Building shelves from scrap wood, will this actually work? 

Looks great!

Good job always use what you got first it's less expensive and probably better quality

Good job! No you're not an idiot! With high cost of building materials its smart to keep all leftovers.

Nice! I just built a ladder and some saw horses out of scrap wood. Sanded, burned the grain with a propane torch, stained and spar urethaned. Pretty, and will last SE Alaska's rainy weather. NOPE you are not an idiot! We do what we gotta do with what we got!