"access to scrap" motivated this reply.
I'm very lucky to have an industrial surplus yard just a few miles from my house. The name of the establishment is Moses B. Glick, and there is a website: mbglick.com
If you visit the website, get ready to drool! Click on "SHOP"
Huge inventory of stock steel, aluminum, stainless, pipe, even plastic for fabrication. [I'm going to build a couple of plastic bird seed feeders.] Last time I bought steel there, it was $0.60/lb. I've never NOT found what I was looking for there. Sometimes I go just to get out of the house and wander around to see what's new.
Also a lot of stuff like steel shelving, carts, tanks, and such... A giant shed full of screws, nuts, and bolts, sold by the pound.
-Paul