Welding Tips and Tricks

I have a few questions about my equipment.

Most important question:
Last night I was welding two pieces of angle into a corner. I was welding the inside so the Argon flowed fully into the corner. I had a few bright flashes. The torch/arc was also acting kinda funny too, but I cannot describe exactly what it was doing. It was like someone was messing with my amperage settings, the metal would sometimes pool faster, and sometimes slower (with same foot pressure). As I worked along the joint the pool would look like it was wondering left/right of the arc... BUT when I finished the weld bead would be straight.

It wasn't my hood causing the flashes, it's shading never changed. I also tried a second hood and saw the same flashes. I sharpened the tungsten 3 or 4 times thinking that might be it, even tried a new tungsten. Tried gas flow rates of 5-15cfh.

AND it didn't do it all the time, it did it in 3 corners out of 12 that I did. It never did it with an outside weld, or a straight longer weld. And it there wasn't anything consistent about it.

There was only one thing that I did different last night over previous work, and that was how I prepared/cleaned the metal. Previously I had been using 60grit flapper sander wheels on my angle grinder. Last night I used a wire brush attachment to the grinder.

Is it possible that the wire brush is leaving behind contaminates that I cannot see?

Now to the rest:

1) When to replace the cable cover? Mine is plastic, and has several places where it's melted from touching hot metal.

2) How do I keep the gas hose from kinking where it attaches the power supply. Mine looks like a braided metal hose, but it is kinking right where it attaches to the power supply. To get good gas flow I have to basically prop up the hose so that it's not kinking.

3) My torch hose is 10' right now, and I am contemplating ordering a 25' so that I can work a little easier around my Garage without having to keep moving the work so that I can reach it. My torch is a #17 rated at 150amp. By going with the longer hose how much do I need to worry about the resistance in the line? My power supply is 200amp, and so far I have been working on 1/8" material as the thickest, and setting my petal at 140amp.

Well the flash thing is mysterious - never experienced it - I would think it's either some sort of contaminate burning off - or is it possible as you say the apparent power changed it's a bad earth - you are seeing a second arc from close by - or as the bad earth reduces power you compensate by applying more pedal - when good earth resumes your power is alot higher so it's brighter until you back off again.

1 I've seen / used torches in tatters with bare wires showing - but it not a good idea - anytime a Mig or Tig hose is damaged it at least wants taping up - or heat shrink sleeve is good - replacement covers are available & not that expensive either in quality rubber or cloth.

2 I put some larger rubber hose over my Tig torch hose for a couple of feet from the machine - bound it to the cable with tape then cable tied it to the trolley the welder lives on - that way you can't pull on the switch wire or main cable or kink it - I think maybe the torch assembly that came with yours is not the highest quality as they generally don't kink that easily- perhaps it's time to upgrade.

3 As your 150 amp ( probably only 35% duty ) torch is already under rated for the 200 amp set why not $ up & get a 26 series - the hose on these should be thicker so will offset the slight loss on the longer hose length - all the parts still interchange & I don't think you lose enough power to worry too much.

michialt,

You didn't mention what material you were welding, but the "bright flash/seeming arc wander" is familiar to me, primarily on carbon steel, and I've seen it happen on stainless and aluminum.

For carbon steel, a wire wheel alone may not completely remove all mill-scale, or rust from a small pit. The tiniest bit of rust will flare when you hit it, and even microsopic contaminants will push your arc around a bit.

I'd go back to the flap wheel for a bit, to prove the change made the difference, then follow the flap wheel treatment with the wire-wheel for a few welds, to prove whether or not the wire wheel is introducing contaminants.

Be sure the wire-wheel is stainless steel, and has been protected from outside contamination, including setting it down while still spinning and grabbing paint, oils, rust from a workbench, etc.

BTW, the last paragraph spells out some of the reasons you might see this if you're welding stainless or aluminum.

As to the other questions, if your just talking about a zip-up/velcro over-jacket, as commonly used on water-cooled rigs, you can patch them ad-infinitum with duck tape.

You'll not notice much difference between a 10' and 25' lead on a 200A machine, but noddybrian has a good point about upgrading the torch at the same time... The -26 will have a heavier cable, removing all doubt.

Easiest strain-relief solution for the gas-hose kinking? Get a foot or two of 1/4" "spiral-wrap" wire-loom from your auto parts store, and wrap the line close to the machine, then twist it "lefty-loosy" while pushing it toward the connector. It may even slip inside.

