GENERATOR-welding

[flINTLOCK]

If planning to use MIG machine for up to 3/8" thick steel, how big a generator should you use. My projected shop is not going to have utility line for electric.

 

[MrJimi]

Unless you know something I don't, I was told many times I can't use a generator for mig welding ?
If it works ? I would recommend a 50 amp out for welding 3/8
I hope others will chime in
Jim

 

[texasjohn]

I have a generator.... 20 amp circuit breaker on 220 volts.

I have a Miller 172 mig welder.

They work together. Never popped the circuit breaker so far. Very slight delay as generator senses the load and kicks into high gear.

I've seen numerous TBN threads on this topic. You can use the search function to find them. The key seems to be to have a generator where the output is greater than the demand of the welder.

Lots of people think it won't work... but it does.

If you already own the welder, get a generator with somewhat greater capability than what the welder will pull. If you haven't purchased a welder yet, consider getting both in one unit... on wheels... all this stuff is HEAVY.

 

[schmism]

Unless you know something I don't, I was told many times I can't use a generator for mig welding ?

they make off the shelf engine driven mig welders, which are nothing more than a engine driven generator (to produce the electricy) and a welder unit to use it in one shell

Miller - Engine-Driven Welders - Bobcat™ 225

as for your application, it depends. 3/8" is some heavy stuff, you cant touch that without a 220v mig. 170+ amps and up would be my guess. That sort of output needs something in the 30amp 220v input.

most generators come with a 20 amp or sometimes a 25 amp plug.

to run that size welder off a genny your looking at something in the 8K watt range id say.

 

[Highbeam]

If planning to use MIG machine for up to 3/8" thick steel, how big a generator should you use. My projected shop is not going to have utility line for electric.

Of course it doesn't matter so much the thickness of steel you want to weld as much as the welder you want to use to do it. To figure out what your welder actually needs either do the math or use a clamp on amp meter and then get a generator with at least that much capacity.

For example, my Lincoln AC 225 arc welder is supposed to also weld 1/2 inch material but the more valuable information is that it welds at about 25 volts (input vlotage is 220) and that the highest output setting is 225 amps. So if I do the math 225 x 25 I see that I need 5625 watts but than I need to be realistic and assume some efficiency losses so throw in 10% and that's only 6188 watts. My generator is capable of 6850 surge watts and 5500 running watts so it is slightly undersized for max welder output but welding at the more typical 90-120 amps leaves me plenty of spare capacity and I can tell you it works well for the field work I bought it for. Portable generators get really expensive after you cross the 6000 watt line.

If your welder is very adequate for 3/8" plate and you plan on doing it a lot, then I would protect that expensive welder with a lot of extra generator capacity. Plus, what about lights and fans? the radio in the corner? If this is a semi-permanent mount then I would honestly look in the 10KW range as a minimum. You'll be spending some money for this genset so you may want to be sure that your needs won't necessitate a larger genset in the future. For just the welder, I am betting that a more typical 6-7000 watt hardware store generator will do it. The mig is just a wire burner after all.

Take a look at Rob's solar power shed project for a good permanent mount genset of a little higher capacity. He has good photos and documentation showing the process. What you're doing is replacing the utility power for an "off-grid" shop so the "off-grid" home projects are a great resource.

If the dollars are getting too high for you then HD sells a gasoline powered 15KW genset for only like 2000$. You'd be up and running that day.

Let us know how this project goes. It always amazes me how people think that the power from a generator is somehow not as good as the power from the wall. Also, a 50 amp plug is standard on almost all welders not because you need 50 amps but so that you can plug into any workstation with any welder.

 

[3RRL]

I will second what Highbeam said. I read a lot of his earlier posts telling of his welding adventures on his rural property. He helped me to get my Lincoln 225 arc welder and it works great in the field. I do all my welding off a Generac 5550 Wheelhouse which has 5550 watts and a surge of 8750. I've never needed to crank the welder up to 225. Most of my welding on thick plates of 1/2" or less is in the 175 to 200 range and that's plenty. I've welded 5/8" thick plates onto my boxblade in the field. The generator provides plenty of juice to run it. I got mine at Home Depot and I think it was under $600 at the time.

