Re: Welding in water
Rich Grise
> I was reading a book on welding and it says that if you put your helmet
> between the welding and ground it will destroy it... talking about welding
> under water.
>
> Why is that?
I've crossposted this to sci.engr.joining.welding. There's no real
electrical principle involved here, unless the current through sea water
somehow damages one of those auto-darkening hood lenses.
Good Luck!
Rich
Pete C.
Yes, there is an electrical principal, the electric current passing
through the salt water to the ground (the current will take every
available path) will greatly increase the rate that the chrome corrodes
off the brass parts of your helmet. If you happen to have one of the
really nice all SS helmets, this may not be an issue. I don't believe
anyone uses auto dark lenses for UW welding.
Leo Lichtman
"Pete C." wrote: (clip) I don't believe
> anyone uses auto dark lenses for UW welding.
I would think not. They have a circuit board that would stop working as
soon as it got wet.
Pete C.
Well, you could theoretically mount it inside the helmet, after all you
already have an intercom in there and the water is hopefully not in
there since if it is, you have a problem.
a7yvm1...@netzero.com
Really? When I was growing up, principals were just regular old human
beings.
Ernie Leimkuhler
Pete C. <aux3....@snet.net> wrote:
Actually they do.
A few years back a company came out with a Autodark lens for Underwater
wet welding.
Ernie Leimkuhler
Pete C. <aux3....@snet.net> wrote:
Oh yeah, also if you get your body between the ground and the
electrode, in salt water, while the knife switch is closed...
...YOU ARE DEAD!!!.
Not kidding.
I teach welding at the Divers Institute of Technology.
In fresh water you just get a small electrical shock, but in salt water
it is lethal.
Also all underwater wet welding is performed in the DC Electrode
Negative polarity to prevent electrolysis from stripping metals from
around you and applying them to your weldment.
The greatest erosion occurs at the bronze jaws of the electrode holder.
Ernie Leimkuhler
Lichtman <leo.li...@att.net> wrote:
The autodark lenses designed for underwater use have all the
electronics completely sealed in silicone rubber.
Ernie Leimkuhler
Pete C. <aux3....@snet.net> wrote:
No you can't.
It would violate all safety guidelines by IMCA and the ADC.
You can't have anything inside the hat that wasn't part of it's
original design.
Any dive supervisor who allowed it would be fired and have his card
pulled.
Same goes for ipods.
Leo Lichtman
"Ernie Leimkuhler" wrote: (clip) Oh yeah, also if you get your body between
> electrode, in salt water, while the knife switch is closed...
>
> ...YOU ARE DEAD!!!.
I would assume, then, that the welding electrode is "cold" until you have it
in position to strike the arc, similar to MIG welding. Is this correct?
SteveB
"Pete C." <aux3....@snet.net> wrote in message
news:4afdd7f9$0$27693$ec3e...@unlimited.usenetmonster.com...
In the old oilfield, a good diver had two hats. One for welding and
cutting, and the other for regular diving. Cutting underwater is an
electrical process that will corrode the coatings off the helmets and masks.
Steve
SteveB
"Rich Grise" <rich...@example.net> wrote in message
news:pan.2009.11.13....@example.net...
It is only necessary to wear a lens when welding underwater if you are very
close to the arc because the water diffuses enough of the UV rays that if
your head is more than one foot from the arc, the intensity isn't enough to
burn your retinas.
Also, in underwater welding, there is no movement or watching the puddle.
Moving the rod only allows water to get between the rod and base metal, and
it instantly cools the puddle. "Underwater welding" is done with a self
consuming technique where you crank up the power, put the rod in the crack,
and just push it in as you feel it consumed. usually at about a 45 degree
angle.
Unless you isolate the weld area from the seawater by a subsea pod of some
type of gas, welding underwater with instant quenching is only slightly
better than holding things together with hose clamps or bungees. And even
with a subsea isolation environment, there are all manner of variables that
affect the weld, i. e. humidity, the shielding gas, and inclusions that will
affect the x ray or whatever test is required to certify the weld.
It just isn't done a whole lot. Some, yes, but not a whole lot. Most
things are brought up, welded, and then taken back down. Or at least that
was the way we did it for eight years.
Steve, an ex hard hat diver.
SteveB
Intercoms in a good helmet consist of speakers dipped in rubber. The cheap
common way is a condom wrapped around the speaker, and held in place with a
rubber band.
Factory speakers are good, and last a good while, but the cost of
replacement is so high that when the original set goes out, they are usually
replaced by the lesser units, which are far cheaper, and easier to get in
the field.
Steve
SteveB
"Ernie Leimkuhler" <er...@stagesmith.com> wrote in message
news:141120090122364159%er...@stagesmith.com...
