Newbie stick welding question

Hi,
The other day I was welding 20mm by 30mm and 2mm thick angle iron bars to each other. The resulting thing will be a frame to place my table saw
on. I have used 3.25mm 6013 rods with a current setting of about 125 Amps. But when I started to weld the 30mm side of the bars, the first 15 or 20mm was good, but then I was consistently burning a hole through the wall of the angle iron. So I started to weld in two steps. I first weld 15mm, let it cool, and then weld the remaining 15mm. This worked out quite good. The only disadvantage that I have noticed is of course the more ugly looking weld. Is this practice of welding step by step and let it cool in between right, or is something else wrong?
--
Timur

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I think that if you used 3/32" 6013, at maybe 60 amps (just guessing), your burn through problem may go away. Here your welding rod is thicker than your material.
i
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Hi Timur, all
Here is how you can see Iggy's suggestion is correct...
In general for electric arc welding processes you want about 40Amps per millimetre material thickness. So for your 2mm material you'd be starting your thinking and trying at around 80A. Now because you are welding small section angle iron the heat can't conduct away much (compared to a big sheet of 2mm steel), so you are going to want less current for a weld which is still well-fused.
Say you guess you'd start trying at about 70A. What size of rod is in its ideal operating range at 70A? That would be a 2.5mm diameter welding rod, as Iggy suggests.
Richard Smith
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Richard Smith wrote:

Thanks a lot for the responses guys, very helpful indeed :)
--
Timur

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writes:

Hey, you learn by doing a lot of crappy welds. And then getting some input. Ask any weldor.
Steve
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wrote:

Richard, you got the right idea but the wrong end. Amperage is usually calculated by rod diameter, not parent metal thickness. If it were you'd be using something like 1,000 amps to weld a one inch plate....
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If it was me, I'd use a different rod. I am partial to 7018 and 6010. If you are burning through, you have one of two problems. Either too big a puddle, or heat is too high. Ugly welds are caused by several reasons. One is the deposition of too much filler. The other is incorrect motion. Another can be that the base metal has paint, rust, oil, dirt, water, or some other contaminant in it. The materials you are trying to weld together should be no problem. What caused you to select the 6013 in particular?
Steve
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Sorry, I forgot to mention that using too large a rod can cause burnthrough. When you get to where you can do it in your sleep, you assume that people know more than they actually do.
Steve
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SteveB wrote:

OK, I understand it's time to get another pack of 2.5mm rods :)
What difference would it make if I were to use 7018 or 6010 rods?
--
Timur

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7018 is a great rod for many mild steels and HS steels. It runs smooth, gives decent penetration with a good bead profile. That said, the weldor's actions have a lot to do with getting good penetration and bead profile, too!
In the shipyard, we use 7018, 8018, and 11018 for almost all of our stick welding. Sizes range from 3/32 inch to 5/16 inch.
I would recommend using 7018 for most of your mild steel welds.
6010 is better if your base metal isn't as clean as it could be, use a "whipping" motion. Imagine flipping a lightswith on and off with your welding rod.
The first two digits in the number represent the tensile strengh of the deposited weld in PSI. Hence 6010 is 60,000PSI and 7018 is 70,000PSI.
The only drawback to 7018 is that you need to warm it up before welding. Bake the moisture out of it in an oven at 250 degrees for several hours if it's an open can of wire. For a new sealed can, you can go right to work.
Humidity affects the higher strength fluxed welding wires more than it will the 6010. Higher strength wires will be prone to hydrogen embrittlement and cracking welds if you use them without ensuring they are dry as a bone!
sorry for the rambling on- my only excuse is lots of painkillers.
--
Tin Lizzie
"Elephant: A mouse built to government specifications."-Lazarus Long
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7018 is a great rod, but I would not recommend it to you. The 70 in the number is the strength. So 70 is stronger than 6010, 6011, or 6013. But so what. you are not welding anything with a strength close to 60. So having the weld stronger than the material you are welding makes no sense.
Second 7018 is a low hydrogen rod. Not having hydrogen disolved it weld is important for high strength steels. To protect the molten puddle, 7018 has a flux that lets the rod burn back inside the flux, so the flux protects the molten metal better than flux that burns off and exposes the end of the rod. But the disadvantage is that you have to break off some of the flux in order to restart an arc on 7018. Not a huge deal, but an annoyance just the same.
And some 7018 only works well on DC. Some works well on AC, but you have to make sure that any that you buy will work on the welder that you have.
If you are welding mild steel, having moisture in the flux of 7018 in not a problem. But if you are welding high strength steel , just baking the rods before welding will not hack it. You need to keep them in a rod oven when ever they are not in a sealed container.
I am assuming that you have a AC welder. Nothing wrong with that, but some rods as 6010 are intended for use on DC welders. So buy some more 6013. It should be slightly cheaper than 7018.
Dan
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snipped-for-privacy@krl.org wrote:

