If you're wondering which material to specify for your project, here's an overview of the easy choices.
Please see our Stocked Materials page for a list of the specific alloys and thicknesses we keep on hand.
Aluminum and mild steel:
A1008 cold rolled steel is the universal thin steel sheet. 24ga and 22ga are thin enough that exposed edges generally must be protected or hemmed (folded 180 deg in a sharp bend). 20ga to 16ga are useful for a wide variety of enclosures, mechanical parts, art applications. Sheet in this thickness range is ductile, easily formed and welded, easy to finish and paint.
A1011 hot rolled steel is a universal thicker sheet. At 3/16" the material type transitions to A36, the standard hot rolled mild steel plate. 14ga to 10ga are good for projects subject to substantial loads, welding, tapping with threads. The A1011, and our 3/16" and 1/4" plate, have a clean, uniform, rust-free gray surface. Above 1/4", expect scale and rust, as that is how the material arrives.
Aluminum costs more per pound than steel, but on a per square foot basis it's a bit under 2X the cost of steel. Aluminum costs far less than steel to cut by waterjet -- depending on the complexity of your artwork, your net cost for the same part made in aluminum can be considerably less vs. steel.
Aluminum comes in dozens, perhaps hundreds of alloys for specialized applications. We stock the two most convenient for the type of work we do: 6061-T6, the universal high-strength aluminum, and 5052-H32, the go-to architectural and appearance material.
6061-T6 is available from thin to plate, has strength comparable to mild steel, and is easily welded and formed but not to a sharp radius. In general we don't bend much 6061-T6.
5052-H32 is the most popular aluminum alloy for architectural use, whether left to weather raw, or with paint or powder coat finish. A brush-finished raw aluminum piece in 5052, outdoors but not in an excessively corrosive environment, can look good for decades with little maintenance. When your end objective is a durable powder coated part or fabrication, we recommend using 5052 as the substrate, other considerations notwithstanding.
We stock one other low carbon steel as a flat bar in 6" widths. 1018 is a slightly stronger flat bar processed to tighter specifications, and is popular for small parts that need extra strength without heat treatment. The material cost is 2-3X A1008, but the material tends to be a small portion of the overall cost of small parts.
304 2B is the most common inexpensive stainless sheet. 2B indicates "mill finish": a clean, smooth, uniform dull surface suitable for any further finishing, including brush, swirl and polish. 2B is the standard finish from thin sheet up to 8 gage.
Above 8 gage, 304 is sold as HRAP (hot rolled annealed plate). While free of scale and rust, HRAP has a rougher surface and requires far more work to bring to an aesthetic finish.
We also keep 301 stainless on hand in assorted thicknesses and tempers. 301 has the same chemistry as 304 but has been work hardened to achieve a high yield strength, making it suitable for use as springs, and otherwise in mechanical applications requiring higher strength.