 

[Tom_Veatch]

If planning to use MIG machine for up to 3/8" thick steel, how big a generator should you use.

Match the generator to the current draw of your welder. My MM180 asks for a 25 amp circuit. That is about a 6 kva load. My XL225 stick welder, which I'm thinking would be a better choice for 3/8 material, calls for a 50 amp circuit or about 12 kva. Of course, those are at maximum amperage output. Rarely will you use the full output of the welder. You need to check the specs on your welder to find your specific requirements.

I assume you'll be using a 220v welder which probably has a NEMA 6-50 plug. Both of mine do. It's doubtful the generator has a matching receptacle. 220v power from the generator will probably go to a 4 prong outlet (2 hots + neutral + ground) so that both 220 and 110 can be supplied to the load. The NEMA 6-50 is a 3 prong configuration (2 hots + ground) so you'll probably be faced with adapting the welder plug to the generator receptacle.

My generator has a NEMA 14-60 receptacle for which not a single local outlet stocks a matching plug. Cheapest 14-60 plug I could find online was $50 + shipping. Most places wanted between $70 and $90.

 

[Highbeam]

I assume you'll be using a 220v welder which probably has a NEMA 6-50 plug. Both of mine do. It's doubtful the generator has a matching receptacle. 220v power from the generator will probably go to a 4 prong outlet (2 hots + neutral + ground) so that both 220 and 110 can be supplied to the load. The NEMA 6-50 is a 3 prong configuration (2 hots + ground) so you'll probably be faced with adapting the welder plug to the generator receptacle.

My generator has a NEMA 14-60 receptacle for which not a single local outlet stocks a matching plug. Cheapest 14-60 plug I could find online was $50 + shipping. Most places wanted between $70 and $90.

In reference to the plug issue, I made an adapter using 6 feet of heavy cord that converts from the 4 prong twistlok generator plug to the 3 prong standard welder (6-50?) style. The cord was about 1$ a foot and the outlets were about 12$ apiece. Since a three prong 6-50 plug doesn't need the neutral I chose to utilize the ground, plus the 2 hots from the 4 prong twistlok.

Remember that the generator has circuit breakers limiting the output so the adapted wires and plugs need to be rated at least as highly as the generator's outlet.

All of this talk makes me want to go burn some rods. It's been a long winter.

 

[Tom_Veatch]

In reference to the plug issue, I made an adapter using 6 feet of heavy cord that converts from the 4 prong twistlok generator plug to the 3 prong standard welder (6-50?) style. The cord was about 1$ a foot and the outlets were about 12$ apiece. Since a three prong 6-50 plug doesn't need the neutral I chose to utilize the ground, plus the 2 hots from the 4 prong twistlok.

Wish mine could have done that inexpensively. I have two welders and didn't want to change their plugs - especially not at $50+ per pop. Nor did I want to replace the receptacle on the generator and trash the High Dollar cable the feeds the house from the generator.

So, I bought one of the NEMA 14-60 (4 prong, 60 amp, straight prong non-twistloc) plugs from the online vendor and a 6-50 receptacle (3 straight prong, 50 amp) from the local box store (somewhere in the neighborhood of $15) and about a foot off a length of heavy flexible 3 conductor cable from the local weld shop. Like you, I only wired up the two hots and ground in the 4-prong plug.