My welder is a simple 250A DC inverter. It's an ExpressWeld 250, Lincoln's low end, chinese made welder.
People here had suggested me to get a MIG welder, but those are much more expensive here. And I have also read on this group that a MIG welder lets you make very nice looking welds, but if the settings aren't right, the penetration will not be right and the weld can break easily.
--
Timur

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Well...true enough up to a point...but....and I point this out..never mind..tires are a long story....it is far far easier to get a strong good looking weld with MIG than with any other mode of welding. And if you observe a few things while welding..its hard to get a Bad weld, with a decent and adequate sized machine.
Frankly..If I had the choice of only one machine..Id take a stick welder. But...I use the 3 or 4 MIG welders that I own, far far more often, faster and cleaner than the 5 stick welders that I own.
Gunner
'In the first place, we should insist that if the immigrant who comes here in good faith becomes an American and assimilates himself to us, he shall be treated on an exact equality with everyone else, for it is an outrage to discriminate against any such man because of creed, or birthplace, or origin. But this is predicated upon the person's becoming in every facet an American, and nothing but an American... There can be no divided allegiance here. Any man who says he is an American, but something else also, isn't an American at all. We have room for but one flag, the American flag... We have room for but one language here, and that is the English language.. and we have room for but one sole loyalty and that is a loyalty to the American people.' Theodore Ro osevelt 1907
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I think that it is actually hard to get a stick weld, on clean material, that would NOT have proper fusion.
I mean, if a stick weld spans both parts to be welded, then it will have fusion where it reaches base material. It may be ugly or have slag inclusions or whatnot, but it will have fusion. Not so with mig.
Not that I know all that much... But that has been my experience so far...
i
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On Wed, 22 Jul 2009 14:37:03 -0500, Ignoramus30026

It is entirely possible to get a weld that looks good, bad or ugly..and only sticks to one side or the other. Been there, done that. But with stick..its harder to do than Mig.
But still very possible.
GUnner
'In the first place, we should insist that if the immigrant who comes here in good faith becomes an American and assimilates himself to us, he shall be treated on an exact equality with everyone else, for it is an outrage to discriminate against any such man because of creed, or birthplace, or origin. But this is predicated upon the person's becoming in every facet an American, and nothing but an American... There can be no divided allegiance here. Any man who says he is an American, but something else also, isn't an American at all. We have room for but one flag, the American flag... We have room for but one language here, and that is the English language.. and we have room for but one sole loyalty and that is a loyalty to the American people.' Theodore Ro osevelt 1907
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wrote:

Sometimes that is not possible, though, when said parts have parted company with the trailer and gone their way through the desert or into a very deep ravine. In that case, you only get a good guess. Yet, still, you can look at what IS left, and see if there's fusion or the weld cracked off.
There's things to be said for 7018 burned in real good on adequately thick materials.
Steve
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Fusion is also dependent upon required pre-heats. If your welder says it works up to a certain thickness, you can increase that thickness by pre-heating the base materials (typically 125 to 200 deg. F.).
The fusion zone is very small, yes. But if your heat affected zone has "sharp" boundaries (as in welding without enough amperage), you will create stress risers in the base metals, and could have cracking along the toes of the weld. I've seen welds crack as the weldor was welding, once- the cracks were propagating about two inches behind his puddle when I tapped him on the shoulder...
Cold base metal and low amperage can definitely cause problems.
--
Tin Lizzie
"Elephant: A mouse built to government specifications."-Lazarus Long
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I tried to find some information on your welder and failed. But expect it is a better welder than most of the relatively inexpensive welders available in the U.S. Lincoln has a lot of information on welding rods available on their web site as does Miller. You also got a lot of good info here.
Dan
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snipped-for-privacy@krl.org wrote:

Hi Dan,
It seems this welding machine is only being sold in Turkey. I googled for "expressweld 251" and there are only turkish links. Here is one that also shows the technical specs:
http://www.724magaza.com/HIRDAVAT/Kaynak%20Makineleri/Genel%20Kaynak%20Makineleri/urundetay.html?35859
It is a 3 phase (380V) machine.
Thanks for the tip about the info on the Lincoln site :)
--
Timur

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To me, after thousands of hours of MIG welding, it's the angles, speed of travel, direction of travel, size of the puddle, and the pausing that determines the penetration. Sure, there are some things like thick metal and small wire that won't work no matter what, but there are some small things that will help make it stick.
Steve
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