by Jason Becker
One of the questions I get a lot as an educator is how do I set up my machine?
So today we're going to talk about shielded metal arc welding specifically with the low hydrogen electrodes and we'll just go over the basics.
I'm going to show you how to dial in the correct amperage or a good place to start regardless of diameter and position that you're going to be running in with low hydrogen electrodes. So for example we're going to start off with this 3/32" 7018 rod. So we can do that by figuring out the decimal equivalent to the electrode. So for a 3/32 electrode we just take the 3, divide it by the 32, and wind up with 93, .093. So a good place to start is 93 amps for the flat position.
Now if I wanted to go into vertical let's say good rule of thumb is to reduce that starting amperage and flat position by 10%. So if I take that 93 amps and I multiply it by .90, I end up with 84. So a good place to start is 84 amps for vertical.
Same thing with overhead, but I only want to reduce overhead by about 5%. So same values, at 93 starting amps, multiplied by .95, that's going to give me 88 amps. And that's a good start for overhead.
We're going to demonstrate and show you guys by putting these exact values in the Everlast over here and we're going to produce these welds. We'll do a horizontal, vertical, and overhead with the 3/32 as well as the 1/8 inch electrode.
So same thing when we figure out the diameter or the starting amperage for the 1/8 inch, start with the decimal equivalent so that 1/8 so one divided by eight, it gives me .125. Just get rid of the decimal. I have 125 amps of starting amperage, a good place to start for flat and horizontal.
Same thing if I go into vertical. Remember that 10 percent rule. I'm going to reduce it by 10 percent. So 125 multiplied by .90. It's going to give me 90 percent so it's about 113 amps for the vertical position on an 1/8 inch electrode.
Same thing with overhead, just reduce that by five percent of your original flat position amperage. 125 multiplied by .95 is going to give me 118 amps. So we're going to go ahead and show you guys.
We'll start off with the 3/32, flat, vertical, and overhead or horizontal, vertical, and overhead, and then we're going to do the 1/8 inch, horizontal, vertical, and overhead. So we're going to start off with a 3/32 electrode in the horizontal or 2F position. If you remember our calculations from a second ago, we discovered that that was about 93 amps. I've got my work piece clamp plugged into the negative side which is going to give me about thirty percent of my heat to my base plate. The electrode is plugged into the positive side where the remaining seventy percent of that heat is going to go into my electrode.
Right off the bat I can tell you we've got a smooth start there. It's tying in good to the top and the bottom plate. This 93 amps seems about right. There's no sticking I don't have excessive spatter, Overall it's pretty smooth. I'd say 93 amps for 3/32 diameter electrodes is the way to go. Keep and nice tight arc length in there. Once we get to the end you want to make sure you know you take a second to pause and fill in any crater. All right. So we just completed that 3/32 weld in the flat position. We got a nice even bead profile. 50 percent coverage on the horizontal joint as well as the vertical joint, which is what we're looking for. Good tie in. No undercut. No excessive spatter. I'd say overall it's a pretty decent weld and 93 amps work really well for us.
So now we're going to test this theory again. We're going to go into the vertical position where we're going to reduce our amperage by 10 percent. So we started off with that 93, we're going to reduce that down. I got about 84. You can round up a little bit, it's not going to hurt, an amp or two. We're going to run it over to 84 and hit this vertical and see what we come up with. We get a smooth arc start. Seems like it's digging in there pretty good. Went in on the sides really well. Not blowing anything out. Rod's not sticking. 84 amps seems to be the ticket. Keeping that tight arc gap. We got it really nice. He's going to run a little tie in here. We ran a little short with that first rod. Make sure we get to the top. It's going to want to blow out. Pause a second, fill that crater in. So from the beginning we had a good arc start, very limited undercut, virtually no spatter. I'd say overall it did pretty decent at that 93 amps. I'm pretty impressed with this Everlast over here. Once again make sure that crater's filled out. We got a tie in right about in this area here. That turned out pretty well too so good arc start overall, good tie in, so let's go ahead and we'll swap it to the overhead settings, 88 amps, and we'll run some overhead.
So again coming from your right to left this time because I ran in upside down, good arc initiation, good weld, no undercut, very minimal spatter, I think I got two little BBs on here I could probably get rid of. Didn't have any excessive heat so I wasn't blowing any holes in here or having any undercut. So it looks like 88 is a decent starting amperage for overhead.
So now we're going to switch over. We're going to try out the 1/8 inch rods. If you remember before we listed that as about 125 amps. So we'll go ahead and dial in the Everlast PowerArc 161 and let's see what we can do with it.
All right so we got good arch initiation, no undercut once again, good crater fill at the end, and overall I'd say it performed pretty well at 125 amps. All right guys so we went ahead and we made a goof. Left the machine setting at 125 amps from flat position and went ahead and welded the weld joint up in the vertical position assuming we had the correct amperage dialed in. And I ended up with some undercut on both the left and right hand side. Not too bad, but more than I like to have on there. I don't like to have any undercut at all. Also when we got to the top we went ahead and blew about 3/16 crater in the top there. That's also something you're going to want to avoid.
So had we dropped down to that 112 amp range that we discussed previously I don't believe that any of this would've happened. So now what we're going to do is we're going to set the machine to the appropriate amperage we discussed earlier and we're going to go ahead and rerun this coupon and show you guys the difference. It's lying in there pretty smooth. About the way I like it. A little side to side action. Hold the sides, give it time to cut, give it time to fill. It's about a 10 degree travel angle. Tip of the electrode's elevated about one inch above the end of the electrode. That's how you know you got a good angle.
All right so we just got done running it at the appropriate 112 amps. Once again, no undercut, good arch initiation. Started over here, this is at the very bottom of the plate, this is the top. I could've done a little bit better job of filling in that crater up at the top, keep that edge from blowing out. Run off tabs usually help if you're in that situation. But we're just doing a little bit of practice and some demonstrations here. But other than that, no weld BBs, no buck shot on here. Everything overall looks pretty good.
All right so now we're going to run our overhead on 1/8 inch diameter 7018 with the 122 amps we discussed previously. So let's go ahead and get that started. Right off really well. You need to be getting good penetration. I can see how it's digging in there. I don't have a whole lot of sag. Keeping that tight arc gap. Not sticking so that's always a good sign. I think this 122 amps is about the way to go. So this crater in here at the end, slight little pause. All right so overall we got a pretty good bead appearance on here. Melted in nicely to both sides of the material. I got one spot over here where I get a bit of lack of fusion and that's I think that's more my fault than it is the amperage at what I was selected. It's all in technique. But overall good weld, nice bead appearance. I'd say that 122 amps is a pretty good starting average for your amperage.
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