GL: Stainless steel and brass

[Rex Miller]

Both Naval Brass and Yellow brass are at 450 millivolts on the galvanic
scale and *passive* Stainless Steel is at 150 millivolts so it is anodic
relative to the brass and would be the sacrifial material.  There is a
wrinkle in that if the stanless steel is exposed to heated water the oxygen
is driven out and the steel goes *active* and begins to rust just like any
ordinary steel causing the rust buildup to crack the brass fitting.
Additionally active stainless steel is at 550 millivolts on the galvanic
scale and the brass would become the anodic element causing the brass to
errode.
If you do not want to go back to brass, a better material from a galvanic
perspective with much less problems galvanicly speaking is silicone bronze
bolts, at 260 millivolts on the galvanic scale, available from West Marine
in limited sizes or James Town Distributors.
The rule of thumb is materials should be within 200 millivolts of each other
to reduce intereaction.

-- 
Rex W. Miller SA(r)
Telrex Marine Services