Things You'll Need
Oxyacetylene torch tanks with gauges and hoses
Chalk or permanent marker
Welder's face shield
Heavy-duty work gloves
I-beams are heavy-duty lengths of steel named for their capital "I" shape. Often used in load-bearing applications to support buildings and industrial roofs, I-beams are sometimes installed in garages to support heavy equipment and pulleys used to remove engines. Cutting steel I-beams is often necessary to properly size them, or to cut them into smaller pieces for removal. Steel I-beams can be cut using different procedures, such as an angle grinder. However, these are tedious processes, often requiring patience and time. However, using a torch is faster and cleaner, and doesn't require purchasing multiple grinding wheels to complete the job.
Obtain an oxyacetylene torch set up and cutting torch. If you do not own torch equipment, they can be rented at a local equipment rental shop, such as Taylor Rental, U-haul, and many home supply centers, such as Lowe's or Home Depot. While renting the equipment, tell them the job you are performing, asking for the proper safety equipment as well. The oxygen and acetylene tanks should also come equipped with gauges and hoses.
Set up the I-beam for cutting. If possible, place the I-beam on a pair of sturdy saw horses, making sure the beam portion being cut extends over the end of one of the horses. When the cut is complete, the beam will fall if somebody is not holding the end. Be sure to safely accommodate this before making the cut.
Measure the cutting point and mark it all the way around the beam with chalk or a permanent marker. At this point, don the safety equipment, which should include coveralls, heavy-duty work gloves, safety goggles and a welder's face shield and apron.
Set up the torch. Open the acetylene valve and light the torch using a striker (do not use a lighter, as it can explode). While the acetylene flame is burning, slowly open the oxygen valve until there is a blue flame at the center and white-blue flames at the small holes surrounding the torch tip.
Preheat the I-beam with the flame coming out of the torch. When ready to cut, grip the the torch trigger to produce the cutting flame. While holding the cutting-flame trigger, point the torch to the outer edge of the cutting line and cut along the line. Stop when necessary, and continue cutting where you left off.
Close the gas tank valves when cutting is complete. Turn off the gas knobs and wrap the hose and torch around the tanks. Clean the work area of any possible safety hazards created during the cutting process.