First post, and question about flux core amperage....

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Good evening ladies and gents (not sure if theres chicks around, don't want to get off on the wrong foot).First time poster here with what will be the first of MANY questions here.I'm welding some 1/4" plain steel for some very important suspension components on my 78 dodge w200. I'm using the only welder I have at my disposal, an 85amp Craftsmen (I know, I know).I just did some good investing (I think), into a Miller Performance helmet and my next purchase will most likely be a 125-140amp 110v MIG/Flux Core unit (Hobart, Miller)My question is, I've done a lot of welding in the past but with other people's welders that could easily handle 1/4". The welds I'm making with this unit look strong and there appears to be good penetration.I want to know if an 85amp flux core welder on its highest setting and slowest wire speed getting the 1/4" steel hot to the point of warping is capable of being strong enough for my application.As a followup, before this project truck gets on the road, I may have very well purchased the welder I'm looking at (~500 beans I DONT have at the moment). If I want to go over the pieces I'm making now with the higher amperage welder, will I need to grind the old welds away, or should I be able to pass right over them?Many thanks, sorry for being so long winded. Let me know if a picture of the piece in question would help.Cheers,Pat
Reply:85A is not enough... get a machine with bigger balls...It will do "nice looking" welds but they will not be "good".For suspension parts on a truck I would want no question that the welds are good.  And yes you will need to grind them out if you need to redo them.Maybe just tack them on and have a welder come and burn them on for you?Me!
Reply:I'm afraid I've already gone too far on 4 of the pieces that took me roughly 12-14 hours to cut and burn.But in the interest of safety (these are going to be parts solely responsible for holding up a 5000lb+ truck), I'd be willing to scrap it all and do it right.There probably truly is no easy way to grind these welds out. Oh well.And getting back to what I suggested before, would a 140amp mig welder be able to put these pieces together?What would be more suited to making sure these brackets are rock solid? Stick?
Reply:Appearing to be good welds and being good welds are two different animals.One of the drawbacks of mig welding is the lack of deep penetration. It is very easy to get that kind of penetration with stick and very economical. A Lincoln AC/DC tombstone and some good practice will get you all the penetration you need! They may not be as pleasing to the eye, and it is not in your original post so I'll leave that well enough alone.If you do not get good penetration on a first pass, another pass will not help penetrate any deeper, you will only pile up on a shallow root pass. I would consider investing a bit more into a 220-240 VAC powered mig welder if possible. Where mig is used, slowing down wire speed will not help dig in imho.Last edited by tanglediver; 08-21-2007 at 10:13 PM.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:A 135amp Lincoln wirefeeder welder (the SP135) is one of the better little wirefeeders they make.  This feeder can actually achieve a spray transfer which requires a lot of power.  I was only able to weld 1/4" steel with a slight bevel and an open root and it was MAXED out with flux-core.  It did weld 3/16" comfortably but the duty cycle was kicking in after about a foot of welding and had to cool down for about 15 minutes.I hope that gives you an idea of what type of power you need to weld that 1/4".  You will probably want something a bit higher than 135amp.
Reply:Originally Posted by tanglediverAppearing to be good welds and being good welds are two different animals.
Reply:Not that I'm sure it changes much but I was gasless during this weld. It was my understanding that using flux-core allowed for a hotter weld that thereby equaled a deeper weld.
Reply:Originally Posted by SandyPretty iffy.
Reply:Originally Posted by EnderAgain, in a truck that I'm going to be driving around in, in New Jersey traffic, I want anything BUT iffy. Sloppy and ugly I can take. The truck is both. But iffy and "eh" will not make me feel good.
Reply:Just as an example, these are the pieces in question. I know, as you've said, its hard to just look at a weld and say "yea, its enough", but it may give you some hints.
