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  1. #1
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    Default Current set up for your Mig

    Ok ,it has been a while but I have finally finished it

    Generally speaking, MIG welding produces heat from an electric arc established between a continuously fed, bare metal electrode (wire) and the base/parent metal (what you’re welding on) in conjunction with an external, shielding gas of either argon, carbon dioxide, helium, or a mixture. Dependent on their chemical make up the shielding gases may be inert (chemically, non-reactive as in argon ) or reactive such as Argoshield or Co2.

    When the bare electrode melts, it forms the bead. The arc contains both amperage and voltage. To produce a sound, high quality weld, you must have :
    the correct type of polarity and current, DC - for gas shielded steel welding machines and electrode DC +for FluX core welding ( gasless to some people)
    the correct shielding gas,
    correct burn-off rate,
    and the ability to accurately for the amount of wire feed speed (which is amperage) against the appropriate voltage( The stepped rocker switches on most machines )
    Welding technique in itself is straight forward.

    The controls adjustment setup may be more complex than many comprehend. Initially many have problems finding this correct point- the optimum setting The amperage and voltage must be synchronized. MIG welding has four arc metal transfer modes ( arc types) To keep it simple we talk about the basic two arc transfer methods you are laible to use at home. We will only talk about two of them being short arc or dip transfer and spray arc. Short circuiting (most often used for mild steel applications), spray-arc (used mainly for aluminum, but can be used for mild steel. Much of the material that is used in DIY today is light gauge steel and is welded with short arc.

    So that you are able to discriminate between the two types of arc metal transfer types, we can use audible and visual indicators for you discriminate between these two different arc. The sound for short arc the texts say ,that you are supposed to hear is like frying bacon That’s probably the closest thing we all can relate to when trying to determine if we are close to the required setting. The closer your machine is “dialed in,” the more the arc will crackle like frying grease. I like to set my heat values first –the voltage control/s and then dial the wire speed in until it crackles.
    It goes like this-The lowest voltage control setting is for thin metal and the highest setting is for the thicker sizes.

    Short circuiting is often referred to as short-arc or “dip” transfer. The molten metal is transferred to the work when the wire feeds down and touches the metal surface. This completes the electrical circuit—“shorts out”— and melts the wire. It then recycles the process from 20-200 times per second and uses lower currents and voltages as well as smaller wire diameters.

    What you will see through your shield happens at 200 times/second but suffice to say that this is a bead that is less fluid ,small in volume and freezes or solidifies rapidly. All the above are desirable qualities when you have a little gap that you wish to fill. If you are burning a hole in your metal, reduce your wire feed a bit and reduce your voltage setting by one step.

    Spray transfer sounds like a soft hissing sound. It appears visually as a soft stable arc that wets ( blends and fuses into its adjacent parent metal ) readily.
    Remember its good on thick steel on the flat material. In steel sheet (or aluminium sheet for that matter) expect to burn a hole (note to those who intend to purchase same to weld up their tinny-don”t bother as most tinnies sheet metal aluminium can be too thin. If its four mm or thicker it may be suitable.


    For welding home jobs , MIG wire diameters range from .6 -.9mm. Depending on the wire diameter and the material thickness, voltage ranges from 15-19 volts and 50-150 amps. This is why voltage and amps gauges are desirable acessories to a machine. This technique results in lower heat input, minimizing warpage and distortion, as well as reducing the Heat Affected Zone (HAZ).

    Spray arc produces molten teardrop shaped droplets, which detach from the end of the wire and spray across the arc column to the weld pool (puddle). Spray arc has an intensely hot and higher arc voltage, giving a higher deposition rate. If properly adjusted, the welds are almost splatter free, with deep penetration and high deposition rate. Generally for heavier steel 5mm and up ) in the flat horizontal position good transfer process because of the high heat input. This mode of deposition is essential for welding aluminium. Around 22 volts and up plus 200 amps and up generally for aluminium. Don’t take a salesman’s word that your desired Mig will weld aluminium as advertised - ask for a live demo.
    If purchasing your mig to weld aluminium make sure your mig can achieve the above parameters. Some people will twist the truth in stating the machine can weld aluminium when in fact the parameters will not allow spray mode to take place.

