Whats wrong? 7018

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The rods my instructor brought out for my class today was bigger (3/16"?) than the usual rods (1/8").  I started having trouble with me beads.  I was playing with the amperage all day up to 140 amps and was doing t joints in the horizontal position.THE FIRST PICTURE IS OF A T-JOINT IN FLAT POSITION W/ 1/8" 7018.  The second is all poop. One of the big problems is that the low side seems to not flow and I end up with a noticeably sharp ledge.Thoughts, advice?Thanks,Rusty Attached ImagesLast edited by Rusty Toyota; 09-23-2008 at 01:06 AM.Student on a mission.   Be the best. If I can't be the best I sure as hell won't be the worst.
Reply:first set looks pretty good.try a bit more heat if they are 3/16 and clean some of the dreck off your steel.
Reply:that cold edge..try pointing the stinger more at the middle of the joint and not at the top..
Reply:FIND OUT what size rod you are using.  I run 5/32 at 190 amps.3/32 I run at 85 or 901/8" is run 110 to 165 amps.  I usually hang around 140.Next time try placing your top bead first to see what happens.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:First off congrats and not bad looking welds. It appears that perhaps your work angle needs to be a little more verticle. The first pass approx.45 deg and then the second pass more like ~50-55 deg from horizontal this will put more heat in the first pass and should wet the edge you are concerned with. I think you are just doing a plain drag with no movement in you travel each person has some type of C motion or step motion that helps to control the puddle maybe ask your instructor about that and see if it helps. Good luck and stick with it.
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Reply:I love how the slag from 7018 peels back revealing the weld itself.
Reply:The slag peeling up leads me to believe you heat is pretty close to where you want it to be, but with a 3/16 electrode 140 amps probably wont even start an arc.  Those are 5/32 at largest which is probably a little cold at 140 amps.Try turning the heat up and angling the rod down into the lower plate instead of pushing it up into the vertical plate.Have we all gone mad?
Reply:I checked the can of rods today and it said 5/32".  So I cranked the amperage up to 190 and put a small bit of weave to it.  It got a lot better but now I'm getting a considerable amount of undercut.Student on a mission.   Be the best. If I can't be the best I sure as hell won't be the worst.
Reply:Good!    When you weave, pause at the sides to let the filler fill in, this will get rid of the undercutting.  Try a little less heat or a little more and watch the results until you find your own  comfort zone.Good to see improvement.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:You should not need any sort of motion with a 5/32 7018 rod.  That little wiggle of a weave is most likely what's giving you your undercut.
Reply:A weave is unnecessary in a flat fillet with 7018, and actually opens you up to all kinds of problems. Under the codes I normally work with a weave is not allowed with 7018 even for vertical up. There is actually an order of placement in multiple pass welding. You should be able to find it on Lincoln's website and it is definitely in "The Procedure Handbook of Arc Welding". Available from Lincoln and if you are serious about welding the best money you will ever spend on a general reference.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Sounds like some progress and to all I hope I didn't derail this or misguide the advice with suggesting a little motion which has turned into a weave. I am right there with Jolly Roger. I do believe that you adjust the working angle ever so slightly as you travel and carry as much heat (amps) as you can handle. The order of placement will allow you achieve the correct weld profile and will also give you some guidance on work angle. I have seen a 1 inch 3G bend test fail which was done with a weave due to inclusions and undercut. My weld instructor would not even allow a weave that's why I suggested talk to your instructor and see what advice he might have for you as he watches you.
Reply:"The Procedure Handbook of Arc Welding". Available from Lincoln and if you are serious about welding the best money you will ever spend on a general reference.Yes a lot of info for the money also a good sleep aid.
Reply:The undercut may be caused by moving too slow and trying to deposit too much metal in one pass.
Reply:Looking at the second picture, it appears you are not laying the additional beads in the proper location.  1st pass (root pass) is 1/8.  2nd and 3rd pass with the 5/32 rod should be placed with the Center of the rod at the Toe of the Weld from your root pass.  You shouldn't need to weave at all.  Buy watching the puddle continously (who doesn't) you should be able to determine your speed of travel to produce a proper bead.In the second picture it looks like you are actually laying the beads side by side with very little overlap.If additional beads are required (3,4,5) using the center of the rod at the root of # 2 & 3 passes is the norm.  And, is the norm for each successive layer of weld.It was mentioned, Clean.  Also clean with a grinder and bead brush between passes.  Another item, On your last bead you stopped and started a bead.  Notice the "cold start" and much slag inclusion at the starting point?  With Lo-Hi rods, start the arc on top of the bead you just laid and drag it slowly to your starting point.  Should be able to fuse in to the deposited puddle with no problem.  Worried about the "cold start" deposit on top of the weld?  Grind it off prior to running the next bead.  Good luck and you're gonna be a weldor.
Reply:definetly ur heat! I run 1/8 7018 all day on ol oil field pipe, n my heat range is 143 on a vantage 300. 3/16 rod i ll run 155 to 158 w / my machine! another machine, it could be totally other settings. play w/ur heat, get to know the heat that ur machine puts out.