Using a plasma cutter is very convenient and fairly easy. The benefit is that "freeform" cuts can be made to metal based on guiding the cutter. Since this machine works by directing plasma through the creation of a circuit, a ground clamp is necessary, much like welding.
This instructable is strictly to show practical operation of a plasma cutter. For an example where this operation is demonstrated to make something, refer to Sheet Metal Flower to Practice Plasma Cutting and Welding
I made this at TechShop Detroit (www.techshop.ws).