2" sch160 6G still getting undercut.

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Ive been practicing my 2" sch160 6g for a few weeks now... I've worked through getting my root In then struggled with my filler got past that now I'm working on getting my cover pass Down.. Doest seem to be getting better. My Caps come out really tall and narrow therefor leaving undercut on both sides(double cap). I've been running my Lincoln sa200 at 190-120 range on about 42 fine current. Any advise is greatly appreciated.
Reply:How many stringers are you using in your cap? 3?Are you getting undercut on both the bottom and top stringer on the cap?JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Go down a range , set fine current 75-100 and it will wash in better.
Reply:Get yourself a spray bottle and fill it with water.After every pass spray the coupon and get it cooled back down to about 150 degrees.If.... after welding out the coupon your still getting under cut.... come back and let me know.HoboLincoln SA200's... at least 15 - 20. They come and go. Growing partial to the "Short Hoods" in my old age. Last count on Short Hoods was 13 in possession.
Reply:i cheat a little bit when i do my 2" sch 160 F3/F4, i do my tig/stick procedures the same. Since the new inspector dosent like when we weave the full cap " which is easy " i weave 3/4's of the way to the top of the bevel and purposely get undercut, i then take a 1/4" grinding stone with a nice rounded edge, and grind about 1/4 into my last pass, and just enough to take out the existing purpose undercut with the edge of my grinding disc so i am not making my bevel wider that it should be or "going out of the actual weld zone" i then run one last stringer and i am done. With my tig/stick pipes basically all i do is my first pass is a weave to the center of the bevel, then a weave to the top edge again, grind, and then a stringer. i run 78ish amps for the 6010 root, and 90amps for the hot/fill/cap for 3/32 7018
Reply:I run 2 stringers on my cap, bottem and top, I weave my bottem about 3/4s to the top bevel coming out from the bottem bevel about 1/16". How do I figure out how many Amps I'm running ?
Reply:I also run a stinger on the top, seems like I burn out the bevel and it doesn't get filled back in.
Reply:try grinding the groove in there like i suggested, that way you have a nice clean surface for the weld to take too, rather than trying to blow through a sharp edge. Plus when you grind this bevel you dont have to move as quickly or worry about getting too high of a cap, all i do is watch the edge of the bevel as it burns away, zero undercut
Reply:Originally Posted by JLGaeta1985Ive been practicing my 2" sch160 6g for a few weeks now... I've worked through getting my root In then struggled with my filler got past that now I'm working on getting my cover pass Down.. Doest seem to be getting better. My Caps come out really tall and narrow therefor leaving undercut on both sides(double cap). I've been running my Lincoln sa200 at 190-120 range on about 42 fine current. Any advise is greatly appreciated.
Reply:So I turned my heat down 5 to 35 and weaved a bit faster, I did try grinding a groove and it did help, I think I'm ready for my test next week.
Reply:Also with those sa200's,You are using 190-120 range on about 42 fine current For "Stiff" Arc, "Higher Range" and "Lower Fine Current Adjustment"For "Soft" Arc, "Lower Range" and "Higher Fine Current Adjustment"On my 1968' sa200 for example, and it welds completely different than my 69', as my 69' has 300 amp brushes, and my 68' I have absolutely no clue what was done to it: (My 68', you can also increase rpms via a pull out knob which really plays with your amperage in whatever range you're in.)Anyways, I like to set my machines where in One range, yuo can use a 3/32 electrode and burn at a really good amperage. Next, if I want to use a 1/8th, I just go to the machine and change to a higher gear without touching the fine current, and I have good amperage for the 1/8th. On my machine, my 68' and it will be far different than any of my other machines in terms of heat (not sure what was done to the machine, but it seems to run cold)In second Range for 3/32 7018, I run at 70. 70 is a pretty good overall number, plus or minus maybe 5 or 10.For 1/8th, I run in Third Range and keep the same fine current adjustment. I however am using "Soft Settings" for the arc. (Lower Range, Higher Fine current adjustment)For 2", I like to fill with 1/8th, but when It comes to the cap pass, I like to go for aesthetics, and I always use a 3/32 electrode for capping. With a smaller electrode, you are running less metal, but you can run hotter and be a little more sloppier, that using a larger electrode, running colder, and having to be a little more precise.**You will also notice that when you use a higher range and lower fine current adjustment, you will always *pop* and extinguish out a 6010 electrode - but electrodes such as 7018 will run perfectly fine. I believe it is to do with the OCV of the ranges.. I'm still learning my theory on Volt/Amps, but  I first learned about that years ago as a hand welder trying to root pass a pipe in a higher range and lower fine current, with the 6010 continually popping out on me.Last edited by Thorton; 11-24-2012 at 10:00 PM.46’ sae30047’ sa200 w/Wisconsin VF451’ shorthood56’ shorthood56’ shorthood68’ redface69 redface07’ ranger 305G13’ sae300Inconel/Hastelloy – SS – Duplex – Chrome/Carbon Tig – F3Downhand – STT/RMD – F3F4 – B Pressure
Reply:Thanks for all the info... That was a great vid btw..how do I figure out the Amps on my 200?