Ask a professional welder, and some tips+trick

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G'day all, I work a professional welder, specializing in high pressure tube and pressure vessel's in the power, oil and gas industries in Australia, but also have plenty of experience with structural MIG welding.I don't on here very often, however, i'm here to offer some advice to all who might need some help, with MIG TIG and stick welding, most of my experience is with stainless and various carbon steel alloy's (309, 316, duplex stainless, low carbon, 250 350 carbon, various bisalloy alloy's, Chro-Mo ect), for aluminium advice i'm not much help, as aluminium isn't often used in the industry i work in.I'll give a few of more advanced tips (fore very high quality work) here, and i'll update it as i can time permitting.Fillet welding in a flat position using a power unit of limit power (200 amp or less)-understand that the difference between a perfectly set welder, and a poorly set one can be a tiny adjustment to one of the setting, and that every welding situation requires a different setup, even if the situation is very similar.-Use the smallest diameter wire your machine can use .6mm is ideal for up to 3/8th steel.-Get to know the theory behind different weld metal transfer methods, know the difference between Dip, Globular, and Spray transfer methods, for down-hand fillet welding, i ALWAYS recommend aiming for a spray transfer, spray transfer requires the most heat input to archive for a given wire diameter, and with smaller diameter wire you can achieve a spray transfer with less heat input on a given machine, which is why i suggest the smallest diameter welding wire you can use for down-hand fillet welding on a low power machine, or when welding material 6mm (1/4 inch) and under.the main advantages of a spray transfer, is that is produces almost no spatter when properly achieved, it gives a smooth weld face, doesn't require you to manipulate the hand-piece to get a good looking weld, but is also forgiving if you can't keep perfectly steady, and due to it's high heat input, it will get very good penetration.The disadvantages of the spray transfer are...-It cannot be easily used in any position other then down-hand, it produces a very liquid weld pool, which run's easily for vertical and overheat welding, it is also less forgiving is welding a corner fillet, as your welding on the edge of the plate where the parent metal will heat very quickly, and can result in an uneven weld toe, or over peno.-it can be hard on your equipment due to the heat involved, and a higher percentage of the heat produced being transferred to your hand piece, i generally find using a size larger contact tip (ie using a .8 contact tip for .6 wire) results in less stoppages and maintenance to the hand piece.-the wire feed unit has to be able to run the wire fast enough.If you have a specific question, just ask, and if i have any advice i'm happy to helpLast edited by ttoks; 03-26-2014 at 10:37 PM.
Reply:I get asked alot about what sort of gas should be used for MIG welding at home, and honestly, there is no simple answer.Here in Australia, the largest gas supplier is BOC gasses, i would normaly recommend they're Argoshield universal, which is 80% argon, 18% Co2, and 2% oxygen, mixes high in Co2 usualy give better penetration, but also more spatter, and are harder to get a good looking weld on thin material (under 6mm plate) another gas i really like for thin steel, is a mix called Argoshield 54 which is 1.5% oxygen and 7% Co2, it gives a beautiful looking weld, with little spatter, and shallow peno, which is good for thin steel, but risk's cold fusion (or lack of fusion) on heavier plate.For a good, all round gas, that will do everything okay, Ie. what most hobby welder's want, go for a mix similar to the argoshield universal (Argon 80% Co2 18% oxygen 2%), it will weld 25mm sections without a problem, but can also weld 2mm plate with some care.if your not likely to ever weld heavier plate (say never more then 8mm, and usualy 5mm or less) then go for something with very little, or even no Co2, and a small amount of oxygen like the Argoshield 54, it will serve you better, but it is NOT suitable for heavy plate.Last edited by ttoks; 03-27-2014 at 01:00 AM.
Reply:You like your O2 down under.  75/25 argon/CO2 it's the De facto standard home welding mix in USA.   Difficult to get anything special in less than.255cf tanks.  Esp if you want a sub 100cf tank fillSent from my SCH-I545 using TapatalkTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:interesting, 25% Co2 is usually used only for very heavy welding here (heavy earth moving equipment ect), and even then only where weld appearance is less important due to how much spatter it creates, even with a spray transfer.
Reply:C 25 is a practical choice for home use because most people are operating small machines that do not have the power to go into spray transfer.  Carbon dioxide is an active gas increasing penetration so more is better when you have a small power source.  For larger power sources that can go over 27 volts and run spray transfer the gases with high percentages of argon ( inert gas ) are practical.  Remember that you cannot go into spray transfer unless you have 20 %  or less carbon dioxide.   "Heavy welding" in North America is done in spray transfer and mixes typically over 95 % argon.  Amperages are 250 and on up.  It reminds me of the time I worked with a Kiwi here in Canada.  He spent a year in Scotland and in the shop he was in they were all using short circuit transfer.  They had the correct gas to go into spray transfer so when he turned his machine up and started outproducing everyone else the boss thought he was God and the crew thought otherwise LOL.
