DIY Generator Muffler Build (Version 1.0) - The Trashcan Franken-Muffler Lives!
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- Опубликовано: 8 сен 2021
- Can you really turn a metal garbage can into an effective generator muffler? Yep! Since I recently posted a video showing my DIY Generator Shed build, I have had lots of people ask me for a parts list for my unique, trashcan-based generator muffler. In the following video, I lay out my design ideas, I show details on the parts used, and pics from the build process. While the whole garbage can muffler idea might seem strange, it turned out very cool and works incredibly well. In the end, it dropped the sound level on the exhaust about 20 db! Hopefully this video can give fellow DIYers some ideas on how to build something similar themselves.
** UPDATE: JUST ADDED:
Check out the NEW and IMPROVED FrankenMuffler in this video -
DIY Generator Muffler Build - Version 2.0 - "The Bride of FrankenMuffler":
• DIY Generator Muffler ...
DIY Quiet Generator Shed with insulation, Baffles, and Muffler (Shed tour with sound tests):
• DIY Generator Shed Bui...
Links to the 3 sound tests, and the final shed project results (below)
Generator Shed Sound Test #1 - (No Sound Insulation):
• Generator Shed Sound T...
Generator Shed Sound Test #2 - (Sound Insulation Installed, Side Baffles, but no muffler):
• Generator Shed Sound T...
Generator Shed Sound Test #3 - (Full sound insulation, side baffles, and muffler):
• Generator Shed Sound T...
Disclaimer: This video simply shows what I built, and it is intended to provide a few ideas when building your own shed or muffler. I am NOT an expert builder or designer, so take my advice with a grain of salt, and use common sense in your build. This was a proof of concept to make sure the concept would work, and it did. I intend to make a few tweaks to the setup, like increasing the flexible pipe diameter to a larger pipe, and shortening the length of the pipe. 
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Everything you did is exactly how we soundproof airplanes (turbine engines are very noisy yet passengers take the engineering that quiets them for granted); I'm an Aerospace Engineer and I am very familiar with all the concepts you used to soundproof your generator; I watched your other videos and found an important piece of the puzzle: generator rigid frame isolators, aka... the transport four fat tires!... you hit every noise source on the nail, thanks for a very comprehensive video of you work; good work!
I used this material in my shop around and above our saws and cnc to help kill the sound. I was trying to figure a way to do this for my generator....now all the thinking has been done for me! Thanks for these videos, I'm going to start on this muffler tomorrow.
Great job on the shed! I loved the attention to detail, the intake and exhaust air flow. I had also planned to use rockwool, so great confirmation for me! Love the muffler too!
You did a great job! Very impressive! I'll definitely use some of your designs for mine. Especially the boxes idea for the inlet and outlet.
You’re doing Gods work with this video! Excellent design and excellent presentation.
For someone who has no clue how to do things, you helped me a lot! Thanks!
Excellent build and videos…, thanks for sharing
Great video - thanks. I really appreciated all the exact information on the muffler build and your thinking on it.
Glad you enjoyed it
Good job! Ingenuity at it's best.
For retrofitting generators to control noise "on the shelf" mufflers, I like to use Walker 21528 (excellent noise control with very little added restriction). If space constricted I use 22266 or 21012
Great idea and great video. Thank you.
Great Job . The best i have seen !!
I apologize. I made a comment on your last video asking to see inside the muffler. And I just found this video. Thank you for sharing your ideas!
Great tutorial - THANKS!
You're welcome!
Great idea's looks like they work well. I am going to use some of them. You could decrease exhaust back pressure and increase max output wattage of the generator by running the flex pipe straight out thru the side, shortening the flex pipe as much as possible and using a conduit 90 degree bend instead of the pipe 90. Every turn increases back pressure and the tighter the radius of the turn the more it increases.
Agreed. All good points. I had originally intended to use a conduit 90-degree bend. But the garbage can is short, and by the time the bend completed, it was half-way down the garbage can, and I only had about a foot of usable perforated pipe. I wanted more surface area for the perforated pipe. But definitely agree with your assessment. I also put the pipe exit in the shed below the level of the generator muffler just in case there was some water ingestion in the pipe, it wouldn't work it's way back into the generator. I also later raised the generator about a foot on those big wheels, which lifted the generator up. If I were to do it over again, I would use larger pipe, and a slightly bigger garbage can to maximize sound absorption without compromising flow.
Great build I've watched a lot of youtube channels for a good muffler build and found the same results, not much improvement. Will be using all your tricks for sound redirection .Just finished insulationing a garage conversion with that Roxwool insulation, best stuff ever for sound reduction and love the fack that its fire resistent up to super hot temps.
Forgot before I entered my question. Awesome video!
Appreciate this tutorial!
