I was considering dynamat on my back wall but with all the air leaks, loud pipes, and general road noise would it really matter? I am going to carpet the floor and back wall but i wanted to do the sound dampener if i would matter. What have you done?
sound dampening materials
- Thread starter Dlampe
- Start date
Ron Earp
Admin
You don't want that stuff, it'll just add weight and slow you down! 
Search on dynomat, I remember a discussion some years back on that and other materials. I think Lynn was involved with the discussion as well as some others folks who had used different things. Ross maybe was involved as well because he's a sound guy, in both senses of the word.
Ron
Search on dynomat, I remember a discussion some years back on that and other materials. I think Lynn was involved with the discussion as well as some others folks who had used different things. Ross maybe was involved as well because he's a sound guy, in both senses of the word.
Ron
I've used the foil-backed felt material before. It seems to insulate well for both heat and sound. It's about 3/8" thick so it adds some cushion to the carpet as well. I think it gives the interior a little more of an "OEM" feel.
It's a lot cheaper than Dynomat too. I think I paid about $20 for a 3' x 6' roll from J.C Whitney.
Charlie
It's a lot cheaper than Dynomat too. I think I paid about $20 for a 3' x 6' roll from J.C Whitney.
Charlie
I would strongly advise using it or a similar material(Sound Damplifier is the best) it cuts down on drone and that can be very tiring after awhile. I plan to add a neoprene layer on top of my dynamat to absorb different wavelengths. Go to the Sound damplifier web site, great info on the subject.
Sound Deadening Materials for Noise Reduction from Second Skin
Sound Deadening Materials for Noise Reduction from Second Skin
I wrote an article for the GTD boys a while ago, and here is an excert from it. The high end cars that Year One(builder of high end custom rods) uses is pretty much Dynamat. It is however rather expensive. Some have gone to other forms of insulation. Lyzard Skin, LineX just ot mention a few. I haven't used either, but am planning on using one or the other in the next couple of weeks. They seal all the leaks with just a little buildup in those areas that are small. Thickness is about twicde that of paint. To cover say drill holes, they cover the reverse side(if accessable) with the thick sluminized tape like they use in the A/C industry. The Lizard skin uses some ceramic balls incororated into the spray to block heat. Don't know how really effective it isw. Some go for triple protection and use an amalgamation of these products. If you are really serious about killing sound, get ready to spend some money. They all run up quickly. You have to do the insides of the doors, and voids or double skin pieces etc(the expandables). It will pay off in the end though, because you will have a solid sounding car(door shutting), and a more rigid car to boot. You have to be careful with the expandables, as they can move things around if you aren't careful. Have to do it in stages. All thee things have been discussed here somewhere. Do a search and you will find it. If not let me know as I have quite a library of post subjects from the forum on my hard drive.
Here is the excert. It is becomming a little dated with the advances that are being made. Do a Google search as well.
Bill
For non-strength sealers, Urethane calk is best. Elastomeric is next then Latex and butyl rubber is last. All are paintable. GE Silicone II DAP, Polyseamseal NP1 by Sonneborn (found in roofing supply stores only) and 3M Marine sealant are some of the brand names. Most are flexible and paintable. Most cure from ½ hour up to a week
Duramix™ Side Glass Channel Adhesive a 3M product that is a semi-rigid urethane material for bonding side glass to metal or plastic channels, sets within 3 minutes. Glass becomes structurally bonded to channel within 10 minutes.
Each of these products along with many others is used in the automotive repair industry in place of welding where warpage is the prime culprit. All have shown through crash test to be as strong as welding.
For ordinary sealing of holes or leaky joints, the typical silicone calks found at most home supply houses works well. Just be sure to get the kind that, 1. dries clear and/or 2. is paintable. It might be noted here that anytime you use rivets, you should consider putting a layer of these materials between the panel and the frame member being bonded preventing the eventual vibration induced rattles that can sometimes accompany rivets. With as many rivets as are being used, you can count on one or two not setting properly.
