I know this question was most likely asked a bunch of times, but I'm going to ask anyway. Has anyone ever use the expanding foam that comes in an aresol can to fill in areas such as A-pillers, rocker panels, torque boxes, etc? I'm contemplating it, but thought I would hit you guys up on wether its a good or bad idea.
Expanding Foam
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67coupe351w
New Member
Because it deadens sound.
It's a great idea - most production cars today do this, except their foam is usally inserted via bags of pelts that expand and fill the cavities once they hit a certain temperature - a temperature seen at somepoint while the unibody is being manufactured...like say during ecoat curing.
Just make sure you spray it in slowly and let it cure before adding more. IF you squirt too much in it won't set up and will remain a liquid. Also, the foam is capible of applying alot more force than you might think - another good reason to go slow with the insertin of the foam.
ratio411
Founding Member
I don't know if this is a concern or not, but the stuff in the cans is said to be extremely flammable.
There was a discussion like this once, and that was a concern.
I don't know how one would catch it on fire inside body panels, but it came up.
There was a discussion like this once, and that was a concern.
I don't know how one would catch it on fire inside body panels, but it came up.
just make sure you use the right stuff
from sport compact car:
In any high-performance car, it is impossible to make the chassis too stiff. The stiffer the chassis, the higher its natural frequency, making the energy imparted to it by bumps less likely to excite the body's structure. A stiffer chassis enables the use of stiffer springs and shocks without hurting the ride. This is because a stiff, non-flexing chassis transfers more force into the suspension where it can be dissipated by the springs and shocks instead of transferring the force to the occupants. A stiff chassis is also more responsive to roll rate tuning for balancing understeer and oversteer. This is one of the reasons why automotive engineers are continually investigating ways to stiffen chassis without adding weight.
In a final bit of reengineering to stiffen the body, we injected the chassis with catalyzed rigid structural polyurethane foam. Structural foam, in the 2 lb per cubic foot density that we used, can stiffen chassis members up to 40 percent.
Higher densities of foam can increase stiffness by up to 300 percent. Since we cannot retool custom parts to redo the Z's body, we figured that this would be an excellent, low-cost way of greatly increasing chassis stiffness. Injecting foam is not a new technique for chassis stiffening. The Infiniti Q45 uses this sort of foam in some of its chassis members to increase stiffness, as do a few other premium cars. In fact, the foam we chose is the foam recommended to repair damaged Q45s.
To get the correct foam for our project, we contacted Art Goldman, Foamseal's automotive product manager and author of an SAE (Society of Automotive Engineers) paper on the use of structural foam for the stiffening of automotive unibody structures. We used Foamseal's two-component foam kit, p/n 11-22 to fill the main members of the chassis. Like we mentioned earlier, Foamseal is the supplier that I-CAR, a national certification group for quality auto repair, recommends for the repair of damaged, foam-filled chassis. The Foamseal kit uses a two-part catalyzed polyurethane foam, which quickly cures into rigid, waterproof, closed-cell foam. To prep the car, we carefully masked off all painted areas anywhere where the foam could drip. As this sort of foam is a thermosetting catalyzed plastic, we realized it could be icky if it spilled on paint or any part of the car's interior. This foam is nasty stuff. It is impervious to all known solvents and cleaners.
Rubber gloves must be worn. Get some of it on your hands and it will stay there for more than 3 weeks--don't ask how we know. Do not get this stuff on your paint. Wear old clothes; we ruined ours while learning how to handle the product. We injected the foam into the rocker panels and frame rails of Project Z through existing bolt and drain holes. When injected, the foam reacts like shaving cream and quickly expands to fill the empty space. You can judge how much foam to add by watching its expansion progress through some of the holes. Once injected, the foam expands and begins to cure in about a minute so you need to work fast and plan how you inject the foam before you start.
The life of the foam kit is limited to a few hours once the seal is broken. We filled all of the Z's unibody frame members using five foam kits. When foaming a chassis, you must remember the wires and other lines that pass through the chassis must be relocated or they will be entombed forever.
