lph??? You mean lpm, right? (If so, I agree to try 7 lpm, because 14 lpm will likely cause turbulence and draft in air with that size cup.)
It looks like you've got some workpiece overheating going on with the small coupons on the right pics, with the heat running away. Counter-intuitively, the cause is using not enough amps (and traveling too slow.) Start with those small coupons close to room temp (not pre-heated) and move a little quicker with them to "outrun" the heat.
The heat build-up didn't seem as much of a problem with the larger piece on the left pic. It looked a little cleaner as well. I prefer welding aluminum without the largest cup size possible... I prefer about a #6, or even a #5 works very well. Gas lens is not very important on aluminum, either.
Practice getting a good torch angle, so that your filler rod doesn't melt before getting it to the puddle. Learn to recognize the puddle, and consistently and precisely adding filler, and maintaining proper torch angle. When you feel ready for a change, try the flat coupon joining (laps or butt welds with tight fitup are good. Tack both ends first, then weld the middle.) You could even focus your practice on just making good tack welds (it may not be easy.) Best tack weld needs to be not lager than your final weld bead is going to be (so you can make it disappear afterwards.)
Keep at it... Doesn't look bad for a first go.
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Originally Posted by jakeru
