View Full Version : C25 vs C02
08-23-2009, 10:28 AM
Having recently realized the regulator on my Millermatic 35 mig is argon and helium compatible, and cost not being much of an issue with the amount of welding I do, I thought I'd step my game up and try some C25. Now my welds look like crap, I'm mad as hell, and I'm just about ready to throw that $60 of argon mix over the fence!
Instead of a nice steady sizzle I'm getting periods of a strange hiss. Wire's still melting and getting deposited but it ain't exactly pretty and definitely isn't controllable.
My Miller's got 6 taps for power, so I have no idea on amperage, but dropping a tap and upping the wire speed seems to help some. I was way better with CO2 tho. Any suggestions?
08-23-2009, 01:53 PM
Not without knowing what it is you are welding, if you are welding Aluminum or stainless steel then the C25 simply will not work. If however you are welding plain carbon steel and it is not working as good as CO2 then either something else is wrong or you have a tank of contaminated gas (or possibly a mis-labeled tank, I saw that happen a few years ago but it is not likely).
08-23-2009, 02:18 PM
Yup, as Radkins said a little more info on what you are doing would help.
All else being equal you should have a smoother arc with the c25 than straight co2.
Less penetration but a smoother bead profile with the c25 and a little less spatter.
You should get decent gas coverage at about 15-25cfm unless you are in the wind and then all bets are off. The regulator is flowing...?
Miller still has a downloadable .pdf owners manual available on their website for your machine, basic welding parameters and guidelines are there if you need any model specific info.
08-23-2009, 04:06 PM
Sorry for the lack of info guys. Mild steels are all I've ever welded so I tend to forget about the others.
My regs got a floating ball that I usually set and forget about midway. After cleaning the glass for a look it's at 25.
I kept fooling with it and things got back to normal. For awhile. LOL! I'm beginning to get suspicious of my hose. I'm usually careful about how I lay it out behind me, but sometimes you just gotta twist it into tight places. As an experiment I twisted the hose into 2 circles and the wire just about stopped. Is that normal?
FWIW, it's the original gun/hose from when I bought the welder new in the early 80's. It's showing some age ....
Thanx for any advice.
08-23-2009, 04:25 PM
No that's not normal however it is, unfortunately, not uncommon either. Take the gun loose from the welder and with no wire in it take an air hose and blow through the liner to try and clear out any grit and other crud that may be in there, if it has a lot of hours on it you may want to just replace the liner. Take a look at the wire on the spool, most of the time welding will also have grinding going on in the vicinity and if sparks from the grinder hit the wire spool the wire may be toast! That grinding residue will weld itself right to the wire just like welding spatter and once on there it is nearly impossible to clean it off or get it to feed properly, if the wire is contaminated by grinding dust (which is a very common ailment) then a new spool of wire is in order along with cleaning/replacing the liner.
08-23-2009, 06:50 PM
.Wire with film rust won't feed either,you may need fresh wire or at least reeling off the outer few layers.
08-23-2009, 09:11 PM
Thanx again guys. I went poking around at the reel and noticed the wire was coming off kinda crosswise. When I ran all that off and out I found a kink! It's still picky about how the line's laid out but I got my sizzle back.
I also downloaded a manual as Willy suggested and using that I'm looking into replacing the original liner. I don't use this welder professionally but over the last 25 years I've used it so many times I couldn't begin to remember it all, so I can't imagine a new liner won't help.
Bottom line tho is I still don't like this C25. It's true the beads are smoother with less splatter, but, they are also bulgy looking and on any vertical work gravity kicks in and they really look like .....
How does that MTV jingle go? I want my, I want my, I want my CO2 .....
08-24-2009, 02:00 PM
Don't know what is happening with your C25 but it is by far the most popularly used gas for a very good reason, it just does EVERYTHING better with the exception of penetration. Are you using solid wire? Some of the duel shield flux core tubular wires tend to run a little better on CO2 but honestly I just can't imagine someone actually preferring CO2 over C25. :confused: However if it works for you and you had rather use it I can't think of a single reason not to use it and it will even save you some money on your shielding gas. :)
08-24-2009, 06:34 PM
What everyone said about C25 running a little nicer than straight CO2 is correct. That said, I really really lke CO2 bercause it's inexpensive, gives very good penetration and, with proper use of nozzle Gel, the tip stays perfectly clean.
I get a 20 pound cylinder refill at Airgas for $23 plus tax and Cal. Haz Fee. At approx. 8 cu. ft. per lb, it's equivalent in volume to a 160 cu. ft. cylinder of C25. Airgas charges more like $65 ++ for one of those. So, for HSM work for me, it's CO2 all the way.
My Lincoln SP175 Plus Manual mentions unstable arc as a symptom of a dirty liner.
If I'm understanding the original poster's issue correctly, the liner has not either been cleaned or replaced iin 25 years? This is a new Guinness World Record!
From the Lincoln Manual:
GUN AND CABLE
FOR MAGNUM™ 100L GUN
Gun Cable Cleaning
Clean cable liner after using approximately 300 lbs
(136 kg) of solid wire or 50 lbs (23 kg) of flux-cored
wire. Remove the cable from the wire feeder and lay it
out straight on the floor. Remove the contact tip from
the gun. Using low pressure air, gently blow out the
cable liner from the gas diffuser end.
Excessive pressure at the start may cause the dirt
to form a plug.
Flex the cable over its entire length and again blow
out the cable. Repeat this procedure until no further
dirt comes out.
08-24-2009, 11:29 PM
The hiss does sound like the wire speed is too slow. I'd also vote for a liner change given the issues. It's also possible that your voltage is entirely too high and you're in a globular transfer approaching spray.
You shouldn't be having so much trouble with this. CO2 is an active gas, C25 is less active due to the substantial reduction of oxygen present with the argon blend.
There's also the possibility that the inductance on your MM35 (a fine old machine) is set such that it will simply run better on CO2. I don't know if that one's adjustable or not.
Two other things to check:
Although unlikely, your gas could be stratified. Roll the cylinder back and forth on the floor.
Verify compatibility of the wire to the gas, though that usually works the other way (switching to straight Co2 after using C25).