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Help identifying if gasless mig is AC or dc

Steve.Bridges

New Member
Hi, just wondering if anyone could help me identify whether my welder welds in ac or dc. Please refer to picture below.
Welder is a workforce m100 gasless mig. Thanks in advance! IMG_20191013_095148_compress5.jpgIMG_20191013_095133_compress35.jpg
 

gophert

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It looks to me as if a transformer brings AC line voltage down to operating voltage with a transformer and the lower voltage AC signal is rectified with a single diode to make a "pulsating DC" current (I.e half-wave rectified).

CD2572A9-997D-44A0-85EE-60151BEBE279.jpeg
 

Reloadron

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They mention a No Load (Open Circuit) voltage of 49 VDC and while welding was not my area all of the large MIG and TIG welding systems I worked with were DC machines. So in this case DC has my vote.

Ron
 

dr pepper

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The straight line with dotted line underneath means Dc, also to the left of the red circle gophert drew there is a diode symbol, depicting a rectifryer, so your weld set certainly is Dc.
Other things you can do, an Ac weld set would show very little voltage with a multiometer set to Dc, but full 50v or more ac voltage set to Ac.
Also when using a Ac mig you can hear a fairly loud buzzing noise from the arc, Dc is more of a crackle.
There are raw 50/60hz 'mig' sets out there, I wouldnt like to try and weld with one.
Gasless takes a lot of getting used to.
 

shortbus=

Well-Known Member
Also when using a Ac mig you can hear a fairly loud buzzing noise from the arc, Dc is more of a crackle.
Isn't MIG, flux core or gas by definition DC? Or at least it used to be. The one thing I also was taught is that when you use a MIG welder for flux core you need to reverse the polarity of the work and gun.
 

dr pepper

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Yes, some flux core is DCEN, ordinary ER70 wire is DCEP, as I'm sure you know.
Really cheap weld your own car up sets are sometimes AC for cheapness, I dont know if its even possible to get any kind of decent weld.
 

Ian Rogers

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Isn't MIG, flux core or gas by definition DC? Or at least it used to be. The one thing I also was taught is that when you use a MIG welder for flux core you need to reverse the polarity of the work and gun.
We've been there haven't we shortbus….. God, gasless caused me soooo much hassle... Without too much info... Gasless with DCEP ( this is the way they come from the factory) I could get no more than 3mm thick sheet to weld... After that the metal would not get hot and the welds just ran off... I tried to weld 5 ~ 6mm and the spatter and smoke made it impossible to weld anything to anything.. Fortunately my mig has a gas input and is now welding 10mm as easy as pie... Mine is a 200a device, but with a 100a you'll manage around 80a max... Some machines can be swapped to DCEN but my leads were too short..
 

Steve.Bridges

New Member
Thanks guys, there just seems to be soooo much spatter that I thought something might be wrong in regards to polarity.. obviously its just not the most efficient process haha.
 

Ian Rogers

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My reg was only £12 from ebay and the 10L gas bottle, from a local supplier, is £50... £30 of that is deposit... Its a no brainer as 0.9kg of flux wire is the same price as 5kg of copper coated steel wire..
 

Ian Rogers

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Cheers guys.. I was just thinking it was AC because it produces sooo much spatter when welding haha.
Has your set got a gas input?? Which model is it..

Whoops... Sorry.. I found it in the first post... 100A at 20%... You can only do up to 4mm sheet after that the spatter gets worse and worse.. There isn't enough heat generated to penetrate, hence tons of spatter... You may have to crank the amps down and make several passes to get a weld..
 
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Ian Rogers

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Workzone Titanium M-100 (second line of first Post and on the pages of the manual above in first post).
Yep, I saw it as soon as I posted... I have edited it since..
 

gophert

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Cheers guys.. I was just thinking it was AC because it produces sooo much spatter when welding haha.
Are you using the specified wire for your unit. It says to use "Tubular Flux Cored (Gasless) wire" in the manual page you posted above.

 

shortbus=

Well-Known Member
Are you using the specified wire for your unit. It says to use "Tubular Flux Cored (Gasless) wire" in the manual page you posted above.

That is called "flux core", and it makes much more splatter than when using solid wire an gas. With the flux core you are doing a stick weld without stopping to change electrodes. Changing the polarity on the machine will help some but not ever going to stop the splatter. Some of it has to do with the flux changing form from a solid to a gas. Even MIG using gas has a certain amount of splatter but no where near the flux core amount.
 

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