That Steelworker site is a dandy!
I donít necessarily agree with every thing they say about mig (only thing I looked at) but itís a very informative site nevertheless.
The ďtriangle weaveĒ is also known as the ďdouble-pass weaveĒ and Iíve used it for many years. It makes a nice looking weld as seen in Jackís photo above. There is one chronic problem with using that particular weave with mig-SC though. If the operator isnít right on his toes with this weave, heíll have cold-lap right where the edges of his puddle (lower two triangle corners) overlap. Especially if the welder skips the root bead! Adding a root bead to any joint when using this weave will help minimize but not alleviate the chance of getting cold-lap.
Iíve witnessed far more welder qualification coupons fail the face bends with this weave then the historically accepted mig weave. The failure will usually occur on the side of the weld in direct correlation to which hand he/she is holding the gun. Using the above photo as an example, the cold-lap would normally be on the right side of the weld as we see it if Jack is right-handed. The same welders switching back to the basic, inverted ďUĒ weave will usually pass on retest.
In my opinion this weave is far better option for most folks when used with either stick or especially with flux core itís great. I know of no training center or institution personally that teaches or recommends this weave with mig-SC.
There's no such thing as a welding problem, there are only welding puzzles of assorted sizes!