FIRST WELDS!! 250EX TIG on STEEL!! Some good, Some BAD
I decided to "freestyle" together a prototype for an engine stand for rebuilding Harley-Davidson motors. I'll explain. "Freestyle" means that you get out some pieces of material, your metalworking equipment, including markers, squares, clamps, tools. etc. Then the pieces that you want to go together, and just "figure it out". What I ended up with is a functioning prototype of what I'll ultimately end up with. But that's another thread. Here, I have some pics and commentary on the learning curve I'm going through with my 250 EX.
I needed a bottom plate for the stand that I'm building to reinforce and hold the mounting tab. I went to the local steelyard and picked up some drops out of the bin. The first piece is about 8" x 11" x 5/16" and is being welded to some 10 gauge angle iron on the old stand. I cleaned everything off with MEK and used a 60 grit flap wheel to get down to virgin material.
The first pieces of this assembly were rusted, deeply pitted steel salvaged from old farm equipment, so I tested the stick welding capabilities of the machine. In spite of the fact that all I had on hand was some 3/32" 7018 where 1/8" would have been better, I was extremely pleased with the smoothness of the arc this machine puts out in stick mode (see the thread on this).
Here, I got everything cleaned, clamped onto place, and tacked on all 4 corners. I used 1/8" Thoriated tungsten in my EVERLAST WP-20 torch, ground to a point, with a number 7 cup and the stock flowmeter set at 10 LPM. 200 amps with the foot pedal, and no pulse. 2 sec. preflow, and 6 sec. postflow. I used 3/32" ER70s2 for filler, as that's all I have on hand. Below is the setup. I always asked myself "why in the hell would I ever want a flex-head torch?" I just answered that question. I used two of Jody's TIG FINGERS to keep my digits from roasting while running these beads. They worked Excellent, as usual. I will now ALWAYS have a flex-head torch on hand, no matter what.
Arc starts were perfect, and I would go from start, then floor the pedal, focusing the arc toward the thicker bottom plate. Then step-pause in a tiny circular motion. I kept the filler tip in the argon zone, and dipped on the "back-step" part of my step-pause. At the end, I would back off slowly, trying to come up with a decent looking finish. One last dip, a quick floor of the pedal, then a smooth back-off to zero. Below is the result of the first weld.
Flip the part 180 degrees, and repeat the process.
You will see that on the second one, about 2/3 of the way down, I nipped the edge, I want you to realize that these two welds are, honest to GOD as my witness, probably the seventh and eighth TIG welds on steel that I've ever made in my life. I became interested in TIG welding to weld ALUMINUM, not steel, so other than my welding test that I took a few months ago, I've tried razor blades, and MAYBE 2 or 3 other beads on steel. All other TIG welding that I've ever done has been on aluminum.
Next was to weld the mounting bracket to this baseplate. Here's where things got ugly. A simple Fillet weld. 3/8" plate to the 5/16" baseplate that I just attached. I used a couple of those triangle shaped magnets to align the bracket, tacked in place. Then went to town, using the same settings as I was already using. All I can say is ICK!!! Smoking, popping, smut, just a nasty looking weld. I figured that since this steel looked clean that all it should require was a quick wipedown with MEK and we'd be good. WRONG!!! Below is te result of the first weld.
See the black soot, and overall poor quality? About halfway through, I fouled the tungsten, and since all I had was the one 1/8 red, and another 1/8 tungsten with a brown tip, I decided to give it a go. It was awful, went WHITE hot and spit a little, but I managed to finish the weld (I later looked it up and the brown tip was ZIRCONIATED-not recommended for steel).
Out came the tungsten grinder to freshen up my single stick of 1/8" Thoriated tungsten, and the other grinder to clean the mill scale off the other side of this joint. Even though that gray surface looks clean, It's mill scale nonetheless, and for a good TIG weld, I found out the hard way, MUST be removed. If I were stick welding, I wouldn't have bothered, but that's a different deal altogether. Once clean, I went to work on the other side and the ends. Below is the result.
Even though the resolution of my camera leaves something to be desired, it's clear that the weld on this side is much better. Arc start was easier, and less soot, smut, and the filler flowed into the puddle. I should have cranked up the amps to 225-250, but I think it will hold. Penetration was good.
So, there you have it, All said and told, the welds you see pictured above represent more than 1/2 of my total experience TIG welding steel ever. As stated above, I got into TIG welding to weld aluminum, so since day one, I've been single-mindedly focused on AC welding of said metal. As far as the machine goes, I'm in love with my 250EX. I believe that it handled the task at hand as good as anyone could expect. I'm looking forward to more steel welding so I can use the pulse function and 2T/4T with all the other functions available in the machine, and I have a long project list, including motorcycle frames and exhaust, a "Y" pipe for my truck exhaust (stainless), and the tables for the machines I will be producing are going to be 2" x 4" x .125" wall mild steel. This will be the test as to whether the machine can hold up to an industrial setting. I have no reason to think it won't.
Feel free to comment and give me some pointers, as I'm still learning. Thanks for looking!!
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