Carl Fogel writes:
>> Why are brass nipples silver?
> Brass spoke nipples can be plated silver or black (and probably other
> colors), partly for looks, partly for corrosion.
> Doubts have been expressed about whether plain brass nipples normally
> corrode, often in conjunction with rants about cosmetic foolishness.
> Spoke companies ignore both the doubts and the rants.
I have no doubt because the nickel plated spoke nipples I use. Flash
tin plated ones I once used lost their tin (a sacrificial anode as
zinc on corrugated sheet metal roofs that lose their plating) and
turned black as copper alloys do. The next step was that they turned
green in winter and made themselves hard to turn, being corroded
inside and out.
> DT Swiss offers brass nipples in either black or silver, the
> difference being aesthetic:
I think they are both nickel that can be treated to be black, often
called "black chrome" being mainly the nickel plate. Why waste chrome
if you don't need it silver sheen?
http://www.dtswiss.com/index.asp?fuseaction=nipples.bikedetail&id=9
> Click on the black and gray rectangles to see the two different
> colors.
> Here's Wheelsmith's corrosion claim:
> "Wheelsmith nipples are coated with a unique intermetallic substance
> second only to gold for its corrosion resistance. Nickel or chrome
> plating, once the preferred coatings for many bicycle parts, was
> gradually replaced by superior materials, except on spoke nipples.
> Duristan produces a brilliant, shiny surface with a slightly blue
> cast."
> http://wheelsmith.com/index_files/spoketech.htm
That's pretty hard to take! I'll bet it is tenacious as well. Don't
leave out any buzz words when writing this sort of stuff. Rick has
always been an expert at this.
> It would be nice if someone could explain what Duristan is.
As I recall Stnnum is:
# Alchemy Symbol
# The symbol for the metal tin was sometimes interchangeable with the
# astrological symbol for the planet Jupiter. Tin was also known as
# stannum, the name from which the element's symbol is derived (Sn).
Duristan would then be hard tin plating, if there is a hard version of
this process.
Jobst Brandt