 

[thingy]

,,,Schimes,said you need a 170 amp welder to weld 3/8 inch steel??!!What would you need to weld 1 inch thick steel than schimes?? A 350 amp machine?? How about inch and a half,a 500 amp,,,,man! Thats not how you weld.3rrl,,you stick weld 1/2 inch with 170-200 amps,,man,you gotta be using a 3/16th rod,,do you ever burn any holes in things?Get any splatter? again,thats not how you weld. You can weld 1/2 inch just fine with 1/8 inch rods at maybe 120-130 amps,,,,,you put more than one pass,,,5/32 would be better at about 150 amps, but you would need a second or third pass even with 5/32,,,again,you don't go about trying to weld everything in one pass.
Yeah,getting a generator,,guess you ain't got one so you might as well get a good sized one,than you have some wiggle room and you got a generator for your house as well. I'd get a generator welder for 2-3,000 and stick weld the stuff,but thats just me,,,,,thingy

 

[weldingisfun]

Here you go flINTLOCK: Hobart Champion™ 10,000 Engine-Driven Welding Generator
Have fun!

 

[schmism]

,,,Schimes,said you need a 170 amp welder to weld 3/8 inch steel??!!What would you need to weld 1 inch thick steel than schimes?? A 350 amp machine??

going off of specs i see listed on MIG (not stck) welders.

Miller - MIG Welders Product Guide

Clearly states up to 3/8" on the 170 amp machines. One would deduce that the max SINGLE PASS thickness is at the max rated amps.

TO look at it from the other direction, does that mean you can weld 1.5" plate with a 110v mig "just use 20 passes"

You also have to keep in mind duty cycle. Nothing like trying to weld 3/8" plate that is at the very exteam bleading edge of a welders capaiblity, with mulitpasses and preheating vs useing a welder that was more appropratly sized.

So while you can bust out that buz box, You have to ask is the amount of time spent welding, chipping slag, welding a second cover pass, and chipping MORE slag worth it?

(not to mention the poster specificly mentioning want to MIG weld it)

 

[schmism]

To be honest i dont know how i would go about finding the perfect solution to this situation.

1)do you go PTO genny to supply power for the entire shop includeing welders?
2)go with a box store 6K portable genny and limit the amount of items you are useing when welding.
3)Go with a stationary propane powered 10K for the entire shop?
4)Go with a 10K welder/generator knowing that it will supply power to the rest of the shop, and be portable?

1) pro-its cheep, large enought to supply all reasonable demand, con-got to tie up the tractor for the entire time you want power.
2) pro - its cheep, portable, con-might not be big enough to supply your entire demand, not to mention serious long term maintaince/service/upkeep issues
3) pro - your own mini grid power, can supply all shop needs within reason, con-non portable and expensive
4)pro - all in one solution, portable (within reason), meets power demand con-expensive, bulky, cant use welder on grid power

-so you could get a solution (welding 3/8") for like $1200, $500 tombstone, $600 box-store 6K genny

-a all in one welder/generator seems to be about 3-4K (depending on size, brand features etc)

-a MIG sized to handle that (MM210 or simular) sets you back about $1200, a 10-12K propane powered stationary genny runs ya another $2500

If it was me and i was wanting to do it "right" Id go 250 class MIG (MM or hobart) and high quality construction grade honda genny)

id budget $5k for the project by the time you figure a nice helmet, gas bottle, other misc stuff

 

[thingy]

Schisim,,,,thats just an advertisers way of selling you non welders a machine.
If I was buying a mig machine would look for amps at duty cycle,,along with what size wire I would be running.,,,120-140 amps,19-20 volts,thats about the range for .035 wire,,,,would want a high duty cycle at that amperage with a mig,60 percent or more.

And yeah,thats how you weld thicker stuff,,multipass,,with above set up.

Chipping slag?,,you act like you are welding for a living here.I've probably cleaned more slag off in half a day than you have your whole welding career.
You seem to be saying,yeah,I don't know how to,,but I'm doing it the right way anyways,,man,,it don't take some people long to be old hands at this welding stuff,,,it seems??!! thingy

 

[schmism]

If I was buying a mig machine would look for amps at duty cycle,,along with what size wire I would be running.,,,120-140 amps,19-20 volts,thats about the range for .035 wire,,,,would want a high duty cycle at that amperage with a mig,60 percent or more.

a "250 class" machine show 100% duty cycle at 120-140 amps.

even a smaller "210 class" welder can hang with those amps and duty cycle.

