okay so I bought a 1982 dialarc hf from work that was gathering dust in the corner of the shop and figured I would teach myself tig welding. So far I picked up some scrap steel from work to practice on and some other steel for an exhaust probe I am building. the first problem I have had is with the scrap. I think it used to be part of an old diesel fuel tank and the beads just don't wanna flow at all on it also I get alot of slag coming up into the puddle when welding it. I have ground both sides down and cleaned everything the best I can with acetone is there anything I can do for welding on this old crap or is it better off just going back into the scrap bin. only reason I ask is I do not have much spare metal other than the scrap at work to practice on. other than that ran a couple beads on the end of some new 1 1/2" x 1/4 flat stock and it was a night and day difference so I just went ahead with the project. Any advice or criticism is much appreciated. running a dialarc hf, 3/32 2% lanthanated tungsten, 3/32 er70s-2, about 80 amps on the 1/8" scrap 115amps on the 1/4" and 90 amps on the square tubing. Lastly i dunno if he will see it but I just wanna say thanks Jody for the vids and podcast they have been a huge help so far.
first welds on the scrap
tig stringers.JPG (72.93 KiB) Viewed 822 times
second practice on the flat stock
tig 1.JPG (51.39 KiB) Viewed 822 times
and the exhaust probe
ehaust probe.JPG (62.21 KiB) Viewed 822 times
ehaust probe weld.JPG (67.88 KiB) Viewed 822 times
ehaust probe weld 2.JPG (62.7 KiB) Viewed 822 times
ehaust probe weld 3.JPG (53.73 KiB) Viewed 822 times
ehaust probe weld 4.JPG (55.21 KiB) Viewed 822 times
I don't believe that your problem stems from crap embedded in the metal. See how your beads look like caterpillars crawling across the metal? That's called cold lap. When you light up on the metal, you should have enough amperage to cause it to puddle instantly. That molten puddle should be as wide as the bead that you're planning on running. If it's not and if it didn't happen instantly then you're not laying enough beans to it. It's gonna take a minute to get the hang of it because you're likely trying to sneak up on it to compensate for your feed hand not being able to keep up. Try about 100 - 110 amps on the 1/8" stock and 150 - 160 amps on the 1/4" stock. When the puddle starts to get out of control then you just start backing off of the peddle. When you get the heat and travel speed right then the bead will be crowned down it's center and it will smoothly taper into the toes where it ties into the base. It's just gonna take practice cause tig has so many variables and moving parts to consider, all while not allowing the arc to hypnotize you. Your eyes have to scan the entire area while you weld.....puddle - dip, toes of the weld, eyes in front of the arc and move the torch forward, repeat.
See how dug in your weld is on the tubing? That's either too much heat or from moving too slowly. My guess would be moving too slow. It's a little more difficult with the tubing because the back side of the weld isn't laying on a metal table that is quenching some of the heat away.
As a general rule of thumb: contamination is either gonna cause porosity in the weld or it will cause the weld to explode and blow back into your tungsten. It just depends on what the contaminant is.
tried to go 100-110 amps on the 1/8" and I would get the long v shaped puddle >>>>> with a line down the center and some undercut I thought that means you are running hot so I backed it off to about 90 or so and that seemed to work but the main problem I had with the scrap in the first pic was more the slag. the back of the puddle would look like I was running stick for some of the weld and parts of it had a layer of slag over the top and there would be slag inclusions along the edge of the puddle. after the bead I would have to chip it off and grind the edge off before the next one. not really sure how to explain it but it also seemed that I would have to kinda fight the puddle just to keep it moving forward. as for the pedal I don't have one so im still trying to figure out how to get it to start hot and not get away from me once the piece heats up. currently I just sit at the start and kinda swirl it for a second until the puddle gets big enough then move on but it still sometimes gets too hot at the end. not sure if that's the right way to do it but it kinda seems to work. for the tubing one im not quite sure what your talking about being dug in? some of it is a little low but most of it is flush with the tubes it was just kinda a deep groove to fill where the two tubes were laying side by side due to the rounded edges of the tubes. the main problems I was having with that one is getting it hot enough for the puddle to flow between the tubes without burning through they are kinda thin wall tubing.
Under cut on tig can also come from not adding enough filler, or from bad torch angle, its posible that you might have been too hot on the 1/8. If your undercut is from being too hot then as you weld and the heat builds up the undercut will only get worse. But as you went farther down the square tube there are places that the undercut went away. That makes me think it has more to do with torch angle and arc length. I.e. Just practice more.
I like to run about 120-140 amps with 3/32 or 1/8 filler on any steel that's over 3/16 inch thick.
RamboBaby wrote:See how dug in your weld is on the tubing? That's either too much heat or from moving too slowly. My guess would be moving too slow.
I'd say his weld is flat because the tubing has round corners which makes a groove to fill when the tube is butted together.
