Question on setting up to Weld Aluminum

Discussion in 'Metal Boat Building' started by youngtrout, Aug 31, 2010.

  1. pwsf
    Joined: Oct 2011
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    Location: Alaska

    pwsf New Member

    What are you going to use the welder for. My first wire feeder was a Miller regency 200 with a spoolmatic 3 spool gun. This proved to be a great gun and setup. I have built boat in the shop as well as fix them in the rain with this gun. I have more welders than a person should including a couple of cobra's with advanced prossessers on them. Great shop guns but much more fickle than a good old fashion Miller spoolmatic 1,2, or 3 ( The ray gun). I purchased an old airco spoolgun that was welding aluminum with a cc welder. i have never tried this gun but it has a great rep and looks real robust. They are now built by Profax. Check them out. Check spoolgun out on ebay also. Be careful of some of the cheaper guns becouse there duty cycle is low. Also you will need a pretty hot welder for aluminum. At least 200 amps.
  2. PSG-1
    Joined: Oct 2004
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    Location: XX' 5313 N, XX' 0526 W

    PSG-1 Junior Member

    The general rule of thumb is 1 amp for every .001" of material thickness. I.E. on 3/16" (.1875") you would use about 187.5 amps. BUT, remember that aluminum has 3 times the thermal conductivity of steel, so the HAZ (heat affected zone) spreads much quicker than it does on a piece of steel plate. In other words, you start with the heat set up high, but once the material starts to get hot, your puddle size will rapidly increase, and you have to stop and let it cool, or you risk blowing gigantic holes.
  3. Magic Rat
    Joined: Oct 2011
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    Location: Wales, UK

    Magic Rat New Member

    I trialed one of these yesterday

    It was set up for ally using a teflon liner and the standard v groove wire rollers were swapped for u grooves, a small roll of 1mm mag wire was used via a standard euro torch. Once you typed your preferences into the machine, basically just material and thickness you were away and it was a doddle to be honest. I can't tell you how easy it was for someone who has never used a mig on ally before. Beautiful welds on 14 guage sheet almost as good as a tig.
  4. 805gregg
    Joined: Apr 2010
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    Location: Ojai, Ca

    805gregg Junior Member

    Go with either Red or Blue and get a push pull machine, that way you can use larger spools of aluminum. Don't buy the Chinese crap.
  5. Ilan Voyager
    Joined: May 2004
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    Location: Cancun Mexico

    Ilan Voyager Senior Member

    Hobart has a 210 Amps MIG. Very good welder, largely strong enough to weld the plates of a 40 feet alu boat. Ready for spool gun.
    about 900 USD.

    For alu a spool gun is a great bonus; 240 bucks. The spool is not a problem, in all ways you have to organize the weldings for making them with enough place, or you'll be unable to control them. And that means **** work. Alu doesn't forgive...

    I have one and works great, and I've welded a few miles with it. (about 200 pounds of alu 5356)

    Welding alu without a spool or a push-pull is a pain on a boat. Push pull are pretty expensive.

    Hobart has also a 230 Amps more professional 1700 bucks with spool gun. Forget the used items, you're will be betting...
  6. pdwiley
    Joined: Jun 2008
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    Location: Hobart

    pdwiley Senior Member

    Funny, I'm on my 12th 15kg spool of wire in my Chinese MIG welder. No hassles whatsoever, no jams, no birdnests, nothing except trouble-free performance.

    I suspect that you're indulging your prejudices rather than speaking from experience.

    Not that there's anything wrong with Lincoln or Miller gear, just they're not the only manufacturers of decent welders on the planet.


  7. Ilan Voyager
    Joined: May 2004
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    Location: Cancun Mexico

    Ilan Voyager Senior Member

    I do agree, as I have used a lot of different welders (stick, MIG and TIG) from a lot of countries, even India. Now with the inverters any good electronic shop can make a decent welder.

    I have also for light work a MIG 175 Eastwood with spool gun (500 USD...) pure chinese that works fairly well, a small Forney AT100 stick and scratch DC TIG made in Italia, a sweet inverter working on 110 Volts 15 amps and weighting about 7 pounds, and a no name chinese WESP 200 amps TIG and stick AC/DC that does its job: weld all that is weldable without complaining. And it draws only 20 amps on 220 volts...

    In fact the lone welder that gave me trouble was a Miller MIG luck, probably a lemon.

    There are many good welders around the world, it's not rocket science...and we are talking about a MIG for welding an alu yacht. Something basic.

    So no need of a super welder with a lot of useless whistles and bells: just a good honest MIG, inverter if possible as it saves a lot of electricity and simplifies the electric installation. Pulse is a very nice feature, but it's for the moment expensive.

    187 Amps for a 3/16 plate is too hot, you won't go far unless you're Speedy Gonzalez...130 amps looks more close to reality for spray alu welding. Preheating the starting place is not forbidden and helps a lot...

    The Hobart is one of the best ratios price/quality in the market, and it's sold everywhere in the States. Light enough to be taken anywhere in the boat, that's very useful.
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