Yes, you can use a saw to cut metal pipes. The best saw to use is a reciprocating saw, but even a fine-tooth hacksaw can get the job done. No matter which saw you use to cut metal pipes, wear protective gear, like work gloves, safety goggles, and ear plugs. Apply a firm, steady pressure to the tool, and always ensure the pipes are secured so they don't move while you make the cuts.

Cutting rectangular ductwork requires careful measurements and the right technique. Use a measuring tape and pencil to mark the cutting lines accurately. Tin snips are excellent for straight cuts on smaller ducts. For more extensive or thicker rectangular ducts, a reciprocating saw with a metal-cutting blade is effective. 

Ensure the duct is well-supported and secure while cutting to prevent wobbling and maintain precision. After cutting, use a metal file to smooth any sharp edges, ensuring safety during installation. 

Some welding projects, such as repairing pipes or fences, require travel, whereas others, like furniture repair, do not necessarily require the welder to come to you. Travel and overhead factor into the overall cost of your welding project. Some of the most common welding projects include:

• Metal furniture repair: $35–$100

• Pipe repair: $200–$1,000

• Small gates: $550–$750

• Fencing: $1,200–$1,800

• Fabricated sheet metal welding: $750–$2,500

Welding is the process of using extreme heat—and, sometimes, pressure—to attach two pieces of metal. In contrast, metal fabrication is a more involved process that can include welding, sheet metal work, bending, and other forms of metal manipulation. Metal fabrication is a large-scale project that may or may not involve welding, while welding is more often a step in larger fabrication projects.