How to Build With Expanded Metal and Tubing

Possibly one of the most unglamorous inventions of the 19th century, expanded-metal sheet is still popular with designers worldwide. Invented in Britain and patented in the United States in 1894, expanded metal is a strong but relatively lightweight sheet material and forms part of many everyday structures. Typically used to clad a perforated metal, expanded-aluminum and expanded-steel mesh feature in applications that include structural engineering, architecture and ship-building.

1

Study the fabrication plan for the item you intend to build and find the cutting list. If there is no cutting list, create one by writing down the description and dimensions of each part shown on the plan. Identify parts made from tube and parts made from expanded-metal sheet.

2

Find the first tube part on the cutting list and select a length of metal tubing of the required type. Mark out the length of the part on the tubing. For example, if the cutting list calls for a 12-inch length of 1/2-inch-square steel tube with 1/8-inch wall thickness, find a length of that size tube and measure 12 inches from one end. Scribe a line across the tubing, using a combination square to make sure it is at right angles to the edge.

3

Cut the tube across the line with a miter saw. Check the plans for details of any miters on the ends of the part. Mark them on the part, ensuring you mark the miter angle correctly. Adjust the miter saw to the specified angle and cut the ends of the tube across the miter lines.

4

Mark out and cut each tube part in the same way. Remove any burrs or sharp edges from the ends of all the parts using a coarse file.

5

Check the assembly sequence shown in the plan. Clamp together the first two tube parts. Wear appropriate protective equipment for welding, including a welding mask and gloves. Tack-weld the two parts together and unclamp them.

6

Clamp the next part to the first two and tack it in position. Continue according to the plan until you have tacked together the complete tubing frame. Check it for dimensional accuracy, then weld all the joints in full. Clean all the welds with a wire brush to remove all welding debris.

7

Find the first expanded-metal part on the cutting list and select a sheet of the required type. Mark out the dimensions of the part on the sheet using a permanent marker. For example, if the cutting list calls for a 12-inch-by-18-inch piece of 1/4-inch #20 mesh, take a sheet of that type of expanded metal and mark each section across the mesh at 12 inches from one end. Then mark each section along the mesh at 18 inches from one side.

8

Use an angle grinder with a cutoff blade to cut along the marks on the mesh. Wear appropriate protective equipment including safety glasses, ear defenders and gloves. Cut until you reach the intersection point of the two sets of markings.

9

Mark out and cut each expanded metal part in the same way. Remove any burrs or sharp edges from all the parts using a coarse file.

10

Lay the first piece of mesh in position on the welded frame and clamp it with welding clamps. Fix it into position according to the plan, either by tack-welding it at 6-inch intervals along each edge or by using mesh clamps. If you use mesh clamps, tighten them with a wrench. Remove the welding clamps once the mesh is secure.

11

Attach each piece of mesh according to the plan until you have completed the assembly. Clean all the welds with a wire brush to remove any welding debris. Check the assembly for dimensional accuracy against the plan.