Smokey wrote:
Thanks to all of you for some excellent suggestions and help. Colin, I fell
of my chair reading yours !
I realize now that "carborundum powder" is one of those things that ham
project books describe but, in reality, was never invented.

Poppycock!

Carborundum is the 3M trademark for Silicon Carbide. It is very much available,
and is the grit on any of the black sandpapers, such as "Wet-or_Dry".

Less than a minute with google would have found you plenty of information on
the subject, and a few suppliers.

-Chuck Harris