 

[Highbeam]

The poster's question was simple enough, I don't think he wants to get into the "arc vs. stick" or even the "which MIG welder" debates. Just the best way to get power. My experience with my arc welder was used because it is powered by a generator and I thought it would apply.

Thanks to Schmism for a good pro/con approach.

 

[AlanB]

I think this is much like a trailer and shop debate. It is very, very seldom that you ever hear of people saying thier XXX is too big.

I run a Miller Trailblazer and dad runs the newer model, if I remember correctly, his runs at 1800 RPM generating.

The Honda generators are very nice, and I know in the smaller ones, you can link them together (very unusual feature in generators). That may be something too look at as well if you want to buy in slowly.

 

[thingy]

Yeah,mig welding,,duty cycle is the thing,how much a weld you can put down with it in one pass,,nonrelavent,,,,if you want 80 to 100 percent duty cycle at 120-140 amps,,you gotta go big,,thats just how they make them. And thats what you want with a mig,,high duty cycles more than anything,with the amps you plan on running. Not saying you can't get buy with way less,,just take your time is all,,,,but duty cycle at amps you plan on running is the key to figureing out what machine you need,,not if it will weld 3/8 inch in one pass,,that one pass stuff is all bullcrap,,,what,,you reckon you can weld them amps overhead,,or uphill??? See,,it don't make any sense,,,just a gimick to try and relate to nonwelders,,,welders don't go into welding something that way,,,they run the amps they need for what postion and material they are welding,,and they make more than one pass if nessacary,,and it generally is unless you are welding sheet metal,,,don't limit your selfs,,,this one pass thing just limits you to what you can weld and in what postions,,,,thingy

 

[Ford960]

Unless you're welding in a fixtured operation that rigidly holds the work then you need to use a multipass welding process. Otherwise the heat and shrinkage of the single pass weld can and will pull your work out of position and all the time that you saved by doing a single pass will be wasted by trying to get the work back in position. The correct way to weld thicker materials is with a multipass system of at least three passes. Therefore all this talk about a machine big enough to single pass weld a 3/8" plate is just bunk. I can and do easily weld 1/2" plate with my Lincoln 225 AC/DC tombstone using an 1/8" 6013 rod at 120 amps. This follows the wisdom afforded me by a master welder, using the minimum amount of heat for a given weld will make the strongest weld. He should know as he held 13 certifications in his wallet most of them for experiemental welding on aircraft gas turbine engines. He had to recertify every day he went to work at Pratt and Whitney which he would do consistantly without any practice. He was my dad and he taught me to stick weld when I was about 10, heli-arc aluminum and stainless steel when I was 25, and I had to teach myself mig since he wasn't a fan of mig.
My mig spool gun is portable and has a 100% duty cycle for welding flux cored steel, solid steel, aluminum, and stainless steel.

AlanB, I've got a pair of the Honda EU2000i generators and made a cable to connect them in parallel to supply 30 amps for my 5th wheel home. They are inverter type generators and have the ability to syncronize the phases and allow a parallel connection. Plus they are very quiet and fuel efficient.

Also, I have the perfect generator for powering everything that a well equiped shop could want. It puts out 347 amps, 120/208 volts, 3 phase at 1800 rpm and I've got $305 for parts and lots of hours of work invested in it. Plus if I wanted I could pick up some 3 phase equipment at a real savings and lathes and mills operate much better on 3 phase. It's pretty good on fuel too and not very loud even without a muffler.

 

[Casey1]

It seems to me that if you have say a 150 amp welder (preferably dc)with a decent duty cycle you could weld just about anything using multiple passes with a 1/8 or 5/32 rod. The last two posters make a lot of sense and could save us a few bucks and some aggravation with their advise.