lot of that.
I've had the ash tray door get smoking hot before too, but only at night when the ash tray light is on.
I use radiant foil all the time in attics and basp00gets.
I have it in my attic, and it cut the heat in summer up there from 115 deg. to about 75 deg.
Also have it on my garage ceiling. holds heat in like mad. I buy it by the 500' roll.
Eastwood dynamat extreme (foil sided)
http://www.eastwoodco.com/jump.jsp?itemID=14920&itemType=PRODUCT (http://"http://www.eastwoodco.com/jump.jsp?itemID=14920&itemType=PRODUCT")
Sweet! I wonder if the foil backing on mine will work that way:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=002&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=120216476835&rd=1
If not, where can I get a small amount? I've only seen it in 1000' quantities...
This is the place I get my foil from
http://www.radiantguard.com/ (http://"http://www.radiantguard.com/")
I'll check to see if I have any other places with less in a roll.
I'm guessing just for the floor you would need about 5'x8' or mabe 10'
How much comes in that bulk pack? I wanted to do my car but that stuff is always like $60 for a door kit so I always thought it would be way too expensive to do it but that price is not too bad.
yes, I was reading the specs on the fat mat. It has a decent amount of foil in it.
That will reflect the heat back out or in for that matter. It will also help in the cooling too (air cond.)
If you want maximum heat reflection find some foil at a home improvement store, or mabe a insulating contractor with some extra. Do above the headliner and behind your back seat that goes into the trunk.
Bulk pack has enough to do most of the car. I'm going to do a layer on the inside of the outer shell of the door (maybe dbl behind the speaker), followed by a 1/4" layer of closed cell foam and a layer of fatmat on the inner shell (just behind the door panel). Also will do the firewall and floor (not sure how much yet) and trunk... I'll let you all know how far it goes. Not doing the headliner yet, nor with this stuff cause I guess it could come off... gonna get something better for up there... but later...
I do definitely want max heat reflection, espeically while I have everything torn out. Driving today was interesting... just a shell and a seat. The entire floor panel was hot to the touch... no wonder I sweat to death in the summer!! So I want to keep that out and minimze how high I need to have the AC (whenever I get it reconnected and charged!!). Maybe I'll try craigslist for some extra foil...
Hey Jerry, how thick is that radiant foil? I'm trying to assess whether or not I need it by Thursday, I'd like to compare to the fatmat backing. I'm actually thinking I'm going to do a dbl layer of the foil backed fatmat on the firewall and floor now, so that may be enough.
that shiznit is what gave me bloody knuckles, but it was surprising how heavy that stuff is.
What is, the fatmat/dynamat stuff or the radiant foil?
Brett,
The radiant foil that I use is double sided 5 mil.
You could use spray adhesive on it if you had to
If you use it on top of insulation surfaces, use a perforated foil.
If you use it under, you can use solid foil
ok, well, the fatmat has 3 mil foil. Two layers on firewall and floor = 6 mil of foil. Sufficient? I'm having a hard time finding this stuff. Should theyhave small amounts at home depot? Asked yesterday and the guy thought it was all attached to foam insulation...
I think all they have at home depot is the foil bubble wrap stuff.
call an insulation company and see if they have the foil. or some you can get from them. unless you need some for your house also.
The foil is very popular in the south and california/nevada.
I'll check in a bit and see how much I have left. mabe I have enough left to send you. how much are you looking for?
Yeah, I'd think there'd be a lot here in SoCal.
I was thinking about 60-70 sq feet...? Enough to cover the firewall, trans hump and floorboards to the rear seat. How heavy would that much be?
I can get this in my area:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=13357-56291-13357&lpage=none
But 5/16"? Can I pop the bubble layer in the middle? LOL
i tell you to soak the old stuff down with engine degreaser. that will help break down the bond that holds it on. it worked great for removing body side molding without hurting the paint. the stuff just about fell off used a bondo spreader to scape it off and it fell right off
Used Accumat on my truck not mess and super easy to use but i don't its designed for a full car or i don't think i would want to cut it up to make it fit a whole car..
You may be over doing your project.
A good foil barrier will cut down 97% of heat radiated through it.
You can put another layer on or under it, but you would again be stopping 97% of heat radiated. But the 2nd layer would only be stopping 97% of the 3% that filtered through the 1st layer. (you do the math, because I can't figure that out. lol) So I would say that it wouldn't be worth another layer it unless you've got it laying around or someone gave you some.
or unless you want that other 2% of protection. I don't think anyone would notice an amount that small.
As long as the mat that your putting down, has no spaces between pieces, you will have a good barrier against heat.
Its like soundproofing, all it takes is a small hole to let sound pass through. use the same theory with radiant heat and you'll stop it.
and if you still want some more, I have about 20-30 feet left on my 4 foot roll.
BTW that bubble wrap stuff would work real good behind your back seat.
Why bother removing it if your planning on replacing it with a Dynamat anyway?
I always figured the only reason to remove it was for the racer that wanted to save as much weight as possible.
I have some Dynamat ready to install in my car when the weather gets back into the 50° range and higher, but I was just going to leave the factory stuff in place and then fill in everywhere that they missed with the Dynamat.
