A while back I posted a picture of a MIG weld that had that stack of dimes look of a TIG weld.
This last weekend I was working on a fabrication project for my wife. She wanted me to make a light weight exo-skeleton for an actor in a play she is involved in. Basically a framework for a set of angle wings. She is the costumer for the play so she will be doing the fabric and feathers over the whole thing.
Anyway I immediately thought of aluminum. I made a back piece shaped to fit the actor's back by clamping it to my table saw and pounding it with a hammer. That part worked out pretty good.
Then the for the actual wings I cut some 2 inch wide pieces 1/8" (0.125)
5052 and designed a pivot point. All pretty simple stuff. I decided for a little rigidity and stability without adding a lot of weight to weld a piece of 3/8" (0.375) 5052 round rod to the edge of the long sheet pieces. It worked pretty good for its intended purpose.Now to the point of my post. I tacked and the welded. My welds looked a lot like the welds in that picture. What did I do right or wrong? I'm not going to post a picture, because there are places where it does not look good where I had to go back over skip holes where I went to fast, and not all of the weld looks like that ridged stack of coins, but the vast majority does look like that. I looked at the other side, and I got pretty good penetration so I don't think I was cold welding or running under powered. I was running the wire quite a bit faster than Miller recommends, but I have found that almost universally their guide line table puts the power right on and the wire speed to slow on everything I have tried with aluminum.