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  #11  
Old 06-02-2018, 02:12 AM
longyard longyard is offline
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Cass Nawrocki says that if this issue happens with TIG welding, it can often be overcome by setting the amperage much higher than usual, but cutting the burst time significantly. He believes that in TIG welding, the issue is caused by "cooking" the metal and getting it to boil. Melting the metal should be the goal, not boiling it. He suggested to me a two-step pedal action. The first step is to melt the rod, but then move right on to a burst of pedal to melt the panel, but end this quickly. Cass has done many rosette welds with a TIG.
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  #12  
Old 06-02-2018, 07:59 AM
Rick Mullin Rick Mullin is offline
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I agree with Cass that you can over heat causing the puddle to percolate. Although I have experienced that, my experience with an occlusion that has erupted has been about oxide contamination.

In the certification courses that I have taken for aluminum MIG, ramp down, tailing off and allowing the gas post purge to complete is always a serious consideration. I realize aluminum is different than steel but I would think that the same rules would apply.

The new advances in welders, both MIG and TIG, when used to their potential have eliminated so many of the operator error issues making it much easier to produce a strong and attractive weld. I would like to think that I am a good welder but I have yet to out smart my new machine with all of it's software.
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Old 06-03-2018, 07:50 AM
Kabous Kabous is offline
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I had the same problem with stick welding - if we are talking about the same thing - where the last second of welding ends up looking like a microscopic vulcano. I guess under magnification the cone-shaped arc means the rod is melted and sprayed in a circle thus creating an inner lack of material and leaving the pinhole.
I have solved this problem by 'smearing' the last half second of the weld finish across the face of the pool to fill up the hole.

Dont know if this might pertain to mig welding as well.
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  #14  
Old 06-28-2018, 07:34 PM
Oldnek Oldnek is offline
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I actually had this same problem today, welding brackets to a old diff housing.
After I welded and ground smooth there were craters, so I drilled those out and tried welding again, only to be in the same situation, so my issue appears to be contamination, from Diff oils and impregnated corrosion on the housing.
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