New to CO2 need help

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I just switched from CO2/Argon to 100% CO2 and have a few questions. So far only running practice beads, no actual welding.  Using a Miller 130 welder.Instead of the constant "buzzing" sound when welding, I get some spit and sputter, like the arc is breaking and making.  Beads look marginal, but I'm not really happy with them. Have experimented with wire feed speed settings from 30 to 60 percent (operators manual recommends 40). CFH set at 20 (recommended by MIller). Been welding on 12 ga to 1/8", mild, reasonably clean, but not new, steel. Holding the gun tip 1/2" or less from the work. Welding inside so wind is not a factor. The regulator sweats a little, but I don't think it's freezing. Should I try reducing the CFH?It would be helpful if some of you exerienced guys could tell me how you set up and run your machines...........tx..............Jas
Reply:CO2 will cause more spatter than 75/25. I haven't used 100% CO2 for years. Even then it was with a friends machine, so I can't help on the settings I'm afraid. The only real benifits of 100% CO2 is that it's cheaper than 75/25 and it boosts the penetration slightly which can help stretch the range on the small 110v machines. ( I'm leaving out using it with dual shield wire since his machine doesn't have the balls to run that) The down side is that you don't get as clean a weld as you do with 75/25.Is there a reason why you chose to change from 75/25 to 100% co2?.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:Are you using the same regulator? You need a CO2 regulator or it will freeze. You may not be getting coverage.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:So long as he has the tank upright, has welding grade gas, doesn't pull the gas out too fast, and doesn't run the welder continuously (which the machine shouldn't do anyway), freezing shouldn't b a problem.With straight CO2, the wire needs extra elements like manganese, aluminum and such to counteract the oxidizing nature of the gas; I typically run 70S-6. What are you using, no_arc?
Reply:1) Switched to CO2 simply to save money. 2) Using the same regulator (with adapter) I used for mix gas.3) Wire (both 0.023 and 0.030) is U.S. Forge, ER70S6I'll keep trying things and watch this forum for ideas. The welds look OK, but I've seen other machines run CO2 and they have the nice "buzz" when welding.  Maybe, as suggested, the 130 just does not have enough "umph".
Reply:No-arc, I used to have a 117 VAC, 70 amp output welder.  Using 0.035 flux core, I was welding 12 gauge up to 1/8 inch thick metal.  When I changed to MIG with CO2, I could not weld even 22 gauge steel!  The long story can be found at: http://weldingweb.com/vbb/showthread.php?t=6117In my case the reason turned out to be that my particular 117 VAC welder didn't have the 'balls' needed to make the flux-core to CO2-gas transition.Maybe you may find some clues in that posting.BTW, 20 CFH seems overkill to me, I went from using 15 CFH to 4 CFH with no visible or audible effects.In your case of changing from C25 to 100% CO2, I have no advice to offer - never having used C25, only CO2.Hopefully some one who does have that 'first-hand' experience may chirp in.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Rick: I went and read the "long story".  Some good info there.  Looks like I need to keep experimenting with wire feed speed and gas flow.  I suspected the flow was too high, but for some reason never messed with it.  I read some about metal globules flying around.....I notice some of that when running my machine.  I'm gonna' make a few welds and grind them to see how fusion and penetration look.  Will respond to forum afterwards..........It may be a week before I get it done.........Jas
Reply:What's the price difference?  I think I pay $40 to refill my 125cf tank with 75/25.Jack OlsenMy garage website
Reply:Price for 125 cf 75/25 here in SW MO is $37 +/-Price for 20 lb CO2 is $19 +/-The LWS and others tell me the CO2 will last 3X as long as the 75/25.
Reply:The CO2 will last a lot longer as it is a liquid in the bottle and turns to a gas as it boils out.I think your problem may be that your tip is too far from the metal. You have to keep it close. I use flow meters with mine and have them set around 10. I have CO2 set up on both my steel machines. The welds with it look almost exactly like the ones using a mix. Keep trying, the savings are worth it if you do a lot of mig work.
Reply:No_arc, here's a good posting talking about differences between MIG with C25 gas and 100% CO2.http://weldingweb.com/vbb/showthread.php...um+penetrationThere is lots of discussion on the use of these two gases with smaller 110 volt MIG welders.  Maybe something there will echo what you are experiencing.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:you have no doubt blowed on yer soup when it was too hot.  that gas is cooling yer puddle..
Reply:Since the CO2 is boiling off from a liquid, is the gas a lot colder coming out of  the nozzle than the 75/25 mix?MillerMatic 252, HTP 221 w/cooler, Hypertherm PM45, Lincoln IdealArc 250 AC/DC"I'd like to believe as many true things and as few false things as possible"
Reply:Originally Posted by frieedSince the CO2 is boiling off from a liquid, is the gas a lot colder coming out of  the nozzle than the 75/25 mix?
Reply:Just wanted to let everyone know I've been reading all your posts and references.  It will probably be this weekend before I can get out to my shop and try some of the things you have suggested.  Thanks a bunch!  I'll give you some feedback after I get things figured out...........jas
Reply:I slowed the wire feed speed down to about 10% and the machine is now working the way I want. Don't have any idea what 10% relates to in inches per minute (but it doesn't matter if the welding is good). Also running shield gas at about 12 CFH (but again, that's just a reading on the regulator). Thanks for all the help..........james
Reply:James, now that you appear to have got it "dialed in", how does welding with CO2 compare to C25?Recall that you switched gases to save $$, so why not experiment a wee mite more - try turning your gas flow rate down below 12 CFH.e.g. turn it down until the weld starts showing porsoity then back up to where you feel is reasonable.Depending upon your set up, you could end up welding well at say 6 CFH - another major $$ saving.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet