Explanation from the Mig Gurus...

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Ok guys, to start with I have never had any formal welding training I am pretty much self taught everything I have learned which is why I probably don't already know this.  I have always primarily been a stick welder and even in my shop now a stick is used 70% of the time.  Mainly because it is better suited for the type of repair, and work we do.  I never have known much on the mig aspect.  Yes I can set the machines, and run a weld next to anyone, its the process I have a question on.  I keep hearing people making references that on a mig machine the wire feed is the current like amps on a stick welder would be.  Could someone explain this for me? Exactly what the Voltage and the wire speed are in relation to the arc.  Thanks  ~JacksonI'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:May not be any help, and probably isn't even on the same subject, but as the wire comes out of the gun it makes a momentary connection and short circuits melting the wire and the work at the same time. more wire comes out and melts into the work and the bit of wire from the first cycle. Wire speed too fast and the work wont have time to melt yet the wire keeps coming out. By this time the length of wire is too long and wont arc properly.(being that there is an optimal spacing between the gun and the work) Wire speed too slow and the work has cooled and wont there wont be enough wire in play to make a weld. Higher amperage simply gives a hotter burn. I hope I explained the process properly. But I cant understand the reference you made about wire/current=stick/amps. Did I help any or confuse the issue.I'm not a Engineer, I just play one on the weekend.
Reply:dlturman,  What you said makes since, I have just read on several forum people referring to the wire speed as the same as amperage, and I was just trying to make sense of it.  I do appreciate the comments.  ~JacksonI'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:I keep hearing people making references that on a mig machine the wire feed is the current like amps on a stick welder would be. Could someone explain this for me? Exactly what the Voltage and the wire speed are in relation to the arc.
Reply:Most wire feed welders are constant current power supplies and stick machines are constant voltage.  When you strike an arc with constant current (CC) the amperage is set and any change in arc length changes the voltage and the amperage stays relatively constant.  You can prove this if you connect a regular voltmeter across your electrode cable and ground cable.  Set your voltage to read up to say 100 volts so you don't cook anything.  With no arc you will have up to 75 volts. ( open circuit voltage)  When you strike up you can vary the voltage down to around 25 depending on how tight an arc you maintain.  You adjust the arc length by moving your rod closer as it burns off.In the olden days when wire feed welders had radio tubes they were constant current and the voltage sensor would tell the motor to speed up and feed more wire when the voltage climbed and visa versa.  It was cumbersome and motor response was not good.Constant voltage is the modern wire feed.  The motor is set to a given speed before you start.  The wire feeds out and an arc is started.  The power supply also sets the voltage which determines the characteristics of the arc.  ( short circuit, globular, spray)  If you want more amperage you set the motor to run faster.  The power supply maintains the same arc voltage and gap so the amperage has to rise in order to burn off more wire in a given time.    This explanation is pretty simplified but it gives you the idea of what is happening.  "Something that changes amperage sharply in a wire feed is stickout length.  That is the distance the wire sticks out past the contact tip.       You have some control over that.  Pull back and your amperage will drop.  Move closer and the amperage will rise.  That is what makes wire feed such a great gap filler.Yes I actually had seen tubes in wire feed units in 1964.  They were constantly changing them.
Reply:Lotech,  I mean no disrespect, as I know you almost personally, IE my wife.  However, I read your post and could swear youve got the cv and cc machiens backwards.  Can you double check what you wrote in your last post regarding the very first statement, umm  "ost wire feed welders are constant current power supplies and stick machines are constant voltage"  did you by any chance have this backwards?  If im totally off in la la land I apologize and disregard this.  I believe you added later in the post that the wire feed machines were CV machine, but seemed in the begining you were sayin that most wire were CC and most stick were CV?  Just a clearification as I have high respect for your opionions and waht you think, but this goes against what I was to beleive and so I just want to verify its not just a typo or if its my own ignorance.  Thanks Lotech. CHRIS
Reply:WHOOPS!  Thanks Chris.  My first sentence is wrong.  Stick is CC and wire feed is CV.  Brain Fart!
Reply:Try ThisShort Circut 75-25 GasSet Voltage At 17-18 VoltsSet Wire Feeder At The 10 Oclock Position, Doesn't Matter What Feeder It Will Normaly Work. With .035 Wire You Will Get About 150 Amps, Then Fine Adjust The Feeded For Solid Crackel.Spray92-8 GasSet Voltage At 26-28Set Feeder At Between 3 And 4 Oclock PositionWill Yeild 250 Amps With .035 WireThen Fine Tune With Wire Speed Small Adjustments Are All Thats Usualy Needed.More Wire- More Load = More Amps.If You Have Spatter From Either Setting It Is To Much Wire Speed And You Are Driving The Wire Into The Weld Puddle And When The Arc Occurs It Blows Out The Molten Metal Aka Spatter. So If You Have Spatter Mig Welding Then Turn Down The Wire Speed In Small Increments And It Will Go Away.RegardsChipmasterRanger 250LN 252 ESAB suitcase feedersSP135LINCOLN Square Wave TIG 255Kondia vert millProtoTrak CNC vertical mill13" South Bend Lathe17" South Bend Lathecaterpillar d-4, 15, 22 and a 20
Reply:If anyone wants to understand these processes it helps to hook up a voltmeter on a stick machine and change arc length.  If you have an ammeter on a wire feed you can increse and decrease stickout and monitor the ammeter.  These two little exercises will give one inisight into how important stickout and arc length are.
Reply:OK new aspect. How does the rate that I move my hand factor into this? I learned early on that is I move too slow the work blows through and the weld looks not so good, but when I speeded up I got a much smoother looking weld, good coverage and I assume adequate penetration. Saying that, if I speed up the wire feed( or run a relatively fast wire speed) and move faster how does that effect what ya'll are saying as far as amperage, etc. is wire speed in important?Not trying to be difficult, but this is interesting.DTI'm not a Engineer, I just play one on the weekend.
Reply:Travel speed is depended on the thickness of base metal, thicker slower thin you get the idea. the weld should be about as wide as the pieces of metal being welded. 2 pcs 1/4 inch weld about 1/2 wide in a t joint. wire stick out and contact tip placement also fall into this soup of variables.for short circut mig contact tip should stick out of the nozzel 1/8 to 1/4" then 1/2" wire stickout. for spray mig contact tip 1/4" inside the nozzeland 1/2 to 5/8 wire stick out{ using gas to help cool the contact tip in spray mode}. not t be a wise guy but this is why it takes so much time to be a welder, practice practice practice. .035 wire can do most thickness of steel up to 1/2" in spray mode and down to thin gage metals in short circut 16ga to 20 ga no problem. flux core and metal core different rules.RegardsChipmaster Ranger 250LN 252 ESAB suitcase feedersSP135LINCOLN Square Wave TIG 255Kondia vert millProtoTrak CNC vertical mill13" South Bend Lathe17" South Bend Lathecaterpillar d-4, 15, 22 and a 20
Reply:Originally Posted by dlturmanOK new aspect. How does the rate that I move my hand factor into this? I learned early on that is I move too slow the work blows through and the weld looks not so good, but when I speeded up I got a much smoother looking weld, good coverage and I assume adequate penetration. Saying that, if I speed up the wire feed( or run a relatively fast wire speed) and move faster how does that effect what ya'll are saying as far as amperage, etc. is wire speed in important?Not trying to be difficult, but this is interesting.DT