Voltage and amperage

admin

So I'm new to welding and I'm trying to learn about mig welders before I purchase one and I need some information about voltage and amperage. What is the difference in the amperage for a regular house outlet like the DIY versions and commercial versions that run off of higher voltage? Is the higher amperage DIY mig welders better for all around welding meaning that I can weld bigger things together? I just don't want to choose something to do auto body and exhaust (stainless) work and then find out later that it's not up to the job. Also as far as duty cycles go they're rated by 10 minutes correct? So if the manufacturer says 30% at a 100 amps it can weld for 3 out of those 10 minutes at that amperage?
Reply:Welding requires wattage or very nearly watts mean power. Power is calculated by multiplying amperes, a measure of current, by voltage a measure of pressure. A twenty amp circuit at 120 volts can provide 2400 watts for a short time. A twenty amp circuit can supply 4800 watts at 240 volts. A 40 amp circuit can supply 9600 watts at 240 volts. It is my opinion that a welder using less than 10,000 watts will often be inadequate. Keep in mind that all welders should be supplied by a dedicated circuit. A dedicated circuit is a single piece of cable running from distribution panel to receptacle installed for the purpose. The same cable can supply a 120 volt welder or 240 volt welder. The cost of breaker can be greater, but the 120 volt outlet is to be gfci protected, not so of 240 volt. I urge you to save money by not upgrading a welder, buy one that works the first time. I've never heard anybody say; "I sure am glad I bought a 115 volt welder, it's all I want.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Yeah I'm looking at the Millermatic 211.Millermatic 211 230V MIG Welder with Thermal Overload Detection https://www.amazon.com/dp/B002RXO1SA..._Fbqxvb126XRX4
Reply:MM211 is good.  Here's a good price ($1,115.). Note the $200. rebate or $400 in accessories, plus the free spool gun. Quite a deal!  http://www.weldersupply.com/P/275/Mi...c211Auto-Set11  Of course if you are limited to 120V operation, the spoolgun wouldn't do you much good for Aluminum due to low output.Another unit to consider is the Tweco Fabricator 211i.  $941.  http://www.bakersgas.com/THEW1004201...FRCNaQodLhQAUA  or http://store.cyberweld.com/tharcfa21...FYNDaQodAB8ATAHere it is with a free TOG torch for $995.:  http://www.weldersupply.com/P/605/Fa...iPartWFREESHIP"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Any machine in the 200amp range will do for a hobby/home gee rage guy.Lincoln, Miller, Hobart, Tweco, ESAB.The MM211 will suit yer needs quit nicely.As far as duty cycle goes, don't panic on the 3 mins out of 10 mins scenario that you mentioned. Look at your watch for the next 3 mins- it's a long time Also- you don't weld for 3 mins straight so it becomes a little confooosing trying to decode the duty cycle.Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:If you go by Miller's online calculator, with Argon 75%/CO2 25%, 1/8" fillets require 140-150A @ 18-19V. If all you're doing is welding automotive sheet metal, or anything non-structural up to around a max of 1/8" thick, a 115V machine like the Millermatic 135 plugged into the standard dedicated 20A garage circuit is fine. The problem is, welding gets addictive. Once you start there, you're gonna want to start building things around the house/shop, and suddenly that machine isn't enough. I'm with Broccoli and Oldendum on the MM211. You can plug into a standard 115V plug for thinner stuff if you don't have a 230V outlet, or for more juice use the adapter and plug into a 230V outlet and you're easily good up to 1/4" thick mild steel/stainless (or possibly thicker depending on the joint type, passes, wiring/breaker/plug rating, etc.). The 230V also opens up the possibility of welding aluminum. Great dual voltage welder that will do most anything a hobbiest could throw at it.Some of the light commercial welders also run off of single phase 230V. The main difference with the commercial machines is they have much higher duty cycles, and are capable of outputting much higher voltages for a specific amperage.  As a result, they of course draw much more current at those higher values i.e. consume a lot more power, possibly drawing more current than a typical household 230V circuit is rated.BTW when people refer to outlet voltages, 110/115/120V refer to the same thing and 230/240V refers to the same thing. There are regional differences, and some of these voltage standards have changed over time, hence the different numbers. If I measure the 240V outlet in my garage, it generally reads 244V, but this changes with time-of-day and if there are other major house loads running at the same time.Last edited by Jieve; 05-21-2015 at 05:19 AM.
