Opsec, the quality of the metal used as the electrode in arc welding, and the cleanliness of the metal surfaces are critical to the strength of the resulting weld. A coat hanger wire electrode will result in a weak weld. The surfaces to be joined must be completely clean of paint, oil, grease, solder, or any other contaminant (including the oil that human skin produces). Home Depo (and similar stores) sells a beginner's book, supplies, and equipment for arc or gas welding.