RE: my custom exhaust project
Exhaust gasses run 900 degrees and up, where they exit the engine. They're usually a lot cooler by the time they reach the muffler but if you wrap the pipes the wrap holds in heat and the gas will probably still be well over 550 degrees entering the last section of pipe. The steel of the pipes actually gets hotter under wrap than it does with steel heat shields. Also, having just wrapped the pipes on my bike I can tell you that it won't do much to hold anything together. It might reduce vibration and keep the JB Weld from being pounded...but I wouldn't bet much on that.
I really hope that the JB Weld works...but you've put a lot of time and effort into this and I'd hate to see it all come apart within a few weeks. This might be a real good time to rent a small arc welder and teach yourself to weld. Even a poor, beginners arc-weld will probably hold much better than JB Weld and you'll have added something new to your skill set.
2011 V-Star 650 Custom (new in fall 2013)
V&H Cruzer Pipes, Memphis Shades Bat Wing, Floorboards, Highway Bars,
Locking Bags, Tail Rack, LED Signals & Aux Brake Lights, Headlight Modulator,
Brake Light Modulator, 5/8" Gel Pad Under Upholstery.