self made silencer

[Visser]

Hey I'm just wondering if anyone has tried putting dynamat in to dampen the sound? If so how did it work and find anything else that worked better?

[mcguyver]

Dynamat won't work for you. I spent the better part of 10 years working with it and as it adds mass to whatever you layer it on to, but it won't reduce the report of an airsoft gun at all.

The theory behind mass-loading to dampen vibration (ie sound) is old and is used everywhere. Dynamat, CAE and many other brands use the theory of mass-loading to reduce the permeability of the original substrate to certain frequencies. When you add mass to an object that used to resonate at 2KHz, you will have a new resonant frequency, but it may be 200 Hz or less. You are trading the energy to transmit through the original substrate at 2Khz and using it to resonate it at 200 Hz, which will reduce it's perceived output due to the non-linear way we hear sounds.

But, as the report from a gun barrel will be very low frequency with resonances within the gun itself producing much higher frequencies, Dynamat in a silencer will basically be a waste of perfectly sound dampening material.

Open-cell foam is the best way to go if you want effective silencing

[Visser]

aight thanks mcguyver any ideas where I could find an open-cell foam?

[mcguyver]

Upholstery shops use it for cushions, etc. The black stuff is ideal, but a 2" thick piece might cost you $40/metre, but there's enough there for 20 or more silencers.

If you want to cut it into a cylindrical shape, take a piece of metal that you will use for the body of the silencer. Take one end and sharpen it on a grinder. Then cut a piece of foam that will be the length of the silencer's interior. Twist the sharpened tube into the foam and it will cut through it like a hot knife through butter.

Do the same thing again to create a hole for the inner barrel or the BB to travel through, depending on your application.

[ILLusion]

What if Dynamat were applied directly to the gearbox? I've had a sheet of it to be applied to an AEG gearbox for ages, but I've never gotten around to it. The idea made sense to me... surround the motor cage and the gearbox, and the motor/gear whine will be limited.

Then your gun won't sound like a sewing machine anymore.

It'll sound like... umm... a lower pitched sewing machine!

[Murdoch]

Let me know if you want to get rid of that Dynamat, Illusion. I'd love to test it on my aug. With the mechbox right below your ear when firing, any sound deadening would be a relief...

[Hectic]

Originally Posted by ILLusion

What if Dynamat were applied directly to the gearbox? I've had a sheet of it to be applied to an AEG gearbox for ages, but I've never gotten around to it. The idea made sense to me... surround the motor cage and the gearbox, and the motor/gear whine will be limited.

Then your gun won't sound like a sewing machine anymore.

It'll sound like... umm... a lower pitched sewing machine!

You may also consider doing the inside of the receiver to contain the sound within like doing the trunk of your car to keep the sound of your sub woofer in the trunk and car forcing it forward to increase DBP a good way to see if this may work is if a metal bodie gives a different sound than a plastic one then the sound could probably be changed quite a bit by making the plastic one denser you could also try just temporarily putting it on the outside of the AEG and see how that sounds great idea and I hope to hear more about it.

[CDN_Stalker]

I got some 1/4" thick black open cell foam from work (ESD stuff) and literally made a roll and stuffed it into my MK23 suppressor and it works pretty good, better than the stock assembly that was in it before.

[Jayhad]

Dynamat will work well in an AUG, there are a few guys here in Calgary that have done that and it realy works. When I had my aug with no silencer next to a dynamatted AUG with no silencer there was a noticeable difference.

Not to disagree with macguyver but don't sharpen the tube and push it through the foam, you with then have a sharpened piece of scrap tubing. Heat it up it will melt right through the foam

[Greylocks]

Plumbing pipe foam insulation is dirt cheap, cylindrical and it works. Go to almost any hardware store.

[Visser]

I had thought of that greylocks but is that open cell foam? I thought it would bounce the sound more than absorb it cause its pretty tight and doesn't seem like much air flow would be able to go threw it.

[mcguyver]

Originally Posted by Jayhad

Not to disagree with macguyver but don't sharpen the tube and push it through the foam, you with then have a sharpened piece of scrap tubing. Heat it up it will melt right through the foam

If you are making a silencer, use the extra tubing to make a cutter. Don't sharpen up your silencer.

The pipe insulation doesn't do a thing. Tried it already.

Dynamat on the mechbox shell should reduce the higher frequency resonance that cast alloy will have. Foam around the mechbox of an AUG works better. When I had my AUG with foam around the mechbox and a silencer, guys couldn't hear it from 20 feet away in the bush.

[HaZarD SFD]

I am thinking of putting dynamat inside the stock of my M14 where I can to make the rifle quieter than it already is..

[digital_blue]

Just to let you know, silencers are labeled as prohibited devices. I wouldn't make one if I were you. It wouldn't look too good for the airsoft community if you were caught by a police officer with a homemade silencer and an airsoft gun...

[Amos]

Originally Posted by digital_blue

Just to let you know, silencers are labeled as prohibited devices. I wouldn't make one if I were you. It wouldn't look too good for the airsoft community if you were caught by a police officer with a homemade silencer and an airsoft gun...

It's a foam filled barrel extension.

The foam pads the extended inner barrel so it doesn't have any harsh movement.