The Importance of Shielding Gas
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  1. #1

    Red face The Importance of Shielding Gas

    So a few days ago I posted a question about whether to upgrade my new Spray Master 250 MIG torch to Velocity2 consumables.

    I had set up my new Rebel EMP 235ic and made some test welds, and, to say the least, was NOT happy with my results. I had a feeling something was really not right, comparing how my welding was going compared to so much MIG work I've watched on Youtube.
    And I really thought I'd been careful to set everything up correctly.

    HOWEVER, it turns out I didn't have the torch connector plugged fully into the wire feeder. I had definitely loosened the locking thumbscrew nearly completely, but hadn't pushed hard enough to fully seat the o-rings in the bore.
    When I got back to my shop today, the first thing I knew I needed to check was that the gas was getting to the torch, because I realized my welds looked like I'd run out of gas or something. I put the torch near my ear and pulled the trigger, and could not hear any gas flow from the tip.

    So I loosened the thumbscrew, pulled the torch connector completely out, examined it, and carefully plugged it back in while observing the gap at the feeder. See this photo, which shows the tight make-up of the black connector against the feeder housing; this is as it should be.
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    Below are my first three beads at top, without hardly any gas flow. The bottom three beads are today, WITH gas flow:
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    Same beads after a bit of wire brushing (and better camera focus!):
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    That was a piece of 1/8-inch hot rolled sheet.

    Then I tried spray transfer (since my gas is C15) on a piece of 1/4-inch hot rolled plate. The bead to the upper left was definitely spraying, based on the sound:
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    Same image after light wire brushing:
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    The last bead, at upper left, was at 450 IPM wire feed and 28.0V. This is all with .035" wire (Aristorod 12.50 copper free). Gas flow about 30 CFH.
    For some reason it starts out spraying nicely, no popping or bacon sound, pure hissing; then after maybe 2 or 3 seconds it degenerates to some popping and not so clean of a hissing sound.
    I'm wondering whether that could mean I should turn up the gas flow?
    Also after the welding stops the display is showing only about 165 amps; I would have thought with 450 IPM and 1/4-inch plate the current would be higher for 28 volts.
    BTW, I tried to maintain a wire stick-out of 5/8", and I did notice this nozzle/contact tip combination has the contact tip recessed about 1/8".
    The welder is running on a 240 VAC 50 amp circuit, so there shouldn't be any lack of input power.

    Do you think I need to turn the WFS up even higher to force the amperage up?
    There is no doubt this is putting down a lot of metal in a hurry, and also putting a lot of heat into the plate!!
    It's also obvious I need to start working on running a straight, parallel bead, and to keep the torch speed constant. Easier said than done!

    But you can see from the first three beads at the top of the photos, why I was REALLY disappointed with my first welding attempt!!

    I am planning to get some in-person training from a local welder who has agreed to help me. This is just me setting up the system and wanting to get familiar enough with the equipment and setup to be able to really absorb what he's going to teach me.

  2. #2
    Join Date
    Apr 2019

    Re: The Importance of Shielding Gas

    It's also obvious I need to start working on running a straight, parallel bead, and to keep the torch speed constant. Easier said than done!
    I find that some torch manipulation really helps to get into a rhythm, thus making the bead more consistent. It also helps to "play" the light around giving you a better view of what's going on, as well as where you are going.

    EDIT: If you have not already found him on Youtube, Jody from Welding Tips & Tricks is an excellent resource for everything welding.
    Last edited by Flat_Bastard; 06-01-2019 at 01:20 PM. Reason: more info
    Just say, Know.

  3. #3
    Join Date
    Mar 2005
    Under a Rock

    Re: The Importance of Shielding Gas

    remove "spray transfer" from your vocabulary for now.

    try welding something together VS bird turds.

    you will soon learn you are too cold.

    crank it up.
    try a T joint.... it's pretty easy.... kinda like walking the cup/nozzle.... and it traps the gas in there....

    then beat it with a hammer and see where it fails.
    Miller 211
    Hypertherm PM 45
    1961 Lincoln Idealarc 250
    HTP 221

    True Wisdom only comes from Pain.

  4. #4
    Join Date
    Jul 2018
    Cumbria, UK

    Re: The Importance of Shielding Gas

    Regardless of what amperage the machine is showing, it should be in spray transfer at that voltage and wirespeed, assuming C15 gas. It's crackling because the wirespeed is good and high.

    settings sound good to me. You need to run some proper joints to verify. It will run differently than it does just running a flat bead.

  5. #5
    Join Date
    Sep 2013
    central Wis.

    Re: The Importance of Shielding Gas

    A poor ground connection will often cause the popping.
    Miller xmt304, Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.

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