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Gary,
I have a lot of respect for Burt Rutan's judgement but this one has me
baffled. I just finished reading the spec for stainless steel welding
rods (ANSI/AWS A5.9-93) and can find nothing to cause alarm. Each
filler metal designation is based on the base metal designation. For
example the weld rod ER309 has the same alloying elements as regular
ASTM specified 309. The prefix will distinguish between solid rod (ER)
and flux core (EC). Various suffixes will designate variations from
the standard alloying elements/percentages. If the AWS designation is
used the rod must comply with the spec regardless of the manufacturer.
I spoke to the metallurgists in our materials testing lab who
specializes in welding and he was likewise curious about the reason weld
wire was shunned. He could not think of any reason weld wire would
cause a problem.
I was not able to locate a copy of the outdated QQ-W-423 material spec
used on MS20253 hinge pins. The condition appeared to be cold worked ie
higher strength/less ductile than the substitutes we are discussing. I
might just test an actual piece of hinge pin to check this.
I'll let you know if I find out anything interesting.
Chris Zavatson
N91CZ
garyhall@ix.netcom.com 06/27/02 07:52AM >>>
Subject: Hinge SS wire properties
Christopher.Zavatson@udlp.com wrote: Could you please elaborate on this. What are the properties that could make the weld wire more brittle and unsuitable. . . . The drawing process can impart some brittleness, but this applies to all stainless wire unless it is anealed afterwards.
Chris Zavatson
Hi Chris,
This discussion took place back in 1985-7. I was not part
of that discussion, but was told to me by Rutan that this
was a possibility and that he wanted better quality control
using "know" metals. He was steadfast against using anything
that might / could / possibly create a problem of *any* sort.
That is why we have a certified metallurgical report with every kit. And I do believe the wire has been annealed.
Hope this helps.
Gary
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