tig root falling in

admin

I am welding carbon steel pipe schedule 40, tig root and hot ,stick out. lately the sides and top have been falling in on me.I run about a hundred 115 amps, loose 5/32 gap with 5/32 wire.I've tried running faster and turning it down but seem to have the same problem.I've never had this problem before but somehow I've gotten stuck into a bad habit and I can't figure out, what it is. I've watched a few of the other guys running about 120 to 130 and they don't seem to have the same problem.it looks to me like I'm doing the same thing they are,But I can't figure out what I'm doing wrong
Reply:sounds like you're welding tooo hot my friend! dial back the amperage and it should be good
Reply:I know I'm not good enough to handle that gap, with that amount of amps. I like 3/32-inch gap, knife edge for land, with 1/8-inch filler. About 95-amps. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:try feeding a little bit more wire and maybe try going up a little bit higher on the bevel when putting in the root
Reply:5/32 wireI don't think so.Try some 1/16" with less heat....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by CEPI know I'm not good enough to handle that gap, with that amount of amps. I like 3/32-inch gap, knife edge for land, with 1/8-inch filler. About 95-amps.
Reply:I can do it with a tighter gap but sometimes you get what you get, in the field. I've seen it done at 120+ amps. I'm wondering what I'm doing different. Is it torch angle, tungsten stick out or maybe filler rod placement.  I've tried feeding more but I end up with excessive reinforcement when I do, I get a grape in my root. As for wire, 1/8 is the smallest on the job.I've also tried about 100 amps with no avail.
Reply:Youtube my friend! Always the best for good demonstrations
Reply:Originally Posted by tiginator1/8 is the smallest on the job.
Reply:When they stick the filler threw the gap, how do they get it to not stick to the pipe on the upper end when the arc catches and travels threw the filler?
Reply:I x-ray tig for a living and I hate these kind of posts. Reason is there's such a wealth of poor information being thrown around by guys that think they know what to do or how to do it. I'm not trying to be disrespectful but even 1/8" filler at 85 to 100 amps is absurd. If I even thought about filler that big I'd be pushing 150+amps. Small filler is way better, you get a more fluid puddle that breaks the sidewalls down better. CEP I value your post and knowledge but in my work that root would get you your last paycheck. Excessive penetration for sure. Not sure how big of pipe your running all you mentioned was sch 40. If it's 4" or less I'd run a 3/32" to 1/8" gap with a slight land and with 1/16" filler and absolutely no bigger than 3/32" filler I'd be welding all the tig joints after Qc seen my roots and finished welds. Remember the gap WILL narrow up on you so start a little big.jmo
Reply:^^^The guy already said 1/8th was the smallest wire on the job and you're telling him to use 1/16 to 3/32 at the most? How is that helping him?
Reply:Originally Posted by Showdog75CEP I value your post and knowledge but in my work that root would get you your last paycheck. Excessive penetration for sure.
Reply:It doesn't arc out, on the upper bevel.you can actually rest the filler on a tack if you want to. Take a look at the videos posted in thread.
Reply:Originally Posted by TimmyTIG^^^The guy already said 1/8th was the smallest wire on the job and you're telling him to use 1/16 to 3/32 at the most? How is that helping him?
Reply:as for gap and filler wire size, this seems to be the norm with just about every welder. pipe size ranges from 1 inch the 48 inch and up.the bigger the pipe the bigger the gap because as mentioned before it does want to close up.I've worked for  several outfits on several power plants and this is what they want.  Large gap also keeps wire from hanging up when backfeeding.I'm not saying that one technique is better than the other, but this is how most welders that I've seen tend to weld.
Reply:Showdog, usually when backfeeding you can use lower amps. Its not something I have done but I have read a bit about it. Seems 1/8" filler is common for backfeeding.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:When I'm welding open root joints I usually like 1/16" or 3/32" filler and 95-115 amps, 3/32" gap. Often if I'm WTC I will use 3/32" or 1/8" filler and about the same amperage range, maybe a little higher. After the root/hot pass crank the amps up a bit and push some filler into the joint to fill.Welded this at 110-115 amps with 1/16" filler, keyhole/dip. 3/8" plate 3/32" gap.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:I tried that back feeding a few times, I made the biggest mess out of it you ever seen in your life. My reading glasses that I weld with are the wrong range to see clearly at the far side of the pipe.Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Originally Posted by CEPI tried that back feeding a few times, I made the biggest mess out of it you ever seen in your life. My reading glasses that I weld with are the wrong range to see clearly at the far side of the pipe.
Reply:I know several guys who do it quite often, only because they weld on nuclear powered submarines everyday. I need to throw a rope around one of them to show me how, but with my eye sight not sure it would help. Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Backfeeding is difficult at first, I didn't see the point in it. However,  once it clicks , you will never go back. When backfeeding you do want the rod to fall through the gap, all the way around. As I mentioned before,  I see it done every day. 120 -130 amps, root opening 5/32 all the way to 1/4 and filler 1/8-3/16. It can be done and is done at powerhouse all across the nation. I guess I'm not ready for 120 amps yet. Just gonna have to stick with 90-95 for now.
Reply:Turn your heat up, do the opposite of what you think. Swing wide on your root, that spreads the root and helps with excessive penetration. I also like to read on forums where people say to push your root in with your second pass, lol.
Reply:Originally Posted by Showdog75Turn your heat up, do the opposite of what you think. Swing wide on your root, that spreads the root and helps with excessive penetration. I also like to read on forums where people say to push your root in with your second pass, lol.
Reply:I haven't tested this but I Will.  I have seen guys run a very nice root at 130-140 with a 3/16 gap and 5/32 wire and it doesn't fall in. I haven't tried it because it seems opposite but maybe that's the trick.Do people backfill a root and then hot pass/fill/cap the normal way?  Not seeing the argument for 5/32 gap.  The only time I've seen backfilling a root was for when the backside was unassessable.  Run your root and then mirror out.  Smaller initial gap means less fill.  Start out with 3\32 to 1/8 gap but open the front a bit for better visability and feeding.  I'm only talking a max. 3" o.d. though.  Are you saying when  you get up to the larger o.d.'s you need the bigger gap to see. 3/16 gap at 130 amps.....might get some of that 5/32 to play around with.  Never seen it on the job.Last edited by OldSparks; 12-28-2013 at 02:47 PM.
Reply:the pipe size I'm talking about is usually 10 inch to 36 inch and yes most welders do backfeed.I was not taught this way however the last few jobs I've been on have had 2 to 3 hundred welders from all over the country and I would say that 8 out of 10 do it this way. when it comes to the guys that are considered Hot Shot welders they all seem to do it that way. so I wanted to learn. one reason that I've seen for back feeding is that it is nearly impossible to miss an edge when the wire is already on the inside.you can watch them burn away so there is no question of whether you're getting them or not. second reason is that on larger pipe the gap will want to close up on the top and if you're not fast enough you can find yourself in a lot of trouble.finally the third reason is speed yes wider gap means more fill, but backfeeding this way puts a nice heavy root in and you can slick a hot pass in at about 220 without worrying about suckback, and it goes pretty dang fastLast edited by tiginator; 12-28-2013 at 04:39 PM.