And tested to what depth? I doubt you could find a depth test rating on one
of those. I know I have seen good high dollar watches that were "tested" to
330 feet or something ridiculous, and didn't hold. I had an Omega that I
spent big bucks on, and only wore it topside, never exposing it to pressure
of more than 1 atm. Brought it to the jeweler when it wouldn't work, and he
said the in side was all corroded and flat worn out. Real commercial divers
don't wear a watch. They are another thing to hang up, they are easy to
lose, you can't see the thing 90% of the time, and the surface radio man and
dive master keep track of your time anyway.
Steve
SteveB
That's odd to hear, Ernie. We got zapped a lot, sometimes pretty heavy.
Lots of just tingles. But nothing bad where we had to do CPR, or where it
left a mark. Just lots of cussing over the radio.
Steve
SteveB
after that. I am commenting on methods and equipment used at that time. In
the ensuing years, I'm sure there's been changes and better stuff. Ernie
would know about that. So, my comments are just on the way we did things
back then, and with the new stuff, someone who has used it recently should
comment. Autodark for even above water welding wasn't even a figment of
someone's imagination at that time.
For all other things I say that are wrong, please consider that they are
just in error, and not really wrong.
Steve ;'-)
SteveB
"Leo Lichtman" <leo.li...@att.net> wrote in message
news:Xe6dndD6BpCS92LX...@giganews.com...
No. Control is totally topside with a knife switch. Diver sez make it hot,
and the knife switch is thrown. When done, he's SUPPOSED to say make it
cold so he doesn't get zapped, or the corrosion on his helmet continues. On
the work we did, it was all done with a knife switch topside run by an
assistant of the radio man.
Steve
Leo Lichtman
"SteveB" wrote: Control is totally topside with a knife switch. Diver sez
make it hot,
> and the knife switch is thrown. (clip)
^^^^^^^^^^^^^^^^^^^^^^^^
I can think of two reasons for using a knife switch: 1.) It is possible to
see at a glance whether it is on or off. 2.) The switch carries the full
welding current.
Am I on the right track?
SteveB
It's for safety. It removes any chance of the welder doing something
stupid, or say a cable gets cut or mashed or pinched, and goes to ground.
Or the diver narcs out or is kayoed. It takes control of the on/off out of
the hands of the diver.
Steve
Ernie Leimkuhler
Lichtman <leo.li...@att.net> wrote:
You are in constant audio contact with your knife-switch operator
topside.
When you are ready to weld, (assuming you are at the Blue station) you
say "blue diver, make it hot"
The communications person repeats that statement "blue diver, make it
hot"
The knife switch operator closes the switch and replies "blue diver hot"
Communications relays the info to the diver "blue diver hot.
When you are done with your rod, you go through it again with "blue
diver, make it cold" and so on.
You never change a welding or burning rod with the knife switch closed
or you get zapped.
If you are caught trying to do it on the job, you will be fired.
Employers don't appreciate you endangering their insurance policies.
If one diver screws around and gets hurt, you can lose your insurance
and hence your contract for that work.
Ernie Leimkuhler
<old...@depends.com> wrote:
Commercial diving has changed little in the last 30 years.
The only real change has been greater and greater enforcement of safety
procedures, and equipment maintenance.
Also the hats have gotten better as far as regulator designs.
Divers don't like new stuff if the old stuff works.
There is less and less underwater wet welding due to insurance costs.
They have developed new dry habitat welding procedures for pipeline
repairs.
check out
http://www.neptunems.com/nepsys/applications.aspx
It isn't like the insurance companies actually "like" divers.
They just don't like paying their widows large cash settlements.
Leo Lichtman
"Ernie Leimkuhler" wrote: You are in constant audio contact with your
knife-switch operator
> topside. (clip)
^^^^^^^^^^^^^^^^^^^^^^^^^
In my earlier post, I asked, "Why a knife switch?" Every time one of you
talk about turning the welding power on or off, you specifically say "knife
switch." Not contactor, or breaker or just "switch." So I wondered whether
it is because it is because it has to carry the full welding current, and
because you can tell by looking at it whether it is on or off.
SteveB
My take is that the welding machine may be remote from the dive station, so
one wants to have the on/off control close at hand to the man who's talking
to the diver. Not to mention having the noise of the welder farther away.
And the fumes. And you are right on the two counts in MHO. The switch is
heavy metal, and one can tell by looking if it is open or closed.
Steve
Steve
SteveB
Looks like what we called a SPAR, or subsea pipeline alignment rig,
seriously heavy, seriously difficult to get into position, seriously
difficult to cut and align a repair pup, and seriously crowded, with an
argon atmosphere where men had to be masked to weld inside. Didn't work
very well.
Sounds like stuff hasn't changed a lot except the hats. I see a lot of new
Kirby stuff that was just on the cusp of evolution in 1980. Most were
Kirby-Morgan band masks, and few had neck rings, except some of the old
Descos and Savoies. There was a black one that looks like the current
Kirby, but I do not recall its name. Head protection was something you
strapped on OVER your band mask.
For us, safety practices and equipment maintenance were just a cadre thing.
