amp outputs mig vs. stick

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These small inverter welders that are rated to 140 amps can only do so with 220-240 connections. At 115 v. these welders are not quite achieving 90 welding amps for the most part. A 110 volt mig is rated at 140 amps and can weld to 140 but many seem to think that anything beyond 1/8" thick metal, they become inadequate. I thought amps were amps. A 140 amp stick can easily weld 1/4" or even 3/8's with a few passes when connected to a 220 circuitry. Why is the mig not as capable at the same amp rating?

 

[Rock knocker]

Power: V x I = Watts. And then there is Ohm's Law where R is varied by arc length.

 

[Mark @ Everlast]

Good answer. Actually the most limiting factor on the stick units is the fact that most people do not have the luxury of a 30 amp breaker.

Amps are Amps, but not all welders put out the same voltage. Think about it. At 140 amps you are burning maybe .030" wire on a MIG. On a stick you are probably burning 1/8" electrode with 24 volts or so. It's got to take something more to burn it....and it does so with voltage. Also current varies with stick arc length, where as you may be welding a steady 17.5 volts while the amperage can vary somewhat due to the length of stickout.

Also to answer your question, what heats up faster? A bic lighter with a small flame or a flame thrower? It's the flame thrower which would correspond to the wire thickness issue.

 

[arrow]

Good answer. Actually the most limiting factor on the stick units is the fact that most people do not have the luxury of a 30 amp breaker.

Amps are Amps, but not all welders put out the same voltage. Think about it. At 140 amps you are burning maybe .030" wire on a MIG. On a stick you are probably burning 1/8" electrode with 24 volts or so. It's got to take something more to burn it....and it does so with voltage. Also current varies with stick arc length, where as you may be welding a steady 17.5 volts while the amperage can vary somewhat due to the length of stickout.

Thanks Mark. As a result of the wire thickness, heat transfer is minimized with the mig so what a stick can do at 90 amps, a mig needs either a thicker wire and/or more voltage output correct? Are there any studies that begin to size up equivalency of mig to stick in this regard depending on metal to be welded thickness?


RN, thanks for the input but for a numb skull such as myself, I cannot recognize it as a "good answer". I'm not a math guy enough to equate an equation to practical usage without understanding how it works first. I need the big picture and work down from there and sometimes working downward for me is not what you'd call "repelling " if I can use a mountain climbing analogy. Its more like "where the heck do I place my foot next" My brain wonderment goes to things like: What would they call the a measure of electrical output if the guy who was at the forefront of the steam engine was named Atatomonwalaumalau and not James Watt? Many times the question has arisen on how I've survived life thus far.

 

[LD1]

Alot of the confusion and problem with a question like this...IMO....is due to the fact that you dont actually know what amps you are running with the mig.

With TIG and Stick BOTH, you set amperage. With a mig, you have no clue what the amperage is, only volts and wire feed. So all "I" can do is guess. My wire feeder is a 225A machine. So I "assume" that cranked all the way up, it would be 225a. On the same tolken, at half wire feed and half voltage, I would "assume" it to be in the 110A range.

My machine has a wire feed of 1 to 10, and a total of 24 voltage settings. A 140a is roughly 62% of max power. So I would "assume" to achieve that, I would need to choose the # 15 heat setting. Which would be heat range 3, heat control 3. (4 selections on heat range and 6 on control). I would also need a wire feed of the 6 setting.

From experience, that is generally about where I weld 1/4" at. I could be wrong, but I think the reccomendation of NOT using the 110v machines for over 1/8" has alot to do with duty cycle. I think most are only like 30% at max. SO I think it will weld the 1/4" okay, but not good if you have alot of it to do. A larger machine is likely near 100% duty at that setting.

 

[arrow]

Alot of the confusion and problem with a question like this...IMO....is due to the fact that you dont actually know what amps you are running with the mig.

With TIG and Stick BOTH, you set amperage. With a mig, you have no clue what the amperage is, only volts and wire feed. So all "I" can do is guess. My wire feeder is a 225A machine. So I "assume" that cranked all the way up, it would be 225a. On the same tolken, at half wire feed and half voltage, I would "assume" it to be in the 110A range.

My machine has a wire feed of 1 to 10, and a total of 24 voltage settings. A 140a is roughly 62% of max power. So I would "assume" to achieve that, I would need to choose the # 15 heat setting. Which would be heat range 3, heat control 3. (4 selections on heat range and 6 on control). I would also need a wire feed of the 6 setting.

From experience, that is generally about where I weld 1/4" at. I could be wrong, but I think the reccomendation of NOT using the 110v machines for over 1/8" has alot to do with duty cycle. I think most are only like 30% at max. SO I think it will weld the 1/4" okay, but not good if you have alot of it to do. A larger machine is likely near 100% duty at that setting.

You may raise a valid issue about duty cycle as I have heard of people welding this (1/4") thickness with a 110v mig. People who disparage this type of usage with this type of machine however also mention something about " a 110 mig machine doesn't get hot enough to weld 1/4 or 3/8 or whatever" so there might be something else to this as well. Now about your percentages……

 

[LD1]

Now about your percentages……

My machine is 61% larger than the 140.

The 140 is 38% smaller than my 225.

My 225 is 161% of the 140

The 140 is 62% of my 225:laughing:

Okay, enough with that.

About it not getting hot enough......I dont know. Honestly, I have never ran a 110v mig. Knowing how MY machine runs on ~62% of max, I wouldnt be the least bit afraid to try it.

Heck, I think my 225a machine is only rated @ 1/4" capacity. Does that mean I wouldnt use it to weld 1/2" plate together......NO. You have to learn about joint configuration, and v-grooving.

I think what the 1/8" refers to is how far you can penetrate into a butt weld with ZERO root gap.

I guess what I am saying is...In the hands of a good welder, and using proper joint techniques, you can do alot with 140A.

But then onto the dilema, there will ALWAYS be something just a Tad too thick for what you want. It dont matter if you have a 200a, 350a or a 500a welder.

 

[arrow]

My machine is 61% larger than the 140.

The 140 is 38% smaller than my 225.

My 225 is 161% of the 140

The 140 is 62% of my 225:laughing:

Ha… you're wrong! Your machine is 62% larger than the 140 but probably you're not wrong somehow

 

[LD1]

225/140=1.607

The 225 is 160.7% (or rounded to 161%) of the 140. In this case, the 140 is considered 100%, and therefore the 225 is 61% larger.

140/225=.62 Or 62%

The 140 is 62% as big as the 225. In this case, the 225 is considered 100%, so the 140 is 38% smaller than the 225

 

[muddstopper]

The only problems I have had with the 135amp lincoln mig has been duty cycle. It will weld 1/4 in with ease, using .023 wire, as long as I dont pass that duty cycle. When welding, it gives you clues as to when its about to max out welding. It will run fine for a few minutes, but then it will start to fizzle and splatter. If you stop and wait at that point, it wont trip the reset, but if you keep trying to weld it will shutdown and then you have to wait for it to cool down before turning it back on. I have found the same thing is also true with the Miller 175 mig. Once you start approaching the max duty cycle, it wont weld worth a hoot either, but tkae a break, drink a glass of water, and everything will be fine. And like LD1 said, you will always find something your welder wont do and wish you had a bigger machine. I bought the miller because I was tired of waiting on the little Lincoln, now I wish I had of bought the 250amp machine instead of the 175. In fact, I am keeping my eyes peeled for a good used 250 machine at the right price.