MIg welding

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I use a Hobart 140 MIG welder. It has flux coil compatibility which is what I'm using at the moment. It sprays alot, and around the area that I weld I get a coat of a white brownish powder. I consider my self a novice at welding, so am I welding with an improper technique or is this the down fall of not having an inert gas?but I've been thinking about getting a tank for 75% argon 25% CO2 mix. Not sure on the size.. maybe 40cf or 60cf, but can someone tell me how long every 10cf lasts? Would 100% CO2 get the job done as well the argon/co2 mix or not? What are the advantages of each?also, does mig produce strong welds? currently I'm trying to polish my skills, and get the necessary equipments to do quality work, but my work will later go into my car. So will I be able to do safe projects with the mig or would I have to switch to another type of weld? Obviously no one wants a bracket to brake and have the axle of the car go while you're going 75MPH. Does flux coil give you any weaker of a weld than an inert gas one or is the presence of an inert gas all about control and having nice looking welds?
Reply:Your in good hands here.  These guys can answer all your questions.  What kind of mig wire were you using? weld it like you own it
Reply:Flux "core" (not coil) welding  produces lots of spatter and the "powder" your talking about. Flux is used as shield for the weld, producing it's own environment and keeping out contaminants that are detrimental to the welding process. The flux is in the center of a hollow wire you are using, hence "flux core." The outer coating of stick rods are types of flux. Argon or CO2 and 75/25 are shielding gases for the mig process, acting in place of flux, creating an environment for a proper weld. Depending on what you are welding, the process you're using and experience, determines the type of shielding needed. How much gas is used is determined by all of the same parameters. I'm a stick welder, not a MIG welder, but I think this will explain the basics of your questions. There are welders here that can get very technical about MIG. Ask your question and someone will answer them for you. Welcome to the forum! Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.                                         -Cree Indian ProverbSA 200 LincolnVictor Torches
Reply:Do a search on this forum it has been discussed alot, also if you go to this site, you may be able to save money on the information they provide.Depending on shop air movement you can go down to 15cf on your gauge.http://www.netwelding.com/
Reply:Originally Posted by lewrayYour in good hands here.  These guys can answer all your questions.  What kind of mig wire were you using?
Reply:Originally Posted by pistolnoonDo a search on this forum it has been discussed alot, also if you go to this site, you may be able to save money on the information they provide.Depending on shop air movement you can go down to 15cf on your gauge.http://www.netwelding.com/
Reply:A 140 amp wire fed welder used on axle parts would cause me to raise an eyebrow. Nobody wants you losing parts while doing 75 mph either, especially if that somebody is behind you! Skimping on shielding gas use raises the possibility of losing gas coverage and allowing porosity to form. Outside the shop, I have used as much as 35 CFH. There is a limit at the upper end of the scale because too much gas flow causes turbulence, this also causes a loss of shielding gas, and the introduction of porosity. 15 CFH will barely cover things with no wind present, that little amount of gas flow will blow away with ANY breeze at all. But inside of a shop, it may be ok.Fluxcore is said to dig in more than solid wire. The 140 amp machine is fine for light guage work, but before you hang an axle with it, get lots more information and practice. You may find it under powered for critical automotive work, which should be done with definite skill, knowledge and the right equipment.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:Originally Posted by tanglediverA 140 amp wire fed welder used on axle parts would cause me to raise an eyebrow. Nobody wants you losing parts while doing 75 mph either, especially if that somebody is behind you! Skimping on shielding gas use raises the possibility of losing gas coverage and allowing porosity to form. Outside the shop, I have used as much as 35 CFH. There is a limit at the upper end of the scale because too much gas flow causes turbulence, this also causes a loss of shielding gas, and the introduction of porosity. 15 CFH will barely cover things with no wind present, that little amount of gas flow will blow away with ANY breeze at all. But inside of a shop, it may be ok.Fluxcore is said to dig in more than solid wire. The 140 amp machine is fine for light guage work, but before you hang an axle with it, get lots more information and practice. You may find it under powered for critical automotive work, which should be done with definite skill, knowledge and the right equipment.
