At 06:53 PM 6/15/2012, neil n wrote:
>My old boss was pretty "old school". We used straight up Borax and
>water at work for Bronze pellet and silver alloy filler brazing. For
>small stuff maybe not the best flux. Still, it worked. He built quite
>a few trombone bells using Borax as flux.

Sufficient expertise (and expert use of a reducing flame) can work
seeming miracles.

Really good flux makes duffers like me look at least a little better
than we really are.  And lets us keep farther away from that
mysterious line where the brass suddenly slumps and vanishes.
<g>  Even more mysterious for us slightly colour-blind folks.  Don't
even talk to me about aluminum.  That's silver magic.  Looks (to me)
just the same from cold until just after it melts.  Bah.

>One trick I was taught, was to warm up the borax/water solution on the
>work with the torch til it starting "foaming" to a white bubbly
>finish, let it rest, hit it again with torch til it settled down a

If you give it too much heat right away the water flashes off and
blows the flux away like popcorn...

RVC - I've done both bronze and silver brazing on and near Vanagon parts.

Yrs,
d