This little project might be one of the most simple DIY water heaters I have come across. With a few items from your local hardware store, you can build your own solar water heater that is portable and perfect for any outdoor adventure... Shopping List... Copper Tubing 1/4' x 50ft Flat Head Phillips Screws (4 pack) #8 x 1in #10 x 2.5in 1.5' #16 Wire Nails 1/4' Coupling 1/2' to 3/4' PVC Swivel 3/8' Square Dowels 23.7' x 23.7' Sheet of Plywood 20' x 20' Sheet of Plywood 20' x 20' Pane of Glass 2' x 2' Lumber Cut - (2)