reversing the polarity
 

my 110v mig has reverse polarity control and i was wondering if i were to reverse it would i be able to lay an actual bead on thin sheet metal? i need to do some thin stuff and tacking it every inch or so works but its a bitch to grind smooth. any help would be appreciated

Re: reversing the polarity
 

Reversing polarity is for using Flux core or MIG wire. My lincoln listed that in the manual.

Re: reversing the polarity
 

also if you add tig gun to your mig you can weld aluminium with reversed polarity. =)

Re: reversing the polarity
 

Can you explain this a little more?

Sorry if that sounds like a complete noob thing to ask but I just recently bought a welder and I'm leaning the hard way. The polarity on my welder can be reversed but like the other guy said 'the book' shows doing that when switching between flux core wire and mig wire with shielding gas. Any help would be greatly apprecitated here. Thanks

Re: reversing the polarity
 

???i can make my mig a tig??? ???

Re: reversing the polarity
 

you can make an arc a tig but im pretty sure not a mig into a tig. anyway read your manual, 2 polarities are there for flux core/mig/aluminum

Re: reversing the polarity
 

I also haven't heard of making the MIG into a TIG.

Re: reversing the polarity
 

Its for welding aluminum. I’m pretty sure that you cant change a mig to a tig and i think you mean a spool gun, a spool gun is for when you are welding ammonium so that the soft wire doesn’t get stuck in the wip.

Re: reversing the polarity
 

about converting mig to tig. you have just do "downgrade" your mig. remove spool and other mechanics for wire and connect tig gun to it. it's same as converting arc to tig =) but it's just theory. i am about doing it. i've already bought tig gun with rods. i am looking now only for nice connectors, etc. =)

Re: reversing the polarity
 

lol, you cant add a TIG gun to clear that up for everyone.
What he meant is you can add a spool gun which holds a spool of aluminum wire in itself.
Aluminum wire is to fragile to go through the entire spool system of a regular mig, so they made a gun specifically for aluminum.
http://img.epinions.com/images/opti/...resized200.jpg

Re: reversing the polarity
 

The reverse polartit is for as stated running mig, and flux core, also metal core regures a diffrent seting. YOu Cannout run a tig, or arc of a mig machine. Also if you wish to weld aluminum you must run argon gas, and either a spool or conditioner/lub setup.

Re: reversing the polarity
 

how can you make an arc a tig? i've got an arc.. i just suck at it.

Re: reversing the polarity
 

you need a tig tourch and a regulator, and gas then hook it up to the machine and go it will be a scratch start tig , ao if you suck at stick it may be hard to learn

Re: reversing the polarity
 

Well. Today i've tried to run Tig torch from a Mig. It work successfully. ofcourse I've added bottle of argon. but i was unable to weld aluminium even with a reversed polarity. Rod burns too fast when it in reversed polarity. But SS and plain steel is welded just cool! i have no hotos right now, but it works! =)

Re: reversing the polarity
 

k this is the way it is....
For steel/stainless the welder is normally put on DC (direct current)
the polarity of the welder will determine what gets the majority of the heat, either the work piece or the torch/stick(for arc welding).

For MIG welding, the workpiece gets the heat for maximum penetration of the material. This means that the workpiece (aka: ground) must be Positive. This is normal polarity. Use a mixture of 75% CO2, 25% argon for the shielding gas if you are welding mild steel (called C25 shielding gas), 100% argon if you are MIGging stainless

For Flux Cored welding (if your machine doesn't suck ass, some use AC current) use reverse polarity (ground is negative)

For TIGging steel and stainless, use normal polarity, ground is positive. Use 100% argon on SS, C25 on Mild

Now if you wanna weld any aluminum, you must use AC current and 100% argon shielding gas
What this does is cleans the aluminum before melting a puddle and then welding...
if you try welding aluminum on DC normal, all this will do is heat up the aluminum and make it soft, but it will have sort of a skin on it (think of the skin that forms on cooling soup) and no welding filler rod will be able to be added.
Trying aluminum on DC reversed will succeed in burning the tungsten because all of the heat goes to the tungsten.

stick welding is gay and not worth discussing.
i may be wrong about MIG polarities... i do TIG almost all the time...

Phil

Re: reversing the polarity
 

yeah. everything just right. thanx MrGreenGanes =)

now question, we need AC to weld aluminium. How much Hzs? and what need to make ac from dc ?

Re: reversing the polarity
 

Are you pulling or pushing the weld?

I've read somewhere that pushing the weld makes it easier to weld thinner materials.



Wink

Re: reversing the polarity
 

I agree with most of what you said, but the rest I don't. It's most likely that you just havn't had experiences that differ from your statements.

Using C25 to tig mild steel is an absolutely wrong shielding gas to use. Use 100% argon for tig of mild steel and stainless steel. There are other gasses that wil work, but C25 is NEVER a good option for tig of any material.

You can weld aluminum on DC, but it must be with electrode negative (like you do with stainless and mild steel)...but with either pure helium gas, or a mix of argon and helium (high helium content).

If your machine doesn't have AC ability, don't even think about some way to get that out of it, as you'd spend way too much money and have a POS in the end anyway.

oh, and for those wondering, DC (helium gas) isn't the way I'd reccomend doing things like intercooler piping. It welds a lot hotter than AC and isn't good with thinner materials.

Re: reversing the polarity
 

When it come sto MIG, Alternating current (AC) has not been successfully used. Direct current, electrode positive (DCEP) is normally used (this is what you will be using). Reverse polarity (DCEN - electrode negative) is only used (with MIG) if you are using special emissive-coated electrode wires, I highly doubt you are since they are not popular and are hard to come by. The Reverse polarity on your machine is for the flux-cored welding process. The flux-cored process can use either DCEP or DCEN depending on the wire you are using. The nice thing about flux-cored is that you can get self shielded wire (no gas needed).

Re: reversing the polarity
 

we have a Mig welder with an Aluminum gun on it at my skool. it is pretty sweet, real easy to use, i welded up my ebay intake and bov flange with it