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Vance (Dan, Jay, all the others)
The discussion has come full circle as Vance
noticed.
I thank everyone who input their expertise and
views on the subject. It was enlightening.
My view may change when I build a sub. It's easy to
deliberate a subject that hasn't stared one in the face.
It was a good discussion of what has been
done, what can be done, and what people feel should be done.
Disclaimer......I want anyone who read
the topic ( who didn't participate and are considering building a personal sub )
to consider the risks before making a decision of welding and inspection. It's
your life that hangs in the balance. The people who participated in
the discussion will probably be at home doing what they do, if you have an
catastrophic weld failure. It's your responsibility to construct a sub,
as close to perfect, as you can.
James Long
Owner/Designer
Lil Brother LLC (Instrument Division)
----- Original Message -----
Sent: Thursday, July 26, 2007 10:41
AM
Subject: Re: [PSUBS-MAILIST] Re: Mig
welding a sub
This is going around in tiresome circles, kids. Yes, some Ks
were migged some hull welds. Yes, they were ALL X-rayed as far as I know if
built by George (He is a very thoroughgoing man). Yes, if history serves any
purpose, the Ks are safe. Yes, you should check and double check. And, yes, if
you have the expertise, then you should X-ray. If not, find an ultrasound
expert and scan using some of the new software developed for the purpose. If
the metal is thin, do your best to check it adequately. If it is thick, how
about do the same thing. And yes, it's your behind--but our behinds will
be LEFT behind wondering what happened and whether we could have
helped. On the good side, a weld would most likely weep on you, rather
than fail catastrophically. One can only hope. Vance
-----Original
Message-----
From: Lil Brother LLC
<lil_brother_llc@bellsouth.net>
To:
personal_submersibles@psubs.org
Sent: Wed, 25 Jul 2007 11:06 pm
Subject:
Re: [PSUBS-MAILIST] Re: Mig welding a sub
Dan,
Here is the problem I have with this thread at it's
current point.
We know there are K 250 subs out there that were MIG
welded.
Are they safe?
I know safety is the main issue here.
Can a 250 fsw sub be built safely using MIG? (it
should be stated the MIG be a proper unit.....not an ebay $99.00
special)
James Long
Owner/Designer
Lil Brother LLC (Instrument
Division)
----- Original Message -----
Sent: Wednesday, July 25, 2007 8:05
PM
Subject: Re: [PSUBS-MAILIST] Re: Mig
welding a sub
To James K.
Thank you for lending your indivdual experience to this thread. This
subject needs to be discussed as much as possible. I look forward to meeting
you at the convention. I hope we can continue this thread there.
Dan Lance
----- Original Message -----
Sent: 7/25/2007 11:23:26 AM
Subject: Re: [PSUBS-MAILIST] Re: Mig
welding a sub
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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