>>Get it coated with a ceramic material at a place like Jet-Hot coatings.  It
>>is rather expensive, but you will end up with a muffler that will not rust,
>>and very resistant to heat (to 2000 F.).  It will make your muffler the
>>last one you'd buy for a long time.
>
>But what about rust from the inside?
>

I called Jet-Hot coatings, and they told me that they derust and repair any
small holes in your "piece," and ceramic coat it inside and out.  It is a
baked-on metallic-ceramic coating that is very resistant to corrosion,
heat, and vibration.

Wolf