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Hi Dan,
I appreciate your input. I have done failure testing prior
to welding on my sub with exceptional success. I think that some of the time
flux core gets a bad rap because of the fact that the little buzz boxes use flux
core. Mine is a 350 amp mig computer controlled pulse welder as speced by both
lincoln tech specialists and my coach, an extremely experienced and active
pressure vessel welder.
I concure that one cannot be too cautious.
I am interested in talking with you more at the convention
about this subject and appreciate your feedback.
Rest assured that I did considerable homework prior to
choosing the method that I am using now.
Thanks again & Best Regards,
Jim Kocourek
----- Original Message -----
Sent: Tuesday, July 24, 2007 7:50
PM
Subject: [PSUBS-MAILIST] Re: Mig welding
a sub
James
I believe it would be in your best interest to strive for the
highest possible weld integrity for the pressure hull of your submarine. A
weld procedure that is acceptable for a backhoe bucket isn't
necessarily adequate for Pressure Vessel Quality work. Typical
Quality Control standards for PVQ require full penetration X-ray quality
welds to acheive 100 % of the strength required for such a demanding
applicaton. While there are many welding processes available to the average
person, ( mig, tig, stick). Some are better suited than others in a given
situation depending on a particular individuals skill and experience
level. As an example , I have seen "side bend" Mig weld tests performed
by highly skilled welders with ten's of thousands of hours of welding
experience split apart in the weld bead zone. Mig has a tendency to exhibit
very shallow penetration in certain circumstances. The trick is to know
WHA! T circumstances. If you are going to perform your own welding I would
recommend that you do what industry does. Take a weldor qualification test in
the weld process and welding procedure you intend to implement in your build
project. Get a copy of "The Procedure Handbook of Arc Welding" by
the Lincoln Electric Co. of Cleveland Ohio. This an excellent reference
book with a chapter devoted to weldor qualification tests. If you have a
hydraulic press in your shop you can perform your own tests. If you
plan to hire someone to do the welding for you insist that they pass an
approved test administered by a qualified laboratory. Rework is
expensive , do it right the first time. And of course,......what is your life
worth?....... someone who says they can do it or someone who can prove
that they can do it.
Happy sub building,
Daniel Lance
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