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I'm familiar with the general GTAW theory on aluminum.
I do have two questions:
1) With OA welding on aluminum, the flame/gas creates a zone of protection similar to what you get with the gas when GTAW welding aluminum. It would seem impossible to ensure that what with spot welds, and interruptions in the work, that the weld had never cooled out of the gas (no post flow), or you never cut into a section that had already been welded, and would have some oxide on it. Why is it fine to weld this way, but you can only GTAW aluminum with an AC current (usually pretty sophisticated AC)? How does OA de-oxidize the join as you work along? Why is OA considered good, but DC GTAW on Al doesn't work.
2) Someone once mentioned they used to sell Al stick electrodes. What is the story on that? How well or badly did they work?
3) When forge-welding steels, including SS, you can get real good results. The means of keeping your surfaces clean relative to weld quality is to use a reducing flame, and a flux. When DC GTAWing on SS or maybe even TI, the recommended strategy is to backpurge the weld area, or even in some cases weld in a sealed cabinet. Is it ever possible to use a flux to protect the joint? Let's say you have a well fitted joint, and it at the borderline of needing purging, are there any fluxes that could be used to preserve the joint integrity while doing GTAW.
I'm just curious about this stuff, I'm not trying to rewrite the book on nuclear sub welding. Sometimes there are fixes out there that might help redneck engineering. In some cases they may have been standard practice until they were superceded with more modern methods.
I do have two questions:
1) With OA welding on aluminum, the flame/gas creates a zone of protection similar to what you get with the gas when GTAW welding aluminum. It would seem impossible to ensure that what with spot welds, and interruptions in the work, that the weld had never cooled out of the gas (no post flow), or you never cut into a section that had already been welded, and would have some oxide on it. Why is it fine to weld this way, but you can only GTAW aluminum with an AC current (usually pretty sophisticated AC)? How does OA de-oxidize the join as you work along? Why is OA considered good, but DC GTAW on Al doesn't work.
2) Someone once mentioned they used to sell Al stick electrodes. What is the story on that? How well or badly did they work?
3) When forge-welding steels, including SS, you can get real good results. The means of keeping your surfaces clean relative to weld quality is to use a reducing flame, and a flux. When DC GTAWing on SS or maybe even TI, the recommended strategy is to backpurge the weld area, or even in some cases weld in a sealed cabinet. Is it ever possible to use a flux to protect the joint? Let's say you have a well fitted joint, and it at the borderline of needing purging, are there any fluxes that could be used to preserve the joint integrity while doing GTAW.
I'm just curious about this stuff, I'm not trying to rewrite the book on nuclear sub welding. Sometimes there are fixes out there that might help redneck engineering. In some cases they may have been standard practice until they were superceded with more modern methods.
I have the torch and it cuts like no OA I have ever used (percise) & uses 80 percent less gas (4psi acetolene & 4 psi oxygen on 3/8 steel and non ferrous metal) Have not had much time to practice on welding but looks very promising.
I WOULDNT WANT TO USED IT ON THIN STUFF FOR SURE. PENETRATION WAS MY MAIN CONCERN THEN AIR TIGHT BUT IT WORKED OUT WELL 
BUT ILL STICK TO AC UNLESS THERE IS A REASON NOT TO. BTW I did a lot oF oa work with propellers at H&H Propeller for 12 yrs I oa'd bronze propellers and tig'd alum,st,sst,and nibral,OXY/ACET BRAZING/WELDING WAS A LOT OF FUN I THOUGHT BUT THE BLUE FLUX WAS MURDER.I HAD TO EAT A ROLL OF ROLLAIDS EVERY DAY TO KEEP FROM GETTING THE FLUX FLU. THAT STUFF IS BRUTAL.
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