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Well i bought a 90 amp flux core wire welder from HF the other night. I'm doing some sheetmetal stuff on my truck and needed something besides my stick welder. Anyways, when i went to weld i would go just to put a tack and it would splatter and otherwise look like bird sh**. I am in a shop, ive asked some people who have mig welders whats up and there saying i need argon gas but its a gas free welder? Is the wire on it junk and i just need better wire. Any help would be nice
Reply:if you aren't using gas, you need flux core wire.also, welcome! "Ask not for whom the bone bones, it bones for thee" - Bender
Reply:Welcome, but we need more information on what you are using, Polarity, AWS # of wire you are using, volts, amps, and Pictures.  JohnSMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:Ok I will assume you were using flux core wire. The problem is that is about as good as it gets with that machine. I bought my dad there 140 amp MIG and although not great it works good just a very light duty cycle. The unit I have is a MM350P and I use fux cored in it and it works great but I am running 1/16" wire at 400 to 600 IPM. You are better off with the ability to use gas because it makes a cleaner weld with little spatter. I would set up to run 100% argon because you can weld steel, stainless steel and aluminum all with one gas. If you take the unit outside use the flux cored. I would recomend there 140 amp MIG if you are on a budget or a Miller, Lincon, Hobart, etc. Mig in 150 to 170 amp range for general light duty use. With the extra power you should be able to run flux cored wire ok. Steel Thunder Welding LLC. St. Thomas VI USAMM350PBOBCAT 3MAXSTAR 150 STH375 EXTREME PLASMA6.5 HP COMPRESORDEWALT 18, 24, AND 36 VOLTO/A TORCH SETAND SO MUCH MORE I DONT REMEMBERALL IN MY 2005 2500HD EXTENDED CAB L/B
Reply:IMO, you bought the wrong welder for doing autobody sheetmetal.  Fluxcore  is not MIG.  You need a welder that runs solid wire with an argon\Co2 mix of shielding gas.WeldingWeb forum--now more sophomoric banter than anything else!
Reply:Ok, to start, I would agree with Chevy that true MIG (GMAW) would be the ideal process for this sort of work. However, I'm going to assume that the reason you got that welder was because you're on a pretty tight budget, I've been there, I understand completely.You can do autobody stuff with fluxcore. It won't be as pretty as TIG (GTAW) but you'll probably be grinding everything flush anyway. It won't be as easy as GMAW but it will be easier than with stick.First, you need to double check that you are, in fact, using self-shielded fluxcore wire. This is easy to do, just look at the spool, if the wire is gray, then then it almost definitely fluxcore, if it's copper-colored, then it's regular GMAW wire and won't work with your welder. If it is fluxcore, make sure it is not the spool that came with the welder or from Harbor Freight at all. If it is, you should not use it unless someone is holding a large caliber weapon to your head. Go to a Home Depot or Lowes or (better yet) an actual local welding supply place (LWS) and get a spool of brand-name self-shielded fluxcore wire of the same size (probably 0.035"-0.030" diameter).Weldgault asked about polarity. Your machine is hard-wired for DCEN (Direct Current Electrode Negative) so you don't have to worry about that (just about all the self-shielded fluxcore wires you are likely to encounter, unless you become a professional weldor, will need to be run with DCEN). As far as settings, there are some settings listed in the manual that came with the welder (page 18).I have welded as thin as 18 gauge with my Harbor Freight 110V welder with fluxcore but haven't tried any thinner than that.Here's the method I used:1) Clean base metal.2) Tack parts together with as little gap as possible (take your time making them fit and they'll be easier to weld) with tacks spaced 4"-6" apart.3) No matter how low you set the machine you will probably not be able to make a continuous weld on sheet with fluxcore, so you will have to "trigger weld"4) Start at a tack, point the wire at the leading edge of the tack and pull the trigger for maybe half a second. The idea is to mainly weld on the tack but to allow the puddle to flow forward just a little and fuse the actual sheet together. Don't try to really move the gun, you'll just burn