Stainless tig pipe

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I'm having trouble with 2 inch stainless pipe getting pinholes when I finish at top when I press button to slope down I get pin hole amps is set to 65 purge is at 10 one pass can anyone give me some tips
Reply:Pipe pressurizing? Do you have a feed and vent hole in your purge tape?
Reply:Originally Posted by That Guy TherePipe pressurizing? Do you have a feed and vent hole in your purge tape?
Reply:Yep have all that
Reply:Have you tried dragging the puddle as it slopes down?Ian TannerKawasaki KX450 and many other fine tools
Reply:How do u mean like keep button pressed  but move ahead. ..... If I move to far forward might blow through
Reply:Right after I leave off button should I dip wire
Reply:Trying to post a pic
Reply:Thanks for ur help
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Reply:The crater at the end of your weld is caused by the metal shrinking as it cools. It cools faster at the edges of the puddle, near the cold base material, so, as it shrinks, it pulls on the adjacent material, and since the center of the puddle is hot and soft it gets pulled out toward the edges and creates a void in the center, your crater. It's the heat differential which causes the crater, the cold edges and hot center. There are a couple ways to combat this, first and most common way is to slowly ramp down the heat so that the differential isn't so big, in this case the puddle still shrinks from the outside in, but the shrinkage is spread over a larger part of the puddle and you get a wider and shallower crater, which is less likely to pinhole. Another way to combat this is to move the puddle as it shrinks, which also spreads the shrunken area over a wider area, in this case, instead of a round crater, you get a teardrop shape. Both methods require a gradual ramp down of the heat.Looks to me like you need to adjust your ramp down settings. You will need to adjust these settings whenever you weld on a different material or thickness.Also, don't add filler right it the end, unless you are done with the weld. When you do a restart you want to be starting in a hole, down in the base metal to get the best tie in, and avoid a cold lap.Last edited by fortyonethirty; 05-21-2015 at 02:53 PM.Ian TannerKawasaki KX450 and many other fine tools
Reply:Thanks had to read that a couple of times to try and picture it in my head where the pin hole is is where I released the button to slope down then I travelled  on to the left side wall it's hard to see it in photo but I will try the things u said tomorrow  iv more of an understanding  no with what is happening  when it's cooling down
Reply:if you back up onto your weld it will negate the depression
Reply:I weld a lot of .065 carbon steel tube and have found that running back onto the weld with the down slope produces a clean finish.  Holding it still for the down slope just cooks it too much and the result shows.  My down slope is a little over 3 seconds.
Reply:Fortyonethirty pretty much nailed it.  Altho there is a lot of talk about ramp down and buttons.  If your looking to weld pipe for a living, I'd learn how to do it, lift/scratch start, electrode always hot, no remote amperage.  I say this because its pretty common in the industry to weld with a standard stick welding machine, generator or small electric machine.   There is a guy at work that brought his own machine in and when his button broke, he went to ****.
Reply:That crater is the least of your worries, if thats your first pass you aint getting all the way in there at all your just filling up the bevel...that first pass should be below flush if your getting full pen. As far as that crater, I just roll my cup back slowly on the side wall and snap it away with a scratch start, and with a pedal I slowly let off and swirl the puddle around. But its really a non issue, just grind it before you start again, thats what I have been doing with a scratch start rig because it leaves the end of the weld oxidized.
Reply:Hi Steve it has penetrated  through  ,im trying the  2 inch sch 10 one pass technic,  the picture is zoomed in looks like a sch 40 pipe I will try what u said thank
Reply:Don't be afraid to really clean that oxidation from your coupons with a stainless wire wheel before you start welding. You want that really clean and shinning, inside and out prior to welding.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Thanks so