Here's the tools we'll use. Pretty standard except for that odd shaped, dark dremel bit. It's a very fine abrasive polishing bit that is similar to a rough pencil eraser. The weird pigtail looking piece of wire is wrapped around a 30watt soldering iron and is used to locate and start the barrel ports. The drill bit is 1/8".
Here's our materials. An empty caulk tube (or quickcrete for yellow!), some cottony material (I used a ripped up aquarium filter), some fbr blanks (I used pool noodle material) and a few rubber bands.
Fill the caulk tube with hot water. Clean the inside surface with a toothbrush to remove the caulk residue and free the plunger in the end of the tube. After it sits a few minutes, empty the water & push on the plunger (through the nozzle hole) with a blunt instrument till it falls out. Clean out the remaining caulk. Cut the nozzle off the tube. Add a starter hole to the middle of the plunger with the small burr-style dremel bit. Enlarge the hole there and at the nozzle end with your drum sander bits until they fit tightly over your barrel like so:
Now we'll port the barrel. Make sure that the first hole will wind up inside the caulk tube when it is fitted on the barrel. I like having the muzzle stick out a bit past the suppressor so I can really push the barrel into the coupler.
Here's the soldering iron with my weird, makeshift tool attached. Let the iron heat up for a few minutes. If the wire slips off the iron, let it heat up a minute before you try to make another hole. It should take about 10 seconds to burn each hole.
Here's where I placed the first port. The mark shows the inside edge of the suppressor. The hole should wind up a ways back from this to improve airflow.
I then marked a spot directly across from this hole with a mechanical pencil.
Now we can easily drill though both holes. Here I show the process repeated. This "cross" of four 1/8" holes will allow us to eyeball the rest, making construction smoother. The rest of the holes will be kept smaller.
Continue burning holes in the barrel in 2 lines, for a total of 16 holes. Start the second line of holes behind your original to ensure that the ports stay inside the main body.
Now we'll bring the ports to their final shape and smooth the interior of the barrel. I will start by running the burr dremel bit along the inside edges of the holes at an angle as pictured. I use my thumb as a brake on the collet of my janky dremel and go at a low speed to avoid scratching the interior of the barrel.
Now to concentrate on smoothing out the inside of the barrel port area. You can see that I have worked on the first line of holes. I will use my Stanley knife to carefully remove the debris that I can. I will go over any stubborn areas with the burr bit again. After that there are usually a few small bits of flash left. I'll use that red conical polishing bit, by hand, to remove that. The dark rubber abrasive bit is used at the very end to hone up the whole area (again by hand). It is all important that this area be completely free of any burrs or flash. If there is any effect to accuracy at all to your blaster the answer will likely be to check this area.
I chamfered the outside of the ports and sanded the whole area.
I added 4 holes to the endcap like so:
We can assemble it now. Push the endcap on all the way. Wrap the cottony material around the barrel and secure it with rubber bands.
Insert the barrel into the main body. Stuff some blanks in the space left. I used 8.
Push the endcap into the main body and feed the barrel through, stopping when it's flush like so:
Done! Shown on my BBB, since it was nearby. This is for Spring and Air powered blasters.
I've tweaked this design 4 or 5 times and this iteration is particularly effective. Some sophistication can be added. A 2 stage system can be implemented by adding another plunger (with perforations) in the middle of the main body. 2 caulk tubes can be linked to provide more volume. Some experimentation with the damping materials can likely yield benefits. Variables like volume, location & diameter of ports, length of the barrel between the port area and the muzzle, etc., can be played with. There are some improvements that can be done to make the suppressor easier to move from blaster to blaster and be more secure. If I manage to stay out of Guantanamo I will update this thread.