    Most people have had experience with stick welding where the desired amperage is set, and the machine automatically selects the correct amount of voltage based on your rheostat setting. MIG welding requires a welder to be adept at setting both wire feed speed and voltage separately. The basic premise on which this process operates is that the wire feed speed is in directly linked to amperage .The faster the wire the more amps delivered. Amperage is the source of penetration or bite into the metal, which melts both the wire and base metal. The higher the wire feed speed, which is calibrated in millimetres per minute (MPM), the higher the amperage.
    Safety
    Safety is of paramount importance, and is a most often overlooked and/or neglected aspect of welding. Most people think that when you’re “just welding,” the only concern for injury is your eyes from the welding “flash” arc. However, that isn’t the only thing that can be damaged by the invisible rays given off by the process. Safety glasses must be worn at all times, tight against the bridge of your nose. If you receive a number of flash injuries from your welding experiences, they may lead to blindness. Consider use of flash glasses, especially if you’re just beginning to weld.These are just safety glasses with CLEAR lenses. They take a little getting used to, especially if your work area doesn’t have sufficient lighting, but this additional layer of protection is beneficial. Glasses also protect your eyes from not only a flash but flying metal particles expelled during MIG welding.
    . When welding, skin injury can result from not wearing gloves, wearing a short sleeve shirt, or shorts. Your skin can be harmed by these rays. Those rays from the Mig are more intense than stick welding when measured as Mig amps against stick amperages settings. It’s possible to get severe radiation burns in ten or twenty minutes of exposure.
    Leather gloves should be worn to protect your hands from molten droplets, sparks, and heat. They should have a long gauntlet (cuff) also made of leather to protect the forearm. A long sleeve shirt of 100 percent cotton should also be a part of your attire, as well as a pair of 100 percent cotton pants. Blue jeans are usually a preferred choice. Clothing of synthetic fibers, nylon, rayon, and polyester are highly flammable and should not be worn. Frayed material on clothing, even cotton, will catch fire. Grease or oil on clothing is a definite risk to personal safety.

    You should wear high top, insulating boots (not tennis shoes) for welding. Burns infect easily, especially in areas not readily exposed to free air movement that tend to stay damp, like your feet.
    Your welding helmet should be of sturdy construction, a fiber-metal type. The recommended shade lens is between 10-12 for MIG welding.

    That should generate a few questions then?
    Cheers
    Grahame

  2. #2
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    Default

    Grahame, You have done an excelent job there mate. I have no experiance with home Mig welders at all, infact, the smallest mig I have ever used was a 350 amp machine, but you could turn that sucker right down & weld 3mm or even 1.6mm if you wanted to.

    If you don't mind, I would like to add to your thread.

    As Grahame has already said, safety is the key. There are a couple of other issues to be aware of. The glassy residue that some times forms on the weld has a tendacy to fly off as the weld cools, so don't lift your glasses for a closser look after you have just done your weld. Also, on the same subject, it is sharp like glass as well. Don't run your finger over the weld even when it has cooled. If you do get it under the skin, it is difficult to get out as it shatters when you grab it with the tweezer.

    If you have had some stick welding experiance, you will know to drag the rod from in front of the the weld pool in most applications. With a mig, you feed your wire into the weld pool while pushing the gun forward. In other words, with a 90 degree "L" joint, the position of the stick would be at 45 degrees to the plates & 45 degrees forward. The MIG gun would be at 45 degrees to the plate, but 45 degrees back. (clear as mud) There are ofcourse exceptions to the rule, a vertical down would be one.

