John Noid wrote in message
...
I have a minature steam engine - heated by electricity. It has a 1/4 in
OD
brass threaded pipe that has a needle valve on top that feeds steam to the
cylinder and also holds the cylinder, flywheel etc to the boiler. It
has
been broken about a 1/4 in fron the end that goes into the boiler.

I would like comments advice criticism etc on my plan to repair. I need
to
butt solder this little pipe so I found a number drill bit that would fit
snugly inside the pipe to hold it straight - then if I put a washer over
the drill bit so I could lightly clamp it together - could I then silver
solder it with a butane mini torch with a chance of it holding....I could
shim the pipe so I wouldn't need to have the threads be ok where it broke.

Would I solder the drill bit to the pipe - would coating the drill bit
with
grease or something stop that?

Anything else wrong with my plan - I admit that I do most of my
metalworking
with a hacksaw.


If you can get both pieces of the pipe off the engine you can probably
silver-solder them together and they'll be strong enough without
re-inforcement. The pipe was only brass to start with, after all; and it
will be annealed after you're done and so is less likely to break again -
it'll bend first.

What i'd do is hold the larger section with a set of large tweezers in a
vise, so that the broken end is vertical; I'd flux the broken end and drop
some teeny-weeny pieces of silver-solder (the real kind) onto that end after
heating it with a propane torch. You have to heat enough that the solder
flows onto that end of the joint-to-be. Then I'd flux the smaller part and
set it carefully on top, just as it would have been originally. I'd heat
the pair carefully - starting about an inch away from the joint, watching
the top part, maybe holding it with tweezers or a bit of wire inside. The
flux should bubble and then get glassy-sticky - at that point if the
sections are aligned correctly you heat closer to the joint until the solder
melts and flows; the top part will settle into place, and you dump it in the
pickle.