Brent
:cougarsmily:
Well, it may sound like over kill, but here's my thought process:
Good foil will block 97%, you're right, I read it all over the net. But the slightly thinner stuff on the back of the FatMat is probably poor quality. So, if it blocks even 40%, a second layer will block 40% of the remain 60%. Also, I was already planning two layers because my whole goal with this car is the comfort of luxury and the performance of a sports car. Does this all make sense?
And BCA, I replace for the above reason and because the factory stuff sucks. why keep it in there doing nothing... my car has a lot of road noise and gets so hot I can barely touch the sheet metal on the floor (with the factory stuff that is)! That's no fun in SoCal!
I'd hazard a guess that the aftermarket sound deadeners are superior to the OEM stuff. I don't have any empirical evidence to back me up though.
I would also like to start from a clean sheet, so to speak.
WRT the foil:
The optimum placement of a Fatmat type barrier is on the exterior of your firewall. The aluminum foil is good for rejecting heat via radiation. There isn't a lot of radiation going on in the interior of your car. When applied to the interior of your vehicle, the butyl layer becomes the primary insulator of heat, not the aluminum foil.
I recall reading that for optimal absorbance of the sheet metal resonance that the "Fatmat" has to be in direct contact with the sheet metal.
And on Jeremy's note. Wonder if covering the bottom of the car would help?
It will be in direct contact... it's best for heat and sounds. that's why you remove the stock stuff and lay it down, pressed hard with a roller. No different inside or out. Now, the radiation factor as Jeremy is saying may be true, but I don't think I'm going to put it on the "outside" of the firewall...
Direct contact will increase the Damplifier's (http://"http://www.secondskinaudio.com/vibration-mat/damplifier.php") (I'll use Second Skins's product name instead of Fatmat because I'm a shill) effectiveness, at least wrt to sound dampening. It will have negligible effects on heat transfer.
The only place where Damplifier would be useful on the bottom would be directly above the exhaust system. However I don't think it is suitable for outside application. Something like SS Firewall (http://"http://www.secondskinaudio.com/thermal-acoustic-insulation/firewall.php#tab3") would work. Fatmat (http://"http://www.fatmat.com/liquid/gallon.html") and Dynamat (http://"http://www.dynamat.com/products_automotive_dynaspray.html") both have water-based products too.
It is true. Don't believe all the you read about radiant barriers.
http://www.radiantfoil.com/
Radiation is the primary mode of heat transfer for houses? Only in space (where there is no atmosphere, and thus no medium for convection/conduction to operate through).
If that statement were true we'd do away with foam/fiberglass insulation and slap up a layer of Reynolds wrap between the walls.:rolleyes:
Ok, you lost me! LOL So you're saying radiant foil will do nothing unless it is directly facing the exhaust (meaning on the bottom side of the car)?
The real way to stop radiant heat is to have a dead air space between another insulation. as in framed walls, you insulate the studs, allow for a 1/2" airspace and put a foil barrier. then drywall or what have you for finish walls.
Its the air space that stops the convection of temp. between the 2 heat extremes.
ok, right, because temperature transmits slower through the air than the sheetmetal/walls, etc.... right? I guess I'm still confused on what Jeremy was getting at and what would work best for blocking the heat transfer through my floorboards.
pretty much, insulate for sound and heat the way your planning.
unless you had a way to create an airspace on your floor somehow,
you'll be stuck like the rest of us trying to block heat the best we can.
the foil in the mat will still help
Another way to cut heat would be putting a shield between your exhaust and floor.
or heat insulate your pipes
LOL, well, I'm glad I don't care if I feel stupid but I have to say, I didn't even think to wrap the pipes! :hick:
:D Lol
Heat transfer via radiation between two surfaces is described by the equation:
Q/A = ε*σ*( T^4 -Tc^4)
Where, Q/A=Heat transfer per area (W/m^2)
Where, ε=Emissivity (http://"http://en.wikipedia.org/wiki/Emissivity")
Where, σ=The Stefan-Boltzmann Constant (http://"http://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant") (5.6703 10-8 (W/m^2K^4)
Where, Th=Temperature of the hot body (K)
Where, Tc=Temperature of the cold body (K)
Q stands for heat transfer, and A stands for area. So Q/A is heat transfer per area.
We'll assume emissivity is 1. The Stefan-Boltzmann constant is a constant, so it doesn't do anything but get multiplied.
The important concept to come away with is that radiation is dominated by temperature to the 4th power.
Another is how radiation heat transfer occurs. Radiation requires a medium (be it air or a vacuum) gap to occur. If you take a hot surface, and then place a radiant barrier directly on it, the radiant barrier isn't stopping any radiative heat transfer. Heat is instead being conducted (http://"http://en.wikipedia.org/wiki/Heat_conduction") through the barrier. If you moved the barrier out an inch from the wall, then the barrier would being to reflect the radiant heat coming from the hot surface.
