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  1. #1
    Join Date
    Aug 2009
    Location
    Sydney, NSW, Australia
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    1,836

    Default Hallelujah i can finally mig weld!

    I have been looking at the new migs i firstly wanted a synergic because of the set and go than i started looking around and had my eye on the Italco 185IM or the UNIMIG 182 Viper, Both had similar amperage and welding styles being gas and gasless they both also welded steel, stainless and aluminium so today i called the local Sydney Tools and asked about the Viper by UNIMIG i really wanted that machine but it was out of stock and on back order same goes for the Italco on back order too so i checked facebook classifieds and there was a onetime used Italco 185IM few hours later its in my possession a bit of fiddling around in the shed and a trip to bunnings for a argon mix cylinder and these are my first ever decent mig welds this was strait off the bat i just turned the knobs and away i went

    i did try the multimeter across the terminals inside the machine it was reading around 9.5volts than when i hit the trigger 71volts so trying to set my settings by the youtube/multimeter video didin't pan out

    that steel is around 5mm check out how bloody smooth those welds are i have been waiting for years to run beads like this but untill now it has all been gasless mig welding

    this little machine rocks

    there were problems i had a medium spool with a few winds of rusty wire it was Co2 wire so i fedit thru the machine and each stop and start came a puff of rusty smoke out of the torch but i kept feeding it untill the wire cleaned up than ran that long weld in the pic

    i know my settings are probably off i think the wire speed is to high and i am welding to slow

    another thing about a week ago i picked up a ready weld mask and it is like light and day over my china ebay mask!!! i can see very clearly
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  2. #2
    Join Date
    Feb 2010
    Location
    Ballina, NSW
    Posts
    900

    Default

    Good to hear Gazza - both on getting a ready to go machine and also on improving the welding hood visuals - which will help a lot. Next time do yourself a favour and just cut off the rusty wire prior to feeding it through your mig gun/liner.
    Make sure you weld a few test joints and cut them to check penetration/strength as MIG welds are notorious for looking great but not necessarily being reliable - so always err on the side of too hot rather than too cold.
    Cheers
    Mick

  3. #3
    Join Date
    Aug 2009
    Location
    Sydney, NSW, Australia
    Posts
    1,836

    Default

    Thanks Mick, I have had a clean up so i cleared out all my scrap 2.5mm and 3mm material so this 5mm angle was just to see how the welder ran a bead i am quiet happy to see it penetrate all 5mm's on a argon mix

    can't wait to finally run some decent welds on that car trailer i was building and get some motion in to it, i was originally put off on the weld quality of the previous welders i have had that is why i have not finished the trailer but now i have this little machine with gas i love it already

    i will post up some pictures in the build area on the forum once i lay some welds and clean under the trailer frame, I plan on rotating the trailer frame in any position needed as i can only run flat welds left to right

  4. #4
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    6,446

    Default

    Hi gazza2009au,
    It is good to hear you say those good things about MIG welding. Not too long ago when gas and cylinder rentals were expensive, gas or MIG welding was not in real favor with a lot of old forum posters supporting flux core and Co2 shielded welding.
    As lower costs have made it viable again MIG is once again popular. Mig is incredibly versatile as one day you can weld sheet metal on a vehicle and the next weld up a 10mm fillet.
    However, it does take some practice in recognizing what is good and what is not so good.

    I realise your pics were for practice but bear in mind welding on a contaminated surface is nearly a precursor to a defect. Dirt, rust, oil, paint, and plated metals react with the arc to form porosities. Unlike stick welding, there is no additional voluminous flux to entrap the unwanted material bar some low percentage elements of silicoln and aluminium present in the solid wire.

    Some old ratbag has written some notes on MIG which you may find helpful.

    Welding Lessons by Grahame Collins

    Grahame

  5. #5
    Join Date
    Aug 2009
    Location
    Sydney, NSW, Australia
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    Default

    Thanks GC, I have a wire brush but it isnt doing much, once i master the welds with the new machine every previous weld will be ground down and redone so the surface should be cleaned enough i will use a grinding disc to take away the weld than flap disc the rest will this be enough? i will read that link in a few minutes

    i havebeen playing with the welder for around 30-40mins and i opened up the machine and could see i am still feeding that bad wire thru the machine there were around 30-40 meters of rusted wire so i took the spool out and blew thru the torch a puff of rusty cloud came out than i unwound the spool untill all the cable was shiny than i had another go the first weld was crap but the second and third were what i have been aiming for the past 5-6 years the kind of weld that u can see the pool eating into the job as u weld and when your finished the weld looks like a gully rather than a pile of .... lol but i am noticing the beginning of the weld is cold and i am seeing a lot of blob's fall from the weld could this be from my old tacks? u can see it on the corrugated metal below

    forgot to mention those welds are a down hill weld i could have never done before
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  6. #6
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    Aug 2009
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    Sydney, NSW, Australia
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    Default

