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. 

Choosing the right metal fabricator for your project begins with research. Find a reputable fabrication company by searching for reputable contractors in your area, and then reviewing photos of their previous work, customer reviews, and photos of the company’s workshop.

Once you’ve narrowed down the list, contact the companies to ask about the types of metal fabrication projects they specialize and inquire about guarantees and warranties on workmanship. You should also ensure the company uses high-quality material, and ask about the schedule and turnaround time for your proposed project.

The cost to weld aluminum averages about $14 to $22 per pound. The type of metal factors into the overall cost of any welding project due to the cost of the materials and the expertise required to work with it. Some of the most common metals used by welders include:

• Magnesium alloy: $7–$16 per pound

• Low-carbon steel: $11–$12 per pound

• Stainless steel: $13–$15 per pound

• Copper/brass: $24–$29 per pound

• Cast iron: $38–$79 per pound

• Titanium: $60–$85 per pound

Since water heaters are primarily made of metal, they’re commonly accepted by scrap yards and collectors. Don’t expect to fetch a high price, though—water heaters are mostly steel and aluminum, which aren’t high-value metals. Some components are made of more valuable metals, like brass and copper, but they’re a small portion of the heater and won’t affect the price much.