JJ, I've used an inexpensive ($40)
air compressor I bought at WalMart a few years back, primarily for use on car & bike tires. It's self-powered
with a built-in rechargable 12-volt gel-cell pack. I've used it for doing valve adjustments
(best done with the engine COLD!
) on my Accucraft Shay & Ruby; here it is in use on the 3-cylinder Shay...
To get the air actually into the boiler, I used one of the adapters furnished with the air compressor normally designed for applications like filling beach balls.
It's made of a
relatively soft, rubbery plastic
- I just cut it slightly shorter, removed the brass water filler cap from the Shay's steam dome; and was able
"force-thread"
it into the brass steam dome threads. The comparatively soft nozzle material was cut into by the
much harder brass threads, with no harm to the steam dome threads themselves.
While not a
perfect
air-tight fit (there is
some air leakage
), it's adequate for testing / valve-tuning purposes.
I can pressurize the boiler to maybe about 20 PSI or so (even with the air leakage),
enough to turn over the engine for valve adjustments.
Once I'm pretty sure I've got things the way I want, it's even possible to run the engine back-&-forth a few feet on air.
Then it's time for the
actual steam test outdoors
-
- of course, running without the cab, I'll admit a
"topless Shay"
looks a little wierd!
- There was a short article in Garden Railways recently about a
standard plumbing fitting that is a perfect match
for the threads Accucraft uses for these boiler caps
- I'm going to check out the local Ace Hardware store for one to replace that leaky plastic nozzle!
Tom