    Finally, while it all sound very technical, it really is not that hard. Grahame went into great detail with voltage & amperage settings, and he did a great job of it. Once you have learned how to SET those settings, you could teach a gorilla to weld with a mig welder. It is harder to learn how to set than a stick welder, but easier to learn how to use once you have mastered the settings.

    Steve
    The fact remains, that 97% of all statistics are made up, yet 87% of the population think they are real.

  3. #3
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    Default Operating your Mig

    Thanks Ticky,
    I forgot to mention that glassy substance,it is silicon which is alloyed into the wire wire metal along with aluminium and and maganese.It gives the deposited metal (in its molten state) the ability to flux itself.Mind you the metal must be shiny clean first as other than the above merntioned deoxididisers, Mig has no other way of cleaning out the oxides and crap in the molten metal as does the stick welding process.Bear in mind the welding over rust oil grease dirt will also result in porosities and voids.

    In addition I also forgot to mention stickout. Stickout is the amount that the wire projects out of the nozzle from the contact tip.The amount of stickout will also affect voltage input voltage and therefore heat value into your welding pool. For most situations around 10 to 15 mm works quite well. Too much stickout and you risk projecting the wire out of the gas shield area.

    The gun cable can play a part in how your system runs. If the cable has three figure eights and a knot in it , the friction of the wire travelling through the liner will slow the wire speed down. Keep the cable as near to straight as possible. Also wire liner diameters are matched to the wire diameter. Be careful you don't bend or kink your liner The result of friction is reduced amperage at the weld pool and increased voltge ( increased heat). . The contact tip diameter must suit the wire diameter. Replace the contact tip when small diam hole in the end starts to open up in its diameter( bell mouths ).This has a big affect on arc performance.

    Remember that the majority of your MIG sytem is mechanical and and mechanical systems need regular maintainence.Make sure the wire drive wheels are set with the correct tension.How? Easy- pull the gun trigger with one hand and pinch the with the other ,stopping the wire in the area before it enters the roll to try to make it skid and stop in the rolls.Adjust the roll pressure until this happens. When releade the pressureis set. Near enough to a rule of thumb ( and finger) Ok ?.
    Of course roll size must be matched to the wire diam and type.Flux core roll profiles are different from hard wire.Diameter info is stamped on the driver roll while profile shape is like a U for solid wire and serrated for flux core (gasless).
    Some sytems have a spring tension on the axle that the filler wire spool turns on and if it is tight this can affect the system- same reason -friction.

    The shielding gas in the system is kept in the correct place by O rings or mechanical spring seals -( a bit like little piston rings).If they get all sloppy the gas leaks leaks out or worse-the air seeps in and your weld gets porosity.
    I am sure that there is more on this and more questions and comments will jog my memory.
    cheers
    Grahame

  4. #4
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    Default

    Thanks guys.

    Your posts are excellent. I have just finished a short welding course which taught the basics of Oxy, Stick and MIG. I need a lot more practice but given that start and your excellent posts I hope to progress quickly. As an aside my project on the course was the Beisemeyer fence, the subject of another thread on this forum. Turned out very well, although I don't look too closely at the neatness of the welds.

    Do you have any advice on using flux wire versus shielding gas? I have heard that gasless MIG gives a poorer weld. This may be a myth, so I am interested in your experience.

    Regards

  5. #5
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    Default Mig solid wire Vs fluX core

    KRH asked if Mig solid wire welding was better than Flux core.Better or poorer than what
    A simple answer is that it depends on what you want from the weld.

    Economy -Flux core
    Visual appearnace -Solid wire
    Ability to use outside in windy conditions- flux core
    Not having to clean up after the weld is deposited - Solid wire.

    At home I like to bugger around now and again with thin wall box tube to make frames.I can not see enough detail to leave a small clean tack because of the amount smoke and molten flux cover.This is just me and the conditions that affect me. What works for you may be different.

