mig aluminum question

[Gttrucker]

I'm shopping for a new mig and comparing the dual voltage machines from Miller/hobart, Lincoln and a few others.
my biggest question relates to welding 1/8 aluminum square and angle. I forget the alloys at the moment, but I think the structural and architectural are different.

I've done a moderate amount of both with a 110v Lincoln that a friend has, but it struggles. It's a 4 setting tapped voltage and can't quiet get the heat in fast enough. Upping the wire speed/amperage helps compensate but creates a fine line between penatration and burn through. I have to move at exactly the right pace and very my speed at edges and corners precisely.

I'm thinking more voltage would really help and wondering if any one with experience can comment on voltage versus wire speed/amps with aluminum. I generally work with 1/8, .09 sheet, and some .06 sheet and angle.

I'm also thinking infinity variable voltage would really help, but I dont have access to a machine I can use to test my theory.

My point is in trying to decide which features I really need (versus how much $ it'll cost).

The 110 machines max out around 18 volts at full amp; but the 220 machines will run higher voltage even at lower amps, so feedback on what has worked best for others, and what's an unnecessary expense is appreciated.
Thx

 

[Gttrucker]

One other question I have is the tapped voltage settings (1, 2, 3, 4 etc.). Is each setting always the same voltage? If so, why don't they just label it with the voltage so we know what we're using.
Or do they vary based on wire speed/amps?
example: is voltage 3 speed 2 the same voltage as voltage 3 speed 6?
I've always assumed the volts stay the same on a given setting and wire speed changes amps, but it would be nice to know for sure.
P.S. one of the features I like on some Everlast models is the digital display of volts so I will know. I think it'll help improve getting my settings rights

 

[Zeke]

No, each tap is a higher preset voltage that remains constant, or CV.

I've had no luck welding AL with a 120v MIG. You need a machine with more control over the voltage settings that is known as 'continuous. And you find that on better machines that generally run on 240v.

 

[losvre]

Qvqhvvhbaqyh

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[MJD1]

You need 20-22 volts to weld 1/8" . Any less and your basically cold fusing.

 

[Gttrucker]

@MJD1. That agrees with my experience.
Shopping is frustrating, however, because most mfg's don't list whether the voltage is tapped or continuous and even less frequently list what the voltage output is.

I found the output spec on the Lincoln Dual 180. Max voltage on 220 is 20 volts at 130 amps. it's not clear if it will go higher with fewer amps.

Drives me nuts that they treat what should be basic specs like a big secret. If all migs just lited the voltage settings instead of a number we would all understand what we are changing and what works much better. They act like we are too stupid to understand voltage and amps.

 

[vandalthree]

Maybe you don't fully understand since amperage is what generates the heat, not voltage. Quite honestly, it doesn't matter what the output voltage of a given setting is. If 150 amps is needed for a proper weld that can be achieved at 20 volts or 1000 volts depending on the machine's circuitry. Conversely, you could have 24 volts and 0.001 amps given the right resistance. Two 9-volt batteries in series make 18 volts but they couldn't weld tin foil because they don't put out enough current but two car batteries in series could certainly do some crude welding - They can put out the high current needed. Low voltage is used for safety reasons as it will not overcome the resistance of human tissue.

Increasing the voltage causes a proportional increase in current based on the design of a given machine. It is only because of that proportionality that a voltage reading is relevant. Personally I would prefer that output current be displayed, and it is on some machines, because that is the most useful. With a voltage display you have no idea what the output current is unless the machine gives you those detailed specs - and again, current is what creates heat. 20 volts on one machine could be entirely different than 20 volts on another machine. A current reading is universal. Don't believe me? Look again at the specs on the Lincoln Dual 180. With 120V input the rated output is 90 amps at 19.5 volts while with 230V input the rated output is 130 amps at 20 volts. Only 0.5 volts difference but a whopping 40 amp difference in current. Look again, with 208V input the rated output is 130 amps at 17.6 volts. Lower voltage but the same current? How can that be? Answer - Voltage doesn't matter when comparing the machine's output - it's nothing more than a calibrated scale; no different than the 1-2-3-4 on other machines. Another piece of evidence I can provide - no welding code anywhere specifies the voltage to be used for a given weld; they all specify current.