Reply:The transformer utilities across the USA use is designed to provide 240 volts at the transformer under rated load. Energy is lost in the forms of heat, and magnetic field in all conductors. As the three conductors to a house are bundled, and the magnetic field each conductor produces is mostly canceled by the others, magnetic loss is small. We give a name to this energy loss, we call it voltage loss, or drop. NEC doesn't specify how much is too much, but the handbook says 5% loss will not be excessive at the end device. Motor manufacturers selling in the USA have agreed to a tolerance of 10% + or -. However a loss of 10% will cause dramatic increases in motor temperature, and loss of torque. An increase in voltage of 10% will generate less heat, and more torque. It is common to design motors for 230 Volts. A 10% reduction in voltage brings us to 207, which is acceptable when supplied by a 208 volt system. Light industrial, and multi family residential installations sometimes have 208/120 volt wye three phase services. Manufacturers often sell the same machine for 240 or 208 volt applications. It becomes a challenge for electricians to provide adequate starting voltage to these machines. Refrigeration equipment being toughest. For most of us here, adequate voltage is a matter of cabling large enough to preserve precious voltage to the end of a sometimes very long trip from power company transformer to welder. My welder rated at 230 volts will not perform as well at 220 volts as it does at 230. Auto Line welders that adapt automatically to supply voltage may be a bit more forgiving. My Dynasty for example, is rated for 208.It is common to read more than 240 volts at no, or light load, but much less under heavy load.Last edited by Willie B; 05-21-2015 at 07:40 AM.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:How thick of aluminum could I weld with the mm211?My friends keep saying buy a cheap welder but I'd rather get one high quality machine that will do all I want and more. Instead of buying a cheap one and then wishing I got the mm211.Last edited by apierce1289; 05-21-2015 at 11:17 AM.
Reply:Originally Posted by apierce1289How thick of aluminum could I weld with the mm211?My friends keep saying buy a cheap welder but I'd rather get one high quality machine that will do all I want and more. Instead of buying a cheap one and then wishing I got the mm211.
Reply:Miller claims the MM211 will do up to 1/4", I've measured a useable range of 100-165A with 4043 0.035" wire so with proper joint preparation (beveling, possible preheat) that's about reasonable. Trying to use MIG for aluminum thinner than an 1/8" is tricky though.A MM252 would be all the MIG welder you could ever want, and no doubt you'd get a high resale value, even years and years later. But it sounds like for what you want to do, the MM211 would do the job with a much lower initial price tag. I think you'll be more than happy with it. Whatever you do, do not buy a cheap off-brand welder. You'll be kicking yourself when you have to get rid of it to buy a decent one in a few months.
Reply:Originally Posted by Willie BIt is my opinion that a welder using less than 10,000 watts will often be inadequate.
Reply:I can't see myself Welding that much of Aluminum if any at all. So I think the Millermatic 211 will be just fine for auto body and exhaust work. As long as I can weld stainless and do body patch work I'm happy.Wouldn't tig be better for aluminum anyways? Doesn't seem like mig is the right tool for the job.Last edited by apierce1289; 05-21-2015 at 09:34 PM.
Reply:Depends on what you're doing. For aluminum sheet/tube under 1/8" tig is probably gonna be better. It's a lot slower than mig though, if I were building trailers or boats mig would probably be a better choice.You can always hold off on the spoolgun option and purchase it later if needed, or just sell it if you get a really good deal.
Reply:Originally Posted by apierce1289 As long as I can weld stainless and do body patch work I'm happy.
Reply:Originally Posted by apierce1289So I think the Millermatic 211 will be just fine for auto body and exhaust work.
Reply:Originally Posted by apierce1289I can't see myself Welding that much of Aluminum if any at all. So I think the Millermatic 211 will be just fine for auto body and exhaust work. As long as I can weld stainless and do body patch work I'm happy.Wouldn't tig be better for aluminum anyways? Doesn't seem like mig is the right tool for the job.