Reply:You made your own lift? They look good! The lincoln machine is listed for about $600.00http://www.mylincolnelectric.com/Cat...eet.asp?p=2494But, then again, it operates on 240VAC. Flux core from a little machine is still not going to dig much deeper without bumping up the power input. For what you are doing, those look presentable, do you trust them? What you have are spring hangers, aren't they? I'll tell you what, you burn them with a powerful machine and warping will be a real threat. Fabrication aint my bag, so I better defer to the fab masters among us! City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Yeh, looks like most of your joints are some variation of fillet. That's good. I see where it looks like it flowed well in some places but don't see any signs of it really digging in. Like that one closest corner in the top pic,, looks a little concave, grind some of that out for a groove, turn the heat up and fill it in.I'm sort of judging by the bolt hole sizes that these brackets are theoretically beefier than whatever is going to bolt up. That helps. That bottom pic looks okay at a glance. Where you show that inside piece on the left hand side with the three way corner-------I can pretty much tell you there's a lot of porosity in that corner. Flux core can the problematic in corners. Tons of slag being cast out in all directions and it gets trapped in corners and you have to be hot enough to float it out. Hang in there very long and you're just piling wire in there. If you've got a die grinder from hades you can sample one of those and see.The tendacy, mine anyway, is to try and shove a lot in there thinking that long term heat will make it all magically melt and flow together. Not true. It might if you could somehow stop the wire but keep the heat coming. That's called O/A welding.  You're better off with smaller quicker passes, grind out the ridges and cold lap, do another pass. I'm thinking you need to do a couple of mock ups on similar pieces.  Break one if you can, grind one out looking for pockets. You gotta satisfy yourself
Reply:Flux core from a little machine is still not going to dig much deeper without bumping up the power input. For what you are doing, those look presentable, do you trust them?
Reply:What you have are spring hangers, aren't they?
Reply:Originally Posted by EnderAnd getting back to what I suggested before, would a 140amp mig welder be able to put these pieces together?
Reply:Originally Posted by SandyWas thinking and got to chuckling a little. What we used to do and call them hanger kits  . Pieces of flat scrap bolted up with whatever... Some of them even worked for awhile.
Reply:85A FCAW on 1/4 inch steel?  Nope.Remember that rule of thumb about amps and workpiece thickness of 1 amp per 0.001 inch thickness (for single-pass full penetration welding).  So 1/4 inch work would call for 250A of current, give-or-take a little.  If you were looking at a butt weld, you could sort of think along the lines of making a pass from both sides of the joint and then you'd be at around 125A on each pass.  That will pretty much work OK.Running a little 110V-120V FCAW machine at MAX (one of the recent 125-140A class machines, like a SP125, PM140, MM140, etc) -could- do an OK job on 1/4 inch material with multi-pass (like doing a weld pass from BOTH sides of a joint, not just piling up metal on top of more metal) and 0.035 flux-core wire.  But you will be pretty much running the machine at/near MAX and your duty-cycle will be short.  Like in run a short bead for 1-2 minutes, then wait 10-15 minutes for the machine to cool off some, run another short bead for 1-2 minutes, wait 10-15 minutes for machine to cool off, etc.A couple of FYI.  Yes FCAW runs 'hotter' and can do a little thicker material than solid wire in the same machine.  A wire-feed welder typically has two controls, the voltage setting and the wire speed setting.  The wire speed setting is pretty much what controls the amperage or heat going into the weld.  So to get more heat into the weld, you have to turn the wire speed UP, not down.Regarding heat, you can put enough heat into a work piece to warp it, and still not have an adequate or proper weld.  That's called a cold weld, cold lap, incomplete penetration, or 'caulking'.  You need enough heat going into the weld to not only melt the wire (that's the easy part), but to also MELT the workpiece so that the molten puddle of weld consists of BOTH the wire and the workpiece.  You can't just pile up molten wire on top of the workpiece and call it a weld.The little 110-120V wire welders typically are rated at 90-100A output, but the newer ones -can- nudge up to their nameplate 125-140 amps, on a real short duty-cycle and an adequate but not high arc voltage (read that as you are going to be running the machine flat-out and with the tip really close to the work).Moving up to the 220-240V machine would give you more 'oomph', but a 110-120V machine could do your 1/4 inch material with a little more prep work, making more passes, and a short duty-cycle.To run a 220-240V machine, you could just make an extension cord and plug it into your clothes dryer outlet (if you have an electric clothes dryer, that is).  Just unplug dryer, plug in special extension cord, weld.  When done, unplug extension cord and replug in dryer cord.If your panel is full and there are no open/available blank slots, you can get a couple of half-width breakers (two breakers fit in one slot), shuffle around some of your existing breakers, and put in a 240V double breaker for your 240V welder.   You would basically take 4 existing standard 15A or 20A single-slot breakers and replace them with 2 2x breakers (matching the 15 or 20A capacity of the original with the replacements).  That frees up 2 slots, where you can then install a 240A 30-50A breaker for you new machine.Another choice would be to find a bud or acquaintence with a bigger welder and have them redo the welds.  Where in NJ are you, roughly?