I hope at least some of this is helpfull...

Steve S

It is carbon steel (angle iron) that I am seeing the flashing on. I'm pretty sure that the wire wheel isn't stainless, it was a cheap home depot part. I was trying to find a cheaper alternatives to the flap wheels. The flap wheels wear out pretty quick on angle and square tubing. I also have to be extra careful with them around the edges of the steel because they can eat off a lot of metal fast thining the walls and costing me a lot of strength. Not as much a problem on current projects, but when I start building the airplane this could be a serious issue if I am not careful enough.

With the torch, I haven't handled a 26 series torch, but I assume it's also a little bigger than the 17 series. I was holding off on upgrading torches until I get ready for my next project. The next project will be Chrome Molly (4130) thin walled tubing (.035 and .047), and with a bunch of compound angled joints (airplane fuselage). I was seriously considering upgrading to a water cooled setup to take advantage of the smaller torch heads. Right now I haven't had to push beyond 120-130 amps on the 17, and I have no needs/plans to work on anything thicker that .125 angle for the rest of the 2 projects I am working on. Someone mentioned that I currently have about a 35% duty cycle, and that's about right, but the torch gets pretty hot, so the breaks for it to cool work out about perfect.

My biggest issues with what I have is that I only have 1 220v outlet in my Garage, and it's in a corner that is away from my work area so I have to roll my 8' work bench as close as possible and then manhandle my projects to reach all sides of it. My current cable is either 10' or 12' and I've gotten a few too many burns on my forearms from trying to move things around. I'm up against a finite of the 28th on this project, so I'm going to keep with Tig through this weekend and then switch to FluxCore MIG to wrap up this project.

My TIG welds on steel have come a long ways with this project in both looks and quality. I'm still burning through once in a while, and my beads aren't always perfectly straight, but it's been a while since I had issues with penetration, strength issues. I've been working on 1/8" and 1/16" mild steel, and ironically is the 1/8" that I burn through the most. The burn through is always on difficult to reach joints, or joints where my clamping makes it difficult for me to get a good view of the weld.

I am still struggling with one other issue, but I fight this with Gas/Mig and Tig. With items that have several joints to be welded I am still getting distortion when all the welds are completed. I've tried tacking all joints, I've tried clamping them as best as I can, I've tried to guestimate the distortion and undersize the work etc. My current bench doesn't offer me all that great of a surface for clamping though. I've given up on mitered 45 degree corners all together because I cannot create a squared corner joint no matter how hard I try. I've tried just about every trick I have read and that I know, and the weld manages to distort it enough that its off enough to be frustrating. I've went to notching the angle, and this is giving me better results. I just have to grind the beads flush.

I know that 50-60% of my problem is my workbench. I don't have a lot of clamping options, and it's base is wood so I am struggling with warping, and having to roll it around and re-level it is getting frustrating in it's self. This is my last project on this bench, when it is done I am taking a chainsaw to this thing, and not looking back.

I've already started planning my next bench(s). For the plane I need 16'x4' work surface, but building a single surface this large is out of the question in my shop. I've taken an EAA workbench plan, and altered it to solve multiple problems. Their bench plans are modular benches of 24"x48" tops, and you simply lash multiple benches together to give you the larger work area. They use wood for their designs. I'm going to use steel. I am going to build 4 24x48" benches with 1/2" steel plate tops. I am going to drill and tap a 4" square grid on each of these for clamping. Then I am also going to build 4 24"x48" with slats to use for my plasma cutter. This should solve most of the bench issues.

For a 4130 airframe, you will want a small torch, and a gas lens setup with long taper cups, for extended stickout... Some of those spider joints will have narrow angles not reached any other way. Argon dams of heavy foil are also helpful. So is a flex-head torch.

Duty-cycle won't be an issue on a 200A machine, welding .035 and .047 tube.

Distortion is a much smaller issue in an airframe, because of the many redundent "self-clamping" points you get when it's tacked up, but there is still a sequence to follow to minimize it. The video WerkSpace (a pilot and homebuilder) posted here:

http://forum.weldingtipsandtricks.com/v ... f=4&t=3427

actually describes the sequence. This was WWII type stuff, aimed at your grandma in the welding field. It's long, but there's a specific section on welding airframes that still applies.

Steve S