Many questions have come up regarding stock Alum of the variety of shapes allowed in the rules.
Home Depot has some supply. If you want to order stock you can as long as it is not special order. this means that anyone can purchase the stock it is not special made for you. All stock must meet guidelines and specifications.
Here are some suggestions the teams can use if some of the local hardware stores are running short because so many teams are buying up their stock.
www.mcmasterscarr.com
www.smallparts.com