I need to know the pros and cons of mig vs. tig. vs stick welding. Also any heat range differences if you know them. Thanks!

 

Stick welding is unshielded (except for the flux on the stick itself), high amperage, and high penetration. It's for heavier plate welding and is a constant heat once you start going. You weld with the hard wire, flux coated rod, and your bead and weld strength is completely dependent on how well you keep a steady distance from the workpiece, the angle you hold the stick at, and how fast you move along the bead. Because there is no gas shielding, the air around the weld actually burns. This causes instant oxidation, which is the hard crust over the weld known as slag. You have to chip this away and brush it completely off each time. You also have to keep your welding rod extremely dry, because the flux will absorb moisture and will not burn right. You adjust your weld by slowing or speeding how fast you move along the bead, and how close or how far from the workpiece you have the rod. Once you get good at it, you adjust instinctively from the sound of the weld and the intensity of the flash. It takes a lot of practice and a bit of talent to stick weld well. I used to weld 4" hydraulic lines in a 4500 PSI circuit, it's a heavy application.

MIG is a wire-feed, light duty weld. It is almost always shielded with argon gas, but sometimes is not. The argon gas is completely inert, it blows the oxygen away from the weld so it doesn't burn, and you don't get slag on the welds. It is used for light plate and sheet metal. You can adjust the amperage (heat) to the wire and the speed at which it is fed on the welder before you start, but not while you're welding. All you really do is point and shoot with MIG. It's much easier to use cause of the argon shielding, and more precise than stick welding, but is for much lighter application. It does make enough heat to severely warp sheet metal, so you usually only do spots a couple inches apart, and "stitch" them together for a solid bead. Basic rule is that if you can hold the welding handle and pull a trigger, you can use a Mig welder.

TIG welding is by far the most difficult, but the most precise. You weld with a tungstun tip that actually creates the arc. The tungstun does not burn, but it melts the mating materials to form the weld. It is also shielded with argon gas so you don't get slag in the weld. You also have a small wire in your other hand that is filler material. Whenever you need a little more material to fill the weld (when there's not enough melting from the workpieces), you give a dab of filler into the bead. You set the basic heat (amperage) on the welder before you start, but what makes it so precise is that you have a foot pedal to fine tune the amperage at the tip as you go. It is the most difficult because you have to have the welder set right, and then while welding you need to carefully observe what you're doing while using both hands and a foot to control the weld. This is also what makes it so precise.

Those are the basics. If you have any questions in the details, feel free to ask.

 

wow thats was damn good snafu, brought me back to the first day in welding school(long long time ago) .

 

Good info, I couldn't have said it better myself.

 

Thanks for the info.

But while you are at Mr. Wizzard can you explain how a plasma cutter works?

 

who cares... it just works

 

[sm=icon_rofl.gif]

 

i would also like to know about the plasma cutter..keep in mind..im an accountant...ive used mig and stick welders...never seen a plasma cutter in person

 

Plasma cutters work by sending an electric arc through a gas that is passing through a constricted opening. The gas can be shop air, nitrogen, argon, oxygen. etc.

This elevates the temperature of the gas to the point that it enters a 4th state of matter. We all are familiar with the first three: i.e., solid, liquid, and gas. Scientists call this additional state plasma. As the metal being cut is part of the circuit, the electrical conductivity of the plasma causes the arc to transfer to the work.

The restricted opening (nozzle) the gas passes through causes it to sqeeze by at a high speed, like air passing through a venturi in a carburetor. This high speed gas cuts through the molten metal. The gas is also directed around the perimeter of the cutting area to shield the cut.

 

i mean..i understand the basic premise of it..