This may be a little off-topic, but when my job involved machine design, a common structural material was "rectangular tubing" and "square tubing" which were welded products. These were often used as "raceways" for electrical wiring with smooth cutouts for masses of wiring or holes for conduit fittings in other situations.
All of you are likely accustomed to this material; it is commonly used as support columns in industry. I've been involved with its PRODUCTION is sizes like 10 inch by 16 inch by 1/2 inch wall ... not flimsy stuff.