Welding differnces-MIg TIg

Discussion in 'Painting, Welding, Bending and Gas Tanks' started by Patch, Jun 1, 2007.

  1. Patch

    Patch Guest

    So Im considering taking a welding class over summer. I wanna use it for mostly my bikes, go kart, and random metal projects.

    I have the optiion of taking Shielded metal arc (SMAW)
    or...Gas metal arc (GMAW or MIG)
    or even Gas Tungsten (GTAW or TIG)

    I know very little about welding or the different kinds so if someone could tell me which class would help me most for welding mufflers, headers, frames, and mounts, and also what the differnt kinds of welding are used for... that'd be very helpful. :D
     

  2. locoWelder

    locoWelder Guest

    The Definitions
    Gas Metal-Arc Welding:
    (GMAW) as identified by the American Welding Society, is also popularly known as MIG (Metal Inert Gas) and uses a continuous solid wire electrode for filler metal and an externally supplied gas(typically from a high-pressure cylinder) for shielding. The wire is usually mild steel, typically copper colored because it is electroplated with a thin layer of copper to protect it from rusting, improve electrical conductivity, increase contact tip life and generally improve arc performance. The welder must be setup for DC positive polarity. The shielding gas, which is usually carbon dioxide or mixtures of carbon dioxide and argon, protects the molten metal from reacting with the atmosphere. Shielding gas flows through the gun and cable assembly and out the gun nozzle with the welding wire to shield and protect the molten weld pool. Molten metal is very reactive to oxygen, nitrogen and hydrogen from the atmosphere, if exposed to it. The inert gas usually continues to flow for some time after welding to keep protecting the metal as it cools. A slight breeze can blow the shielding away and cause porosity, therefore welding outdoors is usually avoided unless special windscreens are erected.

    However, if done properly, operator appeal and weld appearance are excellent with MIG and it is most welders' favorite process to use. Good technique will yield excellent results. The properly made finished weld has no slag and virtually no spatter. A "push" gun angle is normally used to enhance gas coverage and get the best results. If the material you are welding is dirty, rusty, or painted it must be cleaned by grinding until you see shiny bare metal. MIG welding may be used with all of the major commercial metals, including low carbon steel, low alloy steel, and stainless steel and aluminum with potential for excellent success by a novice.

    Aluminum MIG

    Welding aluminum requires much more than just changing to aluminum wire. Get comfortable welding steel first. Since aluminum is very soft, it requires aluminum drive rolls that have a U-groove and no teeth to bite or cause wire flaking. Cleanliness of the wire and base metal are critical. Wipe the material with acetone on a clean shop rag. Use stainless steel wire brushes that have only been used on aluminum. Drive roll tension and gun length must be minimized. A Teflon, nylon or similar gun liner is needed to minimize friction in feeding the wire and 100% pure Argon gas is required for shielding. Special contact tips are often recommended. Special gun movement techniques are often highly desirable. It is a challenge, but it can be done.

