SMAW 3G Unlim thickness questions

admin

1/8" 7018 on DCEP 3G stringers all the way out. Backing bar is 1 1/2" x 1/4" thick plat is 1". Amps amps from root-cap is around 110-120 dials arnt labeled well/Having trouble figuring out a few things with my run off tab and question about undercut. Ill start first with the run off tab problem. Usually I strike my arc at the top of the run off tab and carry the arc through the bevel and to the bottom, when I come to the bottom and stop to start actually welding the puddle drips down and causes problems later on when trying to put my cap on. What is causing my weld to drip and sag or build a high spot, I even tried to move forward quickly right after I started the puddle and move towards the bevel. But I can progress all the way through the bevel and to the top of the run off tab without it dripping or creating crazy spatter. I even made sure my rod angle was pointing slightly upward and not down still nothing. . The next question is and could be another problem area is when I am doing my cap. Once again i strike at the top and carry my arc down and start welding come up to the bottom of the plate on top of the bevel no problems but when I get to the top and I need to get to the top of the run off tab I have nowhere to go but over to the side and down the middle cause the build up on the run off tab isnt wide enough. Which causes me to pause on the edge to fill in so I don't get the cap to fish mouth on me. So what do I when I come up to the end of the weld so I go in towards the middle then down the run off tab? Last question is when overlapping my beads on my cap by 50% sometimes I get undercut on the previous bead on the top. I'm not sure if that is undercut and will fail me on a test for a job. I usually fill the 1" plate to flush or just below flush then let it cool, I only let it cool twice during the fill pass. Im not sure if I should just run my cap pass colder so I run into less undercut problems, but typically I can get those welds looking flat and beautiful its just the toe of the overlapping side of the bead has undercut., but no undercut on the other toe.Hopefully I was descriptive enough, if you guys need the picture I saved the test I told my teacher I didn't want to cut it and bend it if its not perfect, since I already passed the bend on 3g and 4g. Will have to wait till monday though since its in my locker at school. Im trying to make my cap perfect because CB&I is hiring for welders in my area and the test is 3G and 4G unlim combo test with stick.Last edited by smilexelectric; 06-29-2013 at 08:31 PM.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:I'm not sure what you are asking about with some of the problems. The cap pass undercut tho could be because of the angle you are holding the electrode. The angle of the cap pass and the pass under it means you need to angle the electrode to the side a little when doing 3g. Allot of guys try to keep the electrode straight in with a slight push angle, it can work but sometimes leaves undercut. Another thing is you may need to let the plate cool a little between cap passes.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Originally Posted by SquirmyPugI'm not sure what you are asking about with some of the problems. The cap pass undercut tho could be because of the angle you are holding the electrode. The angle of the cap pass and the pass under it means you need to angle the electrode to the side a little when doing 3g. Allot of guys try to keep the electrode straight in with a slight push angle, it can work but sometimes leaves undercut. Another thing is you may need to let the plate cool a little between cap passes.
Reply:Originally Posted by smilexelectricHad a hard time describing what happens with the drip, basically I strike at the top of the tab, carry arc to bottom of tab. But when I start welding after carrying the arc down the puddle always wants to drip and sag off the run off tab. Or build up which causes problems when building up the bottom of the run off tab. The bottom isn't as big of a concern as the top is.
Reply:Why you starting all the way at the top of the plates and dragging it down to the bottom? Start a Iittle bit above the spot where you want to start,not 7 inches away.  Put the root in at 118-123 amps, don't go below 115-116 amps at all..  I usually run stringers and weaves when taking that test.  If they told u stringers only,than stringers only..Undercut on the cap: either plates are too hot, moving too fast, wrong rod angle,dirty tops of pâtés,etc.. Don't fil the plate flush when stick welding,leave yourself some room to put the cap on..   Yes,pics would be great...Last edited by ShortbusWelder; 06-30-2013 at 12:50 AM.
Reply:Originally Posted by ShortbusWelderWhy you starting all the way at the top of the plates and dragging it down to the bottom? Start a Iittle bit above the spot where you want to start,not 7 inches away.  Put the root in at 118-123 amps, don't go below 115-116 amps at all..  I usually run stringers and weaves when taking that test.  If they told u stringers only,than stringers only..Undercut on the cap: either plates are too hot, moving too fast, wrong rod angle,dirty tops of pâtés,etc.. Don't fil the plate flush when stick welding,leave yourself some room to put the cap on..   Yes,pics would be great...
