homebuilt welder

Discussion in 'Shop Talk' started by centexguy, Jan 19, 2005.

  1. centexguy

    centexguy Well-Known Member

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    I have a small 165amp miller welder and a Kohler 4kw generator. I need a portable welding rig for fence work, etc, but Im too poor to afford a used bobcat type rig which seem to sell for $1000+ . Could I somehow rig up this combo to work or would it be cost prohibitive to do it? :confused:
     
  2. daeve

    daeve Well-Known Member

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    Jan 24, 2003
    Location:
    East Central Alabama
    At a quick guess (not knowing the input amp rating on the miller) but figuring that most of the small buzz box type lincoln arc units I have used operate at about 70 volts on the secondary, that would be 165 amps x 70 volts = 11550 watts or a bit over 10 kw. The units aren't 100% efficient either so at full output power you are gonna need around 15kw to operate that welder. It "may" work at lower power levels but you are gonna be straining the generator even then.

    I highly recommend the Zena welder. I bought one last year after fighting with the lincoln yet again and needing a few more feet than the 100 foot cables and 150+ feet of 240 extension cord would reach. Cost is a lot less than any other unit in its power range and it does a GREAT job on all the materials I have used it on so far. It will mount on a car or truck with some rigging but after mounting it on my old toyota and burning about $10 worth of gas for a couple of hours of welding I took it off and got a 11 hp side shaft honda engine and built a roll around base to put it on and can now weld anywhere I can get it. I did opt for 50 foot cables but they are worth every penny for getting to those hard to reach places.

    HTH
     

  3. HermitJohn

    HermitJohn Well-Known Member

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    May 10, 2002
    The Zena is a nice setup. If however you wanted to use a buzzbox welder that you already own, might look into a used tractor pto driven generator like farmers use for emergency backup to chicken houses around here. They are big enough to power a buzz box. They are backup and dont tend to be worn out when they show at auctions.

    Daeve, does the Zena work pretty well with the 11hp Honda? 11hp seems to be the minimum they suggest to use with the 150A version of the Zena and even then they are talking about adding extra flywheel so engine runs more evenly under load. Course that may only be for the cheapy engines on low end lawnmowers.
     
  4. Cosmic

    Cosmic Well-Known Member

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    Location:
    Ohio
    Harbor Freight is selling a 10KW generator new with no motor for $299. Probably can drive it with a tractor PTO OK. Should be enough to run your welder. 220V outlet too.

    http://www.harborfreight.com

    Item #45416-0BRA
     
  5. daeve

    daeve Well-Known Member

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    Jan 24, 2003
    Location:
    East Central Alabama
    HermitJohn,

    Works great! The motor is off a pressure washer and seems to have low hours. Made a pulley for it as the ones I had weren't the right diameter. Not big enough even so as the billet of aluminum I used wasn't quite round and I ended up taking off more than I had planned to. Need to fire up the smelter and pour one the right size but time hasn't been available.

    Anyway, the welder may not be outputting the full 150A but it will melt a 1/8" 7013 about as fast as you can feed it and will keep on doing that for as long as you want to weld. I was doing some heavy buildup on a piece the other day and ran it wide open for about 30 minutes feeding one rod after another with only time out to chip slag and the Zena got pretty warm but you could hold your hand on it without a problem.

    Now that you mention the flywheel I wonder if that would take care of the slight hunting the motor does when I've been welding steady for a minute or so. Been meaning to clean the carb and readjust it to see if that was the problem. I think I will cobble up some kind of flywheel to go on the motor shaft and see if that has an effect on it. Guess I can just cast a larger piece with a step down for the pulley and cut the groves into it. And while making changes, go to a serpentine belt too. I have to retighten the v-belt every couple of uses. Even went and bought a new one, thinking that the old one from the Corolla was just worn out, but the horsepower the 150a Zena consumes is a bit too much for a single v-belt. With the serpentine I can add a spring loaded tensioner too. Got an junk Escort that's got one that should be about right. Just what I need, another project... :rolleyes:
     
  6. Ozarks_1

    Ozarks_1 Well-Known Member

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    Jan 11, 2003
    Location:
    Ark. Ozark Mtns. (Marion County)
    Maybe a build-it-yourself DC welder?