Two MIG Welding Questions

admin

Most of my welding so far has been stick with some dabbling in TIG.  I more recently bought a multi-process machine and started to fiddle with MIG and FCAW.The manual says 4043 Aluminum wire only.  Why?Is Tri-Mix gas necessary for stainless?  I already have a pure argon cylinder and for some tinkering I don't want to have to buy another cylinder, but will if it's absolutely necessary.  Can I get just as good of a weld with pure Argon?
Reply:Usually 4043 is specified because it takes more amps to spray 5356.  Do you have a Spoolgun?You're gonna get a bunch of opinions on trimix, but apparently you need some CO2 with mig to stabilize the arc with stainless.  Unlike tig where you are GTG with 100% argon.If it's only small SS projects, just tig those.  You're gonna want at least some Ar/CO2 mix for regular steel mig though.
Reply:Use a 5356 wire, it won't birdsnest as easy.Stainless is a tri mix or a 98/2 is supposed to work as well. You can use 75/25  but it will rust.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:@ porosity - a concise & helpful shielding gas selection guide is available at http://files.aws.org/wj/2006/02/wj20...j200602-46.pdf.  ZTFab posted this gem back in 2010.  Refer to  Stainless Steel in the Metal Type column (p.47) and note the tertiary (tri-mix) blends cited.  Your choice will depend on the SS material thickness, mode of transfer (short-circuit, spray arc), and what's available at your LWS.  Forget 100Ar for SS, if you want to retain the corrosion resistant properties after the weld is completed.  98Ar/2 Oxy blend on SS is usually reserved for spray arc'n.  If you are getting into MIG, you're probably looking to weld materials thicker than 14 gauge.  If so, then recommend you weld with a tri-mix of 90He/7.5Ar/2.5CO2.  This is usually available at most LWS.  Good luck!"Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:I have tried using pure argon for stainless mig. It sucks, barely works.Dont do it.I started mixing a tiny bit of CO2 with my argon and it made a huge difference. Works good for short circuit transfer. Don't use helium unless you absolutely have to, its gotten insanely expensive. If I had the power I think I would try 2% oxygen argon mix and spray ss.old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder
Reply:I don't have a spool gun or a TIG torch, yet.  I planned on getting a spoolgun for aluminum and using the regular MIG gun for stainless and I didn't want to spend money on the TIG kit.I've got a Miller Multimatic 200, which seems to have gotten great reviews.  I suppose if I don't want to bother with the stainless MIG, I can easily just stick weld it.  I stick welded other things with stainless...