Insulation
No talk of paneling would be complete without mentioning insulation. The purpose of insulation is three fold. First is the blockage of heat. With waterlines in the cabin, an engine under your elbow and a radiator at your feet, the need for good insulation is obvious. The second purpose is to block sound. GT40s are noisy little creatures, wonderfully so, but we owe it to ourselves and our riders to try our best and abate as much of the noise as possible. Remember, you are in an enclosed space with an engine under your elbow spewing out 250 to 600 H P. That makes for a lot of noise and heat. Any and all panels that are contiguous with the cabin should be insulated. That means door panels, floors, engine bay, foot wells, wheel wells, central tunnels, roof panels, and outfacing bonnet surfaces (inside surface of wheel wells). The third purpose is to block out the transmission of noxious fumes. Not thought of much but is a consideration none the less (see Sealants and Adhesives).
Now all we have to do is decide which type of the stuff is best for what we want. The choices are many. There is rigid low compressible foam, cellulose or fiberglass batt, honeycombed air gaps, expandable foam, dual-purpose aluminized agents, polyurethane, and the list goes on and on. Each has its good and bad points. Since we live in a cramped environment, we need something compact and efficient. Some of the better products that are out there are listed below. This is not an all-inclusive list, as there are so many products out there to choose from. Most have fire retardants added. Some don’t and will support combustion. That is not necessarily a negative point. One must remember that we are surrounded by fiberglass, which also supports combustion.
Most products that should be considered for the first two purposes are a form of foil faced blanket type of material that will block 97% of heat transmission and is from 3/8 to ½ “ thick and is easily trimmed to fit. Some come with adhesive applied. Currently, polyester and polypropylene rank among the top materials of choice for auto insulation commercially. The Urethanes are rapidly beginning to take their place, and can be found throughout modern day cars. Some of the new products in the home building industry (spray on foam) can be adapted to automotive use. Most are a two part polyurethane products with an expansion of about 8:1 with fire retardants added.
Most sound transmission can be eliminated or reduced in one of the following ways:
Damper – by far the most common type of material. It uses mass loading to lower panel resonance and absorb structural vibrations, converting them into low-level heat. Most commonly used throughout a vehicle to control structural related noises. They can also be used in conjunction with a composite to reduce road/engine/exhaust noise.
Absorber – as the name suggests, these products literally absorb airborne sound waves. The sound waves have to propagate through the absorber and the open/closed cell foam will slow its progress reducing the overall level in the process. Most commonly used on floors and firewalls to reduce road/engine/exhaust noise.
Barrier – as the name suggest, these products form a barrier or wall, which blocks airborne noise from passing through. The denser the barrier, the more effective it is, which makes lead (although heavy) an excellent choice for a barrier. Most commonly used on floors and firewalls to reduce road/engine/exhaust noise.
Composite – Best results are achieved by using more than one method of sound deadening, so a composite is quite simply a combination of two of the above types into a single easy to install product.
I am listing two products to give an example of what can be used. This is not an endorsement, but a good example of what is out there.
B-Quiet® Extreme is a 1.15mm (45mil) thick composite mat which consists of rubberized asphalt with an aluminum constraining layer. When the paper backing is removed the adhesive surface forms an incredible bond to ensure optimum deadening performance. It can be used on floors, doors, roofs and trunks, but not under hood (read engine bay). It weighs 0.30lb/sq. ft., comes in 1-foot wide rolls and is available in two sizes: 12 and 50 sq. ft. rolls. $84.99 each is about the going price in the U. S. for the smaller sheet. Discounts for the larger.
B-Quiet Ultimate is a viscoelastic deadener with a supercharged butyl based adhesive. With aluminum constraining layer and a unique composition with suspended mineral particles it has been proven to be extremely efficient at the conversion of vibration to thermal energy. B-Quiet Ultimate is extremely flexible which allows it to properly adhere to a contoured panel. It can be installed anywhere including under hood. B-Quiet Ultimate is 1.6mm (60mil) thick, weighs 0.35 lb/sq. ft. comes in 1 foot wide rolls and is available in 2 sizes - 12 and 50 sq. ft. rolls and is $129.99 and up.
Dynamat Xtreme® is a butyl and aluminum vibration damper. It conforms and fuses easily to sheet metal and other hard substrates. It can be installed anywhere including under hood. Dynamat Xtreme® is 1.12mm (44mil) thick, weighs 0.45lb/sq. ft. comes as nine 18" x 32" pieces for a total of 36 sq. ft. and is $194.99 and up.
