Bad Bottle

admin

So, last week I was welding away on a bunch of aluminum castings. Everything was going along normally. I noticed I was low on argon, so I went ahead and changed out my bottle. Continued welding without incident. In the plant we have 3 argon bottles because the foundry needs it to de-gas the molten aluminum. When I resumed welding the same castings on Friday, the arc seemed to dance around a little more than normal. Manageable as it was, I continued welding successfully. At some point I dipped my tungsten into the weld-pool, upon removing it I noticed a black ring ~ 1/8" wide right where the tungsten protrudes from the collet body inside the cup. Thought that was a little odd, I had never seen that before. I've seen blue tungsten from that spot to the tip, from over-heating due to insufficient gas flow. This was just weird. I continued to re-tip my tungsten (breaking it off first), and went back to welding. Just for the hell of it, after welding for about an hour, I removed the cup to look at the tungsten. Sure as $h*t, same black ring. I checked my water cooler level, 1 qt. low, so I added the appropriate amount, checked my cables for kinks, everything seemed to be in order. Re-tipped the tungsten, went back to it. After a little while I checked it again, same thing again! Checked my gas flow, 18 cfh, full bottle, WAIT!! The bottle I put on when I ran out was only about ¼ full. That was when it occurred to me that maintenance must have swapped out the old bottles for new ones. BAD GAS! I thought, so I took the new full bottle off, put another on, and BINGO! No more black ring. Talk about frustrating."SOUTHPAW" A wise person learns from another persons mistakes;A smart person learns from their own mistakes;But, a stupid person.............never learns.
Reply:We used to get argon bottles that had other gasses mixed in by accident on occasion at my old job.  One time we got a nitrogen bottle that was mis-labled as as argon.  It happens some times.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Aluminum is way sensitive to stuff like that....once upon a time a new start up welding supplier round these parts bought a bunch of old bottles....upon switching out the argon the weld quality changed and it became very difficult if not impossible to lay a clean bead....turned out it was old rusty bottles.
Reply:I guess they didnt bother to clean, inspect and hydro test those used bottles....MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:We've been using the same supplier for years. In the past, the foundry guys would sometimes have a real difficult time de-gassing the alum. It normally should take no more than 2 hrs. of argon flowing in the crucible. But there have been times when they would run the de-gas for half the day and not be able to get a sample slug without gas. I suspect this was the cause of that as well, so now the boss wants me to test all the bottles with the welder as soon as the fresh ones come into the plant. Incidentally, I did weld some steel (DCEN) with the bad bottle and got the same black ring.
Reply:Well...it ain`t a perfect world is it now???  When it happened to us it was funny because it would weld steel fine....Switch to aluminum and it looked like you did not know how to weld. Bad contamination.  After a couple of us had the same results with different bottles and we swapped in another good one and narrowed down the issue...lets just say that the supplier  knew they F--ed up and since that company was a big account for this new startup welding supplier they fixed it really quick and never had the problem again. Just goes to show you how sensitive Aluminum is compared to mild steel.