MIG Welding

[bandit]

I just picked up a MIG conversion for my Lincoln Electric welder. I have been playing with it today and feel good about filling open holes but cannot get the knack for bonding two pieces of metal together. The metal is scrap that is the same thickness as the body panels.

The first attempts I just laid one piece of metal offset over the other and tried welding the top edge to the flat bottom piece. I was not getting good adhesion to the flat bottom piece before it was burning in the edge of the top piece. My first attempt I had my welder down to the lowest setting and running about 3 on the speed. Gas flow was around 27. Wire is .06 I believe. I tried turning up the amps, slowing/speeding up the feed, turning down/up gas, etc.... in all kinds of combinations but cannot seem to get it.

I then tried drilling holes in one piece, laid it on the other and tried bonding the two together welding the hole. Same thing. The bottom was having trouble holding before the top edges would burn in.

Is my wire too big? This is the first time I have ever MIG welded so sorry if my descriptions are off.

I was filling the holes pretty decent with the power setting at its lowest, the speed at 3 and 27 on gas flow using the .06 wire. I hit it then cooled a second then hit it again, etc...

Any tips for bonding the two pieces? I need to get this before I move onto the actual car.

 

[MoparBill]

I have a few questions-
What type of wire? It should be .023- .025 depending on brand
What gas are you using?
Did you switch the polarity if you changed from flux cored wire to shielded gas?

Lincoln is a good machine and has a lot of good info inside the side cover. It'll show you what polarity is correct and approximate heat/wire speed settings.

Make sure your pieces are good and clean and your ground is connected to a clean spot.

 

[bandit]

Wow I totally missed switching the polarity.


The gas is a 75/25 Argon/Co2 The wire came with the kit and in Lincoln Electric brand SuperArc L-56. It is .025(.6mm).

What flow should I have on the gas? I had it at 27 L/min but is that too high? I will have to start all over again testing all the settings after I switch that polarity.

 

[MoparBill]

25 is usually a pretty good place to start with the gas if you're indoors- if your garage door is open or you're outside you may want to bump it up a bit. You'll get porocity if your pressure is low or you're running out of gas (or if you forget to turn the gas on lol).
Make sure your feed roller is on the .025 groove- your Lincoln probably has 2 grooves on the roller- .025 and .035. It should be as easy as removing a screw, flipping the roller and replacing the screw. Also use a .025 tip.

 

[bandit]

Thanks!! This is exactly what I needed to know. The conversion kit instructions are pretty thin.

 

[benno440]

make sure bottom piece does not have anything on it must be clean of oils and paint etc.
point tip at edge of both plates and if the weld is bubbling upt oo much turn your heat up

 

[BeastlyBirdie]

As he posted 27 liters flow, that's way high. You want around 25 cubic feet to start, forgotten the conversion, sorry. Most new welders have a tendency to move too quickly, as well. Sit in a spot until it starts pooling, then move.

 

[BeastlyBirdie]

Make that psi, was thinking of scuba breathing rates, lol

 

[fatecaptured]

Be mindful of your approach angle and stick out. Keep your gun about 90* to the joint with a 10-15* angle towards towards the path of travel. Also if your doing a lap joint, keep most of the heat concentrated on the bottom piece and let it flow into the upper piece. In a plug weld type of situation, you want to concentrate the puddle in the center of the hole and let it flow to the outer edges. Try turning up up your heat(volts) and keep your wire (amps) lower. Too much amps will make a cold (non-penetrable) weld. A good judge to see if your getting good penetration is to flip over the piece after you welded on it and the heat will show you how much is penetrating the piece. A nice solid silver line where your weld is on the other side is a good indicator of proper penetration.

Everyone is so concerned with heat warping their panels. But the truth is if you don't get proper adhesion of the panels, they will fall off or offer no support to the structure of the car. Yes skipping around is needed, but proper heat is a must. Flux core is a no no. Flux core is a crappy thing to use on sheet metal. Its hard and leaves a lot of spatter and ruff surface to grind. Which if the welding doesn't warp the panels, the extra grinding will. Allot of tricks can be used to cool down and reduce heat warpage. Cool with wet rag on weld, also u can wet a towel and place it inches away from the seam or joint to keep the surrounding metal cool.

Tried to find some good pictures, came across this video. Should help if your a newbie to welding:http://www.youtube.com/watch?v=U1GTgDQFE4A&feature=related

 

[440roadrunner]

Also, I haven't been to the Lincoln site lately, but Miller I believe has some GREAT tutorial type info on their site, and Linc probably does, too. I have had a little Linc 100 series 120V MIG, and a few years ago bought a 180 series MIG. Smartest thing I ever did.