In a message dated 2/4/2006 8:08:49 AM Eastern Standard Time, rx7ez@yahoo.com writes:

    I have a "Welders Blanket" cloth which is supposed to handle over
    2300 degF.
    I am hoping that I could use that for "glass packing".

    The "almost empty can" demonstrated at Tracy Crooks Rotary Roundup
    sounded
    good enough for my needs.




    George Graham
    Mazda Rx7ez N4449E
    Sarasota Florida -SRQ

The problem with fillers, or packing if you like is twofold. The usual glass like material used in piston engine mufflers, just melts. If you catch it quickly, you may get to see the glass balls before they are machined away and vanish.
 
If you try a ceramic blanket material like I did, you discover that the hammering of the exhaust pulses mechanically decomposes that material, or any material into fuzz and blows it out.
 
The race car muffler has small tubes with thousands of small perforations. A 4" perforated tube down through the center, with 5 additional smaller perf tubes inside of that tube. Still under 100 dB at 50 feet after 7 years of service. It looks like the Burns mufflers but is very much larger and is about 27 pounds. The Burns mufflers look like the way to go to me. They offer stainless swarf packings which might hold up for quite a while.
 
Years ago, there were mufflers (very big and heavy) used in Mazda race cars that had Lava Rock fillings. There was a bung with a screw in plug so you could refill the lava rock after each race. The Mazda just turns it into dust with the hammering.
 
Lynn E. Hanover