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  1. #1
    Join Date
    Apr 2007

    Default Running a Thunderbolt XL 300/200 off generator

    Hello, first post here.

    I have to weld a manual thumb base plate

    Onto my excavator in the area indicated

    The base plate is 1" thick, and I imagine the portion of the excavator boom I'll be welding it onto is at least 1/2" thick.

    I have never welded anything this heavy, I'm not a professional welder. Sometimes my welds turn out great. sometimes they don't... This will need to be a very good weld.

    The plate was cut off another machine, it had a 1/2" full penetration fillet weld all around the outside of the plate. I'll be looking to do the same.

    A few family members have home generators that I can use, but all of them only put out 50A at 220V... My welder can draw 70A at 220V.

    If someone with welding experience could give me some pointers, that would be wonderful. (What type of rod to use, welder settings, etc)


  2. #2
    Join Date
    Mar 2006
    Ocean City, Maryland


    Those are not bad to weld on. When used, the arm kinda pushes against the boom so the welds do hold it in place but don't really take all the force. I've put a couple on on smaller machines. As far as the generator I've never ran a welder off of one except small MIG. Yours probably won't draw 50 amps though because it draws 70 amps at max output and you wont weld it at 300 amps. Here is a page that I found that has electrode info.

    You could use 1/8" rods which you probably already have,Just might have to make a couple of passes at each weld place. 5/32" would probably be better but not necessary. You could use bigger rods, But I'm thinking to keep your amps down to use smaller than you might normally even if you have to make more than one pass. 7018 would be good but 6011 or 6013 would work too. Use DC+ or AC. You don't have to weld a continous bead just space them out. AS far as amps go it depends on the rod and the position. Probably vertical for you but you could lay the dipper down more and make it close to horizontal or flat. The chart I attached will give you a rough idea of each rod range. You can always grind it back off if it looks like crap and change the amps. Hope this helps some, good luck
    HMW [Heavy Metal welding]

  3. #3
    Join Date
    Aug 2006
    Oklahoma City, Oklahoma


    Just a note on the home generator usage. In this setting I don't think you would have much of an issue. Sounds like it's just a one-off thing. When you look at the generator, make sure it has a suitable rating for continuous resistive loads. A lot of marketing departments try to slip in peak inductive load capacities to make their machines sound really good. Unfortunately, that is only good for a few moments while an electric motor gets up to speed, not several minutes of short circuit,dead load from a welder. If you aren't completely sure, just make short duration welds and give the gen time to cool down if it needs to. Hate to burn up a $3,000 gen for one short job! Anyway, just some FYI....I burned up one I have a Bobcat SSS

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