ebonyandivory
ebonyandivory PowerDork
7/28/19 8:59 a.m.

Just tacking a few things together but need strong tacks! Using a 90 amp, 120v stick-welder with appropriate rods.

Can you estimate the drop in welding power with your ordinary extension cords?

Worst case scenario is I’ll wheel my generator to the work area and just use the supplied power cord. 

Thanks guys!

Streetwiseguy
Streetwiseguy MegaDork
7/28/19 9:07 a.m.

I think the size of the conductor in the extension cord is as important as the length of the cord, but I have no math for you.

ebonyandivory
ebonyandivory PowerDork
7/28/19 9:18 a.m.

In reply to Streetwiseguy :

I know you’re right about that, and like you I’m not sure to what extent(s). Generic extension cord is all I have available at the moment.

T.J.
T.J. MegaDork
7/28/19 9:54 a.m.

In reply to ebonyandivory :

How long is the cord and what gauge is the wire? With those, the rest is fairly easy math.

https://www.calculator.net/voltage-drop-calculator.html here is a webpage that does the math for you as long as you know the inputs.

dean1484
dean1484 MegaDork
7/28/19 10:03 a.m.

You can usually tell the penetration you are getting by how it welds. You can also add heat with a torch before welding. More heat in the metal initially will require less amperage to get a good weld. 

ebonyandivory
ebonyandivory PowerDork
7/28/19 10:07 a.m.

In reply to T.J. :

Thank you! 12ga, 100ft btw...

 

Does a ~16% drop seem about right? Great tool too, thanks again.

frenchyd
frenchyd UberDork
7/28/19 10:15 a.m.

In reply to Streetwiseguy :

Go for a 10 gauge extension cord. 12 gauge will drop  more than 10 gauge.  Use as short as possible. If you need to move the welder 10 feet don’t buy a 25 foot long extension. 

 

noddaz
noddaz SuperDork
7/28/19 10:35 a.m.

Wheel your generator to the work area.

stuart in mn
stuart in mn MegaDork
7/28/19 10:37 a.m.
ebonyandivory said:

In reply to T.J. :

Thank you! 12ga, 100ft btw...

 

Does a ~16% drop seem about right? Great tool too, thanks again.

What are you using for amps in your calculation?  Remember it's not the 90 amp output, it's the amp draw at the input.  Assuming 15 amps, 12 gauge copper and 100 feet, using the calculator in the link I got 5.29% voltage drop.  That's a little more than desired but for making some tack welds it's acceptable.  (and, most likely the welder is drawing less than 15 amps so the actual voltage drop is less than that.)

1988RedT2
1988RedT2 UltimaDork
7/28/19 11:51 a.m.

I've used a 230-volt MIG powered by my Coleman generator and had good results. 

If you use an extension cord, stay short and go as heavy as you can find.

ebonyandivory
ebonyandivory PowerDork
7/28/19 1:24 p.m.

In reply to stuart in mn :

I used the wrong amps, of course! frown.

A 5+-% drop is acceptable. I gave in and wheeled the generator down from the house. Nice to know a 120v stick welder can blow through .120 wall DOM at will!

Got some good, strong welds in after I toned it down on the amps. 

Vigo
Vigo MegaDork
7/28/19 4:03 p.m.

I'm pretty sure if you watched the waveforms of what comes out of a generator when starting a large load vs what comes out of a long extension cord, it wouldn't be much better. Unless it was one of those newer inverter ones and pretty large. You can always check voltage drop with a regular old multimeter. But unless you're losing the arc on the highest amp setting you can always compensate for what you're losing through the cord by cranking up the amps. I think the extension cord is going to have more stable voltage, even if it is a lower number. Educated guesses based more on knowing how things works than actual welding experience. angel

pilotbraden
pilotbraden UltraDork
7/28/19 4:26 p.m.

In reply to Vigo :

100% correct.  On my 8 month old engine driven Lincoln Ranger 250 it does not start as nice as a welder in a shop. Once the arc is established it is as smooth as silk.

Braden

ebonyandivory
ebonyandivory PowerDork
7/28/19 5:29 p.m.

I actually had a great start and really nice control today. Funny enough, I had a terrible time zapping a couple 3/16th plate together plugged into the house.

Today I used 3/32 6013 at about 68-70 amps. Very pleased with the penetration etc.

MulletTruck
MulletTruck HalfDork
7/28/19 5:58 p.m.

Make an extension cord from romex and a heavy amp receptacle and hard wire it into your panel if possible

stuart in mn
stuart in mn MegaDork
7/28/19 6:33 p.m.
MulletTruck said:

Make an extension cord from romex and a heavy amp receptacle and hard wire it into your panel if possible

While people do this sort of stuff, I don't think it's a good idea to recommend it.  Besides, 1) his extension cord is already 12 gauge, and 2) he's already done the welding so it's a moot point.

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