MIG Welding Question
 

I know there are some welding experts that frequent this board (Ben/MB911, Tim Hancock and others); appreciate any input the pro's or others with experience can offer.

I bought a cheap Cambell Hausfeld Flux/MIG welder

http://www.cpocampbellhausfeld.com/welding_equipment/wg2060.html

I started out with it in flux core mode with .35" wire and have been able to lay a decent/solid bead with it. It has 4 settings - with the highest (4) working pretty good on 1/4" steel (larger than it is rated for, but I still got some good welds - tested by trying to bust the weld). It hasn't been too bad working thinner materials by backing the amps down to lower settings (1-2).

I thought for most automotive work, I would want to go to MIG (cleaner welds, more friendly welding stuff to thinner body panels). I puchased an Argon bottle, and some .24 solid wire, swapped out my tip to .24, conveted polarity and gave it a test on some sheet metal I was preparing to weld (~16 guage).

No matter what I tried (highest heat setting, very slow wire feed), I couldn't get a good weld (I got a clean bead, but couldn't get good penetration - cold welds that I could break the bead off of the material/easily break apart the peices).

I decided to try a larger diameter wire. Moved up to .30 and I'm still having the same problem.

The welder is great using the .35 flux core, but for some reason when I try to use it as a MIG, it doesnt' seem to have enough ass to weld the material I am trying to weld.

I hate to give up on using it as a MIG ($$ invested in the bottle, a couple of spools of wire and tips). Looking for any thoughts on why it would weld good as a flux welder, but weak in MIG mode (+ wire).

Wondering if I just need a higher amp welder for MIG - and if so, why (what would be the difference, flux vs. MIG for weld penetration/heat).

Thanks, Gordo

Did you reverse the polarity?

I dont swap the polarity when changing wire. I weld quite a bit and when I switch to wire+gas thats all I do is. I like to use .25 for body panels... I'm working on my Triumph frame and I am using .30, the bigger wire is a bit hard on these light duty welders.

Do you have enough clean power to the welder? I've run into a similar situation when using an extension cord that was too long and/or too thin. I've also run into it when welding at someone's house that hat crappy wiring in the walls.

Thought Mig req'd C25 not straight Argon?

Also you don't mention wire speed and tip out. These are REALLY important when you're playing with sheet metal.

As a start (and i am NOT a sheet metal expert) i'd try slowing your wire speed at a given power setting.

ok, just reread and see you did slow wire speed down.

are you getting a good puddle BEFORE you start moving?

Argon is more expensive than ultramix, but works fine for both steel and aluminum.

I do not understand why you reversed the polarity. I am thinking it could be part of your problem. On top of that, I don't know whether you ever will get full penetration with that sized welder on 1/4" stock.

FWIW, on my tig welder, I use DC "electrode negative" for steel and stainless, AC for Aluminum and DC "electrode positive" only to form a ball on my electrode prior to swithing to AC for welding aluminum.

make sure you're metal is super clean before you start welding. try cleaning it up first and also check your gas. Make sure you have enough coming out. You'll get a ton of contamination and crappy welds if you don't have enough sheilding gas "protecting" your weld.

I weld 16 ga. with gas, power set on the second to lowest setting, wire speed set on 3 to 3.5 (note, that is not necessarily IPS) with a 1/4' stick out, pushing the weld with the torch back at 20 degrees.

For flux core welding I use DC- or straight polarity and for MIG I use DC+ or reverse polarity. The second method puts less heat into the thin metal while allowing the gas to cool the electrode somewhat. Lower stick out has less resistance therefore lower heat.

Try that and then adjust from there.

milt do you mean less resistance therefore MORE heat?

Nope.

well that would explain some of the trouble i've had;)

to explain...when i've found i need just a TOUCH more power welding i first try a shorter stickout. it SEEMED like i was getting better welds that way.

Did you buff the metal where you hooked up the ground ?

You get more gas to surround your weld. It was Ben that told me about the resistance. The wire gets hot, of course, and is deposited in the puddle. But, you can keep the puddle more in control if you're not loosing a lot of heat to an electrode that is out of the puddle. Angle has a lot to do with it as well.

That may not be how the welding engineers explain it, but that's what I gather reading about it.

My welder (Clarke) shows to reverse polarity for gas but have seen others that make no mention of that. I have little experience with the thing, is reversing necessary?
Jim

No, although sometimes when welding overhead you reverse polarity, typically for sheet metal apps and light gauge its not required.

After more research
 

Answer a few Q's up front:
- Good clean 20A dedicated outlet/no extension chord
- Cleaned metal surfaces with a grinder prior to welding
- Material was ~14-16 gauge

Better terminology:
-When welding with Flux Core wire, I have the welder set to DC Standard Polarity (DCSP - Electrode Negative). I have no problems with penetration in this mode, and can easily burn through the material

-When I switch MIG/solid wire, I change the welder setting to DC Reverse Polarity (DCRP - Electrode Positive) and use the gas (75% argon/25%CO2) . This is in accordance with the welder's operations manual. In this configuration, I don't get very good penetration on the 16 gauge material (couldn't burn through if I wanted to).

Stickout: I cut the length of my gas nozzle to expose more of the electrode tip to reduce stick out to ~ 1/4". From what I read (and think I've experienced), shorter stickout = a hotter arc.

Greatly appreciate the feedback, gives me a few more ideas to try (solid wire with gas in DCSP)

Thanks, Gordo

A great site I have been using for welding ref:
http://www.weldingtipsandtricks.com/index.html

I notice at school in my Tig class you need to make sure the area that is grounded is really clean. The area your welding should also be really clean by brushing, grinding, filing or sanding.

In the class we normally weld on steel tables that are also used in the Mig, Stick and Tig classes. I am using the Tig on aluminum plate and .065. The stick welding guys are learning to be boiler makers and they leave a mess on the table during the night class, so I need to grind the table before I start during the day.

Good luck on finding the issue.

Less stickout=more penetration

Higher current=more penetration

more CO2=more penetration

a push angle (pointing the torch toward the unwelded part)=more penetration