I have been able to weld vertical surfaces and horz. surfaces with the gun pointed down but when I am under the car welding up the metal has a tendancy to drip into/onto the gun rather than sticking to the car. I am getting some welding done but it is shitty even by my standards.

I am using a 115V Lincoln Electric WeldPak 100 (Home depot special) and have the settings on B-2.5. I arrived at that setting through trial and error on horizontal surfaces. I guess what I'm asking is this a setting or a technique thing?

Thanks,
John

Taken from Jeff Hails thread Bringing Back the Dead

A few tips for non experienced welders out there:
When welding inverted you want to strike a fast hot arc. Cut your wire with a pair of diagonals everytime you strike an arc. This will create a fast burn in and reduce pooling and puddle sag. Gravity is working against you when you weld upside-down. If you don't cut the wire everytime you have a small ball of oxidized metal on the tip of the wire. This has to burn off first and slows penetration. Cut the wire each time! It will make a good clean fast weld.

I had a welding upside down problem as well.

I fixed it by welding up a rotesserie, putting the car on it, and not having to weld upside down any more.

Not the answer to your question, I suppose, but if you have much work to do on the car, a rot will make that work SOOOOO much easier to do.

Zach

hi i have been a welder for the last 30 years( geez i am getting old) first of all mig welding was not intended to weld overhead. but for repairing car where it does not have to be perfect penetration do a series of very short weld maybe a quarter of a inch long( stich welding) with a little practice you should be able to do a decent job i perssonaly set the machine at the same setting as i would on a flat surface but that just me. yes overhead welding with a mig can be done even vertical up but i take some practice good luck. martin

Welding inverted should be no different than horizontal or verticle. Well in theory it should be no different but it is. There is nothing more frustrating than having a hot pool of metal falling on your arm or chest.

Make sure you cut the end of the wire each time. This gives the wire a sharp point and welds NOW when you pull the trigger instead of having to melt the oxidized ball on the end of the wire. Any delay will cause a puddle to form. We are talking 10/ths of second here but it does make a difference. The cut wire technique also provides the correct amount of stickout as you want the arc to start NOW instead of pooling up in the hole before it starts to heat up and melt into the base metal.

Welding inverted also requires clean metal. More so than horizontal. Any contaminates like rust, old paint or undercoating will delay the burn and cause splatter or puddling. Do not use a grinder because that thins the metal. Use a Roloc disc and get it clean. Really clean.

Another tip is up the voltage a tiny bit than if you were welding horizontal. When wire is melting it lay's flat versus piling up if it the weld is not penetrating. If the weld is popping and crackling it is not hot enough and or dirty metal.

If you are welding plugs on two pieces of the same thickness start from the center of the hole and work your way out. Angle the gun slightly almost if welding a lap weld. If you point it 90 degree's at the center of the hole you are applying heat for two panel thickness into one single panel at the bottom. I bet you were burning holes huh? Learn to push the molten metal where you want it to go. If you get a drip going stop as you can not save it by adding more wire.

Another way to prevent burning holes it to tap the trigger, let off and hit it again just as the surrounding metal starts to cool. The molten steel solidifies in the second that the trigger is off and then you hit the trigger again and it arcs real fast because the metal is so hot. But it has cooled and solidified enough that it forms a stable base to continue the weld.

If you are welding plugs for two different thickness's its a little different. If the bottom piece is thicker then start from the middle and work out. The puddle will be attracted to the thinner piece on top.

I found this helpful:
Learn to work with gravity.

I am sure you have learned that molten metal will run down. It will not run up or sideways, so you are one up on it already. If you know where it the molten metal "wants" to go, use it to your advantage. It is like using a long wrench over a short one, you can take advantage of the science of leverage or you can fight it, it is up to you. When welding a vertical weld you start at the top and go down. This way you keep the weld arc ahead of the molten metal. The molten metal will start to solidify staying in place behind the weld arc as you go. If you were to start at the bottom and go up, the molten metal would hang off the bottom of the weld arc. It will at the very least make for an ugly, lumpy weld, or at the worse cause the molten metal to fall right off the weld arc. You can "fool" gravity and go up that vertical weld however you will find that you will work with the gravity most of the time.

This fact that molten metal will want to flow down is the reason you need your arc to start hot and fast. You need to "push" the molten metal into the weld when you are welding inverted. The arc has to be established fast on the base metal with the MIG tuned well. At that point you have the luxury of making a nice molten puddle that will not fall. Only then do you move "it" over to the edge of the overlying metal. This will produce proper penetration, which of course is the main objective. The weld needs to be well established in the base metal first, then only a little on the edge of the overlying metal is needed.

Thanks for all the suggestions I will give them a try as soon as I can get back out to the garage. I have one question though...Jeff suggested that I up the voltage



I just wanted to make sure that upping the Amperage has the same effect. I think my welder only have an amperage dial (and only 4 settings on that) and a wire speed dial.

Thanks again for the help
John

Sound's like a 115v welder. If it only has 4 voltage settings leave it where it is. Try the double tap method. Tap the trigger, let off then hit it again. If you start to get a drip stop. Another thing if you are using a recessed nozzle shield (tip inside nozzle about 3/8 inch) try switching to a shield that is short so the tip sticks out or is close to the end of the nozzle. Makes it easier to get the correct stick out and see the weld puddle.

Jeff