We were amazed at how this simple procedure improved the performance of the car. The chassis now almost feels like it has a roll cage. A sloped driveway can be driven up sideways with nary a creak. Even though the Z already has a pretty tight chassis, it feels more solid. The ride has improved and road noise has been reduced noticeably. We bet that the car will be even more responsive to chassis tuning measures in the future. If you are a slalom racer, a road racer, have a lowered car or even just want a smoother ride; foaming is a worthy, easy-to-do modification. Foamseal has foams in densities as high as 10 lbs per square foot if you desire to make things even stiffer.
Do not--I repeat--do not attempt to use cheap, hardware-store canned foam. This is not the same thing, and if injected into your chassis, will form a gummy mass that won't dry. Foamseal foam is a professional grade foam, which although it is a little unforgiving to cleanup mistakes, has superior mechanical properties and catalytic curing so it will dry even in an enclosed space.
from sport compact car:
In any high-performance car, it is impossible to make the chassis too stiff. The stiffer the chassis, the higher its natural frequency, making the energy imparted to it by bumps less likely to excite the body's structure. A stiffer chassis enables the use of stiffer springs and shocks without hurting the ride. This is because a stiff, non-flexing chassis transfers more force into the suspension where it can be dissipated by the springs and shocks instead of transferring the force to the occupants. A stiff chassis is also more responsive to roll rate tuning for balancing understeer and oversteer. This is one of the reasons why automotive engineers are continually investigating ways to stiffen chassis without adding weight.
In a final bit of reengineering to stiffen the body, we injected the chassis with catalyzed rigid structural polyurethane foam. Structural foam, in the 2 lb per cubic foot density that we used, can stiffen chassis members up to 40 percent.
Higher densities of foam can increase stiffness by up to 300 percent. Since we cannot retool custom parts to redo the Z's body, we figured that this would be an excellent, low-cost way of greatly increasing chassis stiffness. Injecting foam is not a new technique for chassis stiffening. The Infiniti Q45 uses this sort of foam in some of its chassis members to increase stiffness, as do a few other premium cars. In fact, the foam we chose is the foam recommended to repair damaged Q45s.
To get the correct foam for our project, we contacted Art Goldman, Foamseal's automotive product manager and author of an SAE (Society of Automotive Engineers) paper on the use of structural foam for the stiffening of automotive unibody structures. We used Foamseal's two-component foam kit, p/n 11-22 to fill the main members of the chassis. Like we mentioned earlier, Foamseal is the supplier that I-CAR, a national certification group for quality auto repair, recommends for the repair of damaged, foam-filled chassis. The Foamseal kit uses a two-part catalyzed polyurethane foam, which quickly cures into rigid, waterproof, closed-cell foam. To prep the car, we carefully masked off all painted areas anywhere where the foam could drip. As this sort of foam is a thermosetting catalyzed plastic, we realized it could be icky if it spilled on paint or any part of the car's interior. This foam is nasty stuff. It is impervious to all known solvents and cleaners.
Rubber gloves must be worn. Get some of it on your hands and it will stay there for more than 3 weeks--don't ask how we know. Do not get this stuff on your paint. Wear old clothes; we ruined ours while learning how to handle the product. We injected the foam into the rocker panels and frame rails of Project Z through existing bolt and drain holes. When injected, the foam reacts like shaving cream and quickly expands to fill the empty space. You can judge how much foam to add by watching its expansion progress through some of the holes. Once injected, the foam expands and begins to cure in about a minute so you need to work fast and plan how you inject the foam before you start.
The life of the foam kit is limited to a few hours once the seal is broken. We filled all of the Z's unibody frame members using five foam kits. When foaming a chassis, you must remember the wires and other lines that pass through the chassis must be relocated or they will be entombed forever.
We were amazed at how this simple procedure improved the performance of the car. The chassis now almost feels like it has a roll cage. A sloped driveway can be driven up sideways with nary a creak. Even though the Z already has a pretty tight chassis, it feels more solid. The ride has improved and road noise has been reduced noticeably. We bet that the car will be even more responsive to chassis tuning measures in the future. If you are a slalom racer, a road racer, have a lowered car or even just want a smoother ride; foaming is a worthy, easy-to-do modification. Foamseal has foams in densities as high as 10 lbs per square foot if you desire to make things even stiffer.
