"Chuck Harris" wrote in message
...
Uncle Peter wrote:


Carborundum was a man-made product produced in electric fired furnaces
in the New York region IIRC.. I have a few examples ofearly carborundum
fixed
detectors in my collection. Whether the product is still being
commercially
produced is another thing, but it did exist at one time...

Carborundum is the abrasive used in any of the "black" sand papers, such
as
the brand name "wet-or-dry". It is a trade name for silicon carbide.

Originally carborundum was a mined mineral called moissanite. But now it
is made
using an electric furnace to combine silica sand and carbon. It is such
an easy
process you could make carborundum crystals at home if you wanted to.

Carborundum was the initial product mined by the company we now know as
3M. Back
then the company was known as Minnesota Mining and Manufacturing. They
were the
first to find a reliable way of putting carefully graded and sized
carborundum
granules on a piece of waterproof paper. In essence, they invented
"sandpaper".

-Chuck

Most vintage radio resources credit the Carborundum Company, in Niagra
Falls, NY
with the product. Here is a link:

http://www.chemheritage.org/classroo...m/acheson.html

I'm pretty sure my detector assemblies are labeled as being made by the
same company.

Pete