(not sure if this is the right category, but it does involve metal)
I’m looking for some 2020 or 4040 aluminum extrusions. Several pieces 300-400mm long. Teh Internets tells me that I may be able to find them as scrap if I know where to look.
Does anyone know where to look? 
Discount Steel probably your best bet as they sell drop-offs rather cheaply. But it is random what’s there.
I have a piece of 2020 about the size your looking for. Your welcome to it.
So … Walter … what else do you have laying around? 
I’ve been watching This Old Tony’s build videos of his CNC router. Now that the new Lathe is almost ready we need a new group build. Though we still need to finish the table build and then get the new mill and lathe and create training and … hm.
You might try these folks - I haven’t been there in ages, but their size and selection makes most scrap yards look small.
Gachman Metals & Recycling
2600 Shamrock Avenue
Fort Worth, Texas 76107
Mail: P.O. Box 308, Fort Worth, Texas 76101
Phone: (817) 334-0211
Toll Free: (800) 749-0423
Fax: (817) 332-8340
Oh, lots of very useful stuff. Prior to the departure of the freebie shelf I was bringing a few items in at a time fairly regularly. More often then not they were gone before I walked 40 feet from the shelves.
Now people just need to seek things on talk and jog my decrepit old mind.