Advice on these welds

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I decided to run some practice welds so I picked up some similar metal and worked on running some beads. I tried .035" flux core but It just burned through the thinner tube. Notes-hobart 140, .035" solid wire and 75/25-plate is 1/4" and rectangle tube is less than 1/8"-chamfer, remove mill scale and pre heat 1/4" (with MAPP gas, if that counts)-run 1 root pass-run another pass in a "u" shaped pattern-Let pieces cool and bend in the direction to try and break the overhead weld.So, although my welds may not be the prettiest, the base material broke before the weld. Does this show the weld is strong?welded piecesWelded normal horizontal positionWelded overheadHow far I bent themWorst damage, the tube cracked next to the weld
Reply:There is some undercut which means you need to pause longer on the edges and may want to slow down a little.  Not too bad though.
Reply:Filet welds should only be as big as the thinner of the two pieces. In this case 1/8". You have way too much weld. Just because you glob on 1" of weld doesn't mean it's a "good" weld. 2nd you bend test fillet welds by welding one side, then bending the weld towards the weld, not away for it.For this application you only needed one pass to give you your 1/8" bead. The "pointy" look to the bead tells me you could have slowed down also..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:The weld is not bad for a beginner. The undercut is the biggest problem I see. I have the same problem--filling undercut at the top of a fillet. People always say to pause more at the top to let the puddle wash in at the toe, but whenever I do that, the extra heat just causes more undercut. So it's not a problem that I can really help you solve.The shape of your "ripples" suggests that your travel speed was too fast. They should be more circular and less V-shaped. However, as DSW points out, your weld overall is thicker than it needs to be, so a slower travel speed would make that problem worse. I don't MIG weld, so I can't tell you exactly what to do, but in general, I think you would want to reduce your deposition rate, thereby allowing you to slow your travel speed without increasing the thickness of the resulting weld. With TIG, I would simply use less filler. With MIG, perhaps the equivalent is to reduce your wire feed speed, although this may have other effects on your heat input that would need to be compensated for--for example, you may need to increase voltage to compensate for the reduced heat input of the slower wire speed. I'm sure someone here who MIGs can give you proper advice on the matter.Everlast PA160-STH... and that's about it!
Reply:... incidentally, the V shape may be the result of your weave pattern on the cover pass, in which case forget what I said about travel speed.Everlast PA160-STH... and that's about it!
Reply:I see the under cut, I was focused on the other side of the weld because I kept getting a funny lopsided crown. I had a wide chamfer then welded a wide pass thinking giving the weld more surface area would be good but that's not quite the right way.So the ideal weld would be a single pass no wider than 1/8" wide, fast enough so I don't build an excessive crown, but slow enough you don't see ripples? How would I see if the weld passes? It seems that if I had enough heat to get penetration in the 1/4" I would burn through the thinner metal.
Reply:Originally Posted by _Mitch_I see the under cut, I was focused on the other side of the weld because I kept getting a funny lopsided crown. I had a wide chamfer then welded a wide pass thinking giving the weld more surface area would be good but that's not quite the right way.So the ideal weld would be a single pass no wider than 1/8" wide, fast enough so I don't build an excessive crown, but slow enough you don't see ripples? How would I see if the weld passes? It seems that if I had enough heat to get penetration in the 1/4" I would burn through the thinner metal.