A cheaper more labor-intensive alternative is to consider the insulating foam sealants used in the building industry. Names like Great Stuff comes in aerosol cans at most building supply stores. NTAP X-30 Polyurethane Foam, a 2 part pourable foam expander. Mixing ratio A/B by weight 50/50. Mixing time 20-30- sec., rise time 2-3 min., tack free 3-10 min., with full cure 24 hr. This product is best done in several small pours rather than one big one. Fomofoam, a two-part spray for vertical surfaces. Comes in propane type containers. All form airtight and waterproof seals, bond to most materials, cures rigid and is easily trimmed with an electric carving knife etc. Just be aware that, they can be messy as they are very sticky. If the surface or adjoining surface is a painted surface, it should be covered with “plastic wrap” from the kitchen drawer and taped in place. All holes and gaps should be taped closed. But remember this stuff is expansive and will push things out of its way if there is no place for it to go. If you have double layered panels, it is a great filler and insulator. Just give it an escape route for accidental over filling. If it does get on the aluminum or stainless, most solvents/cleaners/polishes or elbow grease will bail you out. If used in the central tunnel, block off the cooling pipes to cover just them or wrap all wires, cables etc in some form of PVC piping, and line the tunnel with plastic wrap so that it can be removed for repairs. Remember this stuff bonds to all surfaces. Mixing two liquids, a polyether polyol and a polyfunctional isocyanate produces polyurethane foam. Like all organic material, when they are exposed to an ignition source with enough heat, polyurethane foam products will burn. Even the most flame retarded urethane foam will undergo combustion at temperatures exceeding 550C (1022F). There were a few commercial building fires using polyurethane insulation, that were deadly, but investigations showed that the polyurethane’s did not actually burn (although they did char), but what happened, was that they were such good insulators, that the temps rose very fast and caused what is known as flash over, where, because of the reflective nature of the insulation, the fire travels at an extremely high rate of speed. Upwards of 60 to 100 MPH or faster. This and smoke inhalation, because it seals so well, were the cause of one nightclub disaster.
So we see that in paneling a component vehicle, there are a myriad of decisions and paths to take to reach the final product of our enjoyment.
Here is the excert. It is becomming a little dated with the advances that are being made. Do a Google search as well.
Bill
For non-strength sealers, Urethane calk is best. Elastomeric is next then Latex and butyl rubber is last. All are paintable. GE Silicone II DAP, Polyseamseal NP1 by Sonneborn (found in roofing supply stores only) and 3M Marine sealant are some of the brand names. Most are flexible and paintable. Most cure from ½ hour up to a week
Duramix™ Side Glass Channel Adhesive a 3M product that is a semi-rigid urethane material for bonding side glass to metal or plastic channels, sets within 3 minutes. Glass becomes structurally bonded to channel within 10 minutes.
Each of these products along with many others is used in the automotive repair industry in place of welding where warpage is the prime culprit. All have shown through crash test to be as strong as welding.
For ordinary sealing of holes or leaky joints, the typical silicone calks found at most home supply houses works well. Just be sure to get the kind that, 1. dries clear and/or 2. is paintable. It might be noted here that anytime you use rivets, you should consider putting a layer of these materials between the panel and the frame member being bonded preventing the eventual vibration induced rattles that can sometimes accompany rivets. With as many rivets as are being used, you can count on one or two not setting properly.
Insulation
No talk of paneling would be complete without mentioning insulation. The purpose of insulation is three fold. First is the blockage of heat. With waterlines in the cabin, an engine under your elbow and a radiator at your feet, the need for good insulation is obvious. The second purpose is to block sound. GT40s are noisy little creatures, wonderfully so, but we owe it to ourselves and our riders to try our best and abate as much of the noise as possible. Remember, you are in an enclosed space with an engine under your elbow spewing out 250 to 600 H P. That makes for a lot of noise and heat. Any and all panels that are contiguous with the cabin should be insulated. That means door panels, floors, engine bay, foot wells, wheel wells, central tunnels, roof panels, and outfacing bonnet surfaces (inside surface of wheel wells). The third purpose is to block out the transmission of noxious fumes. Not thought of much but is a consideration none the less (see Sealants and Adhesives).
Now all we have to do is decide which type of the stuff is best for what we want. The choices are many. There is rigid low compressible foam, cellulose or fiberglass batt, honeycombed air gaps, expandable foam, dual-purpose aluminized agents, polyurethane, and the list goes on and on. Each has its good and bad points. Since we live in a cramped environment, we need something compact and efficient. Some of the better products that are out there are listed below. This is not an all-inclusive list, as there are so many products out there to choose from. Most have fire retardants added. Some don’t and will support combustion. That is not necessarily a negative point. One must remember that we are surrounded by fiberglass, which also supports combustion.
