How is a car muffler / gun silencer constructed?

[Szech]

No, I'm not planning on killing anyone http://www.sysopt.com/forum/smile.gif. I would actually like to make something similar to these devices and attach it to the air intake/exhausts in my case. From my simplified understanding of it, the inside of the sound suppressing device is lined with some sound absorbing material, and when sound waves from pistons or bullets go through the middle, they are reduced/deadened in that material. Is this about right? What would be a good material to line the inside with? What is the maximum thickness of the airway before it is ineffective?

Thanks!

[rlpos]

as far as a auto mufler goes and especially exhaust pipe. A 2" pipe compared to a 2 1/4" pipe the 1/4" will give you about a 60% increase in flow (if I remember correctly from back in my hot rodding days) Dont know about silencers

[Yar1182]

Bronze screening. One thing to consider when building something for you application is to add baffles like a muffler and less like a silencer. On a silencer the gas behind the bullet will follow the path of least resistance which is into the ports into the silencer. If there was no bullet it would leave strait out the barrel.

A muffler forces the air to change directions several times as it travels though the baffles. this is what quiets the noise.

I don't see how this will help your computer case. Silencers and mufflers work by slowing the expansion of gas which makes the noise. you computer problems are more likely caused by noisy components such as fans.

[MiKe85]

Szech:

I will e-mail you about some instructions on how to make a gun silencer..

The reason i've decided to e-mail you about it, is because to my knowledge your not allowed to have a silencer on a concealed weapon. http://www.sysopt.com/forum/smile.gif

[OuTpaTienT]

Mike85, that doesn't mean you're not allowed to talk about it. What country do we live in again? Sometimes I wonder.

[thekingofpain]

Its called conspiracy, I tell you how to illegally construct a silencer for your threaded barrel Uzi, which would of course be above the law here in California...

con·spir·a·cy (kn-spîr-s)
n. pl. con·spir·a·cies
An agreement to perform together an illegal, wrongful, or subversive act.
A group of conspirators.
An agreement between two or more persons to commit a crime or accomplish a legal purpose through illegal action.
A joining or acting together, as if by sinister design.

[muno]

The things I've wondered are pretty much covered in here -> http://www.howstuffworks.com
I'm not saying they say there how silencer/muffler is built but for future reference =)
-M

[narayan]

I have a piece of light foam, about 8.5 x 11 rolled up into a tube, with another piece of the same foam over the end of it hung by a piece of tape so it can open when the fan turns on. This "muffler" is taped with duct tape to the case around the fan and works pretty good.

[Mr.Goodbytes]

I don't know if it's illegal to construct a silencer/supressor. But it would be illegal not to register it and pay the federal license fee, which i believe is $200. I generally call them supressors, since unless you have a huge silencer, you'll still hear a bit more than the click of the action. I believe that the only round you can truly silence is a .22. Not 100% on that one, but i'm pretty sure.

[Sea Walnut]

YAR!!!! Hey it's Ren from PBD! What's up!? Anyway....

Yar's right about the "sound" changing directions... basically a silencer operates in three functions:
1.Changing/diverting/dividing the path of sound, thus "muffling"
2.Depressurization. Takes the "bang" off
3.Also takes out the muzzle flash, but god help you if you have one of those coming out of your case LOL

Anyway, think of your computer case as a double bass... the noise RESONATES, so really your best bet would be to do something to the WALLS of the case, like line them with fels (even though that's stupid). Your best REALISTIC bet would be to take out as many fans as you could, upgrade to more efficient components and buy higher quality fans. Also, tie your cables and plan out a more efficient flow path.

[YMK]

Run larger fans at lower speeds to get identical air flow at near silent noise levels. I have a single 120mm fan running at 7 volts / 750RPM on the side panel sucking in air and blowing it out the front 3.5" bay. It is nearly silent.

[Yar1182]

Sea Walnut aka Ren

God help this board if it get's flooded with paintball guys. I hope Deadnedz never finds this board.

back to subject
To really quiet your rig swap out the power supply and fans. A PC Powers and coolings "Silencer" Powers supply and case fans will really get the noise level down. If you do too good a job (enough to quiet the rig) by using sound damping material, or baffles you risk raising the temp inside your rig.

[Warthog]

To be "trully" silenced, a round has to be subsonic, ie its speed below the speed of sound. That way it does not make the minature sonic boom because it does not pass the sound barrier. Also, the bolt would have to be cushioned or something done to it so that it does not make a click noise.
Any subsonice round can be suppressed. That includes most, if not all pistol rounds. The .22 is technically a pistol round, just like the 9mm.

You can construct silencers, but are not supposed to use them, whatever that means http://www.sysopt.com/forum/smile.gif. There are many pages on the net that have instructions.

Yes, you are supposed to register a firearm suppressor with the BATF (Bureau of Alcohol, Tobacco and Firearms) for a small fee....but who is gonna catch you? I think it's ridiculous to register it, unless you are a legal freak.

Warthog

[Yar1182]

Most rounds below 9mm can be "suppressed" with the use of a silencer. You can slow down the expanding gasses (what really makes the miniture sonic boom) to a point where it fits the application. Of course this would not work on rounds using "hot" loads (more gun powder) because there would be more expanding gass and the bullet itself would get near sub sonic.

[nilknarf]

okaaaay....getting a little off topic here.....

On topic, there are typically three main noises in computers. HD/fan motors, airflowing, and power supply. Several simple ways to deaden the sound:

1. - Buy quieter components

2. - make sure all parts are locked down tight and place rubber/foam rubber standoffs on everything to isolate it from everything else. (oops! I didn't mean to give away the military's most widely known secret!)

3. - install sound deadening materials such as baffles and sound insulating fabric.

Tim