I did a later video on my Version 2.0 exhaust, which has quite a few improvements over the version 1.0 setup. The newer video has parts lists, shed costs, and other Frequently Asked Questions. Check it out here: ruclips.net/video/y3pUw408jCU/видео.html
great build. You can make the side baffles more efficient if you put 2 horizontal pieces of batting inside the box forcing the air to follow a "S" shaped path before exiting the box.
Definitely could have gone that route. I had a limited amount of scrap wood at that time, and the simple box method seemed to help a lot with the sound vs. no baffles. But totally agree an S-shaped path would have been even more effective.
Love the concept! If you turn the support boards 90 degrees more of the sound would be directed away from the house.
I wonder if you added sound insulation to the outside of the can and tube that transfers the exhaust
So Many GREAT Ideas so Thank You!! Love the intake and output air boxes also! I am thinking of a bigger shed with those components housed inside myself for better weather protection. Question? I wonder if lining a can with rockwool and filling the can with large 3-5" river rock instead of rockwool to the mesh pipe, would better dampen the sound using deflection and absorption? Thinking of a larger dispersion area... Thoughts?
I've had similar suggestions about using gravel as a sound dampener. It would probably work to a certain extent. Of course, it would be at the expense of being very heavy and hard to move around. I do tend to think that hard materials like rock and gravel don't tend to absorb as much sound as softer materials with a little "give" to them. What they do though is make the sound waves turn lots of little corners, which gives the sound no direct route out of the can. I'm not sure what the rock-size to exhaust-backpressure ratio would be for large vs. small rocks, however. Check out my later video on my Version 2.0 exhaust. I address a lot of the issues that this version 1.0 exhaust had. The newer video also has parts lists, shed costs, and other Frequently Asked Questions. Check it out here: ruclips.net/video/y3pUw408jCU/видео.html
Looked at how you design that pretty cleaver should run pipe out of motor to can with muffler at end less back pressure less heat engine will love you for it. Header wrap also works very well on pipe . But thanks again for great tip God bless
I've got a version 2.0 exhaust in the works. Directly to 2" pipe, and then 8" in the muffler. Should work a lot better as far as back pressure. Stay tuned for some new vids soon.
You could run the sound through slotted drain tile buried underground with that white fabric to keep the dirt out.
Very cleaver system. I wondered about using a car muffler...
Just a little hint fill the trash can with number 2 rocks and it will be a lot quiter and not smother the exhaust to burn out your valves
That is an interesting suggestion. Might have to explore that one if I have time.
If you leave the trash can open and just lay the batting on the can sides to keep it from vibrating with sound the engine will breath better and create an open interior for fumigation of bugs and critters like mice or rats. But you do have to run your genset when uethenizing such caught vermin or bed bug sheets.
You can run the exhaust hose in a bucket of water and it will just make a bubbling sound.
I discuss this very question in a later video on my Version 2.0 exhaust. It also has parts list, shed costs, and other Frequently Asked Questions. Check it out. ruclips.net/video/y3pUw408jCU/видео.html
Very detailed, great explanation on how to copy your project. Ever where to buy the material.
While I had some interesting ideas in this video, I also made a later video on my Version 2.0 exhaust, which has quite a few improvements over this earlier version 1.0 setup. The newer video has parts lists, shed costs, and other Frequently Asked Questions. Check it out here: ruclips.net/video/y3pUw408jCU/видео.html
I like the muffler itself but the length of the exhaust tube going to the muffler concerns me . id try immediately increasing the diameter of the exhaust where it exits. using a long exhaust hose even that is the same diameter of the exhaust port has to be increasing back pressure and increasing the heat of the cylinder head
This was definitely an experiment. I'm also looking at building a newer version of the exhaust with larger diameter pipe. This was mostly a proof of concept to see if it would work.
Very nice ... what if you can make a underground muffler
A few people have had this suggestion. It does have a few downsides though, including having to dig a hole, and said hole filling with water. And squirrels: nobody wants squirrels in their muffler. ;-)
My generator exhaust out the back. If I were to extend the exhaust straight into a Rockwool-lined baffle, would that be effective?
I'm sure it would make a difference, although maybe not as much as a fully-lined muffler. Take a look at my version 2.0 video where I discuss a few alternative concepts like this, along with some additional parts lists, shed costs, and Frequently Asked Questions. ruclips.net/video/y3pUw408jCU/видео.html
so what about in a hurricane area? How to hold the trashcan in place during high winds? and the rock wool under the trashcan - how to keep it from getting water logged?