Most products that should be considered for the first two purposes are a form of foil faced blanket type of material that will block 97% of heat transmission and is from 3/8 to ½ “ thick and is easily trimmed to fit. Some come with adhesive applied. Currently, polyester and polypropylene rank among the top materials of choice for auto insulation commercially. The Urethanes are rapidly beginning to take their place, and can be found throughout modern day cars. Some of the new products in the home building industry (spray on foam) can be adapted to automotive use. Most are a two part polyurethane products with an expansion of about 8:1 with fire retardants added.
Most sound transmission can be eliminated or reduced in one of the following ways:
Damper – by far the most common type of material. It uses mass loading to lower panel resonance and absorb structural vibrations, converting them into low-level heat. Most commonly used throughout a vehicle to control structural related noises. They can also be used in conjunction with a composite to reduce road/engine/exhaust noise.
Absorber – as the name suggests, these products literally absorb airborne sound waves. The sound waves have to propagate through the absorber and the open/closed cell foam will slow its progress reducing the overall level in the process. Most commonly used on floors and firewalls to reduce road/engine/exhaust noise.
Barrier – as the name suggest, these products form a barrier or wall, which blocks airborne noise from passing through. The denser the barrier, the more effective it is, which makes lead (although heavy) an excellent choice for a barrier. Most commonly used on floors and firewalls to reduce road/engine/exhaust noise.
Composite – Best results are achieved by using more than one method of sound deadening, so a composite is quite simply a combination of two of the above types into a single easy to install product.
I am listing two products to give an example of what can be used. This is not an endorsement, but a good example of what is out there.
B-Quiet® Extreme is a 1.15mm (45mil) thick composite mat which consists of rubberized asphalt with an aluminum constraining layer. When the paper backing is removed the adhesive surface forms an incredible bond to ensure optimum deadening performance. It can be used on floors, doors, roofs and trunks, but not under hood (read engine bay). It weighs 0.30lb/sq. ft., comes in 1-foot wide rolls and is available in two sizes: 12 and 50 sq. ft. rolls. $84.99 each is about the going price in the U. S. for the smaller sheet. Discounts for the larger.
B-Quiet Ultimate is a viscoelastic deadener with a supercharged butyl based adhesive. With aluminum constraining layer and a unique composition with suspended mineral particles it has been proven to be extremely efficient at the conversion of vibration to thermal energy. B-Quiet Ultimate is extremely flexible which allows it to properly adhere to a contoured panel. It can be installed anywhere including under hood. B-Quiet Ultimate is 1.6mm (60mil) thick, weighs 0.35 lb/sq. ft. comes in 1 foot wide rolls and is available in 2 sizes - 12 and 50 sq. ft. rolls and is $129.99 and up.
Dynamat Xtreme® is a butyl and aluminum vibration damper. It conforms and fuses easily to sheet metal and other hard substrates. It can be installed anywhere including under hood. Dynamat Xtreme® is 1.12mm (44mil) thick, weighs 0.45lb/sq. ft. comes as nine 18" x 32" pieces for a total of 36 sq. ft. and is $194.99 and up.
A cheaper more labor-intensive alternative is to consider the insulating foam sealants used in the building industry. Names like Great Stuff comes in aerosol cans at most building supply stores. NTAP X-30 Polyurethane Foam, a 2 part pourable foam expander. Mixing ratio A/B by weight 50/50. Mixing time 20-30- sec., rise time 2-3 min., tack free 3-10 min., with full cure 24 hr. This product is best done in several small pours rather than one big one. Fomofoam, a two-part spray for vertical surfaces. Comes in propane type containers. All form airtight and waterproof seals, bond to most materials, cures rigid and is easily trimmed with an electric carving knife etc. Just be aware that, they can be messy as they are very sticky. If the surface or adjoining surface is a painted surface, it should be covered with “plastic wrap” from the kitchen drawer and taped in place. All holes and gaps should be taped closed. But remember this stuff is expansive and will push things out of its way if there is no place for it to go. If you have double layered panels, it is a great filler and insulator. Just give it an escape route for accidental over filling. If it does get on the aluminum or stainless, most solvents/cleaners/polishes or elbow grease will bail you out. If used in the central tunnel, block off the cooling pipes to cover just them or wrap all wires, cables etc in some form of PVC piping, and line the tunnel with plastic wrap so that it can be removed for repairs. Remember this stuff bonds to all surfaces. Mixing two liquids, a polyether polyol and a polyfunctional isocyanate produces polyurethane foam. Like all organic material, when they are exposed to an ignition source with enough heat, polyurethane foam products will burn. Even the most flame retarded urethane foam will undergo combustion at temperatures exceeding 550C (1022F). There were a few commercial building fires using polyurethane insulation, that were deadly, but investigations showed that the polyurethane’s did not actually burn (although they did char), but what happened, was that they were such good insulators, that the temps rose very fast and caused what is known as flash over, where, because of the reflective nature of the insulation, the fire travels at an extremely high rate of speed. Upwards of 60 to 100 MPH or faster. This and smoke inhalation, because it seals so well, were the cause of one nightclub disaster.
