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Welders Save My Sanity Please

Discussion in 'Builds and Fabricators Forum' started by Johns1967CJ5, Jan 7, 2017.

  1. Jan 8, 2017
    Focker

    Focker That's a terrible idea...What time? Staff Member

    WA
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    Don't forget this...

     
  2. Jan 8, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    I am not an experienced welder, but Robert of MP&C is. MP&C Shop Projects - The Garage Journal Board

    From looking at his welding, it seems to me your problem is the varying thickness of your welds. This could be because of the thin rusty steel you are trying to weld, or because your welding technique does not put enough new material into the weld, or because the plane of the steel is warping so much that you grind through the high spots. This means the weld goes between thin and thick, and/or not all in the same plane. So when you grind, you go through in some places before the weld is level.

    Robert uses a different method. Instead of welding a few inches of seam at a time, he spot welds the edges of the metal every few inches, then planishes the steel to relieve the local shrinking caused by the welding. He continues to spot-weld, planish and grind until the seam is 100% joined with no gaps. This appears to be a very time-consuming process, but the results are convincing, and it should result in solid steel in the plane of the original panel.

    If I were doing something like this, I would follow Robert's example, and weld just a dot at at time. Welding a few inches at a time (or the whole seam) is going to warp the steel, and disrupt the plane of the original steel, resulting in grind-through when you try to level it.
     
    Last edited: Jan 8, 2017
  3. Jan 8, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    A couple of other comments -

    The short-strand glass filled bondo is the same resin matrix as regular bondo. However, bondo uses talc as a filler rather than glass, and when exposed to the air it will absorb moisture, the interface will rust, and the filler will fall off. When you use glass fiber as a filler, any putty exposed to the air will not absorb moisture, and the underlying steel will not rust. If you coat all exposed putty with paint (ie primer and top coat) the bondo will not absorb moisture and you'll have no problem.

    Body damage is cool... :cool:
     
  4. Jan 8, 2017
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    When welding sheet metal the copper behind the metal will make a Huuuuuuge difference!!! It absorbs the heat and eliminates most of the blow outs.
     
  5. Jan 8, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    It's obvious to me that your using metal inert gas (MIG) but what we don't know is also relative to your success.
    In order of importance...
    What specific gauge is the sheet steel ? 16 gauge, 18 gauge or other ?
    How much rust is present in the sheet metal ?
    What size and what series of spool wire are you using.
    What gas blend are you using ?
    What specific make and model of your welder ?

    Quality welding is mostly about metal condition, metal preparation and finally the proper technique.

    Also we could tell you much more if we could see the weld before the excess grinding.
    While on the topic of grinding I will mention that you are using a relatively coarse sanding type disk.
    Looks like a 50 grit or possibly an 80 grit disk to me.
    A course sand disk is normally only used on sheet steel to remove metal and not intended for removing paint.
    Either go to a smoother grit sand disk or better yet go to a fine grit flapper type disk for the paint removal.
    A fine flapper like 150 to 180 grit will remove far less metal yet easily remove paint.

    If you got to a random pattern orbital with 180 or finer grit for paint removal you will eliminate need for sanding prior to paint.
     
    Last edited: Jan 8, 2017
  6. Jan 8, 2017
    Johns1967CJ5

    Johns1967CJ5 Sponsor

    Northern NJ
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    It is 18 guage steel. No rust, I am cutting back to good metal. Using an argon mixture size of wire is 30. Using a Hobart Handler 130. I do use spot or tack welds then fill in between each, jumping around.

    [​IMG]

    [​IMG]
     
  7. Jan 8, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    OK.
    18 gauge is getting pretty thin.
    Know that proficient use with TIG system provides better or increased control of the weld bead.

    The tacked setup looks O.K. But the beads are a tad tall implying more to grind off.
    Does the Hobart handler 130 have infinate control for both wire speed and amperage ?
    If so a smaller diameter wire will increase your control of the puddle.