Also, as far as I know, wire feed speed is entirely independent of output voltage/current on every MIG machine out there. In your example, in terms of heat output, yes voltage 3 speed 2 is the same as voltage 3 speed 6. All of the Miller "Millermatic" series welders, I believe, offer the infinite output control you're looking for. The Millermatic 211 may be a good option. Bottom line - you should judge a welder's output capability by the current it can produce, not by the voltage at that current.

 

[sberry]

The new machines are good. Don't be scared.

I've done a moderate amount of both with a 110v Lincoln that a friend has, but it struggles. It's a 4 setting tapped voltage and can't quiet get the heat in fast enough. Upping the wire speed/amperage helps compensate but creates a fine line between penatration and burn through. I have to move at exactly the right pace and very my speed at edges and corners precisely. I'm thinking more voltage would really help and wondering if any one with experience can comment on voltage versus wire speed/amps with aluminum. I generally work with 1/8, .09 sheet, and some .06 sheet and angle.

I'm also thinking infinity variable voltage would really help, but I dont have access to a machine I can use to test my theory.

Alum is fussy and takes a lot of skill. The heat on a feeder is the wire speed, you need to turn voltage up to melt off the additional wire without shorting out. Many machines have higher voltage for some of the other wire processes.
The machines yo are looking at are good, taps vs C,,, doesn't matter that much. I actually like tap machines.

 

[Gttrucker]

While I generally understand amps n voltage just fine (abd do a fair amount of electrical work) I am not sure what the effect of voltage is on welding.
Yes increasing amps creates more heat. What exactly does increasing volts do? Is it simply a way of increasing the total energy (watts) without increasing amps? Doesnt seem like that when using my mig. I can't just up the amps/wire speed to compensate for too low a voltage

If it was that simple, they could have just made higher volt machines that just vary amps and we wouldn't need as many amps.

As for the relationship between amps and wire speed, they are absolutely dependant. You set one (generally speed) and the machine determines what the amps need to be to melt the wire at the right speed.

 

[pi_guy]

You need 20-22 volts to weld 1/8" . Any less and your basically cold fusing.

I will confess I have not miged aluminum on 120, but I have TIG ed many 1/8 or slightly greater on 120. I am using a Dynasty 200 to do this. I do have a Al job waiting for me that the mig will be used on. I will try both voltages with the miller multumatic 200 and spool gun.

 

[MJD1]

Your amperage is determined by a few factors. On every MIG I have used you set VOLTAGE, amperage is determined by wire speed in relation to wire size, and also the arc length or stickout you are using.

 

[racingtadpole]

For those of you struggling with the relationship between voltage and current..

https://en.wikipedia.org/wiki/Ohm's_law

 

[zkling]

For those of you struggling with the relationship between voltage and current..

https://en.wikipedia.org/wiki/Ohm's_law

That's not really the case here, completely.

I'd suggest all those struggling to understand how voltage and wire speed set mig welding parameters, to first start by reading the differences between CC and CV (mig and self shielded) power sources.

http://www.lincolnelectric.com/en-g...stant-current-vs-constant-coltage-output.aspx

 

[sberry]

Hobart 210

 

[pi_guy]

Today I used the Spool gun with the millermatic 200. What a joy. Took a bit of practice destroyed a few tips. But overall no problem running it on 120.

 

[Mr_fixit]

I use about 18.5 volts with a Lincoln 255 (240V) to weld 1/8" aluminum

 

[Sycan]

Miller 211. I have had alot better success with .035 wire in the spool gun. 030 would birdnest alot , all my fault as a complete newb with aluminum.

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[losvre]

Great info here guys, thank you for taking your time to post.

All the best

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[dacuda]

i weld aluminum everyday and my machine of choice is a miller 252 with a spool gun.you can set it up for steel also and weld up to 1/2" alum all day long without a preheat.i also had same machine at home for years.i know you want it for mainly 1/8" but go bigger if you can.i just sold mine for $1600 so good deals can be found.