500amp MIG guns

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I am not that much of a seasoned CV welder, so I got some questions. I am running a dual shield on 1/2 - 1.5" heavy plate, large weldments (600-10klbs). Currently we only run 045, but I was thinking of running 1/16. Lots of gun combos seem like viable options, I wish we could try a few out. Looking at the Bernard Q or S line, but really open to others.  Any thoughts on this? Anyone working with heavy plate regularly learn some things the hard way they would like to share?We used to stick everything, often in the field, but demand has stripped us of the time to do it that way.Last edited by Davidbrown; 06-28-2013 at 06:48 AM.Constant Current Weldor.
Reply:I used to work at a water tower manufacturer.Before working there, I had only used tweco mig guns.They only had Bernard q guns.Now I only have bernard guns in my home shop.We welded everything from 14 ga to 1.25"I think they only had q400s
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Reply:I just got a chance to use a Bernard 'S' Gun recently.  They have a special flat steel coil inside that makes the guns much more resistant to kinking and pinching the wire.  I was able to weld while another guy bent the cable in a 3" radius.  I wasn't able to tell the gun cable was bent at all.  I was also able to stand on the gun cable, using my full weight, without affecting the wire feeding.You can only get these 'S' guns in 300+ amp sizes.  But they are awesome if you have to use a long gun and bend the gun to get into tight places.With regards to 1/16" FCAW.  You'll definitely be able to put down metal faster.  Depending on the brand, and type of wire, shielding gas, etc you may or may not have more difficulty welding out of position.  If you can move the work to keep the welds flat or horizontal, it's a no brainer.  Only other issue I could imagine would be increased chances of burning through; but that can be avoided with a little setup testing and practice.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:What are the max settings for a 1/16 FCAW-G? How much does it depend on the wire?Anyone try the Hobart Vision? Looks like a hybrid of metal cored & flux cored? Seems like a good idea, if very low diffusable H is not a requirement.Constant Current Weldor.
Reply:You can pick up a new take off Q400 on eBay for 100 bucks. I had one but traded it to a friend for his300, as he was doing heavy spray arc on thick plate and I don't do it often.
Reply:I currently run the Q300 on my 12RC powered by my TB302 which tops out at 300 amp @ 100% duty cycle.I run NR 212  .045 all the time on equipment repair jobsNow i find my self welding up race cars running .035 and that big nozzle is a PITA so i just got the small nozzle and tipLove the Q gunBacked my CATMA over your CARMA oops clusmy me  What would SATAN do ?? Miller Trailblazer 302 AirPakMiller Digital Elite  Optrel Welding HatArcair K4000Suitcase 12RC / 12 VSHypertherm PM-45Rage 3 sawRusty old Truck
Reply:Water cooled guns are really the only way to continuously weld at high amps.  The gun stays cool.  The Contact tips last almost a full forty pounds of wire.  The guns themselves tend to be a bit heavier. The big problem is that if you damage the lead you are looking at close to a grand to replace.  We had several Lincoln powerwaves on booms with water cooled gun leads.  Eventually the leads failed after a few years and management changed to air cooled guns.  I noticed production went down.  We started to use many many more contact tips each week but the company saved all that money not replacing the water cooled units.  Also ratings for guns are for carbon dioxide.  For mixed gasses you have to derate about 2/3 so a 300 amp gun really is only good for 200 amps on mixed gases.