Begin cut with metal cutting sheer.
Cutting copper sheet with a torch.
Measure the dimensions needed with tape measure.
The sheers handles are brought together to cut through the sheet.
Elevate and support one edge of sheet with free hand allowing entry point for cut enough clearance for metal cutting sheer to proceed.
Cutting slower will also give you plenty of opportunity to blow away the bits and pieces of copper and dust caused by the cutting process.
Take your time and let the cutter work its way through the copper for a straighter and even cut.
Cutting your own copper shapes can be easier than you think.
Work gloves must be worn during the cutting process as the cutting edge of the copper is very sharp.
While you can still cut the copper material with the plasma cutter you should not force it and cut too fast.
Once the copper sheet has been marked where it needs to be cut the sheers blades are positioned on each side of the sheet as would be regular scissors when cutting paper.
For higher gauges meaning thinner copper you can easily do it with standard hardware store metal snips.