OSHA rules do not apply in international waters, and we would repetitive
dive out of N, O, and Z groups. We were pirates and kings of the world, and
had our own group. We always did have a chamber, and "hits" were common.
Equipment maintenance and all diving equipment hookup, take down, and
operation was left to the dive crew, and not allowed by any other group.
Got on a union job one time for Bannister Pipelines, the Alaska pipeline
people. They found out that they could put a couple of more mechanics to
work, so insisted that we use union mechanics to service our dive
compressors, even start and stop them. That cost several VERY expensive
delays, waiting hours for a mechanic to be airboated or choppered across the
swamp to start up a compressor for a ten minute dive. That lasted about two
weeks until one of them put regular oil in an air compressor, and sent a guy
to the hospital with lipid pneumonia. After that, we were given special
dispensation from the union to handle our own stuff. The two mechanics did
stay on for the duration of the job, though, "just in case." About two
weeks after that, I saved a laborer from drowning, and we raised another
notch in the pecking order with all the union hands. Before that, they had
used union laborers to swim lines under pipelines, and do in water work
until they had a couple of close encounters with alligators, and the
laborers refused to get in the water any more. People were leech magnets
without a wet suit. At first they were standoffish as we weren't union, but
got Davis-Bacon wages. Then when they didn't have to get wet or dive with
the leeches or alligators, they didn't mind so much. Then when I saved
"Jivin' Joe", a black laborer from Opelousas, we were tight. That was 90
miles of 54" OD concrete coated pipe through the Atchafalaya Swamp from
Centerville to Belle Chasse, LA. Quite a job.
All automated FCAW shielded bug welding except for tie ins. 50% cutout
rate.
Steve
Gulf of Mexico work was terribly hazardous, not so much from the dive crew,
but the other crews we worked with and around. And weather. I look back at
it now and ask what I was thinking. It was high adventure, though.
Steve, who misses the good old days, but not that much.
Glenn Lyford
> > talk about turning the welding power on or off, you specifically say
> > "knife switch." Not contactor, or breaker or just "switch." So I
> > wondered whether it is because it is because it has to carry the full
> > welding current, and because you can tell by looking at it whether it is
> > on or off.
I think there's another reason, too. They're using large DC currents,
which contact type breakers don't always do a good job of
interrupting, since there's a lot of arcing (no 0v at 120 times a
second like ac, which helps extinguish arcs). A knife switch gets you
a nice big conductor separation distance in a hurry...
--Glenn Lyford
ramray
interest. Not that I would actually try the procedures described, I am a
bit old for that sort of work, but I always wondered how that type of
welding was accomplished. My thanks to Ernie, SteveB and all the other
contributors for all the information that was provided.
Best Regards,
Ray Ramos
"Rich Grise" <rich...@example.net> wrote in message
news:pan.2009.11.13....@example.net...
SteveB
"ramray" <ram...@earthlink.net> wrote in message
news:YaydnWwYz8Z_k5nW...@earthlink.com...
> This has been a very educational thread and I have followed it with avid
> interest. Not that I would actually try the procedures described, I am a
> bit old for that sort of work, but I always wondered how that type of
> welding was accomplished. My thanks to Ernie, SteveB and all the other
> contributors for all the information that was provided.
>
> Best Regards,
>
> Ray Ramos
When we were in school, they told us that welding underwater would
accomplish up to 80% strength, and 50% ductility because of the quenching
action of the water. They told us that they would show us how to do it, but
that it was not generally used in the field because it was not nearly as
good as a dry weld. In eight years, I saw underwater welding done ONCE, and
that was some hardfacing rods burned on to a rig leg where another was being
put on outside with a clamp. The hardface was supposed to improve
conductivity so as to avoid faster corrosion of the new element. On top,
the welders laid the hardfacing rod on to the new clamp in the areas where
it would contact the existing leg. Underwater, we had to use a 30,000 psi
water blaster to clean off where the clamp was to go. Only the best were
sent down to do those dives. Right after the hardfacing, the brace was
clamped on, forever obscuring investigation or inspection. A couple of
years later, one of the divers, at a party, and loosened by a few Crown
Royals and Cokes said, "God, I hope no one actually looked at those welds.
They were horrible. It is a good thing that jacket legs are pumped full of
concrete because we blew a lot of holes."
IMHO, and only from my own experience in what I saw in the field, no really
important welding is done underwater unless it can be cofferdammed and done
in a dry environment. There was, however, a LOT of electric oxygen cutting.
Everything else was either welded before it was sent down, brought up and
welded and then sent back down, or made in a clamp configuration so that no
welding was required.
It was after those years that I got heavy into welding, and understood that
water and welding don't go together well at all. Just look at what a little
dew or condensation or water absorbed by rods will do to a weld. Now,
magnify that by 100, and you come to the starting point of welding
underwater. Most of what you see on TV is actually cutting, not welding.
Sure, there is a little welding, but not much, and of that, nothing critical
because it just doesn't hold.
Steve