Lap joint question

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I am practicing laps on 1/8 inch CRS coupons, using a 3/32 tungsten ground to a sharp point. The steel is sanded to bright shiny metal and thoroughly scrubbed in acetone (even though it is CRS it has a slight amount of rust on it). I have my amps set to a max of 125 and using the foot pedal to control actual amps. #7 cup, 15CFH of argon. my problem is that I am having trouble getting the heat right...either I have not enough heat, and I get a puddle on the top plate and puddle on the bottom plate, but they never really come together, or if they do, it is seriously boomerang shaped. OR I hit the other extreme and I am eating too far into the top place. I am holding an approximately 70 degree angle to the plate, mostly pointed to the bottom plate, and a 20 degree travel angle. My arc length is very tight, as tight as I can get it without dipping. probably no more than a 16th of an inch. I have the same problem with the syncrowave and the AHP.What's the secret sauce that I am missing? is it the torch angle?Miller Multimatic 255
Reply:No where in there do you mention filler rod. I believe that's the secret sauce you're looking for.  Steel really needs some filler metal for a good joint. It's also difficult to flow weld a lap joint even if it was the right way to do steel.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:I had been trying with some ER 70-s2 in a 1/16th size, and then I decided to try a few without filler just to get the torch hand movement down. I got a little better with using just my torch hand (can't walk and chew bubble gum sometimes).Miller Multimatic 255
Reply:In this case you might try the lay wire technique. Just lay the filler in the corner of the joint and let it melt into the joint as you run the torch across. It's not always the best method but it might help get you started on torch control without worrying about the filler at the same time. On similar joints I've held the filler against the joint and sometimes shoved it in when I needed a little more to help fill for the excess melt of the top piece. It's hard to get enough heat into the bottom piece without melting the top back. That's a area that you'll have to work on.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Laywire helped a bit. I think I am just not keeping a consistent travel angle. Might be fit up too. these coupons have a slight roll to them, and then when I weld one side, the other side develops a gap. maybe a mm or so. not terrible, but not the tightest fit.Miller Multimatic 255
Reply:picts, picts, picts.... We need picts.If using the lay wire method, make sure you have a puddle established and then melt the filler with the puddle. I like to have guys learn to 1st get the puddle started, then "chase" the filler with the puddle. I see a lot of guys who want to simply run the torch over the filler. All that does is melt the filler and it really doesn't melt the base materials many times.Lay wire or keeping the filler in the joint and sliding it on the plate and into the puddle are two of the ways I find it easiest for new tig guys to learn to add filler. If you slide, you may on occasion have the filler rod stick if the temps are borderline though. Bringing your two hands in simultaneously is very natural for most people, so it's quite easy for new tig people to master. A typical dipping motion or tapping the filler in requires you do two different motions with your hands and takes a bit of time to develop. I usually have students say that until later when they get the other things down to the point where they do it all without thinking about it, arc length, travel speed, torch motions etc take quite a bit to handle all at once even if it's just doing it all consistently. Adding a different motion with your filler hand can be a bit much to new people at this point..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Ok, here you go. I wasn't going to post them because I was embarrassed at how crappy they look. Some of these are without filler. some of the pics are the same plates from a slightly different angle.Miller Multimatic 255
Reply:Have you tried ant aluminum yet.   I find it easier to learn on than steel.Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:I wouldn't mind seeing closer better picts of the circled beads.I think the one in red may be a bead with no filler. If so, there's no point to seeing that as you need filler with steel. The others all look like they were done with filler and don't look all that bad. The other 2 beads on the plate with the purple circle are either washed out from the flash, or just too "muddy" to see the bead well. They may or may not have good points depending on what I see later.With closer picts I can better see what issues you were having and point out good and bad points for you to learn from..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:U just need more seat time. It will come to you after a few bottles
Reply:Originally Posted by motolife313U just need more seat time. It will come to you after a few bottles
Reply:He'll ya it's Saturday !  About to put a wine bottle in the freezer right now
Reply:More seat time. You seem to be welding pretty damn good in a few of those peices. More seat time and you will be a pro
Reply:Cheater glasses help alot! Get some even if you were glasses get some powerful reading glasses. I think if your not getting the puddle to join you don't have enough heat or your not pointing the tungsten right in the middle of the joint. Sometimes the puddle doesn't joint for me right at first so I just dab a little filler in there to get it going then maybe stay on it and dab a little more then when you move over a little it should be puddled on both ends. How long you been tiging for?
Reply:Cheater glasses help alot!
