Most of today was spent in welding practice. Yesterday, I reviewed the video series on 4130 Chromemoly Airframe Construction made by Kent White (www.tinmantech.com). I came away with quite a bit of new information to try out in my shop. For those that haven't seen these videos and are thinking about or are building aircraft structures out of tubing, I highly recommend the series! I came away with the realization that I was using a tip that was too big, even though I was using the smallest Meco tip I had (N1). I was getting the metal way too hot and I found out why. I got a gage and measured the hole in the tip and saw that it was .002 to .003 bigger than it was supposed to be. There is no way I could have throttled that tip back far enough and still weld effectively. I must have been careless in cleaning the tip and enlarged it. It should be .028 and it is at least .030, maybe .031. So, I ordered new N0 and N1 tips and three pounds of ER70S-6 welding rod. In the meantime, I made bead upon bead and welded joints on 4130 for practice. Since my tip was too big, I concentrated on heat control of what I had. What an experience! I did make some good, solid welds when the heat was just right.
