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You would be amazed at how many welding rods use to be
found in the hull welds of the Navy’s HY-80 sub hulls. Lazy yard
welders would use rods as fill to get more welding done. Of course these
were found by X-ray and had to be removed with a grinder and re-welded.
For some time now they have been using robotic welders that lay a fast, consistent
bead with no worries of bad filler. R/Jay Respectfully, Jay K. Jeffries Andros Is., Bahamas A skimmer afloat is but
a submarine, so poorly built it will not plunge. -----Original Message----- Dan, You said the magic words: "Most psubers won't spend the money to x-ray their welds , but would'nt you like to know they would
pass a test if you did one ?" I don't care who the person is, how good they are, there is
a possibility of the weld failing x-ray inspection. If that were not the
case, the U. S. Navy wouldn't x-ray every weld on a sub. Just because a highly qualified welder is diligent and
does his best, does not mean he will not make a mistake. He is human after
all. You couldn't actually tell if the weld would pass an
x-ray unless it is actually performed. Granted the welder will be very
careful about his work, a third person is always less concerned with your safety
than you are. This is just a fact of human nature. "If your hull fails at 200 hundred feet you will be
just as dead as if it failed at 900 feet." The statistics would say that you are mistaken. The human
body (if not crushed) would be far more likely to survive the
pressurization(even rapidly) at 200 feet, but is extremely unlikely to
survive at 900. James Long Owner/Designer Lil Brother LLC (Instrument Division) ----- Original Message ----- From: "Daniel Lance" <lanceind@earthlink.net> To: <personal_submersibles@psubs.org> Sent: Wednesday, July 25, 2007 8:04 PM Subject: RE: [PSUBS-MAILIST] Welding Revisited James, If you tell a welder his welds are going to be x-rayed
when the job is completed there is a tendency for that person to be more
diligent in his work. X-ray "quality"welding as it applies to
Pressure Vessel Quality work means a bare minimum of porosity, slag inclusions, undercut
etc. and no tolerance for lack of complete penetration and/ or non fusion in the
root pass. A submarine pressure hull must be built to PVQ standards to
acheive 100% of the hull integrity needed for its intended
purpose.Setting the "bar" high for selecting a weld process, procedure or weldor is
whats necessary for such a demanding application. Most psubers won't spend
the money to x-ray their welds , but would'nt you like to know they would
pass a test if you did one ? If your hull fails at 200 hundred
feet you will be just as dead as if it failed at 900 feet. Dan Lance > [Original Message] > From: Lil Brother LLC
<lil_brother_llc@bellsouth.net> > To: <personal_submersibles@psubs.org> > Date: 7/25/2007 12:45:47 AM > Subject: [PSUBS-MAILIST] Welding Revisited > > Ok, > > We have discussed welding and the methods involved. > > Shouldn't we also discuss the situations that
pertain to each type and the > critical requirement for each? > > I know that a professional welder knows what he is
talking about, but I > think x-ray on welds that will never pass regular
scuba diving depths is a > little extreme on the side of safety. > > I'm not knocking safety at all, I tend to lean to
the safe side of > everything. But there is a point to overkill when it
comes to safety > measures. > > I agree, if you are going to depths of 600 -1000 feet,
I would definitely > have the most certified welder available, and have
the welds tested by > x-ray. > > But I don't see the need to go to that measure if
the sub is only going to a > max depth of 200 ft. I do see the need of the
welds being proper, airtight > and strong. > > But I'm a realist, so I can handle the opinions from
whoever disagrees with > me. > > James Long > Owner/Designer > Lil Brother LLC (Instrument Division) > > > > > >
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