Finally, I just gave up and went to SMAW (aka stick) and had no more trouble. The only thing I can think was happening was the almost closed box I was welding on was venting air from the inside and that was causing the porosity. Going to stick just got rid of the gas and added the flux to stop the problem from forming.
Kevin Caron has been a full-time sculptor since 2006. His public sculptures appear in public and private places from coast to coast. They include public pieces in cities including Tucson, Arizona; Chandler, Arizona; Avondale, Arizona; Temple, Texas, and more than 30 other commissions. On his YouTube channel, Kevin's more than 250 videos about metal fabrication and welding have garnered more than 3.7 million views. See and hear his work at http://www.kevincaron.com. Caron lives and works in Phoenix, Arizona.
You never know what subject you might find discussed in artist Kevin Caron's "The Art of Welding" column, but you can bet it will be right to the point in his usual straightforward style. He usually discusses welding and fabrication as well as the joys and challenges of being an artist, but he may also muse about his other pursuits, such as motorcycle riding or science fiction. One thing you can be sure of, it will never be boring!
To Mig or Tig or just Stick it!?!?!?Written by Kevin Caron July 30, 2013
While working on my new sculpture "The Runner" I ran into a problem. After fiting the top of the base in place and tacking it in place I was ready to do the finish welding. One section was done with no problems at all, but then everything went to worms!! Trying to MIG weld the outside joints was giving me nothing but porosity! I turned off the evaporative cooler, thinking that might have been the problem, and tried again.
Cleaned up the mess and closed the doors..... Same problem!!
Tried a different MIG welder - you have to eliminate the possibilities, right? Same results again!?!?!?