Reply:Down here damn near everyone uses CO2 since it balances out what they earn as opposed to Argon which, to them, is big bucks.I remember the days when the gas whores went from shop to shop with their new miracle mixes and my old mentor said "Sure, that shiitz great if you don't know how to weld".A month later all the CO2 was gone from the shop and C25 was in.I was on C25 from 1985 until about 2 months back my guy ran out so I whined all the way home with a bottle of fhuhkeen Beer Bubbler .Turns out the old man was right. I spit out a nice, almost spatter free weld. The only difference is that it's hard to make it lay down like I like a MIG weld to look. Like a bead of caulk ! You can fart around and make a nice ripple with it tho.I doubt I'll buy any more mix.Not worth the money for what I do. If I need to do body work I'll use my O/A. More fun anyways !Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:I like 95/5 or 98/2 my self.http://www.facebook.com/LockhartMetalArthttp://www.facebook.com/pages/Grumpy...44306259043484
Reply:Originally Posted by grumpycricketI like 95/5 or 98/2 my self.
Reply:Originally Posted by lotechmanC 25 is a practical choice for home use because most people are operating small machines that do not have the power to go into spray transfer.  Carbon dioxide is an active gas increasing penetration so more is better when you have a small power source.  For larger power sources that can go over 27 volts and run spray transfer the gases with high percentages of argon ( inert gas ) are practical.  Remember that you cannot go into spray transfer unless you have 20 %  or less carbon dioxide.
Reply:But you still can't spray out of position.   Sent from my SCH-I545 using TapatalkTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:http://www.advancedweldingsupply.com...guide.html#ACDthis link i just found gives a good description of some different gas mixture's.
Reply:Originally Posted by soutthpawBut you still can't spray out of position.   Sent from my SCH-I545 using Tapatalk
Reply:Originally Posted by ttokshttp://www.advancedweldingsupply.com...guide.html#ACDthis link i just found gives a good description of some different gas mixture's.
Reply:Originally Posted by soutthpawBut you still can't spray out of position.   Sent from my SCH-I545 using Tapatalk
Reply:That engineer was spot on. I like it back here though  This guy didn't even know what draw filing was until I showed up.Ahhhhhhhhhh. Flowers.Last edited by Burpee; 03-27-2014 at 07:50 PM.Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:So how do we go about welding vertical butt fillet weld's?under ideal condition's, using a mixture with no, or very little Co2, and a small amount of oxygen (to stabilize the arc) is the ideal, on thin sections a vertical down weld is quite acceptable (except of course, if welding to a procedure that requires a vertical up weld, regardless of weather it is the best option for said join or not) using a spray transfer at a voltage as low as you can while maintaining a spray transfer, i find 20-21 volts with .6 wire, and while welding vertical down, hold the hand-piece at around a 45 degree downward angle in relation to the work-piece. If you only have access to a high Co2 gas, then you should aim for a short circuit transfer at 19-22 volts, with a larger diameter wire of .9mm or so (perhaps even 1.2mm) with a relatively low wire speed setting for the voltage setting, on material 8mm and thinner, i suggest welding in a single pass, moving the hand-piece side to side a small amount, and relatively quickly, for larger weld's (say on 8mm and over plate, aiming for an 8mm+ toe-to-toe weld thickness), use the triangle manipulation method.Also, if you do have access to a low Co2 gas, and you do attempt a spray transfer, i suggest having a slightly longer stickout then normal (around 10-15mm) and setting the wirespeed as high as you can while maintaining a stable spray arc.Last edited by ttoks; 03-27-2014 at 10:56 PM.
Reply:Hey Ttoks. How long have you been welding for? Did you start out as a structural MIG welder? How long did it take you to become a pipe welder? What are your thoughts on TAFE? I think TAFE sucks *** and should be a lot more intensive. Seriously, they should have programs where students practice welding 40 hours a week. Is it possible to run spray arc on 75/25 Argon CO2? What gas mixtures can run spray arc? Which ones can't?
Reply:Originally Posted by ChadWardenHey Ttoks. How long have you been welding for? Did you start out as a structural MIG welder? How long did it take you to become a pipe welder? What are your thoughts on TAFE? I think TAFE sucks *** and should be a lot more intensive. Seriously, they should have programs where students practice welding 40 hours a week. Is it possible to run spray arc on 75/25 Argon CO2? What gas mixtures can run spray arc? Which ones can't?