Suggestions For An Arc Welder For Up To 1/2" Steel?

An inexpensive used stick welder is just great for welding the thick steel that you mentioned. A previous poster suggested that the xx18 rods work well on AC. If you have a small home type welder, this is not always the case. These welders do not have enough OCV (voltage) to keep the higher numbered rods running smoothly. 7018AC is just a little more costly, and runs great. There is also a difference between the welders with a high or low terminal, like the Miller Thunderbolt. The "low" terminal is low amperage and high voltage and works much better with 7018. But, when I used 9018 (not AC), it was easy to tell the loss of smoothness in comparison to a Miller Dialarc, which is the more industrial class of machine.

These days, Craigslist sellers seem to charge a premium for the name brand welders (Miller and Lincoln). It is hard to find the $100 welder anymore. Don't buy a 120V stick welder unless you really know what you are doing. I once bought a Wards Powerkraft cut down AC stick welder for $75. It was only 180 amps, so it could be plugged into a dryer. These welders have a movable slide adjustment which often comes loose, so you can save some money on Craigslist. A clamp can be used to tighten it in place if it slips while welding. I ended up giving the welder to my apprentice.

My favorite models of stick welder are Miller (Thunderbolt or Dialarc) and Lincoln (tombstone or Idealarc). You can often get a bargain on Craftsman colormatic, Montgomery Wards Powerkraft, Linde, Western Arctronics or some good ol' simple AC stick welder.
 
OK I just picked up a Miller Thunderbolt AC/DC SMAW manufactured between July 2000 and Dec 2000 from a nice guy on craiglist for $200. Machine is in good shape. He struck it up before I bought it. It definitely melts metal. I have a few questions for you guys:

1. First things first. SMAW is bright! A few years ago I bought a Miller Titanium 9400i with grinding shield (1st gen. without info. track) because my eyes are important to me. I just read the reviews and can agree with all the negative comments. But here is the deal, when we tried out the Thunderbolt this morning I cranked up the shade to 13 and it was still not dark enough. Am I doing something wrong? I am considering buying a low number passive lens and sticking it inside where the magnifying glass goes. This is how I want to see, at min. 4:22


Edit: Local Airgas dealer put two new batteries in my helmet at $5 each and says it is good to go. He said the Duracell which I put in about two years ago are not as good as the Miller branded batteries. We shall see.

2. What would be the best electrode, polarity and amperage for welding 1/4" steel to 1/4" steel. The machine has two amperages for AC and also a choice between DCEN or DCEP.

3. What would be the best electrode, polarity and amperage for welding 1/2" bar stock to 1/4" angle? Assuming DCEP (direct current electrode positive) which apparently is best for deep penetration on thick metals, what would be the best electrode for 1/2" steel? On another thread chuck suggested: "I would use a 6010 and finish out with lincoln 7018,s one with a D designation" If so, what diameter 6010 electrode? What polarity? What amperage?

In my recent reading about SMAW, the following statements seemed helpful. Any suggestions, changes, comments?

"One way to look at the polarity issue is by the welding rods that are available to you. 6010 runs DC+ only. 6011, which is similar to 6010 (forceful arc, deep penetration, light slag) runs best on AC, but runs all right DC+. 6012 runs best DC-, not good at all DC+. 7018 runs DC+ up to about 300 amps, better on AC above that. 6013 runs well either AC or DC+ for general welding, but was developed for high speed sheet metal work on DC-. And so forth.

The trouble with that approach is that it goes at the issue backward. What's important is matching the electrode (rod) to the job first, then running it on its best polarity after that. You would rarely match the polarity to the job first, and the rod to the polarity second---with two main exceptions: If you are having a problem with arc blow (the arc wanders off course because of the magnetic field caused by the location of the ground, or some other magnetic field disturbance) which you can't resolve by moving the ground clamp, you can turn to AC, which is not subject to arc blow. The other situation where polarity would be a primary consideration is when you know you need more of the heat in the work than in the rod. DC- provides 2/3 of the heat to the work, DC+ provides 2/3 of the heat to the electrode, and AC is 50/50. 6012 and 6013 electrodes were both originally developed for high speed sheet metal work on DC-, so that would be an example of a time to choose that polarity. I don't do much sheet metal work with stick, high speed or any other way, so I couldn't say. I do know that 6012 running DC- is unusually good at filling gaps in bad fitups, but 6010 is good for that too, and there's not as much slag to entrap with 6010.
DC is generally considered to strike an arc easier and stay lit better than AC, but if any electrode strikes easier or stays lit better than 6013 running AC (or DC, to be fair) I haven't run across it.

There are some real differences between the three polarities in stick welding, but they're not so profound that an inexperienced operator would even necessarily notice them. If your son gets to the point where he can tell just when to use one polarity rather than another, or even just how high to set the current, before he's burned ten thousand sticks, then he's got a real gift and maybe he should look into something that pays better.
All the best, Stan"

"Welding is a process of heating the base metal to where it can accept drolets of molten metal from the electrode to join metal.

AC, DCEN and DCEP are used to control those droplets of molten metal.
The flow of electrons in DC welding circuits is from negitive to positive and is called straight polarity.
When we reverse the welding leads then electron flow is from positive to negitive also called reverse polarity.
When AC current is used for welding, you get a base metal cleaning action that cleans on the alternating phase of the current, anotherwords the current cylces up and down thru the frequency and the base metal is cleaned and filler metal is deposited in both directions. This works well in the flat position and when the base metal hasn't been prep'd as it should be and where the molten droplets has a chance too fast freeze to the base metal.

