Flux-core/MIG for frame welding?

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by JacktheRiffer, Apr 24, 2014.

  1. JacktheRiffer

    JacktheRiffer New Member

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    Would using just fluxcore (no gas) be a bad idea for a frame? If i used gas would MIG be okay?
     
  2. Greg58

    Greg58 Well-Known Member

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    Flux core will work but prep is the key, you have to remove all paint at the joints and puddle up the weld. But if I have access to a mig with shielding gas I'll use it over flux core.
     
  3. 2door

    2door Moderator
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    If your machine will use shielding gas, use it. Your welds were be cleaner and stronger.
    Flux core wire is okay if you're mending fence posts or jobs that you don't care how they look but they can't compare with using gas.

    Tom
     
  4. MEASURE TWICE

    MEASURE TWICE Active Member

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    For MIG or TIG with AR 75 percent CO2 25 percent gas mix I would add that note if using electric welder, the amount of time at max amps is limited to 20 percent duty cycle on smaller welders.

    With my Hobart Auto Arc 130 Amp welder that runs off 120 VAC Single Phase supply, I should ought stop after 2 minutes on highest amps setting and wait for 8 minutes before starting again. This gets 7/16 thick steel welded OK, but time to finish can be a while.

    Pushing it means that even before it thermal cut offs, the welding gets trashy.

    I also have to make close zig zag passes on 7/16 inch thick steel and it is really needing more amps to get it done quicker. The welder chart states for thickest steel that flux core "is" to be use. Not sure of the reason. I get by with the multi-pass though and use the inert gas with solid wire with my MIG.

    If you have 230 volt available then you can probably get more done quicker with a welder that uses that 2 phase.

    Otherwise Oxyacetylene Torch if it is something that can be had.

    MT
     
    #4 MEASURE TWICE, Apr 24, 2014
    Last edited: Apr 24, 2014
  5. massdrive

    massdrive New Member

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    Personally I wouldn't build a frame with a flux core welder... I like to TIG weld. That's just me.
     
  6. GearNut

    GearNut Active Member

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    Some of us don't know how to TIG.
    Some of us want to learn though! TIG is the best.
     
  7. Theon

    Theon New Member

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    Flux core MIG is just for sticking stuff together, I call mine my PIG welder, cause it leaves sh*t everywhere.
     
  8. Greg58

    Greg58 Well-Known Member

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    Funny Theon!
     
  9. oldtimer54

    oldtimer54 Member

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  10. Theon

    Theon New Member

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    It may take a little more practice, but I have been surprised what I can weld with a decent inverter stick welder, and use it for most of my welding these days.
    The old PIG welder don't get used much anymore, I liked it when it was on gas and it got a bit of use in the old days welding up rusty old cars until I started to realize if your going to weld up rusty old cars you'll be patching the thing every year.
    But cause I rarely use it and it's so wet/humid here, I find the wire goes rusty, and the old girl keeps jamming.
    It took me a fair while after swapping to flux core, that I realized the reason the wire kept jamming was because of the bend in the hand piece nozzle, seems the flux core is quite a bit stiffer and does not like to take corners, I straightened the bend in the hand piece and it works better now but gives a weird twist to the wrist when using it.
    I'm no expert with the stick welder, and it takes quite a bit more practice to master than a MIG but gives so much nicer welds once you get the hang of it.
     
  11. JacktheRiffer

    JacktheRiffer New Member

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    I would love to go wwith TIG but I dont have enough money to buy a machine and dont know anyone who would let me borrow one either.
     
  12. Theon

    Theon New Member

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    The cost of the gas is the killer. I have the TIG just no gas.
     
  13. massdrive

    massdrive New Member

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    It cost me $67 to fill my 2500 psi cylinder with argon. That's about 28 hours of welding at about $2.40 an hour for gas. Throw in tungsten electrodes, filler rod and electricity and the operating cost jumps to about $4 an hour. That being said an hour of torch time is a lot of welding.
     
  14. maniac57

    maniac57 Old, Fat, and still faster than you

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    I use a stick welder for the low cost of consumables. I find the tips and gas are always gone when I need to weld and I'm cheap.
    $6 bucks for a box of rods and I can weld for months.
    But the welds are much harder to get right and pretty than a Mig.
    Fluxcore is a compromise that works okay, especially in windy outdoor conditions but is nastier looking and harder to control.
    TIG is by far the strongest and nicest welding process but it does take longer and is more expensive to buy and keep running.
     
  15. Theon

    Theon New Member

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    Here there is bottle rental!
    On top of somewhere around $200 to fill.
    I have beer gas though!
    But at least I own the bottle.
    It might be cheaper in the city, but I don't go there much.
    I'm still learning with the ark welder, but the more I weld the better I get.
    I bought a nice inverter stick/TIG, I didn't get the cheapest, but I got the cheapest HF TIG welder I could find. I'm so impressed with the way it stick welds I've had no need for gas for TIG yet. With the digital amps display, I know that I have it on 70 Amps, or 62 Amps if that's what I need.
    I got some 2mm rods, but now use good quality 2.5 Rods, as the 2's leave more slag than weld.
    I do get a few slag intrusions, but reweld them. I feel that the stick welds I'm doing are much better/stronger than the welds I've got out of my PIG welder.
     
  16. Theon

    Theon New Member

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    I guess what I have found is that with MIG you can get a nice looking weld but with little penetration, however with the stick you know if the weld has penetrated or not by the look of the weld.
     
  17. 16v4nrbrgr

    16v4nrbrgr New Member

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    If you get the MIG amps set right and the feed rate set, you can watch the puddle and tell whether the weld penetrated well while laying it down.
     
  18. 2door

    2door Moderator
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    I concure. Watch the puddle. If you need a magnifier lens in your hood, get one, or place a bright light on your work. You shouldn't have to guess if you're getting penetration; you should be able to see it.

    Tom
     
  19. BobbyT

    BobbyT Member

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    If you use a wire wheel and grinder wheel you can get by with flux core mig. Clean and prep suface. Make sure to atleast wire brush weld each time you stop and continue or cap a weld. I invested in a TIG but used a mig fluxcore for years and never had a problem. Be safe, practice. Use a good welding hemet so you don't get flashed. Good Luck!
     
  20. Theon

    Theon New Member

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    Good bright lighting certainly helps with the MIG.
    My PIG welder is certainly much happier now it has mains power.
    And it is probably 25+ years old!
    Been abused and been worked hard.
    I did think about buying a new one but opted for a HF TIG/Ark welder instead.
    I would like to be able to do a bit of SS fab at some stage.
    As well as the TIG is obvious the ultimate for getting a beautiful neat and strong weld.
    My Tool shop is happening bit by bit.
    But since I got my Inverter welder have only used the old MIG once for welding a really thin wall pocket bike pipe.
     

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