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I got fairly competent using my modified Harbor Freight Dual Mig 151 with FCAW.  I recently converted to GMAW, and had good results welding a patch on a mower deck.  Now yesterday, when fillet welding 2, 1" thick pieces of mild steel end to end, I had some problems.  First I got a lot pf popping and starting and stoping.  I turned up the gas from 20 scfh to 40 and that helped some.  I played with the stick out and when I got it to about even with the nozzle, it welded good as long as I kept the nozzle almost touching the workpiece.  Is that normal?  Through the whole process, when the arc quit the wire had a big blob on the end, and the nozzle was all crudded up.  On more than one occasion the arc stopped because the wire was welded to the tip, and the nozzle had to be removed and the weld broken off.   I tried increasing the wire speed, but it didn't seem to help.  What am I doing wrong?These are some of the wire ends and the nozzle after welding less than an inch long bead. Attached ImagesHF Dual Mig 151 with Bluewelders and Galaxieman's modsHF Digital Plasma TorchHF Blue Flames Hood70's era Craftsman 230 stick welderVictor 100 OA
Reply:I just started as well, but check the grou.nd for good contactMiller Passport
Reply:Originally Posted by Dave1941I got fairly competent using my modified Harbor Freight Dual Mig 151 with FCAW.  I recently converted to GMAW, and had good results welding a patch on a mower deck.  Now yesterday, when fillet welding 2, 1" thick pieces of mild steel end to end, I had some problems.  First I got a lot pf popping and starting and stoping.  I turned up the gas from 20 scfh to 40 and that helped some.  I played with the stick out and when I got it to about even with the nozzle, it welded good as long as I kept the nozzle almost touching the workpiece.  Is that normal?  Through the whole process, when the arc quit the wire had a big blob on the end, and the nozzle was all crudded up.  On more than one occasion the arc stopped because the wire was welded to the tip, and the nozzle had to be removed and the weld broken off.   I tried increasing the wire speed, but it didn't seem to help.  What am I doing wrong?These are some of the wire ends and the nozzle after welding less than an inch long bead.
Reply:Might seem like the obvious ... but did you change the polarity of the machine when you went from FCAW to GMAW?
Reply:Turn your gas back down to 20cfm. By turning it up that high you can actually exacerbate the problem, as that rate of gas flow can suck the atmosphere in to the shielding area. Next check your nozzle and gas diffuser for spatter build up. Also do check the ground. GMAW (mig) likes a solid ground. And please please please! Don't use that mig on 1" steel if it will be load bearing in any way. As I'm sure most will agree, 110 volt machines DO NOT possess the necessary cajones to obtain adequate penetration.  Although at a glance the weld may seem like its structurally sound it most likely isn't.
Reply:Thanks to all who responded.  I should have mentioned that the part  being welded is a 1" x 1"  x 2 1/2" extension to the lug on the rear end of a hydraulic cylinder.Wheels up, you and others suggested a ground issue.  That could have been the problem because at varying points during the process, the ground clamp was moved from the lug itself, to the table, which may not have been making good contact with the part.Broccoli1, The mating surfaces were beveled 3/8".Ranger_5_0, Polarity was switched when I converted to GMAW, and I had no problem when welding on a mower deck.fronty_78, Thanks for the setting me straight on the gas flow.  The Dual Mig 151 is a 220 volt, 120 Amp machine, and mine was modified as my signature states.  It welds FCAW as well as a friends Miller.  Still, I am aware of the machines limitations.The Cylinder's lug will be under compression when working.  The lug extension is to add some beef to the rear of the cylinder retaining pin hole.Everyone seems to be in agreement about the grounding issue.  I think I made the problem worse by monkeying around with all the settings.  I'll have a reliable ground next time.HF Dual Mig 151 with Bluewelders and Galaxieman's modsHF Digital Plasma TorchHF Blue Flames Hood70's era Craftsman 230 stick welderVictor 100 OA
