Both PEX and copper are good options; however, both have some advantages and disadvantages as well. PEX is less expensive, and fast to install, while copper is more expensive and can burst in cold weather.
Again, I'm aghast at the $46 sticker price for ONE! But again, see this as a great Scout craft using found rocks, perhaps painted? Could reuse telephone/cable wires (who doesn't have a bunch of that laying around) or tubing.
Clear Guard is a crystal clear, durable, air drying lacquer that results in a hard, fast drying, and tarnish resistant film. It has excellent adhesion to bronze, brass, copper, and other metals as well as to patinas and rusted metal. Clear Guard is suitable for use with all types of application equipment. Once thinned, it may be used with sprayers.