Welding in water

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?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 12 Nov 2009 23:47:16 -0600, Jon Slaughter wrote:

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Rich Grise wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Pete C." wrote: (clip) I don't believe

^^^^^^^^^^^^^^^^^^^^^ I would think not. They have a circuit board that would stop working as soon as it got wet.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Leo Lichtman wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The autodark lenses designed for underwater use have all the electronics completely sealed in silicone rubber.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Really? When I was growing up, principals were just regular old human beings.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Actually they do. A few years back a company came out with a Autodark lens for Underwater wet welding.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Ernie Leimkuhler" wrote: (clip) Oh yeah, also if you get your body between the ground and the

^^^^^^^^^^^^^^^^^^^^^^^ 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?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"SteveB" wrote: Control is totally topside with a knife switch. Diver sez make it hot,

^^^^^^^^^^^^^^^^^^^^^^^^ 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?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I went to diving school in 1974, and worked for about a total of eight years 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 ;'-)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.