Reply:Just to be clear, a 120 amp class mig whether it's running on 110v or 230v power is still an 1/8" max rated machine. Just because you bevel and pile lots of weld on it doesn't make it a "good" weld. It still lacks penetration into the base material and is just sitting on top. Do a bend test on something like this and it will crack right where the weld meets the original material. All those mod don't increase the output of that machine enough to make any difference at all. As far as comparing it to a friends Miller, if you are comparing it to another 120 amp class machine that's probably correct as far as it goes output wise. If you are comparing it to a current production 230v capable machine, yours will loose every time you actually do real tests.A far as the hydraulic cylinder being only in compression, don't kid yourself. It's only in compression if the forces are perfectly straight on. Any side load and the rear lug will want to rotate and put part of the weld in tension. How much and if it will cause a failure depends on actual circumstances and remains to be seen. Keep in mind when things like this are under heavy load and let go, things get very ugly, very fast..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:To expand on what DSW is saying, what you are running out of on a weldment like that is both voltage and amps (spelled watts) to put enough heat into a piece that thick. My guess is that your voltage at that point was extremely low, in the dirt. That means there wasn't enough power to snap the wire off at puddle contact like normal short circuit, instead simply melting it off in the puddle. Those wire stubs with large globs at the end sort of re-inforce that and the fact hat you had the better results running the tip as close as possible to the puddle re-inforces that. As tip distance increases the voltage will drop slightly regardless of the 'constant voltage' concept. That's all 'constant voltage' means, constant voltage in concept and constant voltage within a small range. When a welding machine is under powered for the task a slight drop in voltage is too much drop in voltage. You may want to do a voltage measurement on a similar piece as a reference for future use. Easy to do. Hook your meter to the output lugs and put it within reading distance while you get a good stable bead going then glance over at the meter and see what it says."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Your machine does NOT have enough power (heat) to weld a 1" thick chunk of steel, no matter how much you bevel it.GMAW on 1" thick steel is done using machines of the 250-class or better, in spray-transfer mode.Look up the needed/recommended parameters here at the Miller GMAW Weld calculator:http://www.millerwelds.com/resources/calculators/http://www.millerwelds.com/resources...calculator.phprecommended value from the calculator:  30V and 315 amps (390 ipm WFS) using 0.045 solid wire and 98-2 Ar-O2And as DSW said, only in a 'perfect' world would the loads on a hydraulic cylinder lug be compressive only.  We don't live in a perfect world.  There will be shear and tensile loads on that lug, as well as compressive loads.And hydraulic cylinders can have a lot of force/load on them.  If something goes 'wrong', the failure can get ugly, nasty, and FATAL in less than an eyeblink.Rethink what you are trying to do.  Your welder is not the right tool for that task, no matter how much you have 'modded' it or how tight you squeeze the trigger on the torch handle.Beefing up a hydraulic cylinder lug -shouldn't- have to be done.  If the lug is getting bent or torn up, then that means the forces/loads on things are bigger than originally calculated/designed by the cylinder maker.  Cylinder overload, or excess side loads, or somthing like that.And welding a 'critical' weld on a highly loaded 1" thick steel piece is in the realm of using SMAW with 7018 rods or a much bigger wire-feed machine (250-class or better) and spray-mode transfer with solid wire or possibly some FCAW 'structural' wire, not a 'small' GMAW-S weld.  The best laid schemes ... Gang oft agley ...
Reply:Thanks to all for the replies.  What I think is so great about this site is the broad knowledge base of the folks on here.  I asked for help with what was causing a welding process problem, and got good advice on what I was doing wrong.  I can use all tha help I can get, as I am not a welder by any stretch of the imagination.  I also got some opinions regarding what I was attempting to accomplish.  I am thankful for those as well, and appreciate the safety concern shown shown by some of you.  That said, please be assured, that I am aware of the limitations of my Mig welder.  The attatched piece was to serve only as reinforcement behind the retaining pin hole, which is entirely surrounded by the parent metal of the lug.Your concerns have caused me to rethink this design and I am currently looking at cutting off the lug, and milling the end of the cylinder flat.  That would create a surface for suitable for welding on a clevis with a base made of 1/2" x 4 1/4" dia. stock.  That was my original design, but it was scrapped because I didn't want to spend the time it would take to make the clevis.  An old lesson comes to mind about not having the time to do it right the first time, and having to make time to do it over again.To give everyone an idea of what I'm doing, Here is a pic of the cylinders.  You can see the odd foot on the end of the cylinder before machining. Attached ImagesLast edited by Dave1941; 04-03-2013 at 01:31 PM.HF Dual Mig 151 with Bluewelders and Galaxieman's modsHF Digital Plasma TorchHF Blue Flames Hood70's era Craftsman 230 stick welderVictor 100 OA