What kind of foam for sound deadening

[woodlandfarms]

Wow guys, FANTASTIC ideas. So....

Got the McMasters, understand the airflow issue... will look at automotive insulation with mechanical fasteners.

PabOh. Is that your rig at the bottom you are working on. I have seen some things similar. Looks way cool. Appreciate all the sound insulation ideas.

Sonex. Yeah, every room I go into to mix a movie has Sonex or some derivative of it. I just don't think it will survive in a tractor environment.

Dynamat is very cool stuff, I have it in my charger, but I cannot add any more weight to the engine housing as it is a real pill to lift as it is.

Exhuast... Lets broaden the topic to exhaust. This is a 65HP engine. The exhaust blows, and right behind the drivers seat. I was mulling over adding a second exhaust. It would have to be like the size of a cherry bomb (exhaust pipe) to fit.. It would vent out the back, close to the intake filter. I think the exhaust outlet is like 2" or so on the current muffler.

Any ideas on this plan? I know on a 4 stroke you want to watch out for too much back pressure, but how about diesel?

 

[mjncad]

I tried Dynamat on my noisy computer and it didn't do squat. Has anyone had success with this stuff? Just because the TV hot rodders use it doesn't necessarily make something good.

McMaster-Carr is my favorite place to get stuff. Are they pricey? Yes; but they have stuff you won't find anywhere else and their customer service has been wonderful when I've had to deal with them on rare occasions.

 

[Treemonkey1000]

I'm not sure if diesel engines need to worry about too much back pressure or not. Unless you really constricted the exhaust flow. Could you change the torque curve with tuned exhaust?. I rode in a buddys 2005 Chevy with the big diesel in it and was impressed by how quiet that thing was. So they have done something right with that exhaust system. A good quiet muffler doesn't have to be huge. And going dual exhaust could decrease the size of a single muffler.. Keep in mind that exhaust temps seem to be higher in diesels so that would be a consideration. Geez I wouldn't have to wear ear plugs if my little Kubota had a decent muffler.
Mjncad if you want to quiet your computer down get one of the super quiet fans that they have out. Better yet they have computer chillers that cool the system sort of like a refridgerator. The fan is the noisiest part of the computer. Sound proof material helps. Here at work we have to change out fans when they get old an noisy on electronic equipment.
Woodlands this is a good topic thanks for bringing it out. I would like to HEAR how it ends up.

 

[Travelover]

I worked in automotive noise and vibration for years. Here are some basic tips.

Quiet the exhaust and intake as much as you can first. Get the exhaust discharge & air intake away from the operator as much as possible. There are sophisticated ways to tune intake and exhausts, but volume works wonders in general.

There are three basic kinds of sound packaging.

An absorber is placed on a surface to keep sound from being reflected. Typically in a car this is on the engine side of the firewall and under the hood. Melamine foam would be good for a tractor. Thicker is better, spaced off the surface increases efficiency.

Damping is provided by heavy rubber or tar paper types of material. It works by mass loading a panel and turning vibration caused by sound waves into heat. Typically this is installed on floors and other panels that are between the operator and the sound source. The Dynamat is an example of a damping material.

The third kind of sound packaging is a barrier. This is basically a heavy, dense material separated from the sheet metal by a soft material like foam or felt. The high end stuff uses lead sheets sandwiched in foam. Typically these are used on the passenger side of the firewall and on the floor,with carpet fused to the top. The thicker the soft (decoupler) material, the more effective it is.

A final tip, sealing of the cab is all important for high frequency noise like diesel clatter and hydraulic squeals.

Good luck.

 

[Treemonkey1000]

Sounds like the voice of wisdom DetroitTom thank you for that input. It makes sense after you put it that way. The exhaust stack points straight up in the sky on my tractor. So you get to see it like a big chimney and smell it. Maybe reroute it down and towards the front of the tractor. The air filter is under the engine shroud by the Instrument cluster. As far as sound proofing the engine compartment I would leave it alone on my tractor just to avoid material for mice and squirrels to use for nesting. And trapping heat under there.
Would the cast iron exhaust manifolds be quieter than steel ones like the ones used on gas engines?
Jim

 

[Travelover]

The surface of the muffler radiates sound in all directions. On cars they use a dual, laminated layer on the muffler and pipes to minimize this. Routing it away from a line of sight to the operator will help.