So we see that in paneling a component vehicle, there are a myriad of decisions and paths to take to reach the final product of our enjoyment.
Last edited:
Lynn Larsen
Lynn Larsen
Dean,
For best price, check out McMaster-Carr. I used a two sheet system in areas that weren't visible (for visible areas I used Dynamat Extreme; although I think there are cheaper alternatives that work just as well now.) For the two layer system, I used a closed cell, flame retardant polyethelene foam over high temp mastic. This is what I used under the carpet on the back wall of my car.
I was worried about making my car too quiet, but that isn't the case. I can still hear the engine and, especially, the exhaust note, but you can carry on a conversation with your passenger without having to scream or invest in an intercom system from Aircraft Spruce. The other advantage is that no one will ever say they are riding in a rattly kit car -- a comment I heard on a Speed Channel test drive program that really got under my skin. Of course, this is totally irrelevant to someone who is building a car primarily for the track, but some of us are building, or have built, road cars.
For best price, check out McMaster-Carr. I used a two sheet system in areas that weren't visible (for visible areas I used Dynamat Extreme; although I think there are cheaper alternatives that work just as well now.) For the two layer system, I used a closed cell, flame retardant polyethelene foam over high temp mastic. This is what I used under the carpet on the back wall of my car.
I was worried about making my car too quiet, but that isn't the case. I can still hear the engine and, especially, the exhaust note, but you can carry on a conversation with your passenger without having to scream or invest in an intercom system from Aircraft Spruce. The other advantage is that no one will ever say they are riding in a rattly kit car -- a comment I heard on a Speed Channel test drive program that really got under my skin. Of course, this is totally irrelevant to someone who is building a car primarily for the track, but some of us are building, or have built, road cars.
I am using a product called b-quiet. Much cheaper than Dynamat Xtreme and seems to be very similar.
B-Quiet sound deadening material
I am, however, looking for what to use on the engine-side of my new aluminum access panel. Something about 1/2 inch thick with excellent heat resistance.
B-Quiet sound deadening material
I am, however, looking for what to use on the engine-side of my new aluminum access panel. Something about 1/2 inch thick with excellent heat resistance.
I have totally covered the interior of my Pantera with Dynamat Extreme and am very pleased with the results--mine is among the quietest and most-solid Panteras I've been in (and I've been in hundreds).
However, I had a resonant buzz in the gas tank shield, which is a rather large and poorly supported piece of polished stainless steel sheet. Dynamat couldn't put up with the heat, as it is right next to the exhaust headers, so insetad I turned to Aircraft Spruce for some super-duper 3M stuff:
http://www.aircraftspruce.com/catalog/appages/dampingpanels.php
This stuff appears to have many of the benefits of Dynamat, as well as being designed for use in the extreme environment of an airplane engine bay. I haven't actually been able to install it yet, but it sure looks promising!
Thanks Mike,
That is EXACTLY the stuff I was looking for!
That is EXACTLY the stuff I was looking for!
Ross Nicol
GT40s Supporter
I have a fair bit of experience with sound control,resonance lowering and acoustics in general but not so much with vehicles.I have nothing in my race GT40 for weight reasons but I did use a type of Vinyl, backed with a very thin material which did make it unexpectedly heavy for it's thickness.Found it Ideal for the firewall in a Lotus Europa. The ultimate for sound reduction is lead which you are unlikely to use but weight is generally a by product of good sound control materials. If I did fit anything in my 40 for road use it would be carpet in the interior and sound deadener on the engine side of the firewall.
Ross
Ross
