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  1. #1
    Join Date
    Dec 2012
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    Default Mig Voltage Levels

    What advantage does a bigger mig welder have with higher voltage? I understand the longer duty cycle part, just wondering if the voltage makes a difference?

    I've always stick welded in the past, so setting a voltage and wire speed is new to me. Setting a current like for stick welding is all I'm familiar with.

    Comparing the output graph of volt/amp chart on the millermatic 211 (~ 21V @ 200Amps) versus the millermatic 212 (22V @ 210Amps) versus the millermatic 252 (28V @ 200Amps), what is the advantage of having a higher voltage at the same current?

    Is the higher voltage simply needed to run thicker wire at the same current as the next thinner wire? If so is there a recommended voltage range for various current levels on different wire thicknesses?

    Thanks!

  2. #2
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    Sep 2005
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    Default

    Simply put, the higher voltage at the same amperage, around 200 amps in this case, translates into more output power or a higher energy arc. Higher energy arc translates into the potential to produce a deeper penetrating weld- less chance of cold lap or lack of fusion to the root.

    Also, with the correct gas mix the higher voltage will allow you to use spray arc transfer. 21 or 22 volts isn't going to produce a spray transfer arc, you need a minimum of 24-25 volts, and the correct gas mix for this voltage range. 98 AR/2 Oxy would be the correct mix.
    Last edited by Danny; 03-20-2013 at 08:32 PM.

  3. #3
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    Default

    Quote Originally Posted by Danny View Post
    Simply put, the higher voltage at the same amperage, around 200 amps in this case, translates into more output power or a higher energy arc. Higher energy arc translates into the potential to produce a deeper penetrating weld- less chance of cold lap or lack of fusion to the root.

    Also, with the correct gas mix the higher voltage will allow you to use spray arc transfer. 21 or 22 volts isn't going to produce a spray transfer arc, you need a minimum of 24-25 volts, and the correct gas mix for this voltage range. 98 AR/2 Oxy would be the correct mix.
    The 211 is only 23.5V at 150Amp, so would the 211 then not be adequate for standard mig welding if the spray transfer arc is 24-25V?

    Not really sure the terminology for spray transfer arc.

  4. #4
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    Default

    The 211 is running short circuit transfer. There are also globular transfer and spray arc transfer methods. Short circuit is common for most consumer machines.
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  5. #5
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    Default

    To put it in simple terms the more volts means a hotter weld with mig like more amps means a hotter weld for stick. You can run larger dia. wire just like you would use a larger dia. stick electrode.

    Many other factors go into it but that is the basic version.
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  6. #6
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    Default

    Quote Originally Posted by MMW View Post
    To put it in simple terms the more volts means a hotter weld with mig like more amps means a hotter weld for stick. You can run larger dia. wire just like you would use a larger dia. stick electrode.

    Many other factors go into it but that is the basic version.

    I wonder then why the 211 doesn't indicate the voltage for different welding material thicknesses to compare it to larger welders. Instead they just have there 1..2...3.....10 dial for different thicknesses. I understand the 1-10 is to make it easier for beginners, but what is the difference in setting to a number 1-10 versus a voltage number. Don't think it would be that difficult for a beginner and it would make it easier to tell if the welder wasn't able to handle a certain process if it didn't have high enough voltage.

    Bottom line I'm taking off work tomorrow to go buy a new Miller Mig and want to make sure I'm not buying too small of a machine to handle 1/4" to 1/4" T-joint and butt weld joints.

    I'm talking welds that I can then take a sledge hammer to and bend the material completely over the weld for testing and the weld NOT break at all.
    Can the 211 do those kinds of quality welds?

    Looking at the specs on the manual here:
    http://www.millerwelds.com/om/o239988e_mil.pdf

    Page 28 and 29 is the settings chart.
    I'm looking at using C25 gas with solid ER70S-6 wire and .035" wire.
    So the chart shows 1/4" at dial #6, but it makes it seem 1/4" is easily within the range of the welder. I find it interesting that they do not increase the voltage dial for the thicker wire?