Do not--I repeat--do not attempt to use cheap, hardware-store canned foam. This is not the same thing, and if injected into your chassis, will form a gummy mass that won't dry. Foamseal foam is a professional grade foam, which although it is a little unforgiving to cleanup mistakes, has superior mechanical properties and catalytic curing so it will dry even in an enclosed space.
1320stang
Founding Member
about 15 or 20 years ago, we used some of the can foam in my buddy's decklid and over the outer wheel well to quarter panel and some in the package tray area. This was because we had made a sub box for a 15" woofer. We need to peel it out of the quarters and see if there is any rust in there.
I have been looking for a flame retardent foam for my drag car.
I have been looking for a flame retardent foam for my drag car.
xoxbxfx
Founding Member
very flammable...I was using a plasma cutter to cut apart a wrecked car and that foam went into flames QUICK
Rusty67
Dirt-Old 20+Year Member
that's a valid point but i've also heard that it prevents air and water from getting into those areas and actually preventing rust, i'd like to know the true story here. i understand that closed and open cell foam may react differently here and closed sell would be the best to use in these areas.
In the areas that were mentioned (rear quarters, and rocker panels) they have built in drains on them and they will have water accumulate in them, that is why there are drains there. If you fill that area up with foam, thus plugging the drain it will trap moisture, trapping moisture will cause rust. If this was a race/drag car I don't think you would be concerned with sound deadening and adding the foam would also increase the weight. IMO i see no real benefit from doing this...... Some good prep, POR-15 or an eqivalent and some lizard skin or dynamat would serve the same purpose. as far as strengthing the body, i don't see foam helping in that area, unless it dries hard as a rock, and if it did imagine how much that stuff must weigh.... Just my thoughts, somebody feel free to prove me wrong
faom in those areas can and does improve structural rigidity as an added bonus it also helps with NVH. the question is will the faom you can buy at home depot absorb moisture. i can't answer that one and would like to know myself, i do know that it will keep rocks and mud out and i know of several off road guys that use it in their frame rails for that very reason. all of those guys live in the austin area and i haven't talked to any of them in a few years so i don't know if their frames have rotted away to nothing because of moisture absorption.
i do know that the closed cell foam can and will prevent moisture absorption and prevent rust in an already clean and rust free car but i have no idea what effect it would have on already surface rusted parts. i would assume it would prevent further rusting because it blocks any further moisture and even oxygen from getting in and causing further oxidation, though.
1320stang
Founding Member
POR-15, Lizard Skin or Dynamat are all going to add weight as well.
If you have ever been inside a chassised drag car with an all aluminum floor, it's very loud due to vibrations of the tinwork.
Another thing, it's very hard to seal all the openings and when you do a burnout, the car tends to fill with tire smoke.
I had planned on putting a layer in the doors and quarters to help deaden the noise somewhat as I figured it would work better than Dynamat at a lesser weight. If you read the article he posted, the stuff they used was 2 lbs. per cubit foot. How much is Lizard Skin or Dynamat per cubic foot? And the stuff they used was structural foam, I don't need structural foam as I'll have a full cage. My thought is, it will be easier for me to hear the engine during a pass and the seal the foam will provide will make the cabin clearer and make it easier for me to see the X-mas tree. Studies have shown that racers at night tend to have a quicker reaction time (delay box racers will change the time in their boxes) so I'm figuring that the tire smoke in the vehicle would affect that as well. I'll have a fire supression system to take care of the engine compartment, the trunk and the cabin.
If you have ever been inside a chassised drag car with an all aluminum floor, it's very loud due to vibrations of the tinwork.
Another thing, it's very hard to seal all the openings and when you do a burnout, the car tends to fill with tire smoke.