Reply:Louie - you're not doing bad at all for just starting Looks like a pretty normal learning curve to me.I tell people that after the first 100 hours it gets a lot easier Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Thanks Dave, here is today's practice. I really focused on moving the puddle, not just the torch.  Pretty much all the same parameters as yesterday, although I had to switch over to the AHP after a while since the air cooled torch on my syncrowave was getting a little uncomfortable to hold on to. I do think I weld better with that syncrowave...more control.  These are in no particular order, but the middle joints on each set of plates was welded last, with the AHP.  Now I am off to the carol sing. Merry Christmas to all!Miller Multimatic 255
Reply:Top bead, top picture looks the best of the bunch. It looks like you are eating away at the top plate a bit too much. Tough to tell how much since I can't easily see where the original edges are. On lap joints, if you eat away the top edge, it's usually a fail on inspection. With 1/8" or thinner material it can be really tough not to eat that edge away and still fill well. I usually don't mind if a student takes a tiny bit off an edge, but not much, say 1/64". I want them to make it to the top more than I care that they loose the crisp edge.  One thing that can help some with what I'm seeing is if you dip more frequently. Instead of that scalloped top edge, you would get a smoother more even edge if you dipped 2 if not 3 times more often. Consistency needs some work, but isn't all that bad at your level.Keep practicing..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:If you watch the top and the bottom edge of the puddle closely you can actually  see it under cutting while welding. That means you need either less heat or more filler or or your adding the filler to late. And it's way cheaper for gas if you buy a 280 or 336 bottle.also you should use a #4 cup and 10 cfh. You will be saving alot of gas that way. How far is your tungsten stick out?Last edited by motolife313; 12-21-2014 at 01:46 PM.
Reply:Seems like you are getting it, lap joints can be a little tricky. Puddle both pieces of metal then dab your filler in to join the pieces. Heat is a little high which is causing undercut. Take your time and make sure the torch is close to the work piece. Practice practice your off to a good start.
Reply:Moto a #4 cup is tiny. You'd get better coverage at the lower gas flow with a #8 cup and a gas lens. Honestly his #7 and 15 cfh is fine for what he is doing. That's typically what we use at the tech school for teaching..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I have been welding some thick stuff with it lately and have had no problems unless I move fast it will discolor the weld a little.  Have you tried a #4 cup? I didn't think it would work good until a tried it now I'm hooked unless I gota pull the tungsten out a ways ill switch to a #6 or bigger
Reply:#4 cup 10cfh. 1/8 lap joint that I never practice. I do alot of t - joints
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Reply:thanks for the input guys, it is exactly what I needed.Miller Multimatic 255Moto, nice job on the consistency of the top edge. I see a few minor hiccups, but not many and those that are there are pretty small. One thing, it does look like your fill might be a bit light. Hard to tell in those picts but the bead looks a bit concave to me. If you draw a 45 deg line from the top of the top piece to the base plate, your reinforcement should meet or exceed that line. In those picts the bead looks concave to me, not convex, but it might be the angle and the lighting that is fooling me. It looks close, but not quite close enough.Part of what makes me think this might be concave is the rally sharp edge to the top toe. Usually if the bead is convex, it's got a softer look to that edge. The edge is a good example for Louie to use as what to shoot for as far as how close you need to be to the original edge of the plate that you can see on the right side at the start..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I'm guessing the flaw your taking about is in the very beginning? I under cut in 2 places a tiny bit speed taking the pieces together. I think it is concave I will check the 45 degree angle when I get home. Will it be stronger if I put in more filler to get it to the point your talking about?
Reply:Originally Posted by motolife313I'm guessing the flaw your taking about is in the very beginning? I under cut in 2 places a tiny bit speed taking the pieces together. I think it is concave I will check the 45 degree angle when I get home. Will it be stronger if I put in more filler to get it to the point your talking about?
Reply:Minor flaws I circled in blue. I'm being very picky on those, but I tend to be a perfectionist when it comes to learning.Yes you could run a 2nd pass over the bead to add reinforcement in most cases if it's not enough. Best way is to do it right the 1st time around of course.Usually when looking at a students work, I'll just  look down from the end and see what it looks like. I just use an imaginary line from top edge to the same distance out on the lower plate IE 45 deg. If the bead looks concave, especially on a lap joint, if the lower leg is close to the right location, it probably needed more filler. In the real world and inspections, you'd gauge the weld and that would tell you if you had enough reinforcement. CEP has shown filet gauges in a number of his posts. These also tell you if your legs are large enough, though with laps, the top edge is usually a pretty good indicator if your leg is where it's supposed to be at least on that side..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Ok thanks Dave and dsw. I've seen some of weldermikes welds that look really concave. Not saying there bad!!!! I heard the more filler you put in the more chance the weld gets contaminated. I could have put more filler in just didn't know it needed it. I'm all self taught. I've never had a welder watch me weld and have only watch a couple welders weld for a few minutes. Ryan at Baisly hi performance (harley guys)is one of them. He's cool!!!
Reply:I should really start practicing lap joints more often. Because they probably teach you control really good
Reply:You can some times get away with a concave bead on fillets if your legs are a bit large. If you need a 1/4" beads, but instead your legs are 5 /16", you may still have enough reinforcement to make that 45 deg line between 1/4" up each leg even with a concave bead. Depending on what you are doing and what requirements you are working to, things like this may or may not matter.I've never heard that the more filler you add, the bigger the chance of contamination. Assuming your filler is good and clean like it should be, and that your base material is cleaned properly, more filler shouldn't make any difference at all. Contamination comes from a couple of things. Dirty material, dirty filler, or poor gas/shielding coverage on average. If you have issues with one of those, chances are you'll have contamination issues no matter what size your bead is..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by motolife313I should really start practicing lap joints more often. Because they probably teach you control really good