This device attempts to dampen the sound of any "pop" accompanying a dart being fired. It re-reoutes some of the air that escapes the muzzle along with the dart upon firing. The space allocated to capture the incoming air uses baffling and pressure to change the sound profile of the "muzzle report" of the blaster. It is surprisingly effective. It effectively silences the report of many blasters it's fitted to. The noise floor is lowered to the point that you will have to go in and silence the internals of your blaster thoroughly. Accuracy is unaffected if it's built carefully. Legality is a non-issue in the U.S.. Outside the U.S.? Dunno.
Testing & Basic Tuning :
1) If you seal the muzzle with your finger and blow through the breech end of the barrel there should be an easy, unrestricted flow out the ports. If there is sputtering or any resistance, and your ports are all clean and evenly shaped, make the holes larger.
2) The 4 small holes in the endcap serve a purpose. There needs to be steady airflow, but with some noticeable resistance here. Assemble the main body and endcap without the barrel. Use your finger to seal up the hole the barrel would fit through and blow through the muzzle end of the main body.
3) The packing (aquarium filter material and blanks) inside the main body needs to have some "bite" on the air flowing through it. Again we can test it by just blowing through it, checking the resistance and adjusting as necessary.
Here's some mechanical silencing methods I have had success with:
They are: carefully laid out draw extensions, self stick linoleum floor tiles as damping material, gel(silicone?) shoe insert material incorporated into the plunger padding, elastic sports wrap around the outside, neoprene and foam wraps, and quickcrete around the plunger tube (as bedding material, think tinfoil for method).
One method I have tried for gel & or rubber plunger padding is to sew & glue a slice between 2 layers of craft foam and cut it down with a stanley knife to shape. It helps to thin down the craft foam & or the plunger itself (when possible) to keep the thickness down. Craft foam compresses too much anyway. I have tried using a smaller disc of rubber cell phone cover material in the center of many setups to create a more conical shape. I haven't been able to get rubber or silicone stuff to glue up well, hence the odd methods.
There's some discussion as to whether this is worthwhile on a springer. I apply a simple mantra to these things. If I can do 20 things that will each give me a 1% advantage I will do those 20 things. This is one thing that you can do to help. This may not work on all blasters, in all situations, but it can be useful.
@Z64052187 This is for air and spring. I do get enough "Pop" out of some of my springers to concern me. A similar design cut about 40% of the noise off my BBUMB. This may do better.
I built this for late night plinking and testing. I live in an apartment complex and my neighbors are... neighbors. "Because it's cool as fuck" came into play as well!!
@Curly about the soldering iron. You're right about the warping but expediency and just the speed of making the holes came into play for me. It's also possible to adjust the position of the hole while it's being made which you can't do with a drill bit.
@Beaver. The barrel vents into the "Can" portion of the suppressor. The ports vent the muzzle blast into the larger diameter open area of the caulk tube.
@Zorn's Lemma - Purely subjectively. It seems about half as loud in a small room. I attempted tests with the db meter app on my phone but the sound of the dart hitting the pillow was too loud. I can try some outside tests. Video is something I am still building upto.
@Aeromech Thanks! I've used a something similar with a hopper. The real place to be worried about losing range here is the barrel length after the ports. The dart is done accelerating by the time it hits the ports if the barrel is sized properly. That dead barrel length after the ports helps the device work though. More to your point, I think the power loss here is negligible. I don't know that the jacket would be considered deadspace. As far as this one being less effective with a clip, as long as there's a noise to be quieted, you're good.
@Z64052187 & Zorn's Lemma, I just don't have the resources to properly get accurate data for SPLs. The anechoic chamber alone (of sufficient size) would run millions of dollars. Oddly, the contested 40% figure is likely very conservative. My BBUMB (not a springer) was completely off limits after about 10:30 pm. Quite a loud crack. Somewhere near a decent pellet rifle. The dart hitting a pillow was louder than the report after I built something similar (crappier) to this for it. I'll re-iterate on the springers though. You have to silence the internals. I tried a slice of dr scholls type gel material on a NF spring perch a while back. Cost me some range but it was nice.
Edited by iamthatcat, 08 February 2012 - 11:26 AM.