    Though if I was buying a unit I would go for a dual gas /gasless unit and stay awy from the El cheapos and No name brands.If you not sure Google it.A while back I researched a Essetti tig unit I had not heard of .It turns out they are a major player in Europe.
    Hope this helps
    Grahame

  6. #6
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    Default

    KRH,
    I am with Grahame of the solid wire also. If you do need to weld outside, you can set a windbreak up using a sheet of ply or MDF or even Tarp. You may also need to just increase your gas pressure slightly.

    Gas is the Go. Mig stands for Metal Inert Gas.

    Steve
    The fact remains, that 97% of all statistics are made up, yet 87% of the population think they are real.

  7. #7
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    Default

    Hi Graeme,

    I to wanted to add my name to the list of recipients who appreciate the numurous threads you have started (and added to) with your excellent advice. Not too many people with your wisdom and experience areas generous or prepared to pass on such advice. I found out when I was doing my toolmaking apprenticeship that some people (within the toolroom) were reluctant to pass on their experience for fear that you may eventually take their job off them.

    Regards
    David

  8. #8
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    Default

    David,
    Thanks for your kind comments, I do appreciate them.

    I have found out a long time ago that it really costs nothing to help someone. In turn people are mostly more than happy to return the favour in different ways such as the excellent assistance I have received much help from countless people in the many other parts of the woodwork forum sections.

    What I have learned is that people learn well when they are really interested in what ever subject area they are learning about.
    I have learned from students that I can learn from them.. There is always some body who has come up with an improved technique or process to make tasks better or even easier , so it pays to listen whoever they are. A mentor of mine used to say that your mind is like a parachute. It only works properly when it is open.

    Cheers
    Grahame

  9. #9
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    Default

    Quote Originally Posted by Grahame Collins
    Ok ,it has been a while but I have finally finished it



    .





    This mode of deposition is essential for welding aluminium. Around 22 volts and up plus 200 amps and up generally for aluminium. Don’t take a salesman’s word that your desired Mig will weld aluminium as advertised - ask for a live demo.
    If purchasing your mig to weld aluminium make sure your mig can achieve the above parameters. Some people will twist the truth in stating the machine can weld aluminium when in fact the parameters will not allow spray mode to take place.


    Cheers
    Grahame

    Very well written.
    Your advice I have extracted above is spot on. Everyones Mig welding machines will weld aluminium (according to the Salesman or the brochure) but ask to see it. The problem I have as a Salesman is when I tell a customer to buy a "better known" brand if they are going to weld aluminium they should buy a 200 amp machine and everyone else is telling them that their El'cheapo 120 will suffice, it's a struggle to convince them.
    The other thing is that we sell quite a few "Synergic" machines these days. After selecting the Material type, Gas type and wire Diameter from a program (usually a digital display) the operator selects the wire speed and the machine supplies the correct amount of voltage (this can also be fine tuned within the Synergic lines if required). The machines can also be used in Manual mode. (A bit like an SLR Camera) Some of the machines have a plate thickness indicator and for example you want to weld 3MM, you turn the dial to 3mm and it automatically sets the wire speed and voltage. (You still have to enter the Material type,gas type and wire diameter. Kemppi have just released a portable mig (I think it's about 10kg) 240v with an LCD screen they call the Adaptive 180 Minarcmig. The 150 has been out for a while but it was a bit underpowered for my liking but the 180 is unbelievable. It works on the "Synergic" principle and takes all of the guess work out of welding.
    Regards
    Bez

    P.S. I noticed you said in one of your posts that Esseti is a major player in Europe but so are plenty of other Italian brands of welding equipment. It will be quite a while before someone will convince me that they are in the same league as Esab,Kemppi or Fronius.

  10. #10
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    Quote Originally Posted by Ticky
    KRH,
    I am with Grahame of the solid wire also. If you do need to weld outside, you can set a windbreak up using a sheet of ply or MDF or even Tarp. You may also need to just increase your gas pressure slightly.

