MIG welding 304 sch. 10, is "Stargon" OK to use?
 

I'm building a turbo header out of schedule 10 304 stainless. I'm going to MIG weld this with my Hobart Handler 140; Harris 308 .035" wire.
I picked up a new cylinder of shielding gas from Praxair last week, -I told them what I would be welding... and they sold me "Stargon" which is Praxair's name brand blend of argon/CO2/Oxygen. Is this the right gas to use? I've been looking for info on this stuff, and can't find anything in terms of recommended flow rates. Also, I'm not finding anything regarding the use of this gas on stainless. Anyone have any suggestions?

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

It's a 90/8/2 argon co2 o2
Yeah that'll do fine. Be aware that you will not have much luck with multiple passes in the same area with that gas so try NOT to need to weld in the same spot over and over.

You'll be in short circuit with a HH-140 so 10-15cfh coming out of the torch. 5cfh or so in the purge. Assuming you dont have a flow meter for your purge and you've just got a little valve on it, I would start out around 17-18cfh on the main flow meter and then crack the purge open.

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

Thanks so much. -I've (literaly) spent ALL weekend cutting and fitting, and have been determined to at least spend a couple duty cycles before the weekend is over.

Now the plan here was to space the parts a wire width gap, then stitch back and forth like you explained a couple weeks ago... I'm going to make a few practice passes, snap some pics, and post them up.

By the way, What are your thoughts on heat and feed speed for this setup? (stargon, .035" 308L wire; sch 10 304)

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

Well you're limited to short circuit so. 190-195in/min @ 20.7-21.3v. (190'ish in/min would be around 120amps) Youd have to figure out what that corrisponds too on your hobart's controls. You can figure it out by feeding wire for 10 seconds, measuring & mulitplying by 60. Adjust till it's around 190in/min & then whatever voltage that runs best at.

It's likely maxed out on the voltage and 35-45% on the wire feed.

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

Here's my first stab at it: again, schedule 10 304 SS, Stargon, .035" ER308L, Hobart Handler 140 set at #4 "heat" (maxed out) and wire feed set at about 40 (0-100 feed speed range) flow gauge is on order, so I substituted an Acetylene LP gauge. -Set to flow at about 17psi is what I believe to be around 20cfh which I'll turn up a bit when I actually begin welding pipe & weld els with backpurge setup

The welds look to be penetrating in some spots, and as you can see, I beveled the ---- out of the ends.
it's quite inconsistent and "dirty" looking...
here are pics:
Attachment 11639
Attachment 11640
Attachment 11641



Stuck the practice part in my shop press and tried to break it (unsuccessful as you can see)
Attachment 11642

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

try running a weld with a gap. It's hard to get 100% penetration with no gap on a mig welder.

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

OK, give me about a half hour (I had to rearrange the garage, rig up a welding table, etc... haven't picked the torch up yet, but I'm going to try what you just instructed. I'll do my best to post a couple pictures of the carnage, but this ------- iPhone I have uploads photos about as fast as old people ----...
- :P

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

that looks like a baller soldering station

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

Damn good eye.

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

hehe no backpurge for practice lol.
Clean the metal before you weld it.
Play with the flow rate. It's either way too high and turbulence is swirling air back into it (my guess) or too low.

Congratulations, that's about as much penitration as the TIG newbies get and you achived that in maybe 1/20th the amount of time it takes them to... not have penitraiton LoL!
voltage looks ok, amps/wire feed looks aight. Keep the arc length steady and using what ever travel speed will get you that exact same bead width - try to run a similar distance in one or break it down into two welds if you want. Whatever you're comfortable with.

Run a 3/32" gap, bevel the pipe at 60* and grind the point off the bevel so you dont blow through the bigger gap.
See how you finally got pen at the end of the weld? That's because all the heat built up as you went and when you hit the end of something it suddenly has no where else to run.
Tack the ends well. Heat will make the gaps draw together.





mofo is rocking some stepped bits and CR batts too LoL

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

Attachment 11603

Attachment 11604

Attachment 11605

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

Attachment 11600

Attachment 11601

Attachment 11602


OK, I see how I get better penetration, but this leaves ---- hanging down inside the pipe. this will be a bitch to grind out inside the actual parts, no?


-The soldering station is being used to build a Megasquirt II v3.0 (fully loaded) -This project is entirely DIY...
gotta get to work for now, -any criticism on the last weld pics, will be gratefully appreciated

Re: MIG welding 304 sch. 10, is "Stargon" OK to use?
 

I know its hard to do anything more than make 50 spot welds when you're starting out. That being said as soon as you balls up and run a bead instead of ---- randomly hanging inside the weld you'll get a smooth bead running bearly on the inside of the pipe.

Like this but smaller.
Attachment 11597
or this
http://www.scielo.br/img/revistas/jb...1/a15fig03.gif
Instead of a bevel groove, that one is a J groove. (Take an angle grinder and just grind into it.) Good illustration of a landing too.

https://i207.photobucket.com/albums/.../photo-109.jpg
Middle bead on that (bearly visible) Now that is proper penitration for this size pipe. Whatever gap and landing that was, do it again and run a bead instead of a tack weld - even if it completely collapses out the backside no harm done. If you do one that does collapse out the backside - travel faster!

When you're welding slow processes like this one, as soon as the bead hits the width you want get moving & move fast/slow enough to maintain the width of the bead! Faster processes than this you just go LoL!