Underwater Welding

[Bob]

Today I actually saw 10 rain drops ... this is a big deal here because it has been very dry this year.

I got to wondering about emergency welding in heavy rain, and even welding underwater. I know it is done. Salt water, in particular, is fair conductive; seems it would short everything out.

Just in case, this is a knowledge question, I am not planning any welding in the rain. Just wondering how it might be done, without electrocuting the weldor. Also seems like the rapid heat, then cool would make a very hard/brittle result.

Bob

[Roger]

Underwater welding is taught at comercial diving schools or military diving schools.

Rule one is don't get between ground and work. Diver checks that welding current is off before changing rod by tapping electrode on work. Diver uses specific phone procedures to have topside turn on or off welding current to diver.
Diver was always in dry suit with dry glove. Now days diver is in dry suit and glove is often wet suit glove with no holes. (get real) They use latex rubber glove under wetsuit glove. Much lighter welding lens is used underwater depending on water clairity. Shade 7 to 9 is normal. Normally use special welding lens holder for diving helmet but welding lens can be stuck to diving helmet faceplate with bead of grease.

When u/w welding was used mainly for ship salvage they used 1/4" rod. That caused loss of strength and ductility. Now underwater welding is common in oil industry and certified welds are required. They use thinner rods with multiple passes each added pass heat treats preceding pass so weld isn't as brittle.

Welding rods are water proofed with electrical tape, epoxy or plastic paint.
Diver has minimum rods to keep them dry.

No AC welding current can be used.
DC electrode negitive is normally used.

Have to vent explosive gases produced by welding current u/w.

Welding in dry chamber has many of same problems and more. Welder in chamber still uses diving gear.

Very hard to do good welds.

http://www.machinist.org/army_welding/Ch12.htm

[Danco]

welding in the rain will give you a good zap when you change the elctrodes, thats for sure! in wet conditions (vancouver's always wet!) i use lined rubber glovers or latex gloves inside my regular gloves. and youre right about the rapid cooling causing brittleness. thats why and welds done underwater or in the rain are emergency only. when they repair ships or barges this way, itll be brought into drydock for a proper re and re. a fellow weld shop owner told me in the old days, they'd shellac 6011 rods and leave them dry overnight before doing underwater welding to prevent the from crumbling in the water. its a tricky weld because your viision is limited due to the bubbles created by the heat.

[Bob]

Thank You Roger!
The link you posted is a wealth of info, not only for underwater but many special techniques. The Army can sure pour on the info in their tech schools.
Bob

[Hobart Expert Rock]

HI BOB..............I WOULD THINK THE NAVY AND THE SEABEE'S, THE MARINES, THE SEALS............WELL MAYBE NOT THEM(SEALS) THEY BLOW THINGS UP DON'T THEY............ANY ONE IN THE MARITIME (SHIPS) INDUSTRY WOULD KNOW HOW TO DO THIS............ MAYBE NEW PORT SHIP BUILDERS, ETC............. IS A VERY SPECALIZED INDUSTRY REQUIRE'S VERY EXPERIENCED DIVERS......... I DON'T THINK I WOULD LIKE TO BE DOWN 100' AND WELDING........... YOUR CALL.............HAVEING BEEN ON A OIL RIG IN THE GULF OF MEXICO WITH SMALL 10'-15' WAVES YOU CAN COUNT ME OUT ON THIS ONE...............HOWEVER I'VE WELDED AT THE SOUTH POLE AND IN NOAM ALASKA............. TEMPERATURE TO RAPIDLY COOLING MATERIAL IS THE KEY...................BE CAREFUL OUT THERE NOW AND WATER DOES CONDUCT AND MAKES YOU JUMP AND CURSE...........................ROCK[email protected]

[Hunter991]

underwater welding

From the military link attatched it seems that it requires no special welder to do underwater welding. It only needs to be grounded to the ship or other source and have perfect cables and a special stinger, as well as waterproofed rods. Am I reading this correctly? Always been curious about underwater welding. I dive at work and do limited underwater construction, never tried welding though.

[chip hayden]

july 2002 issue of "Welding Design and Fabrication" is devoted to underwater welding.

[Bob]

Rock,
I don't plan to try this, just courious. I did once go to sea for 10 days on a Navy ocean going salvage/rescue ship. Saw sea state 4. The sailors were grinding and welding just about everyday. I was part of a science team, doing electronic sonar things. Our "work area" happened to be the open air weldor's storage area. We had a 25,000' wire rope "fishing line" with a 500 lb. sonar device on the end. Lots of custom structure to manage the load.
Bob

[Roger]

Underwater welding part of army welding manual is taken from USN Underwater Cutting and Welding Manual. It has much more stuff in it, ultrathermic cutting, gas cutting, how to make u/w arc welding or cutting torch, improvised cutting rods, big list of waterproofing welding rod procedures and more.

Can also use Oxy/ Gasoline torch underwater to about 145' depth.

The big thing that Hunter left out in his list of requirments for u/w welding is the knife switch operated by phone talker. Phone talker using electritions gloves open and closes knife switch at divers command. Diver says Switch , phone talker says switch on to diver then closes switch.

Diver says switch off, phone talker opens switch then says switch off to diver. Diver then taps electrode on work to check no welding current then he can change electrodes, chip slag ect. This is tought to all USN 2nd class divers and all comercial divers who use surface supplied diving rigs. Mostly training is saftey procedures. Comercial diving schools also have u/w welding classes. USN would hire civilian contractors or have their better u/w welders practice for specific job.