Nothing wrong with the summer of 2019; nice and hot and comfortable. Spent a few days down at the killing fields and enjoyed every second of it. Fell asleep and best nap attack ever!! I Was Warm!! Only thing missing was a beer but Hey, too many cops lurking around under the bushes with long lens and sound recorders and too far away from home to catch the bus.
Aann-y-way... Twice upon a time , in fact, during my time at the fields, I scored a pair of cocktail shaker mufflers; only needed one but the vendor at the swap meet wouldn't split them. Brought them home and proceeded to dismantle them. Come to learn that they were mostly resonator and very little muffler. No packing present at all.
They stayed disassembled for around a year and then I ran across a video from my favorite tech series. The how to dude was in decision mode, he needed mufflers for his project and and was weighing the pros and cons of buy vs build. Cheaper to buy, mostly, but what he had in mind was a pair of cherry bomb style mufflers in terms of shape. Moving on here, what caught my ears and eyes was his solution for sound deadening. What he did was to wrap the central core with, first, a layer of coarse steel wool, and then, second, covered that with a layer of fibreglass mat.
Right. Didn't have any coarse steel wool but my local industrial supply shop carried it by the sleeve. Had plenty of glass-mat. Cleaned the inner resonator of an accumulation of soot and rust and proceeded to apply the layers of wool and mat and then stuff the whole assembly back in to the muffler case. Went pretty well but, (there's always a BUTT, isn't there?), When I went to test fit it again, the mounting stud reminded me that it was not all that securely attached to the muffler case. Now I knew that I could just run another nut down the thread and lock the whole thing into position but, (see!) that option offended me because it was sloppy and subject to vibration that could make it come loose.
Plan B was to replace that stud but, while it turned and turned, it did not come out, but could be pushed in. Bother. Nothing for it but to extract the resonator and packing to gain access to that stud. The "stud" turned out to be a bolt that was just floating around in there and that fell out once the packing that had held it in place was removed. That left me with what appeared to be the head of a bolt that had been soldered or brazed to the muffler case but which then had had the threaded shank removed and a hole drilled into it for the replacement bolt to be shoved into from inside. Must have been at night with a high wind because the drilling was done off center. Like I said, sloppy.
Given what I had to work with, some rehab was in order. The old bolt was a 5/16ths and it rattled around in the hole. So I could just mig a short exhaust stud in and call it a day, or try to drill and tap the existing hole to return it back to 5/16ths, or.....
The more I looked at that hole, the more I hated it. Being off center anything I put into that hole would be, by default, also off center. Time to make an off center hole into a concentric hole. Here, Dremel, dremel, dremel..... and move the hole over and get it centered with respect to the sides of still present head. Now way too big for a 5/16ths anything, maybe 3/8ths?? Ended up drilling the new hole to just over 3/8ths, and tapping it for a 3/8ths fine thread heli-coil. Cut the heli-coil down for height so it would fit, slathered it with locktite red, and slammed it into the ready opening. Let dry over night, pop the coil tang out, run a test bolt into the hole and Le Voila. I have a working mounting point again. Chunk of 3/8ths gr 8 fine thread all thread runs in nice and easy.
Back to the resonator. When I extracted it from the muffler casing that pretty much killed the new layers of sound deadener. Which was sort of okay as I had not been happy with how sloppy and messy the first winding job to wrap them around the perforated center tube had proved to be. I had tried to use copper wire to fasten them down but that had not gone so well; not enough wire placed in too few locations.
On to the re-wrap. First I harvested a bunch of fine copper wire from a length of 10 ga primary. Separated that out into its individual strands and cut them to length. Being softer and more malleable than my last pieces of wire, I figured I could tug and pull on the stuff without having it break. Dug out the steel wool and fibreglass and went at it again. This time I used two layers of the wool but wrapped them as tight as possible around the resonator body and wired them snugly in place with multiple turns of the copper wire. Did that for each stage. Then I did the same thing again with the fibre-glass only this time I cut the mat so that it would be one piece wrapped to create multiple layers and secured it with the copper wire as well. What I got from all this was a very tight set of layers that were held in place much more securely. The proof of that was how easy the whole assembly slid back into the muffler body compared to how much I had had to wrestle with it the last time,
So I am back to having a serviceable muffler again. This cocktail shaker muffler, so named for its shape and resemblance to a cocktail shaker from the 50's, is destined to be attached to the head pipe for my 47 Indian bobber project. Think it will look more period appropriate for where I am headed with this project. The other case and resonator are on the shelf, as a reserve, jic.................
Nick