through.5) Here's where I highly recommend using an auto darkening hood. After you let off the trigger, don't move. After the hood un-darkens (not a technical term) you should see the are where you just welded glow for a second or two after you stop.6) Wait for the glow to go away.7) Make an short weld.8) Repeat steps 6 and 7.9) By the time you go a couple of inches you should notice that the glowing takes longer and longer to dissipate. Stop welding.10) At this point you might want to let the machine cool down a bit.11) start welding (using the same method) at another tack (preferably as far away as possible from the previous weld.12) Continue to skip around to different spots until the part is fully welded.13) Grind to achieve desired cosmetic finish.Don't forget to clean the weld regularly. I recommend an angle grinder with a wire wheel (the chipping hammer/brushes that HF includes with their machines are even more useless than the wire).NOTE: ONLY use this method on sheet metal and other non-critical parts. Never use it on things like roll-cages, brackets, trailers, etc.Post pics and we can provide even more advice.Don't give up,TensaitekiAAS Welding Technology - TSTC 2007Visit Tensaiteki.com
Reply:I was reading through the postings and finally someone said it, thanks  Tensaiteki for saying get some real mig wire, the junk that comes from HF is poor quality. He also gave you some good tips to get you started, practice on some scrap material, I got an old car fender from a buddy to cut and weld on. Practice and get comfortable with your machine. Make sure the area you're working in is clean, you dont want any unwanted fires. Welding on a car, have a spotter, a stray spark can set something on fire or the heat can start a fire on the backside and you wont know. A wet towel can be used to extinguish a fire as well as protect critical but unmovable items (ie; fuel lines). Good Luck and Have Fun
Reply:make sure the wire speed is turned way down for fluxcore.DewayneDixieland WeldingMM350PLincoln 100Some torchesOther misc. tools
Reply:Tensalt*-that is the best most thourough advise I have seen yet on that welder.  I have that same welder (still in the box) and will take your advise about the wire.  I want to weld thickness up to 1/4 butt and 1/4 lap joint (2 1/8 plates) for ornamental iron-is the 90 amp capable of that?  Number of passes and cleanup is no issue-I am retired and have time on my hands.
Reply:As people have already stated, for sheet metal, a true MIG setup is the way to go. flux core (i have one) isn't cold enough for thin stuff to be continuously welded. you spend more time patching burn-thrus than you do welding the original problems. like others have said... "trigger weld" it if you can get by with it. also, to minimize the spatter, use anti-spatter spray. some guys say that PAM or other non-stick cooking sprays work too, but i've never tried them. i helps alot with clean up. use a flexible flap-disk or something similar to help you grind down the welds. it helps to keep everything even in my limited expereince. as far as using the tack welds vs. a true weld bead, it is important to keep the HAZ (heat affected zone) as small as possible. when you see the penetration marks getting further and further out, it means there is more area that is more prone to warpage. warpage=time. this time is either spent with a method of pounding out the warps, or filling it with more bondo than is reccomended. alot of it has to do with the thickness of the metal you are trying to weld. also, placing some temporary bracing pieces (3/8" solid round stock tack-welded in place) around your intended welding area will help to minimize warpage also. another trick that i have learned is to use either a nickle-based anti-sieze lubricant aroud the area, or other suitable heat-sink material. the quicker you can get the heat away from the weld, the better, as far as warpage is concerned.hope that helps.Later,AndyLast edited by aczeller; 11-26-2007 at 12:23 PM.
Reply:Originally Posted by KnotboredTensalt*-that is the best most thourough advise I have seen yet on that welder.  I have that same welder (still in the box) and will take your advise about the wire.  I want to weld thickness up to 1/4 butt and 1/4 lap joint (2 1/8 plates) for ornamental iron-is the 90 amp capable of that?  Number of passes and cleanup is no issue-I am retired and have time on my hands.