Reply:Thanks for all the info, Moonrise.Having things explained like that makes it a little easier for me to grasp. I have no technical training in welding. I've been welding for a few years but only small gauge sheetmetal in body work applications, never anything structural and never anything that high in voltage/amperage.The questions that this thread is spawning in my head deserve and could take up 30 more new threads but I guess it couldn't hurt to ask a few general questions here.Its obvious I won't be using these pieces as/is for my application. I've taken all of the members that have replied experience and know that it is far far greater than mine. My general concern for safety and wanting to do something right the first time outweighs the fact that its going to SUCK to re-cut and redo all of this. I will most likely be doing more welding of this caliber in the future, where strength is an issue. Looks are not a general concern. Would investing my money in an AC/DC stick welding outfit of 220-240V better suite my needs instead of spending a couple extra hundred bucks for a 220-240 MIG outfit capable of the same welds with a little more ease?I only know one person in my area that I used to do some work for but I haven't spoken to him in a while. I'm not really comfortable with just calling him up and saying "hey, wanna weld my stuff together". I'd feel like an ***.I was actually thinking that ganging an exterior 220 connection off the Air Conditioner curcuit shouldn't be a problem. I'll simply make sure the A/C is off while welding. I could always try and fit another 220 curcuit in the box by moving around some smaller breakers (didn't consider that idea).I live in Hazlet Township, Monmouth County.
Reply:Originally Posted by WelderBoyA 135amp Lincoln wirefeeder welder (the SP135) is one of the better little wirefeeders they make.  This feeder can actually achieve a spray transfer which requires a lot of power.
Reply:The AC/DC stick will be the cheapest way to weld larger stock.Like this one on eBay:http://cgi.ebay.com/lincoln-AC-DC-12...QQcmdZViewItemThe DC stick can give good welds that also look nice, it depends on how well you control.  MIG is nice, but if you are planing on doing this and larger stuff (you will) get the 240v MIG, the MM212 would serve you well, and not leave you needing more, but you will pay...Me!
Reply:"ganging an exterior 220 connection off the Air Conditioner curcuit (sp) ..."As in splice some wires into an existing hardwired air conditoner and run those jury-rigged wires to some sort of outside outlet?  Nope, not safe, not legal, not good.    If the 240V air conditioner is a window/wall corded unit (a unit with a plug that you connect to an outlet), then you can unplug the air conditioner and plug in your "welding extension cord".  That's safe (generally) and code 'legal', if the breaker is adequate for the welder.If you have an electric clothes dryer (typically a 240V 30 amp circuit with wires and recptacle to match), just make up your "welding extension cord" and have at it.  After you get your new/used 240V welder.Stick is versatile.  With the right rods you can weld almost anything.  Takes some more skill and practice to do than MIG typically does.Oh, and one aspect of welding thicker stuff I forgot to mention.  As the workpiece gets thicker, it acts as a bigger and bigger heat sink and thus takes more amps to get the workpiece to start to melt (properly).  Without melting into the workpiece, all you have is melted filler (stick -or- wire) sitting on top of the workpiece.You can sort of think of your existing welds as big tack welds, and then grind out from one side a little over half the thickness of the welds.  Redo the welds with an adequate machine (120V FCAW, or 240V GMAW/FCAW or SMAW/stick).  Then grind out the back side until you get through all the old and just into the new, and redo the welds with the adequate machine.  Done.  Die grinder or angle grinder should work (I can't see the pics right now, dang network).Or you could think of the first try as a mockup/prototype.  The next one will go much faster.
Reply:Ah, now I can see the two pics.The welds aren't horrible, but they look just a little bit not-quite-enough.  You typically want the weld bead to be just a touch 'proud' and convex of the surface(s) you welded.  Your's look just a touch concave (curved inward instead of slightly bulging outward).  The fillet weld beads didn't quite melt -into- the base material, the butt weld beads look better in that regard.And before running a new bead over an existing bead, make sure the old slag/crud is removed first.
