Ray Bedard inquires-
>When the drivers have worn plating, how does this effect the overall
>operation of the model? Is
>there a simple fix, other than replacing the entire drives?
The common model locomotive drive wheel plating is nickel on brass.
The exposed brass can tarnish and will not conduct electricity well.
You will have to clean the wheels more often. However (*however*),
the exposed brass wheel treads have a significantly greater factor of
adhesion on our common model nickel silver rails than nickel on
nickel silver. In this regard, locomotives with exposed brass wheel
treads will commonly be observed to demonstrate significantly-
improved pulling performance without slipping.
Factors of adhesion wheel/rail combinations from the highest to the
lowest in descending order:
Brass on brass.
Brass on nickel
Brass on nickel silver
Nickel on nickel silver
Nickel silver on nickel silver.
What do I do? I firmly resist the urge to replate, and just leave
the wheels alone. My own experience is that not only do these
locomotives have significantly improved performance in real time, any
significant brass wheel tread tarnishing is a truly minor matter with
nickel silver rails, and (AND) if you keep your tracks clean. As we
speak, a very smoothly running brass Milwaukee Road Hiawatha 4-4-2
Atlantic with fully-exposed brass wheel treads is cruising around the
layout with its brass six car train. The last time I cleaned the
wheels was about 18 months ago.
BTW, this locomotive pulls these six brass cars up a long 2% grade
without slipping, something it could never have done when the wheel
treads were fully plated.
>
>....what is the best way to remove [tarnish] so that one can
>properly paint it to insure the
>paint sticks to the model?
Do not worry about the tarnish, as long as the brass is otherwise
bare , squeaky-clean and smooth. Bead blasting will remove tarnish,
but the advantage for paint adhesion lies in the creation of a
'tooth', not in the removal of tarnish.
In a lifetime of working with painted brass (in other venues besides
model railroading), more commonly than not, when I remove old paint
(up to 110 years old), the underlying brass is...tarnished- sometimes
almost black. Obviously not a problem.
Denny
--
Denny S. Anspach, MD
Sacramento, California
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