When DCEN is used for welding the most of the cleaning action stops as far as the frequency is concerned as DC current only flows along the surface of a line and doesn't alternate thru the base metal like the AC current did.
Since electron flow is from negitive to positive then the molten droplets flow too the base metal from the electrode causing a very fast deposit of the droplets. The slang term is known as fast freeze between weldors. If the droplets fast freeze to the base metal then the base metal is cooler while welding thus is a good choice for sheet metal welding or filling poor joint fit up.

When DCEP is used for welding electron flow is from base metal to the electrode and most of the heat build up is on the base metal. What this does is allows for greater molten puddle control for the weldor when using the correct electrodes. Transfer of the molten droplets is slightly slower than using DCEN or AC.

This will cover the basics of some of the differences but in reality there's alot more to using AC, DCEN or DCEP than what's been written here, so I will add too this at a latter time.
T_Bone"

from:
http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=toolt&th=176652

This is what it says on the Thunderbolt spec sheet:
 

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First off let me state both wire feed and stick are arc welding. Next you are asking about welding dcep, on steel in the 1/2-1/4 range, but you are leaving out what type of steel. is it cleen or dirty. what are you type of joint so on so on. Unless you are going to be welding some critical stuff you need not woory what is the best rod. A better question and one I will answer is what rods should I buy for all around work. If you want to have the right rod, dia, polarity for every job you better have deep pockets.
For most home/farm work some 7018 in 1/8 and some 6013 in 1/8 & 3/32 would be ideal. if you do not know how to weld buy some cheap rod to burn up while learning. If it is clean with a good joint and you want a good weld use 7018. if it is dirty, poor joint, hard to get at use 6013. if you have to grind it down after and it don't need to be e-ray quality use the 6013. 6010, 6011 are also good rod and used pretty much the same as 6013. as can 7014, 7016, 7018
Heat for mild steel 1/2 with 7018 1/8 in a flat position would be between 100 - 130 and this will depend on many factors like amount of lead(cable) between the welder and the work, the condition of the ground type of joint humidity..........
Put more time into practicing welding and worry less about rod type. I used a AC Lincoln tombstone welder to learn to stick weld on, and for years to do all my welding at home using mostly 7018ac/dc rod made nice weld too.
Keep this in mind to every welder does some things different from the next, so what pattern I move the rod or heat I use may not work for the next guy. I use pretty much all of the common weld patters at different times, and some that just work at that time. Hear is a good example of what I mean. when I do my certifications we all have the same rod same brand/mod. machines same metal and the same joint. but the welding machines will be set at many different amps, and many different patters will be used.
Remember pull stick welds don't push.
Check out Jodi and welding tips and tricks
This link will get you to one of his vids.
I have been welding for 30+ years and I still consider myself learning.
Mark
 
markknx: ASTM A36 1/4" plate primarily horizontal lap joints (welding from above) and vertical lap joints (welding from below) between clean new metal with mill scale removed to existing 1/4" metal which I will flap disk to shiny before welding. I just bought 10 lbs of 1/8" diam. E7018 Radnor No. 64001110 ED032333 DC+/AC 110-150 Amps (dang Airgas didn't have Lincoln) AWS A5. E7018 ASME SFA-5. 7018. I was planning on running it on DC+.
I bought the used Millerthunderbolt XL SMAW welder (not "arc" as corrected by you) because the welds that I have to do are "critical" which have to be done out doors, and I need good fusion.
I have a "wire feed welder" (not "mig" as corrected by chuck) which I run GMAW through but I am not a good welder with it either. I do it. But it takes a lot of grinding off my welds and then rewelding for me to get things done right.
I like Jody's stick video and just rewatched thanks to you. I also like the 1942 GE video I posted above.

chuck: I bought the book and will read it.

So I will start welding some bead pads this weekend. And you guys won't hear back from me until I have something decent to show. Or can't get anything decent and need some help.

The counter guy at Airgas told me that in school they made him weld bead pads with 6010 for nearly 8 hours a day for two weeks before they moved on to 7018. Which was easy after their experience with 6010. So I don't expect to be any kind of wiz kid. I respect what you guys do and what you know. I know you put a lot of time into learning what you do. And I don't expect to ever be at your level or to be at an "acceptable" level without putting some brain and seat time in...

Thanks again for all your help.
 
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Mark: I screwed up. I meant to say horizontal lap joints welding from the side or from below and horizontal lap joints welding from above.
And, if I didn't say it in this thread, I said it in Franko's thread, I tell people "I am a grinder trying to become a welder." So, yes I carry that "user card," not proudly, but I carry it for now...
 
That Thunderbolt is good little welder. The first one that I owned (started welding back in the early 60's in my dad's shop). I bought it new back in the early 80's and used it to weld sections of 12x12 H beam together to make the span on my bridge. I got the steel for free, left over sections of piling from the railroad that were too short for there use. Thirty some years and a lot of heavy equipment over it, and its still there. Don't over think it, Just work the joint with small circular motion at the tip of your rod, keep your rod right at the puddle, and as the old man said when the boy on a New York City street asked him, "Sir, how do you get to Carnegie Hall?" the old man replied "practice son, practice". Mike

Not great pics of the bridge, but the only ones I could find. Fortunately it's pretty hard to see my welds.:cool 2: Mike
0805070002.JPG P1000185.JPG
 
E350, yes you kind of mentioned it in the first post, that is why I added that. Meant in humor.
Mark
 
guys: I bought 5 lbs. of 6010 5/32 diam. today. Should I start padding beads with it or with the 7018.

Mark: No worries. It is what it is.

Fomogo: You have a right to be proud of your view, your bridge and your welds since it has held up so well so long! GoodOnYa'M8!
 
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