...i need to pass the bend test!

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I was browsing another thread where the discussion centered on getting MIG welds to look good. Lots of good advice by guys who've been doing this awhile. One concern raised was appearance vs quality, and the need for us newbs to focus on the latter......agreed.ZTFab suggested that some deviation from the guide printed on the welder could be a good thing. I had been trying to follow that guide to the letter....I'm realizing that with so many variables in play, it's really just a guide. I was testing some welds on some old bedframe. The guide on my 135 called for settings of F 4.5.....by the time I moved on up to a setting of I 5, I had surprised myself with what a boost of power could do. My welds flattened out and I was able to take some time to get a cleaner looking weld by moving in a circular fashion:In the spirit of that conversation, I wanted to check the quality of the weld:I then beat the poo out of it with a hammer and pipe wrench:Same weld, cut in half:To my rookie eye, the penetration looks good. I'm open to criticisms. Again, I'm just starting out with the 135 and learning as I go.DSW has schooled me on the proper way to test a weld......it seems I whacked it in the wrong direction. Also mentioned something about the fillet being too thick......I'm listening. More heat? Faster travel speed?...
Reply:DSW gave me this advice earlier: "One thing I will mention on here is your "test". The fillet is WAY too big for the steel thickness. Filets should usually be no larger than the thickness of the thinner plate. Any larger and you really haven't gained any strength. Also, you bend the test in the opposite direction. You want to fold over the fillet. The idea is to see if the bottom opens up. I'm betting it will since I can easily see the seperate plates clearly in the cut section. That tells me no matter what it looks like on top, you failed to fuse the root in and the weld "fails". This is where people talk about small migs making "pretty" welds that fail to penetrate."So I went out to the garage bent one in the other direction:I suppose one of the reasons this weld fails is due to the "opening up" on the back edge.....Let me guess: If the weld wasn't so thick, I would've had better penetration all the way down to that edge?
Reply:If you were to get penetration to that outer edge with your machine it would be set way to high or if you want you can leave a gap to achieve that also. The weld is to big for how you are trying to test yourself and the heighth of the weld should equal the thickness of the material, you seem to be two times to big. The material you have chosen seems to be on the thin side and your welder shouldn't have any trouble welding it and so you so test yourself on something thicker like 3/16"
Reply:Because the weld was so large the metal bent at the top rather than at the root. If you look at the section pict in detail, you can see just how little the bead actually penetrated into the upper plate. Don't expect 100% penetration with this, but you probably should get more than I see.Details like machine being used, settings for "heat", wire speed, wire size, gas or FC wire, gas type/flow, position (flat, horizontal, vert, overhead), material type and size (SS looks a lot like mild steel in some cases) and so on will help give you the best info to improve your welds.Thanks for starting the new thread BTW, Attached Images.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:Decided to experiment with some thick metal, so I picked up some 3/16 and some 1/8 to play with.Details: Eastwood 135, .025 wire, 75/25 gas mix @ 15psi, volts range from A-J, wire speed ranges from 1-10, max output 28v.Here's the 3/16 weld done with the volts maxed at J and a wire speed of about 3:The bend test:I can clearly see the failure to penetrate on the back end, as well as the split. I knew I was pushing it with the thin wire; also, the info inside the welder says to use .035 flux core for metal this thick. I did this weld to see the effects of falling short. The next test I try with this 3/16 will be with the flux core I have.The 1/8 follows.....
Reply:Up next was the 1/8. I had better luck.Details: Eastwood 135, .025 wire, 75/25 gas mix @ 15psi, volts range from A-J, wire speed ranges from 1-10, max output 28v.Here is the 1/8 test. Volts between G and H, wire speed at about 4:Back view:Cutaway view:Bend test:Looks like the weld is a bit thick. Maybe I need to notch down the wire speed or speed up the travel.