    When welding with thicker stick electrodes, a higher current is needed to run the thicker rod properly. Would then a higher voltage setting not be required to run .035 wire versus .030 wire? On the chart they just have both at #6 for 1/4" and the only thing that changes is the feed rate slows down on the thicker wire which is expected since it is depositing more material at once.

  7. #7
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    Default

    You are over complicating this. Look at the manufactures weld output, and thickness range of metals. The comparable number relative to energy output is the rated output amps. If you are wondering what machine to purchase to do 1/4 steel, anything in the miller line from the mm 180 up will handle it with no problem. Obviously you go with larger welders they will have more horsepower and duty cycle. On little mig machines there is no need for actual voltage and wire speed settings, you just get the feel for where you should start your settings and adjust it in from there after some test welds.
    Last edited by Cgotto6; 03-21-2013 at 09:27 AM.

  8. #8
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    Default

    Like I already said, anything from the 180 up will easily handle quarter inch. There will be no difference in weld quality if the same operator used any of these machines. Proper joint prep is mandatory for any machine.

    Based on what you have said I would hire a professional welder to do this structural project. Not a good idea to teach yourself how to weld on a structure that could kill someone if it fails.
    Last edited by Cgotto6; 03-22-2013 at 01:55 PM.

  9. #9
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    Default

    Quote Originally Posted by Cgotto6 View Post
    Like I already said, anything from the 180 up will easily handle quarter inch. There will be no difference in weld quality if the same operator used any of these machines. Proper joint prep is mandatory for any machine.


    Based on what you have said I would hire a professional welder to do this structural project. Not a good idea to teach yourself how to weld on a structure that could kill someone if it fails.

    Well I wouldn't say I'm completely new to welding. I grew up around welding since my parents owned a oil field welding business for almost 30 years. I grew up stick welding and spent every summer stick welding for my parents company, was a shop welder, welded sometimes at oil rigs, welded some at the potash mines and on one bank construction job as an iron worker.


    I just haven't had much experience with mig except my MM140. So I'm essentially trying to get more info on the mig process from those more experienced for thick material Mig applications.


    i fully intent to destructive test my welds to verify the welder settings and different methods for each Mig position to be welded with the same material thickness used. Hopefully through testing I can refine things but want to get as much info as I can so I can minimize the amount of material used for testing. Steel plate isn't cheap these days.


    I took off work today and went to the Airgas +45 miles away since the local Airgas doesn't even have Miller mig welders on display to look at, they just have Lincoln Migs. Looked at the Miller weld samples for the 211, 212, and drooled over the samples from the 252.


    i was impressed in how the mig gun on the 212 and 252 looked compared to the mig gun on the 211 which has the same gun as the 140 I had sold.


    I was also really impressed with the drive roll setup on the 212 and 252 compared to the 211. So after comparing the prices and what I will be welding in the future, I went ahead and bought the 252.


    While the 252 requires a more expensive spool gun, I won't be doing aluminum any time real soon, so I will save some and buy the spool gun when I have a project for it. This should be a mig I can't out grow.


    Now I just have to wait for my account to be setup at Airgas so I can rent a C25 mix bottle and start welding. They said it takes 24hrs at least, so now I have to wait till at least Monday before I can get a bottle of gas to test the welder.


    Can't wait to test the new 252!


    Thank you all for your help and recommendations.

  10. #10
    Join Date
    Mar 2013
    Location
    Edmonton
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    Default

    As an EE I think the higher voltage machine is due to higher voltage drop that occurs with the higher currents explained by Ohm's Law: V=I X Z. Pump more current (I) through an impedance (Z), you get a voltage drop..here that would be at the electrode. This explains why you can't measure the voltage of a dead car battery unloaded. No load means no current flow through the high internal resistance (because it's chemically dead) and a false normal voltage reading only to find the battery has a large internal voltage drop (large current thru the higher than normal internal resistance)=low battery terminal voltage when the engine is cranked. For the larger MIG's they probably design the higher open circuit voltage based on full load current to give the required terminal (electrode) voltage.
    Last edited by 5440; 03-22-2013 at 10:10 PM.

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