Welding under water

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Been attending a lock repair lately which required underwater welding.The welder/diver used a kemppi stick welder but was wondering if any MIG-welding would be possible under water. I've googled a Jap company that supplies special TIG shielding cups for TIG welding under water but couldn't find anything on MIG-welding under water with or without flux-core wire. Anyone know if it's ever been or being done?
Reply:tig welding underwater....i dont think that is true thats always been a pretty big joke in my shop kinda like overhead subarc...but no their hasnt been anything invented for any wire feed process underwater from what i know of
Reply:Hello ElGuapo, it really depends on how you define underwater welding, there are instances where divers will set up underwater habitats(essentially a tent) that they fill with gas to exclude the water. This allows them to weld in a similar way to what you would do topside. Wire processes underwater would definitely present a whole bunch of problems/issues, how would you keep the wire, wire feeder, and associated circuitry from getting water logged, etc.? Otherwise, if you are talking about strictly trying to weld with water surrounding you, I believe stick is still the norm, the electrodes used have special coatings that promote a successful weld underwater. Some of the underwater training centers use regular electrodes that they paint to help with keeping the water out of the fluxes, however, this is mainly a cost saving measure and I don't believe that they use those electrodes for actual repairs. Best regards, Allanaevald
Reply:Actually, underwater GTAW (TIG), GMAW (MIG), and FCAW (Flux-core) are not only possible, but are actually used (GTAW much more so than the other two). While they are done underwater, they  are not done 'wet' but in hyperbaric chambers. The high pressure atmosphere inside the chamber has some pretty interesting effects on the welding arc. For example, the higher density of the atmosphere means that the arc will have a higher voltage than an arc of the same length/current at normal pressures and the arc will be more constricted. Also, the higher pressure causes relatively rapid tungsten erosion, makes arc initiation more difficult, and requires much higher shielding gas flow rates.So, underwater MIG/TIG? Yes, been and is done, but not by hobbyists/amateurs. Wet underwater MIG/TIG? No.SixxGeeee, you might want to find some new shop jokes, even overhead sub-arc is possible, though I don't know how much it is actually used. In fact I was able to find two different patents for the process, one from 1979 and one from 1991, so it's not even a particularly new development.To quote Shakespeare:There are more things in heaven and earth, Horatio,Than are dreamt of in your philosophy.-Hamlet, scene vVisit Tensaiteki.com
Reply:yeah tig is done in a habitat underwater but all of the underwater welding done in the actual water is stick       ive never heard of mig being done underwater but it seems unlikely for a number of reasonsAaron Olsonmiller dynasty 200dx