Reply:Also i cant go by amps i go by the flatness and sound. CB&I sands all the numbers off their machines dials.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:Originally Posted by smilexelectricAlso i cant go by amps i go by the flatness and sound. CB&I sands all the numbers off their machines dials.
Reply:Not 100% sure eitherMiller Maxstar 200 SDPiperliner #10 Gold
Reply:I just took my 1" unlimited 3 and 4g, ran it at 112 amps. i passed with no problems.sounds like it could be alittle bit hot.they cut my coupons out of the center, so the very top and bottoms of my plates werent used, im not sure if your test is similar but that might help you out if the the bottom is alittle sloppy.Miller ab/p 330Hobart champ 16Miller 140Lincoln Power Mig 255Lincoln SA-250
Reply:Originally Posted by ShortbusWelderThat is stupid.. What's the reasoning behind that?
Reply:On the bottom tab, you could build up a step with weld metal before you start, something to hold your bead. On the top, I can't picture it. How long are the tabs? You say the buildup isn't wide enough, nothing says you can't make it wider...you can do whatever you want on the runoff tab.Undercut between beads on the cap, never had anybody say anything about it. Just don't undercut the plate itself.
Reply:Originally Posted by TimmyTIGOn the bottom tab, you could build up a step with weld metal before you start, something to hold your bead. On the top, I can't picture it. How long are the tabs? You say the buildup isn't wide enough, nothing says you can't make it wider...you can do whatever you want on the runoff tab.Undercut between beads on the cap, never had anybody say anything about it. Just don't undercut the plate itself.
Reply:Originally Posted by joshuabardwellI would guess they want to force the weldor to pay attention to the way the rod runs, and not just dial in a number and stop thinking.
Reply:Originally Posted by MinnesotaDaveThat's my guess too.I'm imagining a teacher who got tired of the question "what amp do I run these at."Or "the box says 135 so I set it there and the rod doesn't work - rods must be junk."Having said that, still think it's dumb though. Dave J.
Reply:Hello smileselectric, I know that a lot of folks replied with various comments on the lack of numbering on the machine dials, Possibly think in these terms though, "calibrated" machines will deliver the amperage that the dials/meters indicate, other machines are at the mercy of a lot of variables and often are not delivering the amperage that is shown on a meter or listed on a dial. This is due to many different variables: type of power source, input voltage and phase, condition of the power source, condition of the welding leads/stinger/ground clamp, size and length of leads, etc.Ideally, as welders and as we gain experience, we will begin to recognize the subtle characteristics of the arc and how the rod reacts when things are "ideal" and working "properly". This mental picture will help us out when we don't have welding procedures and calibrated machines to get us in the ballpark with proper amperage settings for the work that we are being asked to perform, instead we will have to rely on our mental register to know when we are properly adjusted and the welds will meet our quality requirements. Just a little bit more to add to your trove of information. Good luck and best regards, Allanaevald
Reply:Originally Posted by smilexelectricI agree, all ill need is a piece of scrap to run some beads on and ill know real fast.
Reply:Originally Posted by aevaldHello smileselectric, I know that a lot of folks replied with various comments on the lack of numbering on the machine dials, Possibly think in these terms though, "calibrated" machines will deliver the amperage that the dials/meters indicate, other machines are at the mercy of a lot of variables and often are not delivering the amperage that is shown on a meter or listed on a dial. This is due to many different variables: type of power source, input voltage and phase, condition of the power source, condition of the welding leads/stinger/ground clamp, size and length of leads, etc.Ideally, as welders and as we gain experience, we will begin to recognize the subtle characteristics of the arc and how the rod reacts when things are "ideal" and working "properly". This mental picture will help us out when we don't have welding procedures and calibrated machines to get us in the ballpark with proper amperage settings for the work that we are being asked to perform, instead we will have to rely on our mental register to know when we are properly adjusted and the welds will meet our quality requirements. Just a little bit more to add to your trove of information. Good luck and best regards, Allan
Reply:On my vertical plate I will put my root passes in at 110 amps with 1/8 7018. 2 fill passes at 115, then weave the cap at 122.There is no reason to fill flush or almost flush before capping on vertical. You can weave a real heavy cap on vertical up that will flow in very nice.I always build up my bottom run off tab with rod stubs before capping on vertical. it gives my hot cap pass a place to "set up" on the bottom part of the plate.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720