flux core wire - need tutorial

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I stopped by a buddy's shop the other day and he had a welder there (a hired pro) fabbing up a project that he was putting together for him. He was welding fairly rusty metal with a wire feed. Being the curious type that I am, as well as (still and allways) being fasinated by the process of melting 2pc of metal into one (welding) I asked him about the rust, and said that I always heard, and it's been my experience that the cleaner the better for my mig. (Millermatic 250X) He told me to try a roll of flux core. My only experiance with f/c wire is with my little 110v Lincoln that I only use for little things that I need to fix where there is no elec.power and I use my generator that I use at work for power. I was under the stupid idea that f/c wire, that I have only seen or noticed in the small 5# spools, was for these little hobby? type welders. Another nice thing that I hadn't thought about that he mentioned was it's nice in the wind.. duh, It's nice to learn new stuff. Can you guys learn me some new stuff about f/c wire. I mostly repair my own farm type stuff and occasionally fab up some brilliant ideas that I have, but the brilliant part is up for debate!  Using .25 - .50 mild steel mostly, 045 wire and 75/25 gas. (might be 25/75 I never remember)  I have a spool gun for some alum. playing but as of right now I might as well just stick some chewing gum on it, still cant get over how fast that stuff (alum)goes from dull to real shiney to a melted blob!Do you still use gas? Out of position ok? tricks Thanks in advance!
Reply:Lots of guys run FC wire in the field. Basically you get many of the same plusses you do for stick. It's possible to get it in the larger rolls, just like solid wire. It's often used for structural work outside and several guys here use it for on site repairs in the field.Note there are two "types" of flux type wires. Self shielded, the stuff like you use for your small mig that doesn't need gas, and dual shield where you need gas ( usually 100% CO2) as well as the flux that's in the wire. Dual shield is usually a production process rather than for field use.While it's true to a limited degree that some FC wires will tolerate rust/paint and so on better than solid wires, its still a good idea to use good prep practices. They will deal with light contaminants, but not heavy dirty parts.As you probably already know it's got all the down sides of sitck to a certain degree. It's smoky, messy with lots of spatter and you have the flux to clean off before you can run another bead or paint..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I fthink you state above you already have a welder which uses .045 wire, 75/25 gas and generally do farm type stuff on quarter to half inch steel.  I think you will be quite pleased if you get some dual shield wire which can be used with that gas mix.  It isn't for windy conditions, it does use the same polarity as solid steel wire or aluminum wire.  I have three different kinds of mild steel dual shield wire I think some are for 75/25 and one is for that or straight C02 either esab or alloy rods apparently made in the same place.  I really cant tell the difference but the most flexible one I was able to wind a spool and use in the spool gun.  It is possible to get .035 in a 10 pound roll but most of it is larger in diameter and spool size.  I find it easier to trust that the weld fused in than the solid wire.  The stuff is rated all position but for my situation an out of position tack is about the extent of it.Fran
Reply:Ok as for those to major types of wire for farm use will mostly be T-1(dual shield) or T-11(self shield) both have there place. Dual shield is great for fairly clean metal that is thicker it will give great penetration and deposistion rate. If done right the bead should be smooth like glass. It is very easy to run, is low spatter, slag is very easily removed and it uses shielding gas like solid wire and DCEP also like solid wire. As for self shield it runs almost like a 6010/11 has a very light flux and high spatter. It can be used on parts that are lightly rusted without problem, it uses DCEN and no shielding gas. It is great for field repair and general fabracation and with practice you can make beads that look almost identical to a 7018. With either type for those thicknesses I would recomend .045 wire and make sure it is E71T-1 or 11 so it can be used in all positions.