Also, radiation travels in a straight line. It has a line of sight. For example. Say you're outside facing a bonfire on a cold night. The radiant heat of the flames is heating you quite nicely, then somebody puts them self between you and the flames and begins to strike up a conversation. All of a sudden it gets cold. This is because that person's backside is now in the direct line-of-sight with the flames and you aren't- thus they are absorbing all of the radiant heat and you're cold again.
I'm too lazy to look up convection coefficients and thermal conductivities to compare them with radiation, but I'll just show how radiation is really depend on temperature.
On a hot day, the underside of your car (Tc) is 100 degrees. The asphalt (Th) below your car is 130 degrees.
Plugging and chugging into the equation at the beginning of the post gives you Q/A=123.1
Remember to convert Fahrenheit to Kelvin for the formula.
Now let's compare that to the part of car that is exposed to the exhaust downstream of the catalytic converter. Tc is still 100 degrees. Th (Exhaust surface temperature) is 300 degrees.
Q/A=1269.0
Q/A is 10 times greater, even though the temperature difference is only 6.5 times greater.
Assume you have a set of long tube headers (Th) at 500 degrees and an exterior firewall (Tc) firewall temperature of 100 degrees. Q/A=4051.7
Lastly, imagine a race car with the headers (Th) at 1300 degrees, with a firewall (Tc) temperature of 100 degrees.
Q/A=51262
The absolute temperature difference between the first and last case is 40 times. The radiative heat transfer difference is 416 times!
This contrasts with heat transfer via conduction. A temperature difference twice as great will result twice the heat transfer.
Below is a graph illustrating how heat transfer increases as the temperature difference increases. Note that Tc is constant at 100 deg F.
As daminc said, without an air gap, the aluminum foil is not acting as a radiant barrier. The foil primarily acts as a physical barrier between the gooey butyl and its environment (carpet, feet, spilled coffee).
[homer simpson] ahhhhh, coffee [/homer simpson]
Ok, so long story short, neither the foil nor the foil backed fatmat is any better without the air gap...? dude, you know to much technical stuff! You got a girlfriend?!? Jk, wish I knew that much! Ha!
I'm not sure I understand you...
Long story short, applying the foil inside will do a poor job in insulating the cab from outside heat. The foil portion of the fatmat/dynamat/damplifier will do a poor job of insulating the cab from heat, but the butyl portion of those products
will insulate your vehicle.
Furthermore, the best way to insulate the cab from radiant heat is to apply a radiant barrier to the exterior firewall, transmission tunnel, and sheet metal directly above the exhaust system.
(http://www.watsoncrombie.com/t_shirts/college_poster.jpg)
Yeah, I get now that I'd really need to use it on the outside, but what I'm trying to determine is whether adding radiant foil to the top of the two layers of fatmat will make any difference. So, long story short, meaning, all your technical crazy stuff applied to my question would give me a no.
Bingo!
LOL Thanks!
So wait now, if I put radiant foil on the bottom of my floor boards (between the exhaust and the floor) how would that thin layer of foil do anything more than the sheet metal floor would to stop radiant heat? It has no more of an air gap than the floor does from the pipes...
The foil reflects much more of the incoming radiative heat than the painted sheet metal.
ok, good enough for me! :hick:
Boy, what did I miss today.
I believe I saw radiant panels for the underneath of a car.
Not sure if it was a magazine or web.
But after reading that college course post, my smaller brain went ding. and remembered seeing it before. I'll let you know if I find it.
JeremyB, what do you do for a living?
Please don't tell me your a mail man. lol
Here's a visual example of what's going on. Pardon the horrible drawings.
Picture 1:
This is how our cars are currently set up (minus the factory sound deadening material).
Heat pours out from the exhaust pipe in the form of radiation and passes through the air gap between the pipe and the sheet metal at the speed of light. It then hits the sheet metal, which probably soaks up 80-95% of the radiant heat energy.
Picture 2:
You slap on some Fatmat/Dynamat/Damplifier on the outside of your mean machine.
Heat pours out...blah, blah, blah - except when it hits the foil, 90%+ is reflected back. The increase in reflected energy is due to the higher reflectivity properties of the foil itself.
Picture 3:
You put the FM/DM/DF on the inside of your car, under some wicked brown shag carpet. The foil is now sandwiched between the butyl/sheet metal and the carpet. There is no air gap on either side of the foil, thus radiation cannot take place. The foil portion becomes ineffective in deflecting radiant heat.
If you removed the carpeting, then the foil could act as a radiant barrier to keep heat in the car.
I guess what he's saying is reflect it before it hits the floor
here's something
http://www.amazon.com/DEI-010412-Adhesive-Shields-Reflect/dp/B000SJVMAA/ref=sr_1_17?ie=UTF8&s=automotive&qid=1202949793&sr=1-17 (http://"http://www.amazon.com/DEI-010412-Adhesive-Shields-Reflect/dp/B000SJVMAA/ref=sr_1_17?ie=UTF8&s=automotive&qid=1202949793&sr=1-17")
daminc, I'm in modeling and simulation - currently working on Project Constellation. (http://"http://en.wikipedia.org/wiki/Project_Constellation")
Now that is real cool.
Are you shiznitting me?!? That is so fricken cool!!