Reply:Originally Posted by ChamferTrodeO.K. I've stopped laughing, WB what kinda drugs are you smoking?spray w/ a SP135??????It doesn't have the voltage necessary to spray (>24) nor the amperage. let me guess you did this "spray transfer" with C25 as well.thanx for the humor.
Reply:nice looking welds but i think they look a bit cold to me. (but i may be wrong) any thing that has to be rock solid needs to be at least in the 160+ range.the day you stop learning in this tradeis the day your in your grave
Reply:Originally Posted by WelderBoyThe SP135 can spray .030 wire with 95/5 ar/o2.  I've seen it with my own eyes.  Don't be a dick.  That doesn't help anybody.Originally Posted by David RShow me.
Reply:So, you didn't do this, but you saw it done. The teacher was explaining how it was a nice machine and how it packed a punch.
Reply:My gas weldmanpower with an Onan would only spray if it was set on CC as high as it went.  the gas was Stargon, .  Some kind of mix. .030 wire About 200 amps.If ya sprayed with a 100 amp gun, it would melt.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:I didn't know much about welding at the time, but that is what he said.  I've only used those machines for innershield on 16g material personally..  All I remember is the crackling went completely silent and all I heard was the sound of gas and an arc.  It could have been the 175a model though and the wire may have been .023.  This was about 4 or 5 years ago.  Sorry if I am wrong.
Reply:To reach a spray transfer a several factors need to be met. A gas that will have an ionization potential that will allow a spray, amperage that is at least equal to or more than the transition current of the wire, and adequate voltage. Any one of these factors are not met and a spray will not be possible. The transition current for a .030 wire and 95/5 ar/O2 is a little under 150 amps. The SP 135 only rated to  give 90 amps at 19V, and that is at a 20% duty cycle. There is no way that such a small machine could reach 150 amps and still maintain a high enough voltage to reach a spray. The machine just doesn't have enough kilowatts available.Arguing with a Welding Engineer is like wrestling with a pig... after a while you realize the pig likes it
Reply:reddoggoose, could it spray .023?  And would the SP175 (or whatever that higher up model is) spray?  I know for a fact that it sprayed, but now I am not sure if it was the 135 or the 175ish model.  It could have been .023 wire too.
Reply:Maybe the old machine in question was actually an SP130?  The SP130 is/was a 240V machine, rated output 130A at 20V 30% duty-cycle, and rated/made to feed up to 0.045 flux-core wire.  Sounds like a 175/180 class machine.The SP135 is/was a 120V machine.Yeah,  quite confusing how Lincoln had the 125, 130, and 135 machines and they could all be such different power and capacity machines and have names so close!  The WP155, SP130, and SP170 are close to (if not) the same machine, all 230V machines.  They can push 150A at about 19.5V on max, about 160A at 19V on max.  Hey reddoggoose, can 0.023 wire push enough current to reach spray transfer, especially before current saturation?  The charts and references I can see don't list the 0.023 wire for spray, they all seem to start at 0.030 wire (listing 150A with 98-2 Ar-O2 as the spray transition level).Oh, and maybe the old demonstration was with aluminum wire?  Spray transition for 0.030 aluminum wire and argon gas is listed as 95A, easily within  the output of the current 125-140A 120V MIG machines.
Reply:I have never personally tried to spray with a .023 wire, but see no reason why you couldn't. It is a matter of current density for the wire. A .023 will just require less current to reach the same current density as a .035 or any other size wire. When sufficient current is reached, assuming enough voltage is available, and the correct gases are used a spray transfer should be attainable.For practicle purposes .023 is too small to serve any real purpose when used in spray transfer. This size of wire is obviously a smaller diameter that requires less amperage to melt. For this reason the only real practicle purpose if for use on thin materials when amperages need to be kept low. Most times when a spray is used it is for deep penetrtation on thicker materials, and for high deposition rates. Trying to spray with an .023 would really serve no purpose. This is probably why no transition current is listed for that size wire.Arguing with a Welding Engineer is like wrestling with a pig... after a while you realize the pig likes it