How can I build my own pontoon boat? I was thinking I could use 50 gal. drums, but where do I get them?

You should be able to find some at your local feed mill or at some type of salvage yard. You can also try calling different factories in your area and see if they have any. most of your tool and die shops should have some. Just be sure that when you weld them together that nothing flamable has been stored in them.