What type of packing material 1 inch thick x 19 long or so used for motorcycle exhaust baffles that would not?

i have a Honda Valkyrie with custom exhaust. I've tried kiln material which burned out in less than one year. i had a stainless mesh or knit which lasted 5 years, but i can't find the same anyway. i would like to know where to find the same. manufacturer is no longer in business.