    Self-shielded Flux-Cored Arc-Welding process

    (FCAW), or flux-cored for short, is different in that it uses a wire which contains materials in its core that, when burned by the heat of the arc, produce shielding gases and fluxing agents to help produce a sound weld, without need for the external shielding gas. We achieve a sound weld, but in a very different way. The shielding is very positive and can endure a strong breeze. The arc is forceful, but has spatter. When finished, the weld is covered with a slag that usually needs to be removed. A "drag" angle for the gun is specified which improves operator visibility. The settings on the wirefeeder / power source are slightly more critical for this process. Improper technique will have results that are magnified. This type of welding is primarily performed on mild steel applications outdoors. .035" is often used for the 115 volt machines and the .045"is typically used in the 230 volt machines. Farmers have found that these products can save a planting or harvest by repairing a broken machine out in the middle of the field in record time.
    General Usage Rules
    MIG
    As a rule of thumb, it is recommended to use a compact 115volt input (or 230 volt) MIG wirefeeder/welder indoors on clean new steel that is 24 to 12 gauge thick. 12 gauge is a little less than 1/8" thick. 24 gauge is less than 1/16" thick. The smallest wire(.025") will make it the easiest to weld the thinnest(24 gauge) material. The .030" diameter wire will weld a little faster deposition rate. If you need to weld 1/8" to ¼" thick material with MIG, you will need the higher capacity compact machine which will require 230 volt input. The higher amperage range of this machine can better handle your welding needs in a single pass and you may not have to waste time with second or third passes. The 230 volt machine could also run .035" diameter wire. To MIG weld material more than ¼" thick, you need a higher capacity truly industrial machine. If most of your welding will be performed indoors on clean material that is less than 1/8" thick, a MIG machine that operates on 115 volts is probably your best bet for economic reasons in that a 230 volt input machine will be more expensive.
    Flux-Cored
    The flux-cored process is only recommended on materials as thin as 20 gauge, a bit thicker than the 24 gauge we said for MIG. In general, this process is best for welding thicker materials with a single pass, especially if you need to weld outdoors such as to repair a tractor out in the field. A 115 volt flux-cored machine using an electrode such as .035"will generally allow you to weld steel up to ¼"thick. Note that this is more than double the thickness maximum of 12 gauge with MIG on 115 volts. With the proper electrode on a proper machine, such as .045" and a 230 volt input machine, you can weld steel up to 1/2" thick. Note that .045 requires that the machine be setup for DC negative polarity.
    Advantages/Disadvantages
    While there are advantages and disadvantages to both processes, I will try to outline for you some of the most common.
    MIG
    Advantages
    The best choice when cosmetic appearance is an issue since it provides lower spatter levels than flux-cored. The arc is soft and less likely to burn through thin material.
    The lower spatter associated with MIG also means no slag to chip off and faster cleaning time.
    MIG is the easiest type of welding to learn and is more forgiving if the operator is somewhat erratic in holding arc length or providing a steady travel speed. Procedure settings are more forgiving.
    If you are skilled and get specific proper guns, shielding gas, liners, drive rolls, and electrode, MIG can weld a wider range of material including thinner materials and different materials such as stainless, nickel alloys or aluminum.
    Disadvantages
    Since a bottle of external shielding gas is required, MIG may not be the process of choice if your are looking for something that offers portability and convenience. MIG also requires additional equipment such as a hose, regulator, solenoid(electric valve) in the wire feeder and flowmeter.
    The welders first job is to prepare the surface by removing paint, rust and any surface contamination.
    MIG has a soft arc which will not properly weld thicker materials (10 gauge would be the maximum thickness that MIG could soundly weld with the 115 volt compact wirefeed welders we are referring to or ¼" with the 230 volt input compact wirefeed machine.) As the thickness of the material(steel) increases, the risk of cold lapping also increases because the heat input needed for good fusion is just not possible with these small machines.
    Flux-Cored
    Advantages
    The Self-Shielded electrodes are optimal for outdoor procedures since the flux is built into the wire for positive shielding even in windy conditions. An external shielding gas and additional equipment are not needed, so setting up is simpler, faster and easier.
    The flux-cored process is most suited for applications with thicker materials as it is less prone to cold lapping.
    Disadvantages
    It is not recommended for very thin materials (less than 20 gauge).
    When flux-cored welding, machine settings need to be precise. A slight change in a knob position can make a big difference in the arc. In addition, the gun position is more critical in that it must be held consistently, and at the proper angle, to create a good weld.
    This process creates spatter and slag that may need to be cleaned for painting or finishing.
    It should be noted that the same machine can be used to weld with both MIG and flux-cored processes though a special package is usually needed to change from one application to the other. Drive rolls, shielding gas, gun liners and contact tips and procedure settings need to be addressed when changing processes.
    I hope I have given you what you needed to know it took a long time to type this...........LocoWelder......Dave
     
    Last edited by a moderator: Dec 15, 2015
  3. Patch

    Patch Guest

    so if i do the MIG welding course...basically I can figure out how to do Fluxcorded welding (with some practive of course)?

    Thanks Dave that was way easier to understand than the stuff on the net :D

    Thanks again dave
     
  4. azbill

    azbill Active Member

    they don't call him locowelder for nuthin' !!!
    very nice explanation of the different types/methods
    [​IMG][​IMG]
     
  5. jol

    jol Guest

    I haven't read the entire post, but start with mig and continiue to tig. Fluxcord and mig is (roughly) the same technique when welding.

    SMAW is mostly above 5mm thickness wet/black iron welding (tractor stuff). Not to say it's not good to know, but you might never use it. Sure you can weld smaller pieces too, I've done dry/white 2mm a whole summer, but the mig does that aswell
     
  6. prowler

    prowler Guest

    TIG

    I've always wanted a TIG welder due to the excellent quality welds possible using TIG (plus it's a lot easier to weld aluminum with TIG than MIG), but the cost and size of the machines have kept me away. For most home hobby welding, MIG has been fine and machines are available for well under $500 (115V). My "JC Whitney Special" (SIP brand, made in Britan of all places) has been performing flawlessly for over 25 years and I've welded car frames (2 Porsche Speedster replicas), go-carts, mini-bikes, snowmobiles, etc. It's nice to be able to carry the box out to the garage for welding out there, then grabbing it and running back down the basement with it to do stuff that requires fixturing. Watch E-bay and you can probably get a MIG machine for a couple hundred bucks and be off to the races. I just bought a new Campbell-Hausfeld (Farmhand model) MIG machine (for my teenager to use) for $113 off E-Bay. Patch, WCTC has some great welding classes available right down the road from you.
     