    Gas is the Go. Mig stands for Metal Inert Gas.

    Steve
    Sure is Ticky. Gasless wire has a use but I'm yet to find it, it doesn't even make a good tie wire. Seriously though, it is O.K. in windy conditions, if you run out of gas or on thin gal/zincalume materials. As far as cost goes, if you do a bit of welding, it ends up dearer than renting a gas cylinder and using solid wire. It is almost 3 times the price of solid wire.

  11. #11
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    Default Duel Settings

    As I said in an earlier post, I have never used a handyman style MIG, so I don't know if they have a Creater Fill feature. This is a feature I used to use all the time, but not to fill creaters. I used it like this. I would set my primary settings for welding downhand & my secondry settings for V/Up. When I pulled the trigger & released it. I could weld downhand into a corner & then pull the trigger again & hold it, activating the secondry settings to weld verticaly up without stopping.

    I haven't used a mig for a few years now, & while I do not want to dampen anyones enthusiasm, I'm not sorry about that. I have done enough welding to last me a life time, maybe 2. I still have a Goodall stick welder in the shed in case I have to weld anything up, but prefer not to. That said, I'm glad I have done what I have done. Knowing how to weld can save you a fortune & if I was buying a welder now, it would be a MIG.

    I have however enjoyed reading & adding to this thread & would like to thank Grahame for a trip down memory lane.
    The fact remains, that 97% of all statistics are made up, yet 87% of the population think they are real.

  12. #12
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    Default

    G'day All.
    As I have stated here before, I have a CIG Transmig 165.
    I use solid wire with Migshield gas.

    For welding up to 10mm it is great. The instructions say 6mm as the upper limit. This may be for gasless wire, but 10mm is fine with gas.

    Today, I welded up a gate. it was 16mm square ali with 12mm round ali tube. they have 1.6mm wall thickness. 0.8mm ali wire. argon gas. setting was low 2 with 6.5 wire feed.

    This welded great. I found that travel speed with the gun has to be twice as fast as when welding steel.

    I am very happy with the welds.
    My Son-in-law has some ali gates for his tautliner trailer that need fixing where they have cracked. he is bringing them round next weekend for welding.

    I feel that the 165 would weld thicker Ali as there was plenty of volts, wire speed and amps in reserve.

    I also have a Ryobi 100E gasless just in case I need to weld steel while the 165 is setup for ali.

    Also the 165 is still running the steel liner with the ali. When I swap over, all I do is blow the liner out with Compressed air. To date, no problems.
    It is a pain to have rental on 2 cylinders. But, I don't drink. So drinking silver goes on gas & rental
    Hooroo.
    Regards, Trevor
    Grafton

  13. #13
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    Default Re power supply

    Trevor,
    Mate! We are not bagging Transmigs in particular today, but there are factors I have neglected to emphasise ( failed to remember is actually nearer the mark)

    Not all Mig welders are created equall. Years ago when at TAFE, I had ascess to 14 of the same MIG model machines.What I noticed is that nmoving from student to student in different bays that the identical settings on any two machine don't necessarily produce identical output currents.

    My supposition is that there probably were differences due to manufacturers tolerances. Say perhaps a transformer winding having more wire length in one than the other,or resistors or capacitators not being quite the same values.
    Add to this the variation in supply voltages and variance in supply loads in different areas and bingo! The result is that certain machines won't get up to the spray arc mode settings.
    Its great that your machine does.You may have full supply volatge and your full quota of transformer wire windings or whatever.It gets back to the argument that particularly at the lower end of the market you gets whatcha pays for.