    Out a time right now... May comment more later
     
  8. Jan 8, 2017
    Johns1967CJ5

    Johns1967CJ5 Sponsor

    Northern NJ
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    Got it covered

    [​IMG]
     
  9. Jan 8, 2017
    Johns1967CJ5

    Johns1967CJ5 Sponsor

    Northern NJ
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    [​IMG]
     
  10. Jan 8, 2017
    Johns1967CJ5

    Johns1967CJ5 Sponsor

    Northern NJ
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    Calling it quits yesterday helped. Today I was able to fill the blow thru, I think once I get the fuel filler hole replaced I'm calling it for this side. With all the welding yet to do when rebuilding the tub I'll get stuff touched up afterwords. Thanks for the tips. Most of the problem is my inexperience I'm sure. On to the next side.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  11. Jan 8, 2017
    Posimoto

    Posimoto Hopeless JEEP Addict

    Minden, Nevada
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    For sheetmetal welding I use .023 wire. Tough to not burn through with the .030 wire.
     
  12. Jan 8, 2017
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    I use the .030 almost exclusively but I have a big-a$$ piece of copper bar for use on the back- makes life much easier.

    H.
     
  13. Jan 9, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Your fit up looks real good.
    The advantage of small wire is that you can better control low ampers and slow feed speed.
    That yeilds a better controled and smaller weld bead which also reduces warpage.

    Then its a matter of becoming proficient with the disk grinder.
    Knock off the high spots of weld with grinding disk .
    Hold grinder at about 20% angle.
    Then go rto flat disk maybe 80 grit and take weld bead down to surface level.
    Do not blend weld bead with surface unless you do it lightly with 120 grit.
     
  14. Jan 9, 2017
    Johns1967CJ5

    Johns1967CJ5 Sponsor

    Northern NJ
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    I went ahead and ordered the drive roll for the smaller wire for my welder
     
  15. Jan 9, 2017
    sterlclan

    sterlclan Member 2022 Sponsor

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    the problem with plain bondo is the back where it touches steel with tiny holes in it. no shortcuts allowed, use stranded glass filler first then bondo over that the results will last a ton longer.
     
  16. Jan 9, 2017
    Johns1967CJ5

    Johns1967CJ5 Sponsor

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    Typically I would put an epoxy primer down first then the filler
     
  17. Jan 9, 2017
    wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
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    X2 on the .023 wire for sheet metal. And, when I'm spotting in a patch like that, I use a wire brush, often, to clean the area around the welds, when they start getting close to touching each other. Keep it clean as much as possible.
     
    Johns1967CJ5 likes this.
  18. Jan 9, 2017
    sterlclan

    sterlclan Member 2022 Sponsor

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    you are on the right path grasshopper....
     
  19. Jan 10, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Wire feeder roller tension can become critical under certain situations.
    If roller tension is too high then it tends to flatten the wire making it near impossible to push through the gun liner.
    With .023 the wire readily bends and that can potentially be a problem between the roller and the liner.
    One thing that helps is keeping the gun liner fairly straight so that you can reduce roller tension.
    The wire feeder will feed wire much better into a straight and uncoiled liner.

    If roller tension becomes too low the wheels will slip upon the wire and that will also tend to deform the wire.
    Deformed wire cannot get through the copper tip orfice.
     
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  20. Jan 12, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Got a lot of LIKES on the previous post.. Thanks guys so here's a few more MIG tips.

    Many here may never experience this ..... After many many hours of weld time its observed that the gun liner will scrape off the mig wire coating.
    The coating will gunk up the liner and cause it not to feed without increasing roller tension.
    This is but one reason why some wire brands are much better than others.
    NS (National Standard) wire is absolute tops. But it may not be available in small spool quantity.
    To test your wires coating quality you should remove the gun from the feeder.
    Blow high pressure airflow thorough the liner and see just how much gunk blows through.
    This cleaning procedure extends the life of the liner for a time.
    Eventually the liner will go bad from wear and wire will no longer feed through as it should.

    If the liner becomes clogged with wire coating you may also see it accumulating in the copper tip.
    The copper gun tip becomes useless after the orifice enlarges or elongates to an oval shape.
    The copper gun tip itself ensures that the wire accurately feeds straight out from the tip otherwise when the tip wears out the wire begins to feed through without aim.
    Imajine the tip of the wire (the arc) to be your focal point.
    If that's moving about uncontrolled you will never be a really good welder.
    To become a real welder.... simply imajine the weld to be like a Rembrant or Piccasso.

    MIG gun nozzle dip keeps weld spatter off the tip and the nozzle.
    IMHO it is a must have product. A small jar full will last a very long time.
    Get the cup hot then dip it in and then no more of the excess spatter will cling.
    This greatly improves the tip and the cup life.
     
    Last edited: Jan 12, 2017
    47v6 likes this.
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