    This has to be the best knowledge i have ever read about mig welding, using the two dials i knew one was voltage and one was amps but understanding one controls heat input and the other controls penetration i think i got that right? is a big key in what i am missing out on

    It is relatively easy matter once you understand the metal transfer or sometimes called deposition mode as mentioned above and if you have a good ear. An audible indicator is the (Short arc ) crackling noise that sounds much like bacon sizzling in the pan. The trick is to set the voltage switches at what you think suits the plate thickness and then adjust the rotary wire feed/amps dial until the crackling reaches a its pitch. This is the tuning thing, I alluded to earlier. The dial is wound to a point on your dial where the sound pitch, peaks and is set there.
    now to date i have always played with both dials looking for a sweet spot but that has been like winning lotto, the best bit about the above is how easy its explained

    if i was at x voltage all i need to find is the highest crackling sound than from my understanding if there is not enough or to much penetration u go higher or lower on the voltage and adjust the amps to find that crackle sound untill there is a sufficient weld

    gotcha!

  7. #7
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    6,446

    Default

    Hi gaaza2009au
    Even though you are in the sweet spot there's still some yet finer tweaking to do as yet. I take it you are pushing the torch not pulling. Secondly, the wire feed should be cut back a little, say 2 or 3 points.See the beads in your photos are not sitting flat.
    The very edge of the bead where it interfaces with parent metal should blend in at a very low angle, say 5 degrees. Alternately a change in travel speed and a slight increase, again only a couple of points in voltage should help flatten out the bead.

    In mig, the voltage affects the melting rate of the wire fed into the bead. Increasing voltage makes the pool hotter melting the wire quicker and thereby flattening the bead.

    If you have a compressor, pull the liner and blow it out. In fact, the best treatment is to coil the liner and throw in into a 20L drum and rinse it out in a couple of fingers of kerosene, followed by a rinse in the same amount of methylated spirit and blow it out from the feed end.
    The rust and crap off the wire will eventually come back to bite you on the bum if you leave it there.

    It starts with intermittent porosity that the weldor can't find a cause for when in fact the contaminants are stored in the liner and feeding into the molten arc pool.That method was used for many years to maintain liners at the refinery where we did nickel pipe welding that was x-ray quality .Each and every one of the butt joints were radio graphed,so we could not afford surprises.

    As your skills progress you will learn to read the bead and make adjustments if necessary.

    Remember to move the dials for wire feed and voltage in very small increments once you achieve the sweet spot.

    Good luck with it.

    Grahame

  8. #8
    Join Date
    Aug 2009
    Location
    Sydney, NSW, Australia
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    Default

    Thanks GC, What i could not understand was the total difference in appearance between the inside corner weld and the butt weld both used the same settings but from what i have gathered the inside corner would needs more voltage over the butt weld just wondering how come the butt weld looks so cold? i am seeing the reverse of what should have happened i think

    I may just get a new liner, once i buy the metho and kero plus the tub i would probably be down the same amount for a liner, i think you are right my liner is filled with rust causing the porosity i had fed quiet a bit of wire thru it trying to clean the spool i guess a lesson learnt there

    As for the push or pull i tried to search this yesterday and again yesterday afternoon its unclear if i should be pushing or pulling from what i read and see one of the two gives a wider and more penetrating weld but i could not find a answer if one method was to be used over the other for gas welding

  9. #9
    Join Date
    Jan 2004
    Location
    Mackay North Qld
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    Default

    Hi,
    Mig is pushed while flux core is pulled. Drag the slag as we used to say to the students. The inrush of excess wire cools the weld pool on top of the plate. An increase in voltage at this point would make only a little difference as there is still too much wire volume and nowhere for it to go.It would be better accompanied by reducing the wire feed. When a bead sits on plate and rolls back under it self where the edge meets the plate it causes a notch angle where its likely to develop into a crack.

    Overwelding the bead is a common defect in welding. Operators do it as they mistakenly believe more wire filler makes a stronger weld bead. Any filler metal remaining above the edge cross-section point to point line of a fillet or a butt adds no strength at all.
    To be clearer, look at end of the fillet bead end on.There is a triangle.If you have a straight line from where the edges make contact with the plate, any metal above that line does not offer any strength to the weld.

    Cheers
    Grahame

  10. #10
    Join Date
    Aug 2009
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    Sydney, NSW, Australia
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    Default

    Ah ok in this case with the trailer only 1 milk crate off the ground i think i wouldn't have enough room to push the weld unless i weld up i was welding down so i would have had to lay under the trailer lol

    Thanks heaps for all the advice

    I ran these two more welds yesterday and took some vertical pictures to show the depth of the weld pool, keep in mind thse 4 welds i am showing have been done with my head at arms length away just hard to get into a comfy position with the cross braces on the frame I'm a big boy i can't fit in there lol
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