Reply:for starters, your weld profile is excellent.  you do need to work on weld size, but the consistency of motion and puddle control is great.  I would limit myself to 1/8th and under for this size welder.  It just doesn't have what it needs to weld thicker.  I would concentrate on staying on the fron of the puddle  and burning in your root.  this will quicken your speed alittle.  as mentioned before.  you want to limit you legs to the thickness of your stock.  anything more than that is wasting money.
Reply:If you look at the toes of the welds between the 3/16" and the 1/8" you can clearly see a difference. The toes on the 1/8" weld are well wetted in. The toes on the 3/16" weld are not bad, but a bit cold. As Scott said, 1/8" is about the maximum practical material for a machine this size.The 1/8" bead, while a bit large, looks fairly good. Here's what we have the students do at the school. They start on flat, weld a few basic beads on plain plate , then lay one bead at the toe of one of the plate. Next they move in order thru a lap joint, then T joint, then outside corner, and finally a bevel butt joint. After they pass all these, they move on to the same group in horizontal, then vertical up and finally overhead. All the welds are on 6" pieces minimum.All in all it looks like you are doing well, you just need to tweek the speed and settings a bit to get a smaller bead. Looks like you've avoided the big issue most students have of moving too fast and having too small a bead. Usually it's harder to get the guys to slow down rather than speed up a bit..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 problem with mig welding is that it's unreliable at the best of times, and when you make un-necessesary motions with the torch it's kind of a recipe for poor root fusion. Obviously by your post you already know this, so my advice would be to echo what has already been said by Scott about keeping the arc at the front of the weld pool and not let it build up to much, as it wont allow you to catch the root properly with the arc. I see you got a bit of undercut on the first bead, watch the arc length (keep it as short as possible to put all the amps into the material) and the torch angle, as these can both cause that.BTW.Try cutting into the throat of the welds about half way with a slitting disc or hack saw, they will bend/break easier.Last edited by Baila La Pinza; 04-27-2011 at 10:10 AM.
Reply:to help get full penetration you may want to leave a gap or better yet, bevel even the 1/8 material.  you need to be in the habit of doing this for larger material, and I haven't found a 110 machin that will consistantly eat away 1/8th to give a satisfactory full penetration weld.  Now not all welds need to be a full penetration weld, but EVERY weld needs to be fully fused from root to toe.  If it isn't it becomes a large fulcrum and will fail.I would concentrate on tieing in both sides of the joint and staying in the front of the puddle. Ideally you want the front of the circle (if you are using a circular motion) to just cut the edge of the molten puddle and then the back of the circle to cross over the to middle of the molten puddle.  This will ensure you are welding parent metal and not welding the bead which causes cold lap.for what that thin of material I would do what I call a wiggle.  I wiggle the arc from side to side kissing each edge of the joint and staying on the very front of the puddle.  If you do this right you will have a beautifully smooth, small weld profile that looks like it just grew out of the plate and grew into the other.Some shops what one style others want circles.  I just do both depending upon who wants it.
Reply:Plus (good things) = Consistent bead size and shape. Pretty good pictures too.Minus (bad things) =  Weld bead too big for the thickness of the parent material and the weld not really fused -into- that parent material.  You did get just a little bit of fusion into the parent material, but nowhere near what you could or should have gotten.With the way you set up your pieces (inside corner to inside corner with a completely 'open' back part of the joint), you could and SHOULD have been melting/fusing right through that corner.  Instead, you were pretty much piling up weld filler on TOP of the corner and not INTO (and through, at least partially) the corner.  Based on the excessive bead size and lack of weld right AT the corner, I'll guess that you were piling weld on -top- of the puddle and not getting the arc right -into- the joint corner/bottom.Little 110-120V GMAW/MIG machines with 0.025 solid wire and C25 are good for gauge-thickness materials.  They are -usually- out of their power/thickness range for 1/8" steel and up.  IMHO.As mentioned, run some lap joints and WATCH the arc/puddle -just- melt that top edge of the top piece and also dig into the bottom edge of the top piece and into the piece underneath.   Progress from there.And good that you are practicing and checking and listening.    The best laid schemes ... Gang oft agley ...