need help with over head v grove

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I need help with passing a over head bend test my root pass always fails my cover passes every time.. We are using a miller inverter 304. The plate is 3/8 60 degree bevel 1/8 lan. 6010 for root I set it about 80 amps and it comes out mostly flat but not fused in on both sides for some reason.. We use 7018 1/8 rod for fill and cover.. I tried with a backing plat and it did the same on the root 2 1/8 cracks.. Grrrrrr its p ing me off cause i passed vertical up horizontal and flat bend test...
Reply:80 amps should be in the right range, are you getting a keyhole?  1/8 land is heavier than what I am used to, maybe add a few more amps.Are you getting both sides tied in when you look at the back side?  This should tell you exactly what you are doing wrong.  If they are tied in well with good reinforcement then your problem is probably with you first few fill passes, not running hot enough to tie into the root.Have we all gone mad?
Reply:No im not getting both sides tied in all the time and i don't get a key hole at all never have been able to get one but i push in the root pritty hard.. i run 120 amps on hot pass and all the way to cover pass..
Reply:Well I think you should be able to answer your own question then, if your not getting enough penetration how do you fix that?  Pushing the rod in is one thing, the other is....Have we all gone mad?
Reply:I know turn the amps up tried that i even torned it up to 100 amps.. I did get full burn threw but also suck back.. I gess I just need more under the hood time to get better.. We haven't done much with the over head and its my weakest point I can weld everything but that... GRRRRRRRRRRRRRRRRRR
Reply:"""" raises  hand"""""   more heat   or slow down
Reply:Ok I'll try to do more amps and carry a bigger puddle and go a little slower. I don't carry a big puddle.. also i don't do a whip motion I just carry it along that may be part of my problem.. I do want to thank you all for your responses. Tomorrow is my last day so I hope i can get it right..
Reply:You dont really want a bigger puddle, doing so increases the chance that you wont get proper reinforcement.  Turn the amps up, hold the rod right in the joint and watch it burn through the land, as soon as you see this, move forward.  Repeat.Have we all gone mad?
Reply:Ok  I'll try that at this point ill try anything im a profectionist and I hate it when I know I can do it but just can't get it right..
Reply:Gray,Those 304's can be great or nasty, depending upon what you are used to.  They are an adjustment after a nice dialarc or other transformer machine.  I think you may not have your arc force set right.  Take some time to play with the arc force control. It might just suprise you when you find the sweet spot.Also use 3/32 for root at about 80 amps is my suggestion.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Hello Graydevil, your description of your plate set-up could possibly use some experimentation. A nickel-land is a common easy way to remember and set-up that portion of an open-root joint. 1/8" might be just a touch heavy/wide for the land, 3/32" for the land is often times used. 3/32" to 1/8" root opening is pretty standard too(I didn't see where you included your root opening anywhere). One of the other gentlemen included information with regard to the "arc force" control on the XMT 304, it can certainly prevent "stubbing out" issues when you are shoving the rod into the groove.    How are you positioning your body when you are attempting this particular weld? Are you bringing the weld towards yourself?, welding from side-to-side(left to right, right to left)?, exactly how are you viewing the progression of the welding? If you can't get a pretty clear view of the arc while it is in the groove you may have a hard time ensuring that you have tied both sides together and achieved proper penetration through the root. Listening to the sound of the arc will also help you to determine when you are getting a good tie-in and proper build-up on the backside of the plates. When your backside weld profile is sucked-back that can be an indicator that you are running a bit too hot, or as others have mentioned you might not be physically pushing the rod into the groove enough. On machines of the more traditional transformer/rectifier type you can use arc length in a reasonably predictable manner to help control the arc by varying the arc length, longer arc length/more heat, shorter arc length/.less heat. This is due to the characteristic of the machine, CC/VV, constant current, variable voltage, as you increase the arc length the voltage increases and heat is increased slightly, decrease the arc length and the voltage drops and heat is decreased slightly. This doesn't quite hold true for the XMT, as, due to the arc control they will actually boost the arc to prevent the drop in heat and maintain an arc. So, a bit of experimentation on your part with the arc control will likely help you to come to an understanding of this control and it's workings relative to this particular power source. What sort of rod angle are you using for the root pass? Straight in will generally increase penetration and width of deposit, as this angle is laid back more(drag angle increased) you may see a decrease in the penetration slightly and a narrowing of the bead along with more build-up on the operator side. A lot of folks will start their welds by striking the arc and long-arcing 3/16" or so to heat things up a bit and ensure that they have melted both sides of the groove, then they will push the rod up into the groove to  apply the weld metal and build-up on the back side. The technique will be repeated, but with a slightly shorter arc length to allow the weld bead to progress. Sometimes the rod may require a bit of manipulation from side to side or in a sort of a crescent manner to help with even distribution of the weld metal between the two sides prior to pushing the rod back into the groove. With any of your welding that you are practicing, try to only make single changes in technique so that you can isolate what works and doesn't work. I've probably rambled enough for the time being. Don't be afraid to experiment though, particularly when you are training and learning is when you should be trying things, not when you're on the job and it could mean the difference between getting a paycheck or a pink slip. Ask questions and inquire of your instructors to give you examples of the techniques that they use to achieve success on this types of weld. There are many ways to "skin the proverbial cat", don't hesitate to consider all of the variety of ways that you can observe. Good luck and best regards, Allanaevald
Reply:OK here is an update from today.. First thing we are using a 1/8 root opening and 1/8 land I got the coordinator to watch me and help me out with this.. He watched me on my first plate and said the only thing I need to do is keep the key hole I was doing the right movements and right amps so he said its just coming down to more hood time.. With his help I actually had a little reinforcement on the root pass and a little suck back in spots so i just got to be more consistent and it should pass..We are going to try a bend test in 2 weeks he told me he would come in and let me weld even though the school is closed..