I had planned on putting a layer in the doors and quarters to help deaden the noise somewhat as I figured it would work better than Dynamat at a lesser weight. If you read the article he posted, the stuff they used was 2 lbs. per cubit foot. How much is Lizard Skin or Dynamat per cubic foot? And the stuff they used was structural foam, I don't need structural foam as I'll have a full cage. My thought is, it will be easier for me to hear the engine during a pass and the seal the foam will provide will make the cabin clearer and make it easier for me to see the X-mas tree. Studies have shown that racers at night tend to have a quicker reaction time (delay box racers will change the time in their boxes) so I'm figuring that the tire smoke in the vehicle would affect that as well. I'll have a fire supression system to take care of the engine compartment, the trunk and the cabin.
I was not trying to come off like an ass or smart alick, when I said prove me wrong. I have never used foam, nor have I ever heard of anyone using foam, that is why I said prove me wrong, perhaps that could have been worded better, sorry about that. I would still like to see some real results, sorry but tech articles from "Sport Compact" is not my idea of real knowledge....
BTW I found a site that sells rigid foam.
http://www.smoothonsecure.com/store/index.php?cPath=46_49&osCsid=4ee7b4e659098d0f0efd1599ff0a1c34
as far as the tire smoke. Most racers I know with track only cars, use some sorta of seam sealer with their tin work.
BTW I found a site that sells rigid foam.
http://www.smoothonsecure.com/store/index.php?cPath=46_49&osCsid=4ee7b4e659098d0f0efd1599ff0a1c34
as far as the tire smoke. Most racers I know with track only cars, use some sorta of seam sealer with their tin work.
1320stang
Founding Member
I didn't take it that way, I know it's hard to convey meaning in a post. My posts tend to be rather long because in order to convey what you're talking about in a post rather than in spoken word, I find you tend to have to write more in order for your true meaning to be understood.
I also wasn't trying to bag on you when I wrote "If you read" because I know some people tend to not like longer posts. I, on the other hand, love to read and if someone is very good at writing, it's great. I'm working on "proving you wrong" but it'll be a while as I have kids 14,10 & 6 and it's hard to divert monies to the car while performing all my fatherly obligations.
My buddy's '65 Falcon chassis car still gets some tire smoke, but he has fiberglass doors with no weatherstriping. The car also doesn't have any jambs in it either and those Falcons didn't have window frames on the doors like my Fairlane has. I plan on welding all my holes up in the floor as well as any drains in the quarters.
I also wasn't trying to bag on you when I wrote "If you read" because I know some people tend to not like longer posts. I, on the other hand, love to read and if someone is very good at writing, it's great. I'm working on "proving you wrong" but it'll be a while as I have kids 14,10 & 6 and it's hard to divert monies to the car while performing all my fatherly obligations.
My buddy's '65 Falcon chassis car still gets some tire smoke, but he has fiberglass doors with no weatherstriping. The car also doesn't have any jambs in it either and those Falcons didn't have window frames on the doors like my Fairlane has. I plan on welding all my holes up in the floor as well as any drains in the quarters.
Ok I found it! It's called Foamseal. It's specifically made for use in cars. Infinity uses is in their Q45 cars. It's a closed cell spray in expanding foam, that doesn't absorb water. I Googled it today and one kit starts out at $40.00 with shipping and handling, and supposed to cover around one cubic foot. It was used in a Nissan Z-300, which I also Googled. The article is in Sport Compact Car Magazine 
According to sources you can get this stuff in different compounds, and can stiffen a chassis up to 300%
One drawback is that it's supposed to be a real pain to work with. All in all I like the sound of this stuff, I'm getting some for my 67 Fastback
Along with some ceramic lizard skin
According to sources you can get this stuff in different compounds, and can stiffen a chassis up to 300%
One drawback is that it's supposed to be a real pain to work with. All in all I like the sound of this stuff, I'm getting some for my 67 Fastback Along with some ceramic lizard skin
icar 2000 collision repair classes made a believer out of me... take two pop cans,fill one with expanding foam, the other do nothing. whan the foam has properly cured, step on both of them, empty one first. the right foam adds so much strength, and stiffness, it isnt funny. thats not saying the right stuff from lowes will eliminate the need for subframe connectors... it wont. but the foamseal that was mentioned, along with the products made by lord chemicals (fusor) duramix, etc.. will amaze you with how much stiffness they add.
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