Good questions. In hurricane situations, I think the plastic shed and the trashcan would both be at risk of blowing away. You'd need to anchor them down in some way. Fortunately, I'm not in a hurricane prone area, so I didn't build anything to address that use case. As far as the rockwool getting wet, it is probably less of a concern than you might think. Rockwool is actually used in hydroponics because it doesn't wick water into the insulation, and most water drains away. It is also resistant to mold because it is inorganic, and doesn't provide any food for the mold to feed on. It's air permeable, so dries out easily. So, it might be damp for a while, but will eventually dry without getting soggy or moldy. That being said, I'd probably lift it off the ground a bit with some wood or bricks or something. Those are my thoughts, and thanks for the question.
Question: Is the exhaust too close to the air intake on the side with the fan? Is there a danger of that fan pulling in exhaust fumes back through the system?
No, the fan is an exhaust fan, not an intake fan. It blows outward. The air intake is on the side opposite of the exhaust.
Several generator manufacturers advise against altering the exhaust in any way. It VOIDS the warranty!!! FOOD FOR THOUGHT. Firman is adamant about it.
I just purchased the same Generator you have. You say the Exhaust outlet is 1 1/8? Is that an exact measurement? Did you thread the end of the Exhaust outlet? I am a little afraid to do that. Don't want to mess anything up. Can you think of any other way to do it? I have not taken mine apart and looked at it yet. Any advise is most welcome. 🤔
The inside diameter (ID) of the muffler exit is 1". The OD is 1 1/8". This made things a bit hard to put together, since most adapters are made for 1" OD. My original method was to tap the inside of the muffler outlet with 3/4" pipe thread, and then screw a short length of 3/4" pipe into it. The OD of the 3/4" pipe is ~ 1" or just slightly more (but it tapers up to that dimension.) As I said, that is how I did it in the original version. In the quest to reduce exhaust back pressure, though, I have since just welded on a short length of 1" (ID) pipe. (I had a muffler shop weld on the piece of pipe to the muffler.) I then immediately attached a 1" to 2" pipe expander, and then go into 2" flexible pipe. This should greatly reduce the backpressure. Working on a newer video with the upgrades. Doing some additional testing, then will be posting.
@@C5Tor Thank you, I am in the process of getting all my supply's to build it. Some items I had to order on line and I just have to wait. This Generator is a Beast. It was a perfect choice to power a home. I knew I made to right choice. Thank you for your feedback, I will be watching for your next update video. 😀👋
@@TheLakotariver Hello Mark, great information, will also be buying the same Westinghouse generator. Can you share how you remove the muffler components and the following modification i.e. 1" or 2" pipe. Also how did you mount the pneumatic wheels to your generator. Thanks
@Frank Patrick - I actually answer this question and many, many more in an updated video. Feel free to check out my later video on my Version 2.0 exhaust on my channel. The newer video has parts lists, shed costs, and other Frequently Asked Questions. Check it out here: ruclips.net/video/y3pUw408jCU/видео.html
I wonder how much power loss that much longer and narrow exhaust causes.
Check out my later video on my Version 2.0 exhaust. I address a lot of the issues that this version 1.0 exhaust had. The newer video also has parts lists, shed costs, and other Frequently Asked Questions. Check it out here: ruclips.net/video/y3pUw408jCU/видео.html
How long does it take the rock wool to get sopping wet?
Well, the good thing about rockwool is that it doesn't absorb water. It sort of runs off. That is why it can be used as exterior insulation. It is also used in hydroponics, as it doesn't tend to mold when it gets wet. But so far, I haven't noted a big moisture buildup in either the shed or the muffler after testing, if that is what you were referring to.
DId you measure the sound with a meter to determine you got a 20 decibel reduction? That an incredible claim.
See the description for links to the earlier sound testing. I posted three different vids with no sound dampening, with rockwool and baffles, and finally with the muffler. I used the sound meter in all of those, so you can make your own interpretation.
Talk about extreme back pressure, there goes timing and torque. RIP generator lol
Agreed. I did a later video on my Version 2.0 exhaust, which has quite a few improvements over the version 1.0 setup. The newer video has parts lists, shed costs, and other Frequently Asked Questions. Check it out here: ruclips.net/video/y3pUw408jCU/видео.html
Have you compared a regular muffler with this can, or just by itself? I don't suppose you compared a can full of water? I am looking for the easiest and cheapest method , while obtaining reasonable results, not disturbing neighbors. No more, no less.
I haven't personally tested any other mufflers on this build. I was just comparing with and without this muffler. (See the other linked vids for before and after sound tests.) I did a lot of searching around looking for other muffler results. The ones that used aftermarket generator mufflers seemed to indicate they were next to useless. The ones that used automotive mufflers seemed to get varying results, none of which seemed to lower the noise level by very much, at least as far as I could tell from the videos. I've heard of the "can of water" method mentioned several times, and I'm sure it would be effective up to a point, but I couldn't find any videos of one in action. I think it would have several downsides. The first of which would be the excessive backpressure on the exhaust; It would take a lot more exhaust pressure to move water out of the pipe than it does air. The second is that the heat would eventually evaporate the water, and you'd need to refill it fairly often. Also, it could corrode your exhaust pipe. Not to mention the gurgling, motor boat sound it would create. All of those made me look for another method to experiment with. While my trashcan muffler proved fairly good at muffling the sound, I think I can do better. The sound attenuation was more than sufficient, but I think it has too much backpressure due to the 1" pipe and the sharp 90 degree bend in the muffler itself. I'm going to build a version 2.0 using 2" pipe, and a more gradual bend to decrease the pressure and let it flow better. Stay tuned for a new 2.0 video soon.
