Stainless Steel Wire Size

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So I am totally new to welding so forgive the newbie questions.  I got a free Power Mig Astro 130 welder in decent shape.  It is 130 amps and 115 volts.  It takes wire size from .023" - 0.030" and spool size 4"-8".  It says it can weld from 22 gauge to 1/4" steel and from 22 gauge to 1/8" aluminum and stainless steel.http://www.penntoolco.com/catalog/pr...ategoryID=6028I have to weld stainless steel 304 11 gauge - under UTILIZABLE WIRES it says this:Ø 0,6 mm. copper coated mild steelØ 0,8 mm. copper coated mild steelØ 0,6 mm. stainless steelØ 0,8 mm. aluminiumI am assuming 0,6 mm corresponds to 0.023" wire, correct?  For 304 SS which wire should I use, 308?  and if so where can I find it in .023" the smallest I could find was .030".  What would happen if I used .030".I am obviously going to practice a ton before I take on this project - I just want to buy the right accessories.Thanks for any help.
Reply:Hey ckollias,Yes, 6mm is .023/.024 depending on manufacturer. 308(L) would work fine on 304SS. If you're doing sheetmetal, stay with .023. Here's where I get mine.....Dennyhttp://store.weldingdepot.com/cgi/we...308L0xx02.htmlComplete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:Thanks for the reply Denny - It's not sheet metal, it's actually 1/8" SS square tubing.  0.023" still ok?
Reply:Hey ckollias,For 1/8". I would opt for the .030". It wouldn't hurt to get a 2# roll of each as you may need to do some sheetmetal on occasion.DennyComplete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:So I guess that goes back to my original question - can I use .030" stainless steel wire when the instructions says under UTILIZABLE WIRES use 0.0.23" for stainless steel?  If the welder can accept 0.30" wire - why does it say use 0.023" for stainless?  Any harm in using the thicker wire?  Just trying to clarify this.
Reply:Typically the smallest filler is best for stainless requiring less heat to run a bead wetting out without putting too much heat into the parent metal......  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Thank you - that makes sense.  It looks like for stainless steel the best gas to use is 2% CO2 + 98% argon - where would one get a tank and get it filled at?  I have an AirGas and Roberts Oxygen nearby.
Reply:Just for grins I looked at the specs on your welder. It looks like it says "15% duty cycle @ 130 amps". Is that right? Hope you're not in a hurry to get that .125 SS Square Tube project done. I think you're going to be waiting on your welder quite a while.Just sayin...E
Reply:I had one of those for my very 1st mig. From experience I can tell you 1/4" won't happen with that unit. 1/8" is a reasonable practical thickness with that machine maxed out.As far as why they recomend .023 wire with stainless, vs .030 wire, part of my guess would be that stainless is very stiff. I've had feed issues using .023 stainless wire in my bigger mig..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:Originally Posted by Welding_SwedeJust for grins I looked at the specs on your welder. It looks like it says "15% duty cycle @ 130 amps". Is that right? Hope you're not in a hurry to get that .125 SS Square Tube project done. I think you're going to be waiting on your welder quite a while.Just sayin...E
Reply:What it means is you can weld roughly 1 1/2 minutes @ 100 amps then you have to let the machine cool down for the rest of the 10 minutes. On max you will have even less time, maybe 1 minute or 45 seconds before you want to stop and let the machine cool. Weld quality definately dropped off with mine when you went past the duty cycle. It's also very hard on the machine. Mine didn't hold up well to the abuse I put it thru before I knew better.In reality that machine wants to draw almost 30 amps or so on 110v power on max. On a 20 amp line it wasn't at all uncommon to trip the breaker when running full out, especially if you tried to weld for any length of time past the duty cycle.As far as welding 1/8" stainless, it should do the job if you take your time and don't push the machine too much. As far as gas for stainless, my LWS has small cyl's of trimix they recomended for stainless mig. It's been a few years since I did SS mig so I don't remember the mix exactly or the price. I moved on to tig to do most of the stainless I need to do because I get better results with that over mig..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:Originally Posted by ckolliasThank you - that makes sense.  It looks like for stainless steel the best gas to use is 2% CO2 + 98% argon - where would one get a tank and get it filled at?  I have an AirGas and Roberts Oxygen nearby.
Reply:Originally Posted by con_fuse9I love the guys at Robert's, but at least in Maryland, even with my super secrete discount, they are relatively expensive.  That being said, 98/2 doesn't typically come in 80 or any of the smaller bottles.  Roberts will make a special batch for you but you will have to wait a week or so.  Figure $60 for an 80 of 98/2....  for the fill.   Contrast that with $26 for pure argon at Laurel Bottle and gas.  (BTW, AirGas stickers on bottles at Laurel).  Oh, Laurel Bottle and Gas has Sunday hours!!  Welco claims they can do 90/10 at reasonable prices, haven't tried them yet.If you want to try tri-mixes, you might be able to exchange an 80 cf bottle at Roberts.If you do go to Roberts, make them match your best local price.  They will, just need to twist arm a bit.Once you get into the bigger bottles it gets much easier to find.
Reply:Originally Posted by ckolliascon_fuse9 - you mention 100% argon - can you weld stainless steel with 100% argon - I thought that was only recommended for TIG.  Seems like everything I read recommended 98% argon + 2% CO2 or Trimex - 90% helium, 7.5% argon, 2.5% CO2.