this is a cheap diy silencer that I made for my goped with tuned pipe. Lowers exhaust noise considerably without restricting flow
Step 1: Parts
1foot 1/2" copper pipe
2 tin cans ( I used dog food)
1/4" metal mesh
1/2" 1/8" and 5/16" drill bit
Centre punch to make drilling easier
Step 2: Prepare and Drill Copper and Cut Cans in Half
start by cutting the tin cans in half to make the outer case for the silencer, u can cut them longer or shorter depending on the length you want. Remember that you want to use then end of the can with a sealed end
After you have your cans cut measure a mark 2 inches from the end of the copper pipe. Then measure both of your cans and make a second mark on the copper the length of the cans combined from the first mark.
For example if your cans are 3 inches each you will make your first mark at 2 inches and second at 8.(3+3=6 +2=8)
Now evenly mark where you will drill along one side of the tube between the 2 Mark's you have made, space these marks so that the 5/16 holes that will eventually be drilled come close but don't touch. Now turn the pipe 90 degrees and mark another section of holes staggered from the first set(offset).
Make another mark 2 inches down from this second section, this is where you will cut the pipe.
Proceed to place the pipe in a vice and use a centre punch to indent the Mark's to help drilling.
Start drilling out the Mark's with first a 1/8 drill then open them up with a 5/16.
After drilling the holes you will need to debut the holes on the outside and inside of the tube, for the inside you can sue a wooden dowel with a cut in the end with some sandpaper placed in the cut and run your drill through the tube with the dowel on the end.
Step 3: Cut and Wrap the 1/4" Metal Mesh Around the Holes in the Pipe. Drill Holes in Ends of Cans
cut a section of the mesh to length of the section of pipe that you drilled holes in. Make sure you have enough to wrap around the pipe about 3 times.
Wrap the mesh around the pipe tightly and use thin wire to hold the mesh in place
Also drill a 1/2 hole in the center of the bottom of each can.
Use a scrap section of the 1/2" pipe and hammer it through the hole to increase the hole size enough to get the pipe section through
Step 4: Stuffing the Cans
Start by putting one can half on one end of he pipe. Wrap fiberglass around the section of pipe with the mesh wrapped around it and push the one end of the can over top. Once you have the one can end in place you can slip the second can on the other end.
Use tape to hold the cans together temporarily.
Step 5: Seal Can With Job Weld
now you can mix up your job weld and start sealing around where the tube goes into the can and where the cans meet in the middle. Alternatively you can use fiberglass exhaust repair tape and aluminum tape to seal the 2 cans but this will make it hard to paint so I don't reccomend this unless you have high temp exhaust wrap like I did.
Let the epoxy dry before starting the next step
Step 6: Dress It Up and Install It
now that the jb weld has dried and the can is pretty much complete you can choose to install it or dress it up a bit.
I cut the rounded end off a can of brake cleaner and job welded that on the end of the can and painted the finished product black with high heat paint then wrapped it in high temp exhaust wrap.
To install the muffler I used a 2 inch piece of 1/2"id silicone tube sold by ddm racing and some hose clamps