  7. DougC

    DougC Guest

    I am not a professional and it's just my opinion--but I tend to think that a oxy-acet torch is best for what most home-hobby types want to do. ....In particular, you can simply heat up steel orange-hot and bend it into shapes you need, and not lose any strength after it cools. I find that I end up doing that a lot, and you can't really do that with the other types of welders.

    I don't know why it is, but many people seem to assume that an electric welder is safer or better somehow than a torch--but if you go look around on weldingweb.com or any welding forum, go and count all the people having problems getting decent welds with these cheap little mic/wire welders, or of burning holes in thin metal they want to use--you'll see a lot of people asking for help. And then go count all the people having similar problems with gas-torches, and you'll see there's almost none.

    If you spend $700 for a MIG you generally will get something that works GREAT.
    If you spend ~$100 you won't.
    You're better off spending $300 on a oxy-acet torch than you are spending $100 for a 110V cheapo mig.
    ~
     
  8. prowler

    prowler Guest

    torch

    Just my opinion, and likewise, I'm certainly no expert on welding, but I've got an Oxy-acet torch that I used for welding aircraft chro-moly and it's very difficult to use and set up correctly to get a good weld, but the best way to go to weld thin wall Chro-Moly tubing. Haven't touched it in at least 15 years tho' since I started MIG welding. It's just way too easy to plug it in, adjust feed and output and start welding. If you really want to go with Oxy-Acet, I'll sell you a really good quality portable Meco Aircraft Oxy-Acet Welding outfit......cheap. True, cheap/inexpensive MIG welders certainly aren't the best way to go, but they are by far the simplest, most inexpensive way to get into welding for the home user. If you can afford $400-$500 for a Miller or Lincoln MIG welder, that's great, but when I purchased my SIP unit (for $240 in the early '80's), I was not into the big bucks and I've been getting good quality welds from it for 25 years and haven't found a reason to replace it with a more expensive unit. (a friend who's a certified welder used my MIG last summer and was surprised by the good quality of the welds). If I could justify it, I'd go first class and buy a good TIG welder. I guess to each his own.
     
  9. Dockspa1

    Dockspa1 Guest

    I have been told that with the torch set up, you can you coat hangers for filler rod because they are a very low carbon steel. Is this correct?
     
  10. DougC

    DougC Guest

    Yea you can, but quite frankly, there's not much good reason to unless you can steal a lot of wire coat-hangers somewhere for free. Filler rod costs about $3 a lb. A 5-lb pack is a tube about 1 inch in diameter and 3 feet long. Anyplace that sells gas is going to sell fill rod also....

    And coat-hangers are a bit thin in my opinion. I prefer the 3/32" or 1/8" rod.
    ~
     
  11. mickal1025

    mickal1025 Guest

    I have a very old 220V DC stick welder that works very well for heavy welding and would likely work well with a steel bike frames if you took the time to get used to it. but Ive tried welding aluminum with it and had no luck. (might need an AC welder) not sure. I had a cheap carbon arc set up given to me that hooks up to this welder and works very well for heating and bending. hardest thing I thought about welding aluminum (at work, not with above welder) was seeing the puddle. its not defined and easy to see like with steel.
     
  12. ironwarlock

    ironwarlock Guest

    LOCO have you put together any wild bike frames? if not you should.
     
  13. locoWelder

    locoWelder Guest

    Man I would love to start building bike like Iride ,but it would only be a hobbie cause I cant see a real demand for enough bikes at the price that I would have to charge to make a real living at it.
    now if I can get a Discovery chanal spot...and make the bikes famos....I'd could see myself the OCC of the motorized bike world.

    ok let the air out of my head now please! 8)
     
  14. mickal1025

    mickal1025 Guest

    send them a letter with pictures of some of the nicest bikes. there are quite a few here on the forum. they do some off the wall stuff at OCC I saw one show where Mikey and someone tricked out store baught Mopeds and rode them into the city. so start with a one show spot on OCC and work it into a spinoff.
     
  15. Turtle Tedd

    Turtle Tedd Member

    No Coat Hangers
     
  16. Turtle Tedd

    Turtle Tedd Member

    loco welder are you in the trade??? ....a lot of good info you gave for nebee welders...most people think you ca become a welder in a couple of weeks ..takes a couple of years..after 35 years I was still learning and developeing techniques....oh and It would have taken me a couple of weeks to type that post you did..good job
     
  17. Turtle Tedd

    Turtle Tedd Member

    If you have a tubing bender,lathe, milling machine ,and a decent array of welding equipment...design about 5 frames and build them just to fit these HT motors ,,,you would be truly loved by all,,but would probably not make any money in the end... building the perfect frame in 5 models. $450.00 each at least...even after figureing out material cost to the 1/2 and other cost you still have the LIABILITY issue wich has done me in many times
     
  18. DJEEPER

    DJEEPER Member

    MIG:
    [​IMG]

    TIG:
    [​IMG]
     
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