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Tungsten balls & brazing



Original poster: "Scott Hanson" <huil888-at-surfside-dot-net> 

Marco -

The tungsten balls can be ordered through a large industrial supply company
in the USA - McMaster-Carr Co. (www.mcmaster-dot-com).

For brazing steel and tungsten balls, I use high-silver content brazing
paste. This is a blend of powdered brazing alloy and flux - simply apply the
paste to one of the parts, fixture the parts to hold them in place, and heat
until the brazing alloy liquefies and flows into the joint. The brazing
paste can be obtained from welding supply houses; one manufacturer is Fusion
Inc. (www.fusion-inc-dot-com).

For the ball supports, I use copper tubing of various diameters proportional
to the ball diameter. I use a tubing flaring tool to form a slight flare or
conical "seat" for the ball to sit in. I clamp the tubing vertically, apply
the brazing paste to the inside edge of the flared end of the tubing, and
drop the ball into place.

The brazing alloy requires about 1200 degrees F to flow, so everything needs
to be brought to a dull red heat using a MAPP gas or an oxy-acetylene torch.
Small assemblies can be heated with a propane torch.

Done correctly, this yields an assembly with just a tiny, perfectly uniform
fillet of brazing allow between the parts.

Regards,
Scott Hanson