I have changed my welding set up from the flux core to true MIG with a bottle of shielding gas.

I have been experimenting with it, and I have some questions.

1) what kind of pressure do I want to be using on my shielding gas? 5 PSI? 15 PSI?

2) how much lead wire to I want sticking out of the tip of the welding gun. IE, how close is the gas nozzle supposed to be to the working surface.

3) How do you see what you are working on with that big ass gas nozzle blocking your view?

I have been getting inconsistant results. I figured out that my wire speed has to be faster and temp set higher then I was used to on flux core wire if I wanted to get any penetration. But that may be simple as I am going from .035 flux wire to .025 MIG wire. The slower wire speed on the thinner wire seemed to flash melt the wire before it was into the work. But a faster wire speed creates a larger bead then I was expecting. It may be that I am using too thin a wire on too thick metal - my first project was welding up a bottle bracket for my welding cart.

Especially with butt welds, I am having a hard time keeping my bead on the seam.

I bought a 60lb bottle of gas from the local welding supply store. Part of my issues were a gas leak at one of my connectors. Fixed that lateish into my practice session when I realized what was going on. But it means that I still don't know what a good pressure to use for the shield gas is. My shop does not have cross breezes.

So far, I like it a lot. Much cleaner looking welds and less burn through on thinner work surfaces. But I need to get better at judging penetration and wire speed, and needs to make sure that I have proper shield gas flow to stave off contamination.

Zach

http://www.millerwelds.com/om/o1313p_mil.pdf
page 27-32

the millerwelds web site has alot of instructionaal info that has helped improve my skills. they evn offer free videos

http://www.millerwelds.com/swf/flv/flashvi...p;h=240&v=8

pre heating with a torch helps alot. it removes moisture and contaminnts associated with crappy welds

On my Lincoln rig a video came with it and was very helpful to one who had only acetylene and old-style arc-welding...

1. I use 10 - 12lbs depending on whether the work is flat or not
2. Generally about 1/4in to 3/8in works for me. It depends on the wire speed to some extent but doesn't vary too much.
3. Sometimes you can't see. I hate that, but more often than not I'll mockup a piece or two and practice on that if it's in a difficult place.
4. that preheating is ideal except when the whole point is not to heat the surrounding metal. Often the case with a MIG.

Working blind is an adventure right? "Trust in the force Luke"

Good luck!

12-15 lbs

1/8-1/4 "

practice

What welder? Lincolns and I do believe that Millers have a chart on the inside cover to help set wire speed and voltage.

To answer your questions

1. 10-15, I typically keep it at 15. If im outside and its breezy I might bump it to 30.
2. 1/4 to 1/2"
3. I put the gun at a 45 deg angle and support it with my left hand, This allows me to watch the bead.

Here is what you should do, Get a large scrap piece of metal and to a number of beads

start at low low setting and do a 3" bead, then crank up the voltage 1 notch another bead, voltage another notch, another bead. When your done with voltage, crank wire speed up one more notch and start at low voltage again.. Repeat till your at high/high or until your burning through the metal (Try NOT to, Increase the speed of your welding to match).

By the end of this you should be a better welder. Next grab a thicker piece of metal and repeat.

This will help you determine how metal thickness is affected by voltage and wire speed.



Or you could just post a pic of your welds and we'll tell you how to change your setting.. But that doesnt teach you anything

Make sure you have the right tip on your welding gun for MIG. I learned this the hard way. :/

10 -20 cfm of flow is kind of standard a welding gage should have CFM values along with psi values. many wledre have a look up sheet for flows, and power and feed speeds . if your does not have one maybe you can find it on the makers website?

you also want perfectly clean metal both sides no paint nor grease persent up to about an inch away from teh weld 9dirty fumes willpoision the weld0 becarful when welding out side in teh wind or near a draft as the wind can puch aawy the sheilding gas, ifit is windy you will need more gas flow and maybe a wind shield.

for butt welding you need to leave a gap between teh sheets of metal it is that gap that is filled with weld, if the two sheets at actually butted togther you wont get a good penetration. the gap is usually on the order of the diameter of the wire .025 to .035 inch gap is typical for autobody metal butt welds

the purchase of welders sheet metal clamps will be of help in maintaining a good gap. (Northern tool and equipment (see website) has some really nice welders butt weld clamps $9.99 for four of them part number 62886) great product, great price.

happy welding

.023 wire is good for sheetmetal. Thats all I use for most fabbing up to 3/16 thick mild steel. It will take a wide bead to get enough weld to be strong or the pieces need to be beveled so the weld can get through to the backside. If the wire is burning back, the heat is too high or the wire speed is too slow. The trick is to get the best penetration with the least amount of bulge to the bead. And no undercutting. On thin metal you can move the arc in front of the bead and then go back to it to add to the bead to keep from blowing through. Big beads will go a lot slower with smaller wire and the penetration will be less on thicker metal. When the bead is on the edge of two pieces of metal sometimes to gas will blow away too soon and the weld bead will bubble. You gotta think about where the gas is going to go, it will take the easiest path to go away. You might need to turn the gas volume up in some cases. Remember the post flow and leave the nozzle pointed at the end of the bead for a few seconds when you stop. The best process is to cut the burned tip off the wire to restart each time but thats a lot of trouble. The idea is to get rid of the burned wire and to deposit new wire at the beginning of each bead. Get some mig pliars to clean the inside of the nozzle and cut the wire and to change the contactor tip. You really need some of the grease that goes on the inside and outside of the nozzle to keep the spatter from sticking. It comes in a small tub or in spray cans but the cans are really for keeping spatter off the surrounding metal. You don't want to get it inside the contactor tip, it might gum the wire up. There is also a wick and wire lube available to help the wire feed through the sheath and it will make the sheath last longer. It goes between the wire spool and the feed wheel.

When I converted my Lincoln to gas instead of the flux core I had real problems until a buddy opened up the end of the nozzle more for me. I guess I wasn't passing enough gas to shield the arc and I was making a mess. Now I weld like a pr......, well the welds look a lot better than they did.

Oh and I just went back to the welder to do some farm implement work for my father-in-law and realized that I need to go back to flux core to weld 1/4".

Dave,

You could dual shield it.

Just put fluxcore wire in.. Makes for a really hot weld.

Andyrew,

I'm interested in the pressure you using to MIG weld. I've been running at 7lbs for EVER with .023" & .030" wire and great success. Of course this is ONLY in a completely still garage with doors closed.

Am I missing something or are you just using more of gas? At $27 to fill my small
55CU FT bottle, I like to conserve my gas.

Whaddya' think?

Terry

Terry,

I weld outside a lot, and I go through a 80CU tank every year or so. If im in a controlled environment then ya I'll push it down to 10 or so. Also I typically weld with .035 wire, which probably needs little more shielding.

Andyrew.

Got it! I see the differnces are that I'm in the shielded garage and us .030" or .023" wire.

If I ever go bigger, I will look to turning the pressure up.

Cheers,
Terry