On Sun, 11 Aug 2013 13:57:46 -0400, Bob Engelhardt
wrote:

I don't know why everybody says to vee the crack. The depth of the vee
will be so much less than the frame thickness that it can't be
significant. And the braze will wick into the crack without needing a
funnel.

The link Ed posted in the "Joining Stainless Wire" thread about silver
brazing (http://www.aws.org/wj/amwelder/9-00/fundamentals.html) had a
chart showing joint strength versus joint width. The maximum was for a
joint .0015 thick!! That thickness joint had a much higher tensile
strength than the silver itself (3X). Joint strength fell off
dramatically with increasing thickness. Thus a vee will be much weaker
than a close joint.

Bob
Greetings Bob,
It is very hard to get brazing to wick into cast iron. Even silver
brazing alloys. I thick it is because of all the free carbon
(graphite) present at the surface. I have brazed a lot of cast iron
and it is always a bit of a chore to get the brazing alloy to wet the
cast iron. Brazing rod typically has at least as high tensile strength
as cast iron, and typically more, in thick sections.
Eric