Reply:I just tried some flux core today for the first time and I gotta say...I am confused!!!I tried +'ve polarity. I tried -'ve polarity. I tried no gas. I tried with gas (75/25, I think??). I tried Power ranges D-G and wire speeds from 200-500 (Lincoln PowerMig 216). I could not find a combination that would work for me. The wire kept melting (vaporizing really) and barely adhering to the base metal at all. The weld also had a white powder appearance to it, similar to trying to weld galvanized metal - and no the base metals weren't galv. The wire was a silver/grey color instead of the copper-type color I was expecting based on my solid wire.I'll have to check on the number of the wire and see what is was...E71something...I was trying to use the flux-core since the hitch (farm implement) I was repairing was rusty with lots of previous repairs. Hard to tell how the previous welds were cleaned up, although I ground out the crack best I could and had 1/4" bare metal each side of the crack. I was expecting great things! I put the roll back in the box for now until I can get some time to practice with it some more.Andrew
Reply:Originally Posted by Andrew_DI just tried some flux core today for the first time and I gotta say...I am confused!!!I tried +'ve polarity. I tried -'ve polarity. I tried no gas. I tried with gas (75/25, I think??). I tried Power ranges D-G and wire speeds from 200-500 (Lincoln PowerMig 216). I could not find a combination that would work for me. The wire kept melting (vaporizing really) and barely adhering to the base metal at all. The weld also had a white powder appearance to it, similar to trying to weld galvanized metal - and no the base metals weren't galv. The wire was a silver/grey color instead of the copper-type color I was expecting based on my solid wire.I'll have to check on the number of the wire and see what is was...E71something...I was trying to use the flux-core since the hitch (farm implement) I was repairing was rusty with lots of previous repairs. Hard to tell how the previous welds were cleaned up, although I ground out the crack best I could and had 1/4" bare metal each side of the crack. I was expecting great things! I put the roll back in the box for now until I can get some time to practice with it some more.Andrew
Reply:I use and love duel shield flux core.  I run it with a S32p feeder off a sa200.  I have never come to like inner shield.  I just don't like how it runs, but it could well be me.Bruce DeLaetHeavy Equipment Mechanic and Welder1948 SA-200 short hood1949 LincWelder 1801963 SA-200 red faceMiller S-32-P
Reply:Originally Posted by Sandy Of course it will make a bit of difference whether you were running a E71T-GS or a E71T-11 and then each manufacurer will have some subtle differences and then there is the wire size issue. Were you running .030, .035 or .045. and was it a T-11 or a T-GS. Right off I'm going to say you were probably at the very max end for votage. Try taps B, C & maybe D but there again dependant of the wire type and size probably not D unless you want to run the wire at warp speed and pour the filler to whatever hole you're trying to fill.  Voltage tap D is going to be about 20.5 volts. You'll want just less than that most times.
Reply:Originally Posted by Andrew_DI just checked...it is E71T-GS. Should've mentioned earlier that it was 0.035". Hmmm...so looks like I was running too much heat. I'll try it again and see if it is any better.Just did some browsing and saw this PDF: http://www.pdmsteel.com/PDF/welding.pdf. Now this isn't the brand I have, but it mentions E71T-GS at 20.5 Volts, 170 Amps, 204 ipm for 0.180" thick.As a note, with my stick machine, I usually run around 120 Amps, 1/8" 7014 (and also 6013) for 1/4" thick. Bump up the amps for thicker stuff. With the MIG (and solid wire), Usually C or D range, 200-250 for wire speed, again 1/4" steel. With 1/2" thick or better, I'll crank it up to E or F and bump up the wire accordingly. I know it's probably more than most would run, but I'm almost always working on old, rusty (yeah, I clean it...kinda ) 1/4" - 1" material/farm equipment and I figure the extra heat can't hurt....Andrew
Reply:Originally Posted by Andrew_D.....I was trying to use the flux-core since the hitch (farm implement) I was repairing was rusty with lots of previous repairs. Hard to tell how the previous welds were cleaned up, although I ground out the crack best I could and had 1/4" bare metal each side of the crack. I was expecting great things! I put the roll back in the box for now until I can get some time to practice with it some more.Andrew