Rewelding is not a good idea as the metal was probably stress releaved
Glenn Putnam
On Feb 17, 2008, at 3:09 PM, Hartmut Beil wrote:
Guys.
I am a certified welder for arc welding and autogenic welding and
brazing.
While my education focused on welding iron metals only, I had the joy
ones to work with aluminum too.
To say it simple, working with aluminum is not easy.
In my eyes it is impossible to assure that a welded aluminum joint
will have the same strength as before.
Any weld will take away the tempering qualities of the material as
well as the composition of the alloy itself.
Usually the material will crack again in the area where the heat was
not sufficient enough to affect the temper. You are creating basically
a soft area within a hardened area. I would not put my life onto a
welded spar, unless it was originally produced and tested that way.
It is a different thing though for structural pieces on an airplane
that had been welded in its original production process. The extra
strength needed is calculated in the size and the number of the pieces
used. A repair to a cracked weld on an engine mount is ok, because
that is the way the engine mount had been build in the first place.
Hartmut
----- Original Message -----
From: [EMAIL PROTECTED]
To: [email protected]
Sent: Sunday, February 17, 2008 6:55 PM
Subject: [ercoupe-tech] Re: Crack Spar
Regardless of the confusion over where these cracks are forming, I
think the notion of a welding repair to an aluminum structural
component on our aircraft is interesting. I would not be so quick to
assume that there is a government obstacle to such repairs. My motor
mount has a 337-documented welding repair. Though not structural, I
have also seen several of our oil tanks showing evidence of cracks
around the upper flange which were repaired by brazing.
There may be formidable physical problems though. I’m not so good at
welding aluminum, but folks I’m learning from tell me that 2024 is
not an ideal alloy for welding. Also, how the heat and physical
presence of the weld would effect the overall dynamics of the
structure would need to be considered. I would be interested in
hearing the opinions of more accomplished welders.
Cheers,
Bill
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