@@C5Tor , just a thought. when you make your new stand for the muffler, how about adding a block of the Rockwool directly under the outlet, but spaced a few inches away? Thus forcing the soundwave to hit that as it make it's final 90* turn at the ground.
The current setup does have rockwool under the outlet. But yes, any new setup will definitely use that same method.
Maybe attach the baffles to the exterior of the shed with a hinge and simple lock so you can secure it shut and swing them open like a door
Interesting thought. The plastic shed is not very sturdy though, so would not support the weight of the baffles on the hinges. Also, I made them simple and portable so that I could store them inside the shed. If I was a little more thorough, I would have painted the wood baffles and made them a little more weather-proof. But of course, this is just a proof of concept, so you can make the baffles out of whatever material you want to. The wood was cheap (free) and has a lot of mass to absorb sound. Plastic or sheet metal would have been more weather-proof, but more expensive and would have provided less sound deadening. So, pros and cons to all those kinds of choices.
@@C5Tor all very good and valid points
would have liked to hear it?
The other videos are linked in the description. You can hear it in the main shed build and the Sound test #3 vid. Sound test #1 and #2 are without the muffler, so you can hear the difference. Here is the main shed build: ruclips.net/video/CKQu_Pvdh0I/видео.html
why couldn't you just hook up an automobile muffler to the pipe exiting the shed.
You could do that, and I see that lots of people have tried it. However, if you look up "Generator Automobile muffler" on RUclips, you will see that most of the experiments were really less than satisfactory. Either the car muffler made little to no difference, or it was a lot of work with welding, etc. Usually both. Quite a few posters seemed to indicate it wasn't worth the effort. My take on this is that car mufflers are really made to work on larger volumes of air moving at higher velocities, and they are designed to muffle different sound frequencies than you would get on a small generator engine. Most of them use baffles to reflect the sound rather than absorbing it. The car mufflers that use sound absorbing materials (glass packs) don't really have enough sound proofing materials to significantly reduce the sound much. This trashcan muffler concept takes the glasspack idea, but adds a LOT more sound absorbing material than a typical car muffler. (Maybe 10x or even 20x more!) Imagine if your car muffler was the size of the trashcan, and think how much quieter it might be. This was the idea behind the trashcan muffler. While the car is limited on space to put a muffler, my generator shed doesn't have that limitation; it can be large, ugly and non-aerodynamic. The second area of concern is that most of those experiments I saw in the videos seemed to try adding the car muffler WITHOUT any other efforts to soundproof the rest of the generator. So, even if the car muffler might have been moderately effective at muffling the exhaust, the rest of the generator was still so loud that they couldn't hear the difference. I talk about this in the video when I discuss doing the muffler last, after quieting the rest of the generator. But feel free to experiment. That was the point of this video, after all. Good luck!
It must have cost you a small fortune
I discuss this very question in a later video on my Version 2.0 exhaust. It also has parts lists, shed costs, and other Frequently Asked Questions. Check it out. ruclips.net/video/y3pUw408jCU/видео.html
it's metal, the vibration it will create is worst....
The metal trashcan is also completely filled with sound dampening material, and it is sitting on some as well. So it doesn't vibrate much.
I sat and watched a decent presentation for a half hour of YOU building a gen set silencer/muffler. Why on earth didn't you start your generator and present the DB ratings live or at least so we can hear the final sound output of the product....? I am sad.
You may have missed the earlier videos where I had the generator running with the sound meter running. These videos were linked in the description. Here they are for your info:
DIY Quiet Generator Shed with insulation, Baffles, and Muffler (Shed tour with sound tests):
ruclips.net/video/CKQu_Pvdh0I/видео.html
Links to the 3 sound tests, and the final shed project results (below)
Generator Shed Sound Test #1 - (No Sound Insulation):
ruclips.net/video/2KQPr7WZIpw/видео.html
Generator Shed Sound Test #2 - (Sound Insulation Installed, Side Baffles, but no muffler):
ruclips.net/video/f1mk8KNObDY/видео.html
Generator Shed Sound Test #3 - (Full sound insulation, side baffles, and muffler):
ruclips.net/video/2EM6l6kkd30/видео.html
I wonder if this will work in snow country?