Reply:I did not want to turn your post into a cfh vs fluxcore post, you will be much happier with sheilded gas.I believe adjusting the sheilding gas is as integral as wire feed and amperage.I always thought more was better till I started paying for it. If you are planning to work from your garage your rate with the doors closed 20cfh should be all you need, open up those doors abit and it may take 35.You may want to think about purchasing a tank. Here is a post on tank sizes, check with your lws for prices, lease rates.http://weldingweb.com/vbb/showthread.php...cylinder+sizes
Reply:Med!c,First I would like to touch on your idea of using AL fr a bumper. This will require additional knowledge to weld. It is not the easiest thing to weld. You can search the forum, but there is a lot of prep and skill involved. Steel will hold up better in the long run, and do better if impacted. FCAW-S (flux core self shielded) and GMAW have the capability of producing the same strength weld. This is based on the tensile strength. ER70S-6 (GMAW) and E71T-1 (FCAW) are both 70,000 tensile strength filler metals. Additional properties, like ductility, are dependent on wire. You can get some with high or low ductility depending on your needs. As far as shielding gas 35CFH will probably fit your needs. Not something you want to skimp on. 15 is way to low. The final appearance can always be touched up. When using FCAW there is more splatter. This can be minimized by setting your amps/volts at a proper setting. Then cleaned up using a wire wheel on a grinder, a grinder,  sanding disk on a grinder, or a needle gun. Using GMAW there will be less splatter, but running this wire you will want to run in a spray transfer. This requires specific shielding gas and skill. If your not that proficient with GMAW then go with FCAW and expect to do a little touch up with a grinder."Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful." -- Seneca the Younger
Reply:Go to Millerwelds.com and look under resources.  Order a copy of their Student Pack ($25 with free shipping).  The student pack includes an excellent Tig Handbook as well as a very good manual on GMAW along with a bunch of other good stuff.  Best $25 you'll spend on welding.You've thus far gotten a lot of good information and a lot of BS.  Unfortunately, it's difficult for a newbie to sort out the good from the bad.  Only believe about half of what you read on an internet forum.  Rely on established publications for your detailed information.An internet forum can be a great place to acquire "tips" about how to go about a particular task.  It's a lousy place to try to learn the basics of mig welding.If you decide to go with aluminum for the bumper you described, you've got "a lot" more study and practice to go thru before you go in that direction.  Aluminum is a different beast than steel.PS.  Somebody here needs to let me know how the he11 he's going to "spray transfer" with a Hobart 140.  Useless BS.  Just confuses the OP.Last edited by SundownIII; 05-12-2009 at 10:54 AM.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:QAQC,Sorry man, but reading you posting makes me wonder if you've ever mig welded.Ever hear of "short arc".  I mention this because that's the only "GMAW" process that the HH140 is capable of operating in.  Spray arc and 120V, 140A machines do not belong in the same discussion.With a HH140, 15 CFH gas flow is plenty for indoor welding.  Outside, you may need to go up to around 25 CFH.  If you're still getting porosity at that flow rate, you need to put up shields or go to flux core.  35 CFH is way too much for a small 140A mig.  The turbulance will cause problems with that small a nozzle.  These numbers are for C25 (75% Argon/25% CO2).Best to set your flow rate at about 15 CFH and run a test bead.  If no porosity exists, cut back slightly on your flow.  Once you start getting porosity in the bead, increase your gas flow by about 3 CFH and you're set.  Excess gas flow (aside from wasting money) can be as bad as not enough.For spray arc welding, you will use a higher flow rate.  Higher flow rates also apply in tig welding using an Argon/Helium mix.  35 CFH of C25 through the nozzle on a HH140 will dang near blow out a candle.  Only the guy selling gas would recommend a flow rate that high.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Originally Posted by Med!c but can someone tell me how long every 10cf lasts?
Reply:Originally Posted by Med!cBasically what I'm thinking about is ordering a 12"x12" of 1/4 Al plate, and a 4ftx4ft of 3/16 Al plate. The shell/body will be constructed of the 3/16 pieces, and inside I will reinforce and support the structure with rectangular cubes made from the 1/4 inch plate.
Reply:Anti spatter spray will make FCAW cleanup a lot easier. If I remember correctly you simply spray the work piece before welding. Think of it as cooking spray.Lincoln PowerMig 180cVictor O/ABandaids and aspirinI don't know what I don't know!?
Reply:sundown,I'm not sure why your still having issues. Get over yourself. I never advised him to use his 140 for spray, just that it was the preferred method for the intended application. Never said it was impossible either. That's a limit you placed upon yourself. You need to get laid or something, try enjoying life for a change, not being such a prick."Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful." -- Seneca the Younger
Reply:qaqc,As I stated in my previous post, the information you put out is bogus.  Welding inside his garage, 15 CFH is more than adequate.GMAW with ER 70-6 wire DOES NOT require spray transfer.  Just the opposite actuallly.  For thin sheet metal, .023 wire with C25 (in short arc) will give the best results.  If you'd said that his machine may be a little underpowered for the task and that he'd be better off using a 230V mig, I would agree.  A HH187 would handle that bumper with little problem without spray (which it won't do either).An HH140 WILL NOT spray, regardless of what gas you feed it.As I said in a previous post, a newbie is better off reading an accepted text to learn the basics of mig welding, rather than getting misled by a bunch of well intended posters.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.