I agree. You have to jam filler in those rounded edges and you usually end up with a flat weld bead. The OP said he was 80 amps..too cold IMO. Should have been up over 125 amps and on those rounded edges you should go even higher and use thicker filler. I would have used about 160 amps and 3/32" filler. Overall...not bad for a new welder.
ward605 wrote:tried to go 100-110 amps on the 1/8" and I would get the long v shaped puddle >>>>> with a line down the center and some undercut I thought that means you are running hot so I backed it off to about 90 or so and that seemed to work but the main problem I had with the scrap in the first pic was more the slag. the back of the puddle would look like I was running stick for some of the weld and parts of it had a layer of slag over the top and there would be slag inclusions along the edge of the puddle. after the bead I would have to chip it off and grind the edge off before the next one. not really sure how to explain it but it also seemed that I would have to kinda fight the puddle just to keep it moving forward. as for the pedal I don't have one so im still trying to figure out how to get it to start hot and not get away from me once the piece heats up. currently I just sit at the start and kinda swirl it for a second until the puddle gets big enough then move on but it still sometimes gets too hot at the end. not sure if that's the right way to do it but it kinda seems to work. for the tubing one im not quite sure what your talking about being dug in? some of it is a little low but most of it is flush with the tubes it was just kinda a deep groove to fill where the two tubes were laying side by side due to the rounded edges of the tubes. the main problems I was having with that one is getting it hot enough for the puddle to flow between the tubes without burning through they are kinda thin wall tubing.
You simply needed more filler metal to control your puddle. The V is from welding too hot but it also is from not jamming enough filler in the puddle to cool it and control it. I would have gone ALOT hotter and used thicker filler. Those rounded edges of square tube create an abyss and you need to fill it up. You state that you light up and wait a sec for a puddle. You need enough amps to puddle instantly so you were too cold and adding filler which cooled the puddle even more. You also said you have no pedal. Please get a pedal. It makes tig welding so much easier. Overall though you did well for a new guy with no pedal.
The slag is from oxidation when tig welding. If you start to see sparks flying from the puddle......you're welding over oxidation. Not cooling your metal down between passes will make the slag get worse with every pass. The smaller the scrap that you're working with, the more need you'll have for frequent cooling. Use a dunk bucket and then wire brush it off before starting again. A wire wheel is much easier and better.
How many cfh are you running? Too little gas is bad. Too much can be even worse. A gas lense will dramatically help with getting the puddle to behave. They only cost three to four bucks and they're well worth it.
No pedal? Ouch! Moving the torch back from the puddle and then forward to the leading edge can help. But it's probably just gonna piss you off with thin metal.
Here is an example. 2" square tube, .125 wall. 160 amps, pedal, 3/32" 2% lanthanated, gas lens setup, #8 cup, 17cfh, 3/32" Er70s2 filler. I had the pedal floored so I was using the whole 160 amps but I could have went hotter because the rod was sticking in the puddle a little bit. In this case, edges are a gift, other times they are a nightmare but you will figure that all out for yourself. I hope this helps. Good luck and enjoy the learning process
thanks for the advice guys. I plan on trying some more today with some clean metal and seeing how it compares. also running about 18 to 20 cfh with I think a #6 cup. on the tubing I was running at about 90 and I measured the tube its 0.065 wall thickness. as for the pedal not gonna happen anytime soon since a pedal for that machine cost about 500 bucks and that's more than i paid for the whole welder and I haven't seen any up on ebay or anything yet. also now im wondering if maby im doing my math wrong on the ranges cause the amperage's you guys suggest its all i can do to keep from burning through going as fast as I can and pretty much force feeding it rod. so here's how I been doing the amperage. the range switch is 40 to 190 so that's a 150 amp spread. the dial is 0 to 100 percent so the dial at 33 would be 33% of 150 or 0.33 X 150 which is 49.5 and add that to the bottom of the range so 49.95 + 40 = 89.95 amps?
I should have read your post a little better. I thought your square tube was 1/8". Your guess is as good as mine on the amperage with that wide of a range. You are either going to have to really practice or save up for a pedal or struggle to make consistent welds. Without a pedal you need to be dialed in on your amps or you are going to have problems like the ones you describe. Nothing worse than having amps set to high and having to go like a MFer to keep up. Jamming infiller rod will help cool the puddle and give you more control but it won't solve all your problems.
ward605 wrote: as for the pedal not gonna happen anytime soon since a pedal for that machine cost about 500 bucks and that's more than i paid for the whole welder
What source is quoting $500 for a foot pedal?
Try putting a WTB ad on this forum and the Welding Web and Miller forums.
for the pedal its because its an old machine and can't use the new style pedals I think it has a rheostat in the pedal or something. its a rfc-23a. A quick google search showed a new one going for 450ish and I saw an old one on ebay a while ago for about 250 but they didn't even know if it still worked or not and the plugs were cut off the end. as for the welds switching to new 1/8" steel made alot of difference I was actually able to weld at around 110 to 120 amps on it. the old scrap 1/8" anything over 100 and it just wanted to burn right through.
on the first one for the top half I was just running the torch straight across and on the bottom half and the second one I was trying to do the moving back and forth that RamboBaby suggest but I wasn't having much luck with that. other than that the main problem I seem to be having is finishing off the end of the weld I either have a hole in the center of it or I blow through the plate i can't seem to find the middle ground.
new stringer.JPG (70.76 KiB) Viewed 617 times
new stringer 2.JPG (59.8 KiB) Viewed 617 times
also figured Id show the exhaust probe in action this bike had too small of an exhaust to fit it in so had to rig it up with some tubing.
ehaust probe on bike.JPG (61.88 KiB) Viewed 617 times
Don't just snap out of the puddle. Use a piece of copper to trail out at the end of your weld or back out the same way that you came in while sweeping the torch angle backward. That should stop the craters. Give it an extra dab or two of filler on the end as well before you back out.
I've never had that problem with steel though. Only with aluminum.
