ATM Method of Blackening Brass

[Donn Starkey <dstarkey@solaris1.mysolution.com>]

I make many of my telescope accessories from brass.  I often paint the
interior of these brass eyepices flat black.  However, when I comes to
the threaded areas, paint causes the problem of adding to thread
diameter and flaking off.  Some of the purchased brass optical prodcts
have a lovely flat black patina to them which does not appear to be a
typical paint.  Ther most be some ways to either electro-coat or
electro-deposit such a coating which could be accomplished in a small
shop.  Does anyone know a method(s) for blackening brass which leaves a
flat black finish?

Donn Starkey
dstarkey@solaris1.mysolution.com