Cast iron manifolds are quieter than steel, but not worth changing on an existing product.

I understand about the mice and squirrels. Mice nested on top of my radiator and had my headlight wiring for lunch!

One other tip about reducing sound. You have to get rid of sources in order of their relative loudness, otherwise you won't notice the difference. The dripping faucet that keeps you awake at night, isn't even noticeable during the day with all the other noises.

 

[Kendrick]

Mjncad if you want to quiet your computer down get one of the super quiet fans that they have out. Better yet they have computer chillers that cool the system sort of like a refridgerator. The fan is the noisiest part of the computer.

you have not HEARD my servers hdds then i can tell when a email comes in from the front room...

For fan noise you have to pay attension to the db+cfm 120mm fans running at around 2000 rpm are normally pretty quiet.


I agree with the muffler thing. that would do the most quieting in my case. no good room to put sound proofing in the engine compartment and the cab seems to amplify instead of deaden... till i open the window or door

 

[mjncad]

Mjncad if you want to quiet your computer down get one of the super quiet fans that they have out. Better yet they have computer chillers that cool the system sort of like a refridgerator. The fan is the noisiest part of the computer. Sound proof material helps. Here at work we have to change out fans when they get old an noisy on electronic equipment.

After I put in the Dynamat on the PC and the second or third cheap and quiet Chinese made cooling fan puked; I dug out a 120VAC box fan from a Sperry-Univac mini computer and put it on the PC. Solved the cooling and noise issues. The box fan is over 20-years old, runs like a champ and is rebuildable, which I have done every few years. I managed to snag 2 or 3 of these fans before the computer was scrapped, and I wish I had more. Back in 1979, a mini computer consisted of a cabinet about the size of 3 refrigerators placed side by side.

 

[Soundguy]

Sonex. Yeah, every room I go into to mix a movie has Sonex or some derivative of it. I just don't think it will survive in a tractor environment.

?

We've used sonex in outdoor venues for years now.. as long as it has a rain shield over it.. I havn't seen any real problems with it beling left open to the air from the sides.. etc.


soundguy

 

[PILOON]

I have done some soundproofing on aircraft over the years.

Large (thin) metal pannels can 'drum' and many aircraft mfgs simply make an 'X' with a tarry type material on large pannels.
An X with a tube of caulking or a dense tape will improve or deaden that type of nuisance.

Dense foam that is self adherant attached to an engine cowling will cut out many engine noises.

Covering the firewall with dense self adhesive foam (about 1/4") will deaden engine compartement noises.

3M makes a dense self adhesive 1/4" foam coated with lead that is super efficient to deaden most engine derived noises. Bell helicopters use the product to kill turbine noises in the Bell 206"s and is sells as a 'hush kit'

I once did my cesssna with all these 'tricks' and could then hear the valves clacking as all other sounds were deadened.

On my tractor roof (large flat pannel) I glued 1/4" foam followed with a vinyl fabric. This deadened any drumming sounds and also prevented condensation plus kinda insulated heat and cold transmission to the cabin.

For a muffler you could always wrap it in fiberglass (fireproof) a-la hot water tank insulation approach which should cut out the 'tinny' echo sounds.

It all boils down to frequancy and what is best for that particular frequancy range.

Low frequancy wants to be deadened or absorbed (felt, dense foam even tar paper)

Higher freq's want lead or denser plastics.

Tentest is also a great sound absorbant.

My home gas generator is housed in a plywood box with old carpeting stapled to the inside walls of the box. You can now hear the valves clacking but not the other noises as the carpet absorbs most of the middle to higher pitched sounds. (this works great for compressors and pumps also( Just allow enough openings for air circulation.