4130 can't be OA welded?

Blueskies wrote:
"Richard Riley" wrote in message ...

On Fri, 28 Dec 2007 19:46:57 -0800 (PST), "
wrote:


On Dec 28, 2:57 pm, wright1902glider wrote:

the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch.

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Pure bull****. Indeed, for the stresses encountered in bicycles
(which is what he's talking about) there are any number of BRAZING
compounds that yield joints stronger than than normalized 4130.

O/A does just fine airframes... and for bike frames.

If brazing gives stronger joints that normalized 4130, why aren't we
brazing airframes?

(I'm not saying it's an incorrect statement - I know better than to
disagree with VD on something like this. I just figure there must be
a reason, like the brazing compounds are more expensive.)



Won't withstand high temperatures?



Structural brazing works just fine - if done correctly.

But too much heat causes the brass to migrate into the grain
of the 4130 - resulting in cracks.

It HAS to be done right.
And there is no way to tell afterwards if it was or not -
until it breaks.


Richard