This is an interesting trick to easily make a super strong electromagnet. If you take a 1 foot length of 4 and a half inch pipe and tack it horizontally off the edge of say.....a metal work table, you can wrap your ground cable neatly and tightly into a coil. I had to tack a piece of flat iron to the front to keep the cable from falling off the edge. The longer your ground is the better. Wrap the entire cable as evenly as possible working it from left to right about 6 or 7 turns a row. When you have 2 or 3 feet of cable left, clamp the end of it to the work table. Adjust your amperage (current) to a hot temp. Adjust your wire speed too if using a mig. The smoother you get the arc the more stable the magnetic field will be. Any pops or resistance causes the field to keep collapsing. Get a hunk of scrap you can weld on. Before striking an arc you need to know that this coil will make a super super strong EMF every time you strike or close the circuit by welding. It may interfere with somebody's heart diffibulator or whatever those devices are called It is strong enough to hold up a 30lbs sledge hammer This electromagnet can magnetize your tools if you place the tool inside of the coil and weld for about 3 minutes. When you take out the tool it will be a magnet. Permeability of the material is a big factor on the strength of your magnet. The more turns of cable and the amount of current flowing through the coil the stronger the magnetic flux density. Also, the poles will align according to which direction you place the tool inside of the coil. Do not hold up a piece of metal up to it before striking because the force of pull is enough to smash your fingers off. Hope y'all find this experiment intresting. I'm still experimenting with mine. Use thick wall pipe if possible .