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Questions, Answers & Tips - 2
Shorts are easy to come by with metal wheels running on 2-rail
DC layouts, particularly at turnouts. Usually a short is caused by
an operator running against an incorrectly set of points or turn-
out. Other causes are the back of a wheel touching an opposite-
polarity closure rail, wheel sets that are out of gauge, or track
that's out of gauge. Metal pilots and plows mounted too close to
the rails are another cause.
When there is a short circuit, the DCC system's internal breaker
will shut down power to the whole layout. While a single opera-
tor can just remove the problem, it is very annoying when there
are a several operators and the whole layout shuts down.
Sound-equipped locomotives will go through their start-up rou-
tines when they lose, and then regain, power. Very annoying.
Eliminate the issue by setting up power districts. There are three
basic methods:
Add boosters to the original power supply. These are the
most expensive option, and most power supplies can run
several trains at a time. This will not eliminate shorts, but a
short in one district won't shut down trains in others.
Install circuit breakers for each district. These are cheaper
than boosters.
Install 1156 automotive lamps wired in series for isolated
train blocks.
The two-buck 1156 automotive brake lamps will restrict the
current to 2.0 amps when there is a short. Excess current heats
the filament and lights the bulb – warning of a problem – but
the breaker does not cut out. Operation on the other train
blocks is not affected. You still need to do something about
the short, but you get a warning and the short doesn't pull the
whole system down.
For more information, see:
for “Tricks with auto lamps.”
Threads:
.
Video:
Q.
I am working on a kit that has metal parts, and the direc-
tions say to prime parts before painting. What kind of primer is
safe for this adventure?
– Theron
A.
Priming is Step 2. Step 1 is cleaning up the metal pieces to get
rid of flash and casting lines. Military modelers often rinse parts
in diluted vinegar to etch the metal surface a bit. Or, give them
a good clean in lukewarm water and dishwashing liquid to clean
away oils and stray metal.
When the parts are dry, Krylon's Indoor/Outdoor (2) is a pretty
2
3
3. Metal primer creates a strong bond between paint and
metal parts to reduce chipping and flaking. Many cast
metal parts need careful cleaning with files and sandpaper.
2: Hardware store spray primer is
fine for use on scale models when it
can be fogged on in one or two light
coats, just enough to cover the part.
MRH-Mar 2013