    Cheers
    Grahame

  14. #14
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    Default

    Trev, I'm glad you're happy with your Transmig 165. I don't mean to have a go at anyone personally on here when I talk of welding machines but I just tell it like it is. I have been selling welding machines for 25 years now so I have had quite a bit of experience with which to comment. I understand everyone has a budget and my advice is always buy the best you can afford. No one will ever convince me that any 240 Volt Italian machine will weld as well as a WIA 150 for instance. Sure people might think their cheaper machine welds well and it might suit their application but if they haven't welded with a quality machine what are they comparing it to? In our Industry, all Italian made machines be they 240 Volt or 415 Volt are considered to be light duty/low quality. They are often compared to Chinese hand tools which I think is a good comparison. Just last week I had a representative from a fairly sizeable independant opposition company ring me and ask if I had any vacancies. When I questioned his reason for wanting to leave his current employment his reply was, "I'm sick of trying to sell Italian crap that either doesn't perform as it should or worse still, doesn't work at all. He told me he had taken 2 415Volt AC/DC Tig machines to 2 different customers to demonstrate and neither of them worked at all. He said there is a market out there for good quality welding machines (which I already knew) and he knew our Company had a reputation for selling quality. One of the brands of machines he sells is marketed under it's manufacturers name but this is also sold as a Ryobi here, (although that wasn't the brand that failed during demonstration). Every now and then I get a customer in who'll tell me what a great run they've had from their Italian machine and I tell them they should have saved their luck and bought a lottery ticket and with their winnings they could afford to pay someone to do the welding for them. You'll probably even meet someone one day who has had a Lada Niva and been happy with it too. I get reps coming into work trying to flog me the latest piece of cheap crap their company has imported, they look you in the eye and tell you they've had no problems with them and how reliable they've been (even though they've only been importing them for about 3 weeks) and a few months down the track they'll have left their last employer and spill the beans on the failures,warranties and re-occuring problems they've had. I've even had quite a few reps admit they wouldn't buy the product they sell but would rather go for a quality machine.
    It's like the current range of Unimig Procraft series machines, a cheap Italian machine for the price conscious buyer. If it was as good as some people make out, Unimig wouldn't import and sell the Workshop series (which are Hungarian - similar to Migomag). Weld with a Migomag. ESAB, or even a Hungarian Unimig and then weld with ANY Italian machine, there is no comparison. Remove the covers and look inside and you'll see why. All of the cheap machines have no smoothing capacitors, usually"copy" mig guns with less copper, smaller transformers and rectifiers. poor quality drive motors, work leads, construction and less voltage steps just to name a few things. Like I said before, some peoples idea of welding and mine are often on 2 different planes. I get people tell me their little SIP 120 welds Aluminium beautifully so I ask them to bring some in and show me. All that does is re-affirm my beliefs. I had a guy walk in one Saturday with his wife and she had bought him an SIP 150 from Bunnings a few months prior for fathers day and he hadn't used it. When he did go to use it he couldn't get it to work properly so he took it back to them for some advice (because he thought was doing something wrong) and they couldn't help him. He rang me and asked could I have a look at it for him and seeing that I was quiet (Saturday morn.) I said I would (didn't seem like a bad bloke). When I got it out of the box and welded with it he said "see, look at the welds, what's wrong with it ?" (he was using gasless wire). I said "Nothing mate, that's as good as it gets with these". He was so dissappointed. If you don't weld much then a cheap machine will suffice but if you plan on doing a bit of welding, buy a good machine, you'll appreciate it down the track.

  15. #15
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    Default Foot in mouth disease

    Bez
    Seems I was wrong regarding the Essetti comments. I did something I should not have done.That was to make a comment based on someone elses experience. My mate god bless him, is a sheety and being an second generation Australian Italian, when he travelled OS did some time in some Italian metal workshops obviously equipped with Essetti and SIP welders.My comments were based on what he told me aboy them. He is a good sheety but maybe knows Zip about the quality of welders.
    I do stand corrected. I saw an example of what you are talking about just recently.A little "lunchbox" inverter welder called a Telwin, going for $400.I asked how they go.In an uncharecteristic moment the salesman said "Dunno,haven't sold one yet".

    Grahame

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