Reply:Originally Posted by MikeGyveroften be inadequate for what? building I beam building structures and bridges in your garage at a production rate?A millermatic 252 is barely 10kw input... A hobbyist would essentially never need that. A millermatic 211 isn't anywhere near 10kw and it's more than the guy will ever use I bet; normally he'll probably be running it at half power. You can still weld as thick as you want, just not as fast (i.e. takes 2 passes instead of one).Get the MM211 with all the rebates and crap. Sign up for the Zoro.com newsletter and buy it at their next 30% off sale day, and use the miller rebates, you can probably get a new one for like $700
Reply:I guess I'm having a hard time visualizing the limitations of the Millermatic 211. There's not really a lot of aluminum on vehicles except for the engine as far as I know so that's why I don't think I'll need something for aluminum.
Reply:I have the mm211 and I have welded and welded and welded. I have no complaints. Body work 20 gauge to smokers 1/4 in. No problems. I hit the thermal overload once in the time that I had it. I run it off a dedicated 240 outlet. I'm not a professional welder but I have made a lot of money with that "little" machine. It had more than paid for itself. I traded in a lincoln 140c to get it. I had that machine for about a month and the took it back. For me, it just wasn't enough. The mm211 is a fine machine.
Reply:Originally Posted by apierce1289I guess I'm having a hard time visualizing the limitations of the Millermatic 211. There's not really a lot of aluminum on vehicles except for the engine as far as I know so that's why I don't think I'll need something for aluminum.
Reply:The reason I'm mainly looking at mig welders is because I've never welded in my life lol.So I found the Millermatic 141 on millers website and it looks like a good diy machine. Then I won't need any special wiring and duty cycle doesn't matter much since I'll be doing garage projects (mostly body work). It's really hard to decide :/Last edited by apierce1289; 05-22-2015 at 12:01 PM.
Reply:Good price on a MM 211 plus rebate plus free spool gun!  $1,115., less $200 rebate (or $400. in accessories) plus a spoolgun.http://www.weldersupply.com/P/275/Mi...c211Auto-Set11"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:BTW how do you measure metal thickness for setting up the welder? Do you measure the total overlapping thickness (like if you were doing exhaust work- slipping the pipe over each other)? Or the thickness of one piece of pipe/sheet metal?
Reply:How you set the machine for thickness depends on what you are doing. On average, you go slightly higher than the thinner material, and try and concentrate your heat on the thicker piece and wash the bead over onto the thinner one. This assumes the pieces are relatively close in thickness. The farther apart the two are in thickness the tougher it gets to give you a good number. Set up say to weld 22 ga to 1", setting the machine at 22 ga won't penetrate at all into the 1" because of how much heat that thick plate will suck up. Set it too high though, and you'll have nightmares burning thru the 22 ga stuff. Joint design also plays a part. but joints are the hardest to do. Lap joints are much easier as the thicker piece can act as a backer and it will take more heat than you could if doing a but joint.Difference in thickness on exhaust work is negligible. Because of the lap, I'd probably set the machine based on the thicker of the two pieces as the thicker one will act as a heat sink with the lap. That's assuming a good tight fit and not a big gap. If I had to bridge the gap, I'd go with the thinner material, as it's really not too much lower than the settings for the thick one, but it would give me more room to handle the gap..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by apierce1289BTW how do you measure metal thickness for setting up the welder? Do you measure the total overlapping thickness (like if you were doing exhaust work- slipping the pipe over each other)? Or the thickness of one piece of pipe/sheet metal?So I was having a hard time visualizing three eighths of an inch to see if I would ever need that much power and just like everybody said the mm211 should be all I ever need because three eighths of an inch is 4 house keys side by side. And that visual really has me set on buying the mm211 once I have the cash :-) three eighths of an inch is really thick when you look at it like I just did lol.
Reply:10/2 wire and 50amp breaker enough for running a 211 on 230V?
Reply:I would recommend the 211 over the 140. Trust experience to know you will outgrow a 140!
Reply:Originally Posted by in4lo10/2 wire and 50amp breaker enough for running a 211 on 230V?
Reply:Generally speaking:10 GA - 30A8 GA - 40A6 GA - 55ADepends on the thermal rating of the wire and does not take into account derating for welder duty cycle if the welder is hardwired to a disconnect box, length of run, etc.http://www.cerrowire.com/ampacity-charts"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Thank you gentleman!
Reply:Originally Posted by apierce1289So I was having a hard time visualizing three eighths of an inch to see if I would ever need that much power and just like everybody said the mm211 should be all I ever need because three eighths of an inch is 4 house keys side by side. And that visual really has me set on buying the mm211 once I have the cash :-) three eighths of an inch is really thick when you look at it like I just did lol.