The spot I am welding to is the seam between an end cap and the tube. Tabs are 1/8" thick, as well as the tubing.
I welded it with 4043 filler. Tube is 6061 and the cap is 3003 (it's what I could get). Welding them together went fine. But tonight when I went to put my tab on, the bead from where I welded before kind of bubbled out with a greyish goo. Kinda looked like those little black pellets we lit on fire as kids around fourth of July (snakes?). Anyhow, I could not get a puddle going on this at all.
So I took a break and went back to practicing. Most of my practicing looked ok but every now and then, I'd get this same thing coming out of my practice piece. Sometimes only at the beginning of the arc, then it would settle down and I'd run a good bead.
Everything I am welding is brushed and wiped with acetone. Seems like it would be contamination but it looks like I'm getting it clean. Even wiping down my filler rods. Also perhaps looks like I didn't have gas coverage maybe? Running 15 to 20 CFM with about 7/16 stick out. Going into a corner... seemed like a good idea. I've done practice tabs like that before.
Running a CK flex lock with stubby gas lens. Hitting it with perhaps 150 amps to get things going and (trying) to back off as I get a bead going. Never really got one with the tabs. Either I was fighting the goo bubbling up or the tabs were melting away. Or both.
So... should there be any problem putting a bead over top of another bead? Seems like it shouldn't be a problem. Could it be possible to run a weld that looks ok but then weld on the same spot later and have impurities bubble out?
I'm going to do a bunch more T joint practice. It's touchy to get those to go for me as it is. Impossible when the base piece is bubbling stuff out... Wish I could get a video of it...
Thoughts... Besides I suck at this. I got that...
