On Fri, Jun 15, 2012 at 4:20 PM, David Beierl <dbeierl@attglobal.net> wrote:

At 06:53 PM 6/15/2012, neil n wrote:
>
>> ..... We used straight up Borax and
>> water at work for Bronze pellet  ...... 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.
>
>

The really hard part on a brass seam was that the melting point of brass
and the bronze filler were really close. I burned my fair share of holes.
But when things are just right, you just move the torch along and watch the
bronze melt into the seam. Ha ha. "just".

>
>  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...
>

Yes, but heating it to a mound of white, then less of a mound to a
different colour, is not as difficult to do as one might think. I just set
the flame low and more or less slowly wafted it over the flux mix.

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

Inspecting the T at fuel return line on my WBX and noticed it was a brazed
part. Nicely done too!

More VC. I used what little brazing skills I had to make my custom foot
heat flaps on my air to water cooled swap
https://sites.google.com/site/tubaneil2/HeaterFlapMod.jpg

Didn't have a MIG at that point.

Speaking of flux, one will note the mess left behind.   ;^)   At work we
used an acid bath to clean off the hardened Borax flux. I don't recall what
I did to attempt clean up of those flaps. This is one major draw back of
using Borax and water; when you're done you end up with a hard glaze of
flux.

Neil.

--
Neil n

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