made my first internal LDC today
okay, so i thought i’d give it a shot (NPI), and took a trip to home depot. about 90 minutes later, i’ve got quite the silencer. on a power setting of 9.5, she’s whisper quiet. i vented the frame too and the front bushing. there’s quite a bit of air coming out of the four holes i drilled into the frame. i’m going to chrono her in a few after the neighbors go inside and i can get a few shots off in my garage. i used a bunch of fender washers, o’rings, a spring, and some plastic spacers. i can’t believe how quiet she is. i’m sure i’ll take the gun apart in the next few days and i’ll post pictures. i should have my DB meter here sometime this week, so I can take some readings with Tony’s shroud, a rich from michigan LDC, a kirk from arizona LDC, and the logun QGS. Should be an interesting showdown to see which one is the quietest. who knows…maybe mine will win??? lol (yeah right).
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Shadoh: put up a thread in the “For Sale” section with the price, product etc and let’s see how things go. I think that you could get a good response, especially if you are flexible enough to make slightly larger or smaller Baffles if needed.
After asking for suggestions for a fair price for a set of those baffles 150.00 has come up several times. When I asked in the past it was pretty much the same number.
Sooo, if you would like a set that is the number Im going to go with. I could also turn you a custom end cap at the same time out of ali or stainless for a bit more depending on what you wanted.
I think it takes more than just the first baffle to create all that back pressure but basically yes. When I loaded one baffle at a time and just spacers to put them where I wanted them my DB meter showed the sound reducing after adding each baffle so I know the rest of them help in sound reduction and allowing less air out of the front hole.
So most of the backward blast is from the first larger chamber?
And the rest of the baffles/strippers act kinda like a car muffler?
They are pretty much sealed chambers. As each chamber pressurizes it puts back pressure on the air following it. IMO each chamber acts like a little air brake with less and less pressurized air making it through the whole set of baffles. The air has to wait until the pressure drops to bleed off out of the front of the gun or find another way out. With a vented barrel bushing and a vented frame this is the path of least resistance and more air actually comes out of my frame holes than out of the front of the gun.
I was going to post pics but havent got around to it yet but I will describe what I saw when I removed my baffles recently.
Every time you fire your gun a very small amount of led dust comes out of the end of the barrel. Over time this lead dust builds up and you can see a pattern develop and see where the air is going. There are 5 or 6 chambers in my setup depending on how you count them. The first baffle next to the barrel is completely coated with lead dust. Its a solid dark gray coating. The following baffles have progressively less dust than the first one ending up with the last baffle in the series having absolutely no dust on it whatsoever.
My vented bushing was just the stock bushing drilled out in an almost planned out pattern. The holes going through this baffle are completely coated in the lead dust. The holes in my frame also have lead dust on them. I havent removed my barrel but Im willing to bet that there is lead dust in that back chamber behind the bushing.
Looking at the trail of dust I think its pretty easy to see that the air is mostly going out of the rear frame holes. What I need to do next is plug those frame holes or at least pack that back chamber with some dampening material I.E. Scotchbrite or some other type of packing material.
Shadoh-I have a stupid question.
How does the HPA from the chambers escape back through the vented front bushing? Looks like they are sealed off when assembled. ❓
Quote:” Oh, many folks have asked me to make them a set of those baffles but the cost is prohibitive. It just takes so much time to make them. Ive asked this before but nobody can ever give me a direct answer ). What would something like that set be worth?”
Best way to determine cost is to assign yourself an hourly rate for your work times the number of hours needed to build it. Then add 50% to it.
Once produced in quantity your time per unit will drop.
Class III suppressors start around $450 and to look at them I don’t see $10 worth of materials
I will get some pics up soon of the lead dust trail but it definitely goes out the back way and not out the front of the gun. That tells me that most of the blast is being stopped and pushed out those holes in my frame.
Sound Great….. How much would it cost me to get a set of those baffles from you? 😀
Oh, many folks have asked me to make them a set of those baffles but the cost is prohibitive. It just takes so much time to make them. Ive asked this before but nobody can ever give me a direct answer ). What would something like that set be worth?
Material cost isnt huge, its the hours it takes to make them. Ive only made the one set and I bet I would get faster if I set up to make a run of them but the first set took something like 5 to 7 hours on my little machine. All the parts were turned from solid billet, even the tubes that go between the baffles. Maybe if I had something to compare them to, say a set of Anthony’s baffles and what he charges I would have a better idea. You could even PM or Email me with the info if you didnt want to post it here.
Please do. Ive always wondered if the holes actually made more noise than they removed. I even bought some allen screws to put into them just to see but never got around to threading and putting them in.
I will get some pics up soon of the lead dust trail but it definitely goes out the back way and not out the front of the gun. That tells me that most of the blast is being stopped and pushed out those holes in my frame.
I think venting the frame may have made it louder. I’m going to fill the holes and see if that makes a difference after I get the ole DB meter this week. i’ll post my findings.
Yeah, that is absolutely georgous. dont suppose you’d make me a set of those? 🙂
nice piece of machine work there.
I just made mine so that they stacked in the frame the same distance that was available. I then used a rubber Oring to fill the last bit so that I could snug the endcap down and have the whole thing be tight.
I may post an update to my post here
http://talonairgun.com/forum/viewtopic.php?t=83&highlight=baffles
After shooting it for awhile like this Ive pulled it apart to make other stuff and noticed a nice pattern created by the lead dust. I think it tells the tale on how well my rig works.
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Martin, you are dealing with 2 elements, and need to keep them separate in your head. One is air flow, which doesn’t like to turn sharp corners and has inertia (momentum) and is subject to turbulence. The other is sound waves, which in this application is simply air with micro compressions and rarefactions (rapid changes in density). In a car muffler, your object is to reduce sound but you are not restricted to a straight path; you can do anything you want to including placing baffles directly into the path of the gas. In the airgun, if you do that you’ll obviously shoot it the first time you fire it so you must have a clear axial channel, which the air and sound will obviously also try to follow. Your job as a designer is therefore to use what you know about the differences in the two